UPEC 2000 PREVIEW - Working Group - IEEE

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1



IEEE POWER ENERGY SOCIETY


ENERGY DEVELOPMENT AND POWER GENERATION
COMMITTEE


PANEL SESSION: IMPLEMENTING TECHNOLOGY TO LIMIT CLIMATE
CHANGE


SEATTLE, TUESDAY, JULY 18, 2000


Chairman: T. J. Hammons, Chair, International Practices for Energy
Development
and Power Generation (University of Glasgow, Glasgow G12 8QQ,
UK (assisted by
Baldur Eliasson, Head Energy and Global Change, ABB
Corporate Research, Baden
-
Dättwil, Switzerland
)


Overview


The International Practices for Energy Development and Power Genera
ration Working
Group on Implementing Technology to Limit Climate Change activities are limited to
technologies related to electric power generation and relevant energy development,
e.g.: efficient and low
-
emission PP, renewables, CO2 removal/disposal, CO2
recycling turbine, H2 production with CO2 removal and combustion turbine, fuel cells
with distributed power generation etc. In addition, the Working Group addresses what
is being done to implement new technologies in various markets and industry sectors
(u
tilities, industry etc.) and organizations (IEA greenhouse gas program and similar).

The Panel presented view
-
points from reputed international authorities on state of
the art and future technologies that can possibly be implemented and developed to
reduce

greenhouse gas emissions. It also addressed the present situation in the
different markets/regions and what can be done to improve it. In short, the panel
session provided and addressed:




An overview



The Present Situation



Efficient Energy Conversion and U
se



New Efficient Technologies



Improvement in Present Situation in Different Markets/Regions


The session was chaired by T. J. Hammons (University of Glasgow, UK).
Baldur
Eliasson, (Technology Manager, ABB Corporate Research Laboratory, Dättwil,
Switzerland
)

introduced the Panelists. The session was organized by
Dilip Mukherjee,
Technology Director, ABB Alstom Power, Gas Turbine Segment, Baden, Switzerland;

and Tom Hammons,
Chair, International Practices for Energy Development and
Power Generation, Universit
y of Glasgow, UK.



This Panel Session review article was prepared by T. J. Hammons, Chair of IEEE UKRI Section
Power Engineering Chapter; Chair of IEEE UKRI Section; and Chair of PES International Practices
for Energy Development and Power Generation; U
niversity of Glasgow, United Kingdom.





2

Panelists:



Baldur Eliasson, Head Energy and Global Change, ABB Corporate Research,
Baden
-
Dättwil, Switzerland



Susumo Sato, General Manager, Boiler Engineering Department, Power Systems
Headquarters, Mitsubishi Heavy

Industries, Ltd., Yokohama City, Japan



Scott Rouse, Energy Efficiency Manager, Ontario Power Generation, Toronto,
Ontario, Canada



Graham Reynolds, Head of Emerging Business, Rolls
-
Royce Energy Businesses,
Coventry, UK



Chris Marnay, Julie Osborn, and Carri
e Webber, Lawrence Berkeley National
Laboratory, Berkeley, CA, USA



Shigeru Azuhata, Manager, Clean Coal Technology, Hitachi, Ibrraki
-
ken, Japan



Walter Short, Principal Policy Analyst, National Renewable Energy Laboratory,
Golden, CO, USA



Tony Kaiser, Direc
tor of ABB ALSTOM Power Technology, Baden
-
Dättwil,
Switzerland



Abbie Layne, National Technology Laboratory, U.S. Department of Energy,
Morgantown, West Virginia, USA


Presentations:


WG Responsible Members


1.

Overview: WG Scope
-
Technologies in the Power Gen
eration Chain, to
limit climatic change.
Panel Session members and their presentation



2. Present Situation, Boundary Conditions, Kyoto


Status


3. Improve efficiency of power plants:

-

lower losses in steam generation system and auxiliary system, high
er steam
process parameter


-

case studies of opportunities and emissions trading


-

retiring aged plants by state
-
of
-
the
-
art plants or repowering


-

End Use Efficiency



-

Advanced Clean Coal Technologies in the Asian market


4. New Technologies:

-

Ren
ewables


technology potential today and in the future, need for
intensive R&D


-

Pre
-
combustion/Post
-
combustion Decarbonisation



-

Next Generation Power Systems
-
RevolutionaryTechnology



5. What can be done to improve present situation in different mar
kets/regions
(industry, utilities): define measures


D. Mukherjee, ABB Alstom
Power (Chairman) and B.
Eliasson (ABB)


B. Eliasson (ABB)



S. Sato (MHI)



S. Rouse (Ont., USA)


G. Reynolds (RR)*


C. Marnay, J. Osborn, and C.
Webber
,
(LBNL)


S. Azuhata (Hit
achi)



W. Short (NREL)



T. Kaiser (ABB Alstom
Power)


A. Layne (NETL/DOE)



Discussion.
Audience and
Panelists




3

GLOBAL CLIMATE CHANG
E AND ENERGY TECHNOL
OGIES IN THE
21
ST

CENTURY


Baldur Eliasson, Energy and Global Change, ABB Corporate Research Ltd,
5
405 Baden, Switzerland


Abstract


There is no progress without the use of energy, and there is no use of energy
without the use of technology. Technology allows us to transform one energy source,
-

such as coal
-
, into a usable form,
-

such as electricity.

Electricity, more than any other
form of energy, has been the cornerstone of the growth of standard of living, which
started about a century ago in the industrialized world. During the last decade or two,
man has become increasingly aware of the limits of

unchecked expansion of the use of
some energy sources. Global climate change, especially the threat of global warming
of the surface of the earth, might change the long
-
term global energy and technology
prospects entirely. A third of the world's inhabitan
ts still live under primitive
conditions, without electricity and without any substantial use of energy.

In December 1997 the Third Conference of the Parties (COP
-
3) took place in
Kyoto in Japan. It was the third international conference convened after th
e Rio
Conference in June 1992 to deal with the global environmental problems of the earth.
In Kyoto 170 countries reached an agreement on international legal limitations for 39
industrialized Western and East
-
European Countries. The Kyoto limits set an ave
rage
reduction of 5.2% for these countries on their general greenhouse gas emissions in the
years 2008
-
2012 as compared to the 1990 emission level.

The Kyoto conference and the conferences held before it underline the very
political nature of the global e
nvironmental problems. No longer are we dealing with
problems in our backyards, but rather creating a global problem that can only be dealt
with and solved through global co
-
operation and a common effort. A particular aspect
of the political dimension of t
his problem is the fact that in the future the GHG
emissions will come primarily from the developing countries and not the OECD or
industrialized countries.


Mankind is facing three major global climate problems, namely:




Global Warming or man
-
made green
house effect caused mainly by emissions of
CO
2



Depletion of Stratospheric Ozone caused mainly by emissions of CFCs



Acid Rain caused mainly by emissions of NOx and SOx


Of these three problems it is the global warming problem that is the most
threatening an
d the one that directly affects our daily life the most. The agreements
reached at Kyoto are truly revolutionary and will have far
-
reaching consequences for
the development of energy technologies in the world. For better or for worse,
technologies will be

preferred in the future that emit less rather than more greenhouse
gases such as carbon dioxide, methane or nitrous oxide. There is very little doubt that
global warming will be the most decisive force influencing development of new and
improved energy te
chnologies in the future.

In the energy sector the world faces a number of problems today. Although

4

nuclear energy and hydro energy produce practically no greenhouse gas emissions,
their widespread utilization in the energy sector faces a number of obstacl
es. It is
interesting to note that both of the above mentioned technologies produce practically
no greenhouse gas emissions. The third major energy technologies, the fossil fuel
technologies, cover almost 80% of the world ‘s energy needs.

There is a possi
bility of continued use of fossil fuels, by applying the new
technologies of greenhouse gas control. The trend towards non
-
GHG emitting
technologies such as solar energy and wind energy will increase.

The Kyoto Protocol adopted at the COP
-
3 Conference in D
ecember 1997 is, in
the long term, going to change the energy technology market. As the awareness of the
man
-
made global warming issue increases, the demand for GHG
-
free technologies
will increase. These can either be fossil fuel technologies, which includ
e GHG
sequestration as an option, or an increased market for renewable energies, which until
now have played a minor role in the energy market. We are very optimistic that man
with his ingenuity will be able to deal with these problems and continue to be a
ble to
provide enough energy for all citizens of this world to use for their own betterment.
Technological innovation will continuously change the landscape of the energy field
and bring the world closer to a low
-
carbon energy economy.


Baldur Eliasson

was

born in Iceland in 1937. He studied electrical engineering and
astronomy at the Federal Institute of Technology in Zurich from 1958
-
1966. He did his
doctoral thesis in the Departments of Electrical Engineering and Numerical
Mathematics at the same univers
ity on a theoretical subject regarding propagation of
microwaves. From 1966 to 1969 he worked as a radio astronomer at the California
Institute of Technology in Pasadena where he investigated the emissions of radio
waves from molecular clouds within our ga
laxy. He returned to Switzerland during the
second half of 1969, started to work in the newly founded Brown Boveri Research
Center on theoretical subjects in physics, optics, laser theory, holography, scattering,
electrical discharges, and environmental te
chnologies. When ASEA of Sweden and
Brown Boveri of Switzerland merged in 1988 to form ABB he was asked to follow
global environmental issues, first part time and then full time starting in 1991. Today
he is in charge of ABB’s Energy and Global Change Prog
ram worldwide. He reports
directly to the Head of the ABB Group R&D activities. The Energy and Global
Change Program follows all aspects of the Global Change issue, i.e., not only energy
technology developments but also the political, scientific and econom
ic aspects. He
participates for ABB in a number of international programs in this area, such as the
China Energy Technology Program together with the Alliance for Global
Sustainability and the International Energy Agency’s “R&D Program on Greenhouse
Gas Mi
tigation Technologies” of which he is Vice Chairman. He is a guest professor
at the Chemical Engineering Department of Tianjin University in Tianjin, China. He is
a member of the Steering Committee of an International Project on Ocean
Sequestration of CO
2

in Hawaii.

He has published more than 200 scientific papers and is a member of a
number of international scientific societies. He is married and a Swiss citizen. His
wife is an American and they have two daughters.





5

IMPROVEMENT OF STEAM

GENERATION TEC
HNOLOGY

Susumu Sato, Boiler Engineering Department, Power Systems Headquarters,
Mitsubishi Heavy Industries, Ltd., Yokohama City, Japan



In order to provide for increasing power demand in Japan, larger capacity
power generation plants have been constructe
d, which have higher thermal efficiency
with less emission of NOx, SOx, dust, etc. Furthermore, to cope with the requirement
of reducing CO2 emission, which has recently been needed for limiting climate
change, new technologies are strongly expected to re
alize power plants with higher
thermal efficiency and more environmentally benign performance.


For the efficiency improvement of conventional steam Rankine Cycle,
applying elevated steam condition is effective. In Japan, 1000MW coal
-
fired
supercritical u
nits with steam condition of 24.5MPa×600°C/600°C have been
commercially operated since 1998, and 1050MW coal
-
fired supercritical units
(25MPa×600°C/610°C) are under construction. (Fig.1 and Fig.2)


Advanced combustion system contributes to the improvement
of boiler
efficiency. A
-
PM burner (Fig.3) and MRS pulverizer (Fig.4) for coal fired units have
realized lower excess air along with lower unburnt carbon loss and suppressed NOx
emission that results in higher boiler efficiency. Oil and gas fired A
-
PM bur
ner is also
available.


Sliding pressure operation of supercritical unit is effective for the
improvement of the plant efficiency during partial load operation. Vertical waterwall
furnace (Fig.5) with rifled tube, that has excellent heat transfer characte
ristics under
both supercritical and subcritical pressure conditions, has been developed. Since
1989, supercritical sliding pressure boilers with vertical waterwall furnace have been
under commercial operation, now there are 7 commercial units.


One is p
roceeding to develop technology for more elevated temperature.
However, efficiency of conventional steam cycle is approaching to the ceiling of
metallic tube material, even considering the progress of high temperature resistant
alloy. Higher thermal effici
ency will be achieved with gas turbine / steam turbine
combined cycle. For natural gas, 1500°C class gas turbine combined cycle has already
been put into commercial operation. For coal, the most abundant fossil fuel,
Integrated Coal Gasification Combined

Cycle (IGCC) 300 MW
-
class demonstration
plants are already in operation in USA and Europe. Construction of the same class
IGCC demonstration unit is under study also in Japan. (Fig.6)

These developments in technologies shall contribute to mitigate climate

change using the most available fuel


coal.


(NOTE: Photos of Figs 1 to 6 removed to reduce file size. Contact Jim McConnach:
jsmcconnach@iee.org

if needed.)


Fig.1 Example of New 1000MW Boiler (Chugoku EPCO Misu
mi No.1)


Fig.2 Example of New 1050MW Steam Turbine (EPDC Tachibanawan No.2)


Fig.3 Structure of A
-
PM burner


Fig.4 Structure of MRS II Pulverizer


Fig.5 Structure of Vertical Waterwall Furnace with Rifled Tubes

Fig.6 Schematic Flow Diagram of Air Blown IG
CC System


6



Susumu Sato

is General Manager, Boiler Engineering Department, Power Systems
Headquarters, Mitsubishi Heavy Industries, Ltd., Yokohama City, Japan. He
graduated from the Faculty of Mechanical Engineering, Tokyo University in 1972. He
then joine
d Mitsubishi Heavy Industries in 1972 and was engaged in Utility Boiler
Design and Development. In 1988 he was appointed Manager, Utility Boiler
Engineering Section and in 1999 he became General Manager of the Boiler
Engineering Department. Now, he is enga
ged in the design and development of utility
boilers, e.g., elevated steam condition plant and IGCC, etc.



ENERGY AND ENVIRONME
NT PERFORMANCE IMPRO
VEMENT
PROGRAM

CASE SUDY OF OPPORTU
NITIES

Scott Rouse, Energy Efficiency Manager, Ontario Power Generation
, Toronto,
Canada



Ontario Power Generation won Canada’s top industrial energy efficiency
award by reducing energy use and through improved energy production. The
achievement resulted in 1.9 billion kWh/yr. of energy savings between 1994 and 2000.
The e
nvironmental improvement is estimated at 2 million Mg. in emission savings.


Projects ranged across the generation system


fossil, hydroelectric and nuclear
facilities. Traditional barriers were overcome through a proactive program that used a
comprehens
ive approach that included corporate support, business unit targets,
focused internal support team, internal and external communication program.


The program evolved in 1997 to identify possible emission credits from the
energy efficiency improve
ments
. Each energy project had to demonstrate


without
doubt


that there was a decrease in fossil emissions. The time of year and generation
dispatch determines the value of the emission credits


but for ease of use the value is
averaged at 0.5 c/kWh


Projects and approach are equally applicable to others. Using a comprehensive
program and focusing on core business with an eye to improve leads to significant
energy savings.


1.0 Introduction


To help Ontario Power Corporation (OPG) compete in the

North American
market, the company maintained and expanded the energy efficiency program. The
target was the reduction of energy used
internally and the expansion of energy
production

through conversion or thermal efficiency improvements.

The program als
o

achieved several supporting objectives, including;


-

-

helping OPG become the low cost producer,

-

-

increasing energy output,

-

-

developing flexible production capability,

-

-

ensuring positive market presence, and

-

-

potential to develop energy related produ
cts / services.


Emission trading was also evolving within Ontario Power Generation. The

7

details on Ontario’s emission trading program are available from:
www.pert.org
. In
1997, the emission trading program identified t
he potential to create emission credits
from energy efficiency savings
-

providing that there was a decrease in fossil
emissions. Emission trading provides an economic incentive
-

of about 0.5 c/kWh to
eligible energy efficiency projects. These credits a
re then used or sold at 90% of their
face value. Ontario Power Generation volunteered to retire 10% for a net
environmental benefit.

Energy efficiency help in the creation of emission credits is providing
operating flexibility within the fossil fleet in a

cost effective manner. The program
created 1.9 billion kWh annually and almost 50% will lead to emission credits. As the
emission program evolves and gains acceptance in the market, the energy efficiency
projects are expected to increase to above 80%.


2.0


Background



On April 1, 1999, the Ontario government divided Ontario Hydro into three
separate companies;




Ontario Power Generation Inc.:



Fossil Generation




Nuclear Generation



Hydroelectric Generation



Ontario Hydro Service Company




Transmission Ne
twork



Distribution Network



Energy Services



Independent Market Operator



Network operation and stability


Ontario Power Generation is one of the largest generation companies in North
America. It is a financially self
-
sustaining corporation with revenues exc
eeding $5.9
billion. Customers include some 200 municipal utilities and over 100 large direct
customers. Total customers served either directly or through utilities are over 3.6
million. The generating station assets include 69 hydroelectric stations, 5 n
uclear
stations and 6 fossil
-
fueled stations. Total generating capacity is close to 30,000
megawatts.


3.0


Energy Efficiency Program and Results


The goal of the 1994
-
2000 energy efficiency program is to reduce energy used
internally or increase energ
y production. To achieve sustained change the importance
of energy savings was reviewed and current practices examined. Over 33 barriers to
improving energy efficiency were identified, including energy use accounting,
monitoring, awareness, use of cost c
enters etc. These barriers were identifying the five
“A’s”
--

attention, affordability, awareness, attitude and accountability
. Some
barriers remain, however, significant progress has
been
and continues to be made.

The energy savings


once audited and ac
cepted, are passed to the emission
team. The emission team determines if the energy efficiency project led to less fossil
production. If the answer is ‘yes’


then the equivalent emission offset is calculate

8

based on the time of year which fossil units w
ould be operating, etc. If the answer is
‘no’ then those projects are not tracked for emission savings. Only 50% of the
projects have been successfully applied to emission credits because of available
documentation, type of project etc.

Energy savings
for Ontario Hydro’s three generation groups, Nuclear,
Hydroelectric and Fossil, are 1.4 B kWh/yr. The remaining savings were achieved
from transmission and distribution improvements in 1994
-
97.

The Generation groups improve energy efficiency by either red
ucing the
amount of electrical energy used in production, commonly referred to as station
service, or by increasing the amount of electrical energy generated for a given amount
of fuel or hydraulic energy input. The first savings category is called electr
ical
efficiency (EE) improvement, while the second category is called conversion
efficiency (CE) improvement. The latter is also referred to as thermal efficiency (TE)
improvement in Fossil and Nuclear generation business units. Energy savings are
conver
ted to megawatt hours based on the heat value for the amount of fuel saved (in
Joules) and then multiplying by an efficiency factor. This efficiency factor accounts
for the efficiency of converting fuel to electricity. Over the four
-
year program there
ha
s been a shift from energy efficiency to conversion or thermal improvement projects
because of the large opportunities in the power conversion process.


Generation Conversion and Thermal Efficiency


Conversion/Thermal Efficiency Improvements were achieved

from both
operational changes and new technology installations. Operational projects are those
resulting from a change in equipment operation, i.e., optimizing performance,
improving unit operation, or process improvements, e.g., reducing heating
require
ments. Specifically, Fossil improvements were mainly from boiler, turbine,
and HVAC performance improvements. Nuclear improvements were largely in boiler
operation (e.g., reduced boiler blow down) and generator operation. In Hydroelectric,
most of the s
avings reported are from optimizing turbine operation.


Technology related projects are those resulting from installation of new higher
efficiency technology. The largest savings in the conversion category were achieved
through the application of new tec
hnology. Specifically, Fossil improvements were
mainly boiler and operator related; Nuclear and Hydroelectric improvements were
mainly turbine related. In Hydroelectric, many of the upgrades involved increasing
capacity.


In Fossil, operational and tech
nology savings were approximately equal, while
in Nuclear and Hydroelectric, technology savings were much greater than operational
savings.


Generation Electrical Efficiency Improvements


Electrical efficiency improvements were also grouped into operation

and
technology projects. In the Fossil and Nuclear business units operation savings and
technology savings produced approximately equal values of savings, while in the
Hydroelectric business unit, EE improvements were predominantly generated from
technolo
gy improvements

Operation improvements for Fossil were mainly from turbine optimization
projects. In Nuclear, they were largely from operational changes to large pumps. In

9

Hydroelectric, they were mainly due to motor/heater improvements.


Technology impr
ovements involved considerably more projects than operation
improvements. Specific projects within Fossil were HVAC, within Nuclear were
lighting, HVAC and pumps, and within Hydroelectric were mainly lighting, HVAC
and specialty projects.


Generation Proj
ect Types



In addition to being categorized as either a technology or operation, a project is
also categorized by project type: Boiler, Turbine, Operator Improvement, Start Up,
HVAC, Lighting, and Auxiliary/Other. These project types are combined for bot
h TE
and EE saving projects.



Boiler:
These projects are related to the combustion process by saving fuel;
examples are temperature control sensor replacement, boiler control replacement, and
adding flame stabilizing rings. Electrical Energy project exa
mples include optimizing
operation of electrostatic precipitators and using synthetic lubricant in the coal
pulverizers.



Turbine:
These projects involve any process related to the conversion of
steam to electricity. Fuel
-
saving TE projects inc
lude turbine maintenance and steam
heat optimization as examples. Examples of these Electrical Energy projects are
optimizing the circulating and pump controls, and condenser improvements.



Operator Improvement: Significant

conversion efficiency

savings are
achieved by adding computer assistance feedback loop software (ECOS upgrade) to
improve the efficiency of the thermal conversion process.



Start Up: Rapid

start
-
ups for infrequently used turbines result in significant
TE savings.

This process uses waste building heating steam to keep the turbines
warm so that they require less fuel to start up. A warm start is faster (3 hours)
compared to a cold start (about 6 hours).



Heating, Ventilating, and Air Conditioning (HVAC):
TE

projects include
redirecting warm air from the combustion units to the ground, and auxiliary boiler
efficiency improvements. EE projects include installation of auxiliary heating boilers,
free cooling, and insulation capping of vents.



Lighting, Auxil
iary and Other:

Projects improve electrical efficiency
through lighting reductions or reduced lighting levels, replacing fixtures, and adding
controls. Included also, are projects that change secondary equipment that do not
directly affect the electricity

production process. Examples include upgrading service
water systems and air compressor systems.



4.0


Conclusions


There are ample opportunities to achieve additional energy savings and

10

generate greater emission credits. “How much is economically ac
hievable?” is the
pressing question.


1.

What is an accurate estimate of losses?

2.

What is an estimate of economically achievable savings?

3.

What is needed to maintain interest?


These questions are being addressed through different tactics. An important
development is the external search for new ideas and to use existing programs that are
available to private sector industries from government sponsored programs. An
energy efficiency web page was introduced in 1997 to share information and connect
with co
mplementary programs. The site is
www.energy
-
efficiency.com
.

The 2000 energy efficiency program has a three prong approach, specifically:


1.


Maintaining a creditable Tracking System

2.

Developing inter
nal and external communication networks.

3.

Developing useful energy services to maintain progress.



The achieved energy savings of 1.9 billion kWh/year and over $80 million per
year demonstrated the benefits of energy efficiency


particularly w
hen the Canadian
government awarded Ontario Power Generation their top energy efficiency award.
The emerging emission market is improving the economics for projects and helping
lead the way to a better environment.

The types of energy savings and environ
mental benefits are available to others.
Based on our six year review of reported and audited energy projects, the types of
energy savings are common projects. The reported and audited projects are “core”
projects that met strict capital spending limits,

used proven technology and typically
had a simple payback of one to three years. The energy savings help ensure success in
the competitive market. Best of all
-

benefits go direct to the bottom line, can be
controlled internally and energy savings are a
vailable each year with no loss revenue.


Scott Rouse
is Manager, Energy Efficiency Department, Ontario Power Generation
and recipient of Canada's energy efficiency industrial tier one award. Scott has been in
both the transmission and generation business
units for the past 20 years. His current
position is to help Ontario Power Generation meet or exceed an energy improvement
target of 2000 GWh of annual energy savings by the year 2000. The energy savings to
-
date are 1,900 GWh and worth over $80 million (Ca
nadian) annually. The energy
savings are also converted to emission credits to increase operating flexibility to the

fossil fleet as well as increased revenue
--
anticipated to be worth approximately $10
million (Canadian) by the year 2000.

Mr. Rouse has aut
hored papers for IEEE,
CIGRE, and EPRI. He is a Professional Engineer in the province of Ontario.






REPOWERING


ENHANCING WHAT IS TH
ERE
.


11

Graham Reynolds, Rolls
-
Royce plc. Coventry, UK


Introduction

The idea of improving an existing steam plant with a g
as turbine is not new.
The earliest study found, dating back 30 years or so, (no doubt there are earlier
examples), is that of the Magnox power stations of CEGB in the UK, whose operating
temperature was reduced by 50 degrees C due to metallurgical problem
s. The installed
steam turbine capacity was consequently under utilised and it was proposed that gas
turbines (Bristol Siddeley Olympus power plant) be installed, their exhaust gas being
used to raise the steam temperature to the plant maximum. However the

then current
rules on the use of natural gas in the UK prevented this.


In 1991 an operator industry group formed, “Collaborative Advanced Gas
Turbines” (CAGT). They funded the three major manufacturers of aeroderivative gas
turbines to study the

best cycles they could perceive, to create the most economical
and environmentally friendly plant for the future. The independent studies were
examined and a CAGT view was formed. They identified an intercooled
aeroderivative (ICAD) as most attractive to
them; however Elkraft, a Danish member
of the group, applied it to a feed water heating concept, and began a series of
optimisation studies. The outcome after many careful deliberations, was the Avedore
2 project now underway.


Feed Water Heating Repowerin
g.


In his paper “Power Plant Refurbishment” Darren Watson
1
reviewed a wide
variety of steam turbine cycles and options such as “windbox repowering”. The
analysis is detailed including the steam cycles used in Pressurised Water Reactor
systems, advanced G
as Reactor systems and supercritical fired boiler systems. One
conclusion is that nuclear power is an area of potential significance, being 20% of the
world’s electrical generating capacity.

The advantages of repowering are attractive, in more conventional

plant the
net combined efficiency is improved by up to 6

8%, and power by up to 70%. This
can be achieved by relatively minor changes to the steam cycle’s feed heating system
and the addition of a large heat exchanger to recover the waste heat. The
imple
mentation is reversible, judged as low risk, and can be operated to obtain
flexibility in power output and fuel use economics, whilst maintaining relatively high
efficiency levels. The extra capacity provided by repowering can be added at an
approximate ma
rginal cost as low as $350/kWe.


Other Attractions.


The improvement in efficiency, the fuel flexibility and the operational
flexibility all add up to an attractive potential reduction in CO
2
emissions. The
relative enhancement from pulverised coal to rep
owered unit can be seen in the
illustration which follows. The increase in power and the improvement in efficiency
reducing the specific carbon emissions are self
-
evident. The values of which in an
emissions trading market, or carbon tax area are yet to be

proven.




12

*
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0%
20%
40%
60%
80%
100%
Pl ant Effici ency (LHV)
kgCO2/kWh
Coal
Fuel Oil
Nat.Gas
THE INFLUENCE OF PLANT EFFICIENCY & FUEL CHOICE IN
THE PRODUCTION OF CO
2
Current PF
Repowered
System



Avedore 2


SK Power Copenhagen.



This project, commenced in late 1998, and is now scheduled for entry into
service towards the end of 2001. Avedore 1 started up in 1990, a coal fired 250 MW
plant connected to a district heating system, an
d using biomass fuel when available.
Avedore 2 was initially going to be a similar plant with repowering but the Danish
Parliament decreed that the boilers would be fuelled by natural gas together with
biomass as before. The basic performance data initia
lly was
2

:



Electrical
Capacity
MW
Coal
/Gas
Efficiency
Gas/gas
Efficiency
One
Rolls
-
Royce
Trent turbine
Coal
-
and gas-
fired

part
385
0,483
0,499
Gas-
fired

part
75
0,575
0,575
Total

plants
460
0,496
0,510
Two
Rolls
-
Royce
Trent turbines
Coal
-
and gas-
fired

part
385
0,483
0,499
Gas-
fired

part
150
0,575
0,575
Total plant
535
0,506
0,518

13

The present performance is now a little higher without the coal fuel, and the
decision was made two use two gas turbines.


Two Trent gas turbines

102 MW

Steam plant capacity (full load no gas turbines)

460 MW

Total plant output (gas turbines

operating)

600 MW


Efficiency without gas turbines

49%

Efficiency with gas turbines operating

51%


Operation in Hot Climates



Elkraft during their studies examined hot day operation of such plant, the
results of which are shown here:


The first data tab
led above is that for the 48.3% efficiency point in temperate
Denmark. A hot day condition, such as that in Malaysia with cooling water at 35
o
C
shows almost 3 points fall in efficiency due to the environment.



Combined Cycle Repowering


In Singapore a re
powering project is now underway where three 25
-
year old
steam turbine systems of 120 MW are being converted eventually into three units
capable of 360 MW with a 40% gain in efficiency. The boilers are being replaced by
an HRSG, which is heated by the exha
ust gas from three GT26 gas turbines
3
. This
shows the contrast between operators with widely differing goals and different staring
points.




42
43
44
45
46
47
48
49
50
0
5
10
15
20
25
30
35
Cooling Water Temperature degr. C
Net efficiency LHV
300 bar, 580 / 600 degr. C
180 bar, 540 / 540 degr. C
48,3
Denmark
45,4
Malaysia

14


Conclusion


Repowering is not new. It can be used for both new and existing plant. It
shows good sound economics
in the new competitive power generating industry.
Perhaps after more than 30 years repowering is on its way.



References.


[1]. Darren Watson


“Feed water heater repowering using high efficiency
Aeroderivatives” : Conference on Power Plant Refurbishment;

Prague November
23
rd
-
24
th

1999.

[2]. Henrick Noppeau and Darren Watson


“Feed water preheating with Rolls
-
Royce
Trent Gas Turbines”
-

ASME conference Florida 1998

[3] ABB Alstom Power


“ Converting 3X120 MWe to 3X360 MWe at Senoko


Graham Reynolds
' curr
ent position is that of a corporate company function with
Rolls
-
Royce. He is responsible for bringing together the three main drivers of the
business: Technology Change, Business Change (i.e., Deregulation, etc.), and Political
Change. He has had a 35 year

career in gas turbines, covering aero, industrial and
marine. Most of that time has been taken up with advanced turbine engines. In 1989
he became Head of Design and Technology for non
-
aero engines, which included
combustion and emissions reduction progra
ms. Currently he is a board member of
EuMIGT (European Manufacturers of Industrial Gas Turbines) an industry group like
the US GTA formed to influence government policies effecting turbines
-

such as
emissions. He is a Chartered Engineer, a Member of the
Institution of Mechanical
Engineers and a Member of ASME, and has qualifications in both Electrical and
Mechanical Engineering.



END USE EFFICIENCY

Chris Marnay, Julie Osborn, and Carrie Webber, Lawrence Berkeley National
Laboratory (LBNL), Berkeley, CA,
USA


Introduction


Compelling evidence demonstrating the warming trend in global temperatures
(Figure 1) and the mechanism behind it, namely the anthropogenic emissions of
carbon dioxide and other greenhouse gases (GHG), has spurred an international effort

to reduce emissions of these gases. In 1997, the United Nations Framework
Convention on Climate Change concluded negotiations on the Kyoto Protocol, an
agreement that targeted substantial reductions in the emissions of GHG for developed
countries. The t
rue success of this agreement hinges on the participation of not only
developed nations but also developing and transitional countries; the latter's intensity
of electricity production (and CO2 emissions) is substantially higher than most
developed nations

(Figure 2) when expressed per dollar of GDP. Nonetheless,
industrialized countries have historically released the most carbon and per capita their
emissions still far exceed those of emerging economies; therefore, a heavy obligation
rests on the rich nati
ons to contain their energy consumption. Economic growth is

15

often linked closely to growth in energy consumption and energy consumption is
growing rapidly worldwide, yet significant room exists in both developed and
developing nations for energy efficiency

improvements. Carbon savings through
energy efficiency can and should be approached in the supply sector, but energy
efficiency on the demand side is equally important. In fact, at the Kyoto Conference,
appliance efficiency was targeted as one of the mo
st effective climate change
mitigation strategies [2].

Despite improving efficiency of the U.S. economy in terms of energy cost per
dollar of GDP since the signing of the Kyoto Protocol, the outlook for meeting the
Kyoto targets is bleak. Far from decreas
ing or even stabilizing, energy consumption
and carbon emissions are continuing to rise as the economy expands. Current U.S.
emissions of GHG are now more than 11% higher than 1990 levels, an increase that
translates into an average growth rate of 1.3%/a b
etween 1990 and 1998 [8]. Recent
forecasts of energy use in the target years just after 2010 are also more than 1% higher
than they were just two years ago [9, 10], and the associated net reduction in carbon
emissions required for the U.S. to meet the tar
get
--

the so
-
called "emissions gap"
(Figure 3)
--

has also grown. The Energy Information Administration's
Annual
Energy Outlook 2000

forecasts carbon emissions to continue increasing by 1.3%/a
between 1998 and 2020, based on recent energy consumption and

emissions trends
[10]. This growing gap further emphasizes the importance of improving energy use
efficiency as a component in the U.S. climate change mitigation program.

The end
-
use efficiency research activities at the Lawrence Berkeley National
Laborat
ory (LBNL) incorporate residential, commercial, industrial, and transportation
sectors. This presentation focuses on two successful U.S. programs that address end
-
use efficiency in residential and commercial demand: energy efficient performance
standards
established by the Department of Energy (DOE) and the Environmental
Protection Agency’s (EPA’s)
E
NERGY
S
TAR
® program.


Energy Efficiency Standards

Energy efficiency standards are a set of procedures and guidelines that
prescribe the energy performance of

manufactured products. In the U.S., they
function by establishing a minimum legal efficiency that pushes the market towards
higher efficiency by eliminating the least efficient models. In other countries, such as
Japan, standards are structured such tha
t the average efficiency in the market achieves
a predefined target but no specific minimum criteria are set.

DOE was authorized in 1978 to set mandatory minimum energy efficiency
standards for 13 household appliances and products (Table 1) under the Natio
nal
Energy Conservation and Policy Act (NECPA). In 1987 the NECPA was amended
and updated by the National Appliance Energy Conservation Act (NAECA). NAECA
superseded existing state requirements and actually set the first national efficiency
standards for h
ome appliances, as well as a schedule for regular updates, currently
specified to 2012. The standards are required to achieve the maximum improvement
in energy efficiency that is “technologically feasible and economically justified” [7].
Office equipment,

plumbing products, and small electric motors are also now covered
by extensions of the standards program specified under the Energy Policy Act of 1992
(EPAct). EPAct also expanded coverage to certain commercial and industrial
equipment that are now underg
oing analyses for their initial standards, including
commercial air
-
conditioners, heating equipment, and distribution transformers. Today,
NAECA, its updates, and EPAct are at the heart of energy efficiency advances in

16

many U.S. consumer durables and light
ing [1].

Since 1979, Berkeley Lab has provided technical assistance to DOE by
conducting the engineering, economic and environmental analyses in the development
of all U.S. appliance and lighting standards. Existing efficiency standards have
already had
significant impacts. Energy savings through 1999 are estimated at 3.4 EJ
with net consumer savings of $10 billion through 1997. The energy savings translate
into 56 Mt of carbon emissions reductions through 1999 [5]. The expected carbon
mitigation in 201
2 for all current residential appliance standards totals 15 Mt, or 1.1%
of 1990 emissions. As more products are added and the standards for already
legislated products are updated, these savings will increase.

Federally mandated efficiency standards not o
nly benefit consumers and the
environment by saving energy and carbon, but they also help make manufacturers of
energy efficient products more competitive in the market place. Harmonization of
standards, both in the U.S. and internationally, is often suppo
rted by manufacturers
because it can expand markets both regionally and internationally. In Asia, for
example, manufacturers in several countries have expressed their interest in
harmonizing standards and labels to increase the potential market for their
products
[2]. A new consortium, called the Collaborative Labeling and Appliance Standards
Program (CLASP), has been launched to promote efficiency standards and labels in
developing and transitional countries. Berkeley Lab, the Alliance to Save Energy, an
d
the International Institute for Energy Conservation, are founding members of this
effort to help increase the penetration of efficiency standards and labels worldwide.


Energy Star

The
E
NERGY
S
TAR

program takes a different approach to energy efficiency
i
mprovements. The Environmental Protection Agency developed a label (the
E
NERGY
S
TAR

label) to identify high efficiency products to buyers. It is strictly a voluntary
program. EPA, in partnership with DOE, works with manufacturers to identify and
label prod
ucts in designated categories. The most obvious goal of the program is to
influence consumer behavior through the use of a recognizable logo. It is at least as
important, however, to influence manufacturers. The objective is not merely to label
existing hi
gh
-
efficiency products but to increase production of qualifying products,
encourage manufacturers to take energy efficiency into account in designing new
products, and in some cases to promote the inclusion of specific energy
-
saving
features. The
E
NERGY
S
T
AR

label increasingly has been featured in utility promotions
(including rebate programs) and in advertising by retailers and other
E
NERGY
S
TAR

partners.

The
E
NERGY
S
TAR

Program covers more than 20 products spanning residential
heating and cooling, major a
ppliances, residential lighting, consumer electronics and
office equipment. Computers, monitors and printers were the first products covered by
the
E
NERGY
S
TAR

label, beginning in 1993. These devices save energy when they are
idle by entering a low power “
sleep” mode. Other products use different approaches.
In some cases the
E
NERGY
S
TAR

criterion is defined in relation to an existing
appliance standard. The
E
NERGY
S
TAR

criterion for consumer electronics is interesting
in that it addresses power use only wh
en the device is turned off, which is the majority
of the time for most devices. This may seem trivial, but there are TVs that consume as
much as 30 W when they are off, and there are over 200 million TVs in the United
States. In fact, although most are no
t yet covered by
E
NERGY
S
TAR

agreements, small
devices that always consume a trickle of power are an increasing electric load.


17

Berkeley Lab estimates that the
E
NERGY
S
TAR

labeling program saved 760 PJ
between 1993 and 1999, reducing cumulative emissions by

14 Mt of carbon [6]. Most
of these savings are due to office equipment, particularly computers, monitors and
printers. Labels for these products were introduced early and they achieved significant
market share. As
E
NERGY
S
TAR

products capture a greater sh
are of the market, savings
will continue to grow to an expected 20 Mt/a of carbon by 2010. This is equivalent to
about 1.5% of 1990 U.S. energy consumption. Further gains are possible if the
E
NERGY
S
TAR

label is extended to new products.


Conclusions

Energ
y efficiency performance standards and labels, both mandatory and
voluntary, promise enormous carbon emission savings potential that can help move
economies towards more sustainable energy use and assist in the attainment of the
Kyoto Protocol targets with

little or no loss of consumer amenity. The two programs
described here are projected together to lower U.S. carbon emissions by 35 Mt/a in
2012, about 2.5% of 1990 emissions. Such savings are substantial, but these programs
are addressing only a fraction

of the domestic energy demand. Opportunities exist for
other end
-
use efficiency programs to be expanded to new products and new regions,
both domestically and internationally. Further improvements in end
-
use efficiency are
essential if Kyoto targets to be

met.


References

[1]

Adams, Carl E. 1995. "Appliance and Lighting Standards." DOE/GO
-
10095
-
174.
September.

[2]

Collaborative Labels and Appliance Standards Program. 2000.
http://www.clasponline.org/standard
-
label/general
-
info/rationale
-
benefits/index.php3

[3]

International Energy Agency. 1999. "Key World Energy Statistics from the IEA."
France. 74pp.

[4]

National Oceanic and Atmospheric Administration.

1999.

http://www.ncdc.noaa.gov/ol/climate/research/1999/ ann/land.ts

[5

LBNL, Appliance Standards Databook

[6]

Webber, C. A., R. E. Brown, and J. G. Koomey. 2000. “Savings Estimates for the
Energy Star Voluntary Labeling Program.” To appear in Energy Poli
cy.
Forthcoming.

[7]

National Appliance Energy Conservation Act (NAECA). 1987.

[8]

U.S. Environmental Protection Agency. 2000. "Inventory of U.S. Greenhouse
Gas Emissions and Sinks: 1990
-
1998."

http://www.epa.gov/globalwarming/emissions/national/trends.
html


[9]

U.S. Department of Energy, Energy Information Administration. 1997. "Annual
Energy Outlook 1998: With Projections Through 2020." DOE/EIA
-
0383(97),
December.

10]

U.S. Department of Energy, Energy Information Administration. 1999. "Annual
Energy
Outlook 2000: With Projections Through 2020." DOE/EIA
-
0383(99),
December.


18

Annual mean temperature anomalies, based on long
-
term average (1880
-
1999)

source: http://www.ncdc.noaa.gov/ol/climate/research/1999/ann/land.ts


Figure 1. Recent Changes in Globa
l Temperature






















source: IEA, Key World Energy Statistics from the IEA


Figure 2. 1997 Carbon Emissions per Capita and per U.S. Dollar of GDP

0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
India
Indonesia
China
Mexico
Italy
Ukraine
S. Africa
Japan
Netherlands
Saudi Arabia
U.S.
t/$1000 GDP
0
1
2
3
4
5
6
t/capita
t/capita

t/$1000 GDP


19

source: EIA, Annual Energy Outlook 2000

Figure 3. U.S. Carbon Emissions Gap, 1990
-

2012


Table 1. U.S. Energy Efficiency Standards Effective Since 1990



Date

Updates

Product

Effective

effective

Refrigerators, refrigerator
-
freezers, freezers

1990

1993, 2001

Room air
-
conditioners

1990

2000

Fluorescent lamp ballasts

1990

2005

Direct heating

equipment

1990

Kitchen ranges and ovens

1990

1999

Water heaters

1990

TBA

Dishwashers

1990

1994

Clothes washers

1990

1994, TBA

Clothes dryers

1990

1994

Pool heaters

1990

Central air
-
conditioners and heat pumps

1992

TBA

Furnaces

1992


TBA = To be a
nnounced



Chris Marnay

is a staff scientist in the Electricity Markets and Policy Group, Lawrence
Berkeley National Laboratory (LBNL), Berkeley, CA, USA. Chris leads the Berkeley
Laboratory's contribution to a multi
-
institutional research effort on power
system reliability in
restructured markets called the Consortium for Electric Reliability Technology Solutions
(CERTS). Other ongoing work includes maintaining the latest version of the Energy
Information Administration's National Energy Modeling System (N
EMS) and directing its
application to power system development, the effects of changing patterns of energy use, and

20

to greenhouse gas emissions abatement. He holds a Ph.D. in Energy and Resources from the
University of California, Berkeley


Julie Osborn

is

a principal research associate in the Electricity Markets and Policy Group at
Lawrence Berkeley National Laboratory, Berkeley, focusing on energy efficiency, renewable
energy and electricity industry restructuring. Julie received a M.S. from Stanford Univ
ersity in
Biological Sciences .


Carrie Webber

is a principal research associate in the End Use Forecasting Group at
Lawrence Berkeley National Laboratory. She has done work on a variety of research topics
including residential appliances, residential lig
hting, windows, commercial lighting, office
equipment, and consumer electronics, primarily in support of the
E
NERGY
S
TAR

labeling
program. Carrie has an M.A. in economics from the University of California at San Diego.



ADVANCED CLEAN COAL
TECHNOLOGIES

Sh
igeru Azuhata, Manager Clean Coal Technology,
Power and Industrial
System R&D Laboratory, Hitachi Ltd., Ibaraki
-
ken, Japan



The presentation is an overview of coal power plant technologies in Japan. Power
generation from coal has increased and much

effort has been made to improve the
thermal efficiencies of power generation. Adding to the conventional steam cycle,
coal power plants with a combined cycle have been studied and are becoming
commercially available.


Electric power generation in Japan


Since the oil crisis of the early 1970s, Japan has constructed many diverse power
generation plants for energy security. Nuclear power generation, which showed the
largest growth in these three decades, would be one of the technical options to deal
with the concerns of global warming, but there still remains the subject of public
acceptance for future plant construction. The number of coal and natural gas power
plants has increased, cutting the consumption of oil. Japanese power plants started to

use natural gas in the mid 1970s. By the end of the 1980s the combined cycle power
plant, which consisted of gas and steam turbines, appeared on the market . At the
moment it has the dominant role in the power generation owing to its high thermal
effic
iency, quick response to load demand change and low environmental impact.
Instead of transporting through gas pipelines, a natural gas is shipped from other
nations at present as liquefied gas, which has a large impact on the fuel price.


21

Figure 1
Power Generation in Japan
(
reported in April, '00 )
0
2
4
6
8
10
12
1960
1970
1980
1990
2000
Year
Electricity (
×
10
5
GWh
)
others
hydro
nuclear
natural gas
oil
coal
forecasting


Running of coal, which supplies 16% of electricity now in Japan, is predicted to
increase in the next century for as there are still untapped rich deposits. The
improvement of power generation efficiency will be the most important techni
cal
subject for coal power plants because of the high carbon content. A major technology
of today is the PC (pulverized coal) power plant and there are several promising
advanced technologies, such as the PFBC C/C (Pressurized Fluidized Bed
Combustion Co
mbined Cycle) and IGCC (Integrated Coal Gasification Combined
Cycle).


PC power plant

The latest commercial plant has achieved the thermal efficiency of 43% by
increasing the steam temperature and pressure up to 600
o
C

and 24.5MPa. The
development program

with a target of 630
o
C

and 30MPa class supercritical steam
cycle is being carried out this year and planning the next program is proceeding to
attain a further increase in thermal efficiency by enhancing steam conditions.

Air pollution control is anoth
er crucial technical subject for coal power plants.
Combustion modification has been studied vigorously for 20 years. Staged
combustion with an improved low NOx burner has reduced the emission level of NOx
from 700ppm of the early 1970

s to the order
of 100ppm while keeping a high level of
coal burnout. Furthermore, the SCR (Selective Catalytic Reduction) process reduces
more than 80% of the NOx contained in a coal combustion gas. The FGD (Flue Gas
Desulfurization) process is necessary to eliminate
the SOx emission from PC plants.
Many types of FGD technologies have been investigated, such as the active carbon
process, limestone injection, moving bed type reactor with synthesized absorbent, an
electric discharge with ammonia injection, and so on.

From the viewpoints of
performance and reliability, most Japanese PC plants have employed a wet scrubbing
type limestone
-
gypsum process, though the dry process has been shown to be
favorable because it is free from the technical problems related to the ha
ndling of
water


Coal power plants of the next generation


Advanced coal power plant technologies, which are expected to play a major role
in the twenty first century and have been studied for long years, include the combined

22

cycle of gas and steam tur
bines, such as PFBC C/C and IGCC. In 1998 Hokkaido
Electric Power Co. Inc. started the first commercial operation of a PFBC C/C plant
with 75MW power generation in Japan. At present test operations of two plants are
being carried out; the 250MW unit of
the Chugoku Electric Power Co., Inc. and
350MW unit of Kyushu Electric Power Co., Inc. The commercial operation of
250MW and 350MW units will start this coming December and the middle of next
year, respectively. These three units reduce the emission of

SO2 by employing
limestone as a bed material without FGD and reduces thermal NOx by controlling the
bed temperature at approximately 850

o
C
.

In Japan, the IGCC is still in the development stage. Two national projects,
HYCOL and IGC, both of which were s
uccessfully completed in the middle of the
1990

s, resulted in the development of an entrained bed type coal gasifier. HYCOL,
which developed the oxygen
-
blown gasifier with a capacity of 50t/d as a coal feed
rate, was aimed at generating hydrogen from co
al for many types of industrial use.
IGC, which constructed an air
-
blown gasifier with a capacity of 200t/d, intended the
fuel supply to a gas turbine for power generation. To accept a wide variety of coal
types, both projects employed the fuel staging

gasification process, which optimized
the gasification and coal ash slagging temperatures independently by controlling the
oxygen
-
coal ratio of each feed stream. Based on the HYCOL technology, the Electric
Power Development Co., Ltd. is promoting the EA
GLE (Energy Application of Gas,
Liquid and Electricity) project. The plant with a capacity of 150t/d is being
constructed and test operation will start in 2001. EAGLE has a gas turbine to supply
electric power for the plant operation and it employs a s
olid electrolyte type fuel cell.


The IGFC (Integrated Coal Gasification Fuel Cell) is one of the technical options for
coal power plants and a pilot scale experiment with the MCFC (Molten Carbonate
type Fuel Cell) of 1MW power generation was carried out

in 1999 in the site of Chubu
Electric Power Co., Inc.


Conclusions

The consumption of coal, which has been thought to be the most abundant
fossil fuel in the world, has increased, but its environmental impact from the aspect of
global warming has added an
other dimension to the energy problem. Long
-
term
R&D activities are required to realize a society, which is mainly supported by
sustainable and renewable natural energies. Though coal may be an interim solution
to the energy problem, the development of

technologies, which provide the effective
utilization of coal, will be important to bridge the gap between the present and future
of energy supply situations.



Shigeru Azuhata

is Manager of Planning Office, Power and Industrial Systems R &
D Laboratory,
Hitachi Ltd., Ibaraki
-
ken, Japan. He started his R & D experience with
Hitachi in 1975. From 1975
-
1994 he was engaged on processes for thermal power
plants: pulverized coal combustion and gasification; molten carbonate type fuel cells;
and gas turbine comb
ustion. From 1994
-
1999 he was Manager of the Department of
Environmetal Systems Research. In 1999 he was appointed Manager of Planning
Office, a position which he holds today.





23



THE POTENTIAL OF REN
EWABLES TO ADDRESS G
LOBAL
CLIMATE CHANGE


Walter Short
, National Renewable Energy Laboratory, Golden, Colorado, USA



Abstract


Many entities have developed scenarios for addressing climate change in
which renewable energy plays a dominant role in the last half of this new century.
Evaluating the feasibili
ty of achieving such a role for renewables is complicated by
the inherent uncertainties in long
-
term forecasts, the lack of present
-
day data on many
renewable energy resources worldwide, and the wide range of infrastructure
developments that must take plac
e for such a transformation to occur. For renewables
to succeed at these levels will require technology improvements, widespread policy
actions to reduce carbon emissions, and societal acceptance of a shift to renewables.
We are seeing encouraging trends

along these lines. The cost of energy from
renewables continues to decline; policies encouraging renewables are widespread and
growing; green power markets are emergingunder electric sector restructuring; and
worldwide sales of some renewable technologie
s are surging. Additional efforts to
develop and deploy renewables are required and recommended.


Introduction


Renewable energy is frequently mentioned as part of the future solution to
reducing emissions of carbon dioxide from the combustion of fossil
fuels. In fact, the
United Nation’s Intergovernmental Panel on Climate Change (IPCC), the International
Institute for Applied Systems Analysis (IIASA) and the World Energy Council
(WEC), as well as Shell Oil’s renowned scenario developers have all develop
ed
scenarios that present futures for this century in which much, if not most, world
primary energy is derived from renewable energy (Figure 1).



Sources: IPCC 1996, Kassler 1994, IIASA/WEC 1998

0%
20%
40%
60%
80%
100%
1980
2020
2060
2100
Shell Sustained
Growth Scenario
WEC high
growth/technology
(A3)
IPCC SAR LESS
biomass intensive
IPCC SAR LESS
coal intensive

24

Figure 1. Scenarios of Renewable Energy Contributions to
Worldwide Primary
Energy

Moreover, these scenarios are not considered to be outlying scenarios by their
developers. The Shell “Sustained Growth Scenario” was Shell’s business
-
as
-
usual
scenario when developed in the mid 1990s (Kassler 1994). Perhaps more
remarkable,
the IPCC Coal
-
Intensive scenario shows renewables contributing 65% of all
worldwide primary energy use by 2100 (IPCC 1996).

Of course, such scenarios are fraught with uncertainties in their estimation and
difficulties in their actual evolution.

These include the role that climate change will
play in market evolution, the price and availability of fossil fuels as the 21
st

century
progresses, evolving technologies


both renewables and conventional, the extent of
and access to renewable energy re
sources, and the infrastructure developments
required to shift energy markets to renewable energy.

To a large extent scenarios can be envisioned as goals. Their realization can
be impeded or enhanced by the actions we take. Realization of the above goa
ls
requires that the renewable resources be available, that renewable technology costs are
lowered, that governments support the initial market thrusts through appropriate
policies, and that society accept and adopt renewable energy alternatives.


Resource
s and Costs


Table 1 shows that the worldwide renewable energy resource is huge. The
quality of the resource and the cost of accessing it is surely not homogeneous across
the world, but opportunities are plentiful.


Table 1 Renewable Energy Resources (
10
18

joule/year thermal equivalent)


Resource

1990
Consumption

2025 Potential

Long
-
term
Potential

Annual Total
Resource
Flow

Hydro

21

35


55

>130

>400

Geothermal

<1

4

>20

>800

Wind

<1

7


10

>130

>200,000

Ocean

-

2

>20

>300

Solar

-

16


22

>2600

>300
,000

Biomass

55

72


137

>1300


TOTAL

76

13
-

230

>4200

>300,000

Source: IPCC 1996


Today the costs of the renewable energy technologies required to convert these
resources to useful energy are in general higher than those of the competing fossil fuel
t
echnologies. Nonetheless, there is ample evidence to suggest that future costs will be
competitive for many renewable energy technologies. As shown in Figure 2, the costs
of renewable energy technologies have decreased substantially over the last 25 years

and are projected to continue to do so.






25



















Figure 2 The Cost of Renewable EnergyPolicies


While cost competitiveness is a primary driver in the future role of renewables,
there are other barriers. These include, among others, a

lack of consumer awareness
of the attributes and potential of renewables, constraints on consumer choice, the
absence of standards and certification procedures, and external costs (e.g. local air
emissions) not accounted for in market decisions. As much
as possible these barriers
need to be addressed now to pave the way for the renewable energy industries to grow
and mature, bringing down their costs. With climate change concerns there has been a
reinvigoration of efforts to promote renewables worldwide.

Table 2 shows the policy
efforts of European Union countries moving in this direction.


Table 2 European Union Countries’ Renewable Energy Policies


Number of

Countries


Policy

9

R&D

7

Tax incentives

7

Information campaigns

2

Green power

5

Standardization and

certification


Source: van Beek 1998


A recent investigation by 5 U.S. National Energy Laboratories (Interlaboratory
Working Group 2000) shows the role that policies could play in further developing a
renewable energy market in the United States. This gr
oup conducted an integrated
analysis examining the potential for all clean energy technologies to address energy
and environmental issues in the U.S. over the next 20 years. Energy efficiency
significantly reduced the demand for energy (and therefore, new

electric capacity) in
the Advanced scenario of this study. Nonetheless, renewables contribute to the U.S.
electric supply in ever increasing amounts as shown in Figure 3.

0
0.5
1
1.5
2
2.5
3
1980
1985
1990
1995
Cost ($/kWh)
0
0.5
1
1.5
2
2.5
3
3.5
4
Wind
PV in buildings
Geothermal
Bioethanol conversion cost
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
1995
2000
2005
2010
2015
2020
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Cost ($/gal)
Source of future electric costs: EPRI/DOE 1
997


26





Source: Interlaboratory Working Group 2000.


Figure 3. Renewable Energy Elec
tric Capacity in the
Scenarios for a Clean
Energy Future

Study


In this scenario, this growth in renewable electric generation is prompted by a
carbon cap and trade system with a maximum carbon value of $50/tonne of carbon, a
7.5% renewable portfolio stand
ard between 2010 and 2015, new constraints on SO2
emissions, net metering for photovoltaics on buildings, a doubling of Federal R&D
funding, full electric sector restructuring by 2008, and a 1.7 cent per kWh production
tax credit through 2004. With these
policies, renewables start to make the kind of
contribution required of them if they are to be significant in addressing global climate
change in the longer term.


Public Acceptance


Public awareness and acceptance of renewable energy is growing. Recent U
.S.
public opinion polls show 60


80% of U.S. electric customers support renewable
energy and would be willing to pay more for it. Thus far, in those 27 states where
utilities have implemented green pricing programs, the average additional premium of
2.
5 cents/kWh has resulted in only 1


2% of customers actually subscribing.
Nonetheless, the idea of purchasing green power is still a very new concept, and the
numbers are growing, with over 130 MW of renewables now installed in the U.S.
through green pow
er programs.


Trends


The real indication of progress in renewables is evidenced by actual market
movements. Today the contribution of renewable energy to worldwide energy
supplies is limited with less than 15% of primary energy worldwide derived from
ren
ewables and almost all of that from hydroelectricity and biomass wastes.
However, some of the more competitive forms of renewable energy use have been
growing rapidly in recent years as exemplified by wind power growth (Figure 4).


0
20
40
60
80
1997
2000
2003
2006
2009
2012
2015
2018
GW
Other
PV in buildings
Geothermal
Biomass power (ded)
Wind

27


Figure 4. Worldwide W
ind Power Installations


Conclusions


Climate change solution scenarios showing heavy reliance on renewable
energy by the end of the 21
st

century are uncertain, but potentially realizable.
Renewable energy resources are plentiful and costs declining. Nat
ions are introducing
policies that will move renewables forward in the marketplace. The public is gaining
confidence while renewables are gaining market share.


References


[1]

Electric Power Research Institute and U.S. Department of Energy, 1997,
Renewab
le Energy Technology Characterizations
, EPRI TR
-
109496.

Renewable Energy Technology Characterizations
, EPRI TR
-
109496.

[2]

Intergovernmental Panel on Climate Change, 1996,
Climate Change1995:
Impacts, Adaptations and Mitigation of Climate Change: Scientifi
c
-
Technical
Analyses,

Contribution of Working Group II to the Second Assessment Report,
Cambridge University Press.

[3]

Interlaboratory Working Group, 2000,
Scenarios for a Clean Energy Future
,
Oak Ridge National Laboratory, Oak Ridge, TN (ORNL/CON
-
476), L
awrence
Berkeley National Laboratory, Berkeley, CA (LBNL
-
44029), and National
Renewable Energy Laboratory, Golden CO, April, draft.

[4]

Kassler, Peter, 1994,
Energy for Development
, Shell Selected Paper, based on
a presentation to the 11
th

Offshore Norther
n Seas Conference, Stavanger,
August 1994, November.

[5]

Van Beek, A. and J. Benner, 1998,
International Benchmark Study on
Renewable Energy
, Ministerie van Economische Zaken, June.


Walter Short

is a Principal Policy Analyst at the National Renewable En
ergy
Laboratory (NREL) in Golden, Colorado, USA. Mr. Short works with the DOE
Office of Energy Efficiency and Renewable Energy in formulating and analyzing
policy initiatives with an emphasis on the role of renewable energy and on climate
change. Mr. Sho
rt currently leads the NREL Analysis Group in Golden, Colorado.


Mr. Short has served at NREL as the Manager of the Market Analysis Branch
and Program Manager for Market Analysis. He also conducted heat transfer, optical
analysis and engineering economics

studies in the buildings and solar thermal
programs at NREL in the 1980s.

0
2000
4000
6000
8000
10000
1980
1985
1990
1995
2000
GW

28


Prior to joining NREL in 1980, Mr. Short conducted optimization and
engineering
-
economics studies at SRI International. Mr. Short holds a BS degree in
mathematics from the Univers
ity of Georgia and an MS in operations research from
Stanford University.



PRE
-
COMBUSTION/POST
-
COMBUSTION DECARBONI
SATION

Tony Kaiser, Director , ABB Alstom Power Technology, Baden
-
Dättwil,
Switzerland

Verena Schmidt, ABB Alstom Power Technology, Baden
-

ttwil, Switzerland


Introduction

A world
-
wide fuel decarbonisation is claimed to be on
-
going for the last 200
years already. A historical trend towards higher H/C ratios in fuel can been observed
[1, 2]
. It shows. that natural gas will be
the main fuel at the beginning of this century
and will be replaced finally at the end of the 21
st

century by hydrogen from renewable
sources as the ultimate clean fuel
[3]
. This trend towards hydrogen rich fuels is
accompanied with a tren
d towards increased energy. demand world
-
wide

Because of increased public awareness of the threaths of global warming to the
global ecosystem, the international community has decided to take actions in order to
actively reduce greenhouse gas emissions. In
fact, based on agreements in the Kyoto
protocol, the emissions of greenhouse gases should decrease by the year 2010
compared to 1990 emission levels. This means that a substantial reduction below
“business as usual” will be required. The man made CO
2

emiss
ions originates from
many different sources. Power generation accounts for ca. 1/3
rd

of the CO
2

emissions
and will likely bear the main share of the reductions initially, as power units are large
and thus the CO2 reductions technically and politically easi
er than for other CO2
sources.

The three main possibilities for CO2 reduction/ removal from power
generation are:


1.

Decarbonisation of the fuel prior to combustion

2.

Combustion in O2/ CO2 atmospheres and condensation of CO2

3.

Tail
-
end capture solution, e.g. ami
ne scrubbing, membranes, etc.


The decarbonisation of the fuel prior to combustion includes different methods
for production of hydrogen and recovery of CO2 from the hydrogen process and
subsequent use of hydrogen as fuel.

The combustion in O2/ CO2 atmosph
eres includes different power generation
cycles using pure or enriched oxygen as oxidant instead of air.

Fossil fuel based power plants produce flue gas streams with CO2
concentrations around 3 to 15%. The remainder of the flue gas is nitrogen, some
exces
s oxygen, water and trace impurities like NO
x
. Thus, the major challenge in CO2
removal is its efficient separation and capture technology from nitrogen.The tail
-
end
capture solution method includes e.g. absorption by use of amines, different

29

adsorption te
chniques, use of membranes etc. These CO2 capture processes (including
above mentioned three methods) have significant energy requirements, which reduce
the power generation plant’s efficiency up to 10%, and net power output up to 20%.
Using CO2 separation

methods based on chemical absorption, physical absorption or
adsorption it is possible to recover 85 to 95% of CO2 in the fuel. The emission of
NOx, however, will probably be at the same level as in conventional power generation
processes and further redu
ction in the NOx effluent will need use of an additional
NOx reduction system like SCR (Selective Catalytic Reduction).


Proposed Process Schemes for “CO2
-
Free” Power Generation Plants

Many authors have studied the comparison of the integration of the CO2
separation possibilities with combined cycle or IGCC power plants. The conclusion
drawn by the authors is that overall a loss in efficiency of 6 to 10 points has to be
accepted for the CO2 removal for large power generation plants (500MW). High
energy cons
umption is due to low CO2 concentrations (downstream separation of
CO2 from flue gas), air separation processes and/or the fuel reformers
[4
-
9]
. The main
concepts for CO2 separation are discussed in the following.


Gas turbine combined cyc
le with natural gas as fuel and carbon dioxide separation:

This is the base case for most comparisons: a state of the art combined cyle
power plant in combination with a conventional chemical adsorption process (amine
scrubbing). This process gives the hig
hest power plant efficiency. But because of low
CO2 concentration in the flue gas (3
-
4%) the CO2 scrubbing is a major cost factor and
energy sink. Typically a penalty of ca. 10 %
-
points for the power plant efficiency has
to be considered for such a scheme[
4].


Gas turbine combined cycle with oxygen as oxydant and carbon dioxide recycle:

This is an example of a gas turbine with oxygen combustion. By combustion in

oxygen, methane is transformed into H2O and CO2. The water is recovered by
condensation and the
remaining stream is pure CO2. Part of the CO2 is recycled to the
turbine inlet as cooling media, the rest will have to be compressed for storage. This
gas turbine process is not commercially available and the development of a
completely new gas turbine tec
hnology will be required
[4, 10]
.

In the above process scheme, oxygen is provided by means of an air separation
unit (
e.g. cryogenic separation or pressure swing absorption (PSA)). This unit requires
250 to 300 kWh/ton oxygen produced. Sho
uld such oxygen procurement methods be
utilized for the supply of pure oxygen to combustion processes within gas turbine
cycles, the net power output, and hence the thermal efficiency, will be diminished by
at least 20%, and some 10%, respectively. Oxygen
production via cryogenic means
will also substantially increase the price of electric power; it may even amount to 50%
of this cost.

Processes of this type will be more attractive if a less energy intensive air
separation technology becomes commercially av
ailable (e.g., membrane based
technologies).



30

Gas turbine combined cycle with hydrogen fuel produced by natural gas reforming:

In this class of processes, the fuel is processed prior to combustion. Process
options include partial oxidation (reaction with o
xygen), steam reforming (reaction
with water) or combinations thereof. Autothermal reforming combines the exothermic
partial reaction with the endothermic steam reforming in such as way as to run the
reaction autothermal.

The typical reactions with methane

are (based on thermodynamic equilibrium
reactions):



partial oxidation:



CH
4

+ 0.5 O2
-
> CO + 2 H2



exothermic reaction:

HR =
-

35.7 kJ/mol



steam reforming:



CH
4

+ H2O
-
> CO + 3 H2



endothermic reaction:

HR = 206.2 kJ/mol



autothermal reforming (thermal equilibrium, no compensation for heat losses):



CH
4

+ 0.43 O2 + 0.15 H2O
-
> CO + 2.15 H2



isothermal reaction:

HR = +/
-

0 k
J/mol


All of these reactions require a further reaction of CO with water, the so
-
called
water
-
gas
-
shift reaction. Preferably, the shift reactor is separated in a high temperature
and a low temperature stage, in order to achieve a high CO to CO2 conversion
.



water gas shift reaction of CO:



CO + H2O
-
> CO2 + H2



exothermic reaction:

HR =
-

41.2 kJ/mol


These reactions run at different temperature levels and the combination of a fuel
decarbonisation processes with the combined cycle power plant requires a close
integration of the heat exchanger systems of both of these processes. The
combustion
of the produced mixture of ca. 50% H2 in N2 is considered to be possible without
major changes to the actual design of combustor and turbine. Special attention will be
required to control NOx emissions in this case. Depending on the fuel reformi
ng
chosen, the efficiency penalty will be from 7 %
-
points for partial oxidation to 10 %
-
points for steam reforming
[4, 6
-
8, 11, 12]
.

In the case of partial oxidation performed with oxygen instead of air, the CO2
separation is best performe
d by physical absorption at high pressure (> 20 bar).
Oxygen has to be provided only to the partial oxidation reactor and the costs and
energy requirements for oxygen are therefore much lower. The penalty for air
separation amounts to ca. 4 %
-
points and th
e penalty for CO2 separation only to ca. 2
%
-
points because of the more favorable high pressure operation
[9]
.


Integrated Gasification Combined Cycle with Carbon Dioxide Separation:

This is a case of clean coal technology, where the large
r part of CO2 is removed

31

from the flue gas by conventional scrubbing technology. Here again, a more than 10
%
-
points loss in efficiency has to be accepted in order to perform this chemical
absorption step on the dilute flue gas stream. In a modification of

this scheme the CO2
is separated by physical adsorption after the high pressure partial oxidation reaction,
effectively becoming a “coal decarbonisation” technology. This improves the overall
efficiency considerably resulting in a loss of only 6 % points
for this integrated gas
combined cycle plant
[5]
.


New Developments in Fuel Decarbonisation:

Gas turbine and in particular combined cycle technology has been established
as highly efficient power plants with minimal CO2 emissions ( ca. 0.1

kg/s.MW for
GTCC compared to ca. 0.2 kg/s.MW for modern coal based power plants
[13]
). All of
the discussed technologies to further reduce CO2 emissions, discussed so far, lead to a