Power Generation Sector

Power Efficiency Guide

Ultimate Guide to Power Efficiency

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According to the Center for Global Development [18], global power generation emissions have been growing at 3.7% annually, for the 2000-2008 period. It is important to note, that there are massive coal-fired power generation capacity expansions underway in China, India, and other countries. Since such plants have no CO2 mitigation technology planned and can have lifetimes up to 50 years, the sooner such technology is ready for implementation and mandated, the sooner new plants can incorporate such technology and control emissions.

Table 1.1 Candidate technologies for power generation (CO, mitigation projected impact in Gt/year of CO,)

Technology

Current state of the art

2050 Impact

Issues

Technology RD&D needs

Potential environmental impacts/R&D needs

Solar-photovoltaic and concentration (renewable)

First generation commercial, but very high costs

Wind power (renewable) Commercial

Fuel Switching coal to gas

Nuclear Power-next generation

Commercial

Developmental, 1.!

generation III + and IV: e.g. Pebble bed modular and supercritical water cooled reactors

Costs unacceptably high, solar resource intermittent in many locations

High, breakthrough RD&D needed to develop and demo cells with higher efficiency and lower capital costs

Costs very dependent on strength of wind source, large turbines visually obtrusive, intermittent power

Key issue is availability and affordability of natural gas

Medium, higher efficiencies, on-shore demonstractions

Medium, higher efficiencies with new materials desirable

Deployment targeted by High, demonstrations

2030 with a focus on lower cost, minimal waste, enhanced safety and resistance to proliferation of key technologies with complimentary research on important

Reduction in emissions of SOx, NOx, fine PM; fewer mining impacts and residues for disposal or use. Potential upstream emissions/ effuents associate with manufacturing cells/ medium

Reduction in emissions of SOx, NOx, fine PM; fewer mining impacts and residues for disposal or use; possible local impact on bird population/ medium

Reduction in emissions of SOx, NOx, fine PM; fewer mining impacts and residues for disposal or use. Extraction R&D could enhance availability of CH4//ow

Relative to coal, reduction in emissions of SOx, NOx, fine PM; fewer mining wastes. Small quantities of potent and long-lived waste, could contaminate small area/high

Coal IGCC with CO, capture and storage

IGCC: early commercialization. Underground storage (US): early development.

Pulverized coal/oxygen Developmental combustion with CO, capture and storage

Pulverized coal with CO, Underground storage capture and storage developmental;

CO, scrubbing with MEA commercial but expensive

Biomass as fuel gasified or co-fired with coal (renewable)

Commercial, steam cycles

IGCC: High capital costs, questionable for low rank coals, potential reliability concerns; US: Cost, safety, efficacy

Oxygen combustion allows lower cost CO, scrubbing, but oxygen production cost is high, US : Cost, safety and permanency US: Cost, safety and efficacy issues, CO, scrubbing energy intensive: yielding high costs

High, IGCC: Demos on a variety of coals, hot gas cleanup research; US: major program with long term demos at key geological formations to evaluate environment impact, efficacy, cost and safety High, large pilot followed by full scale demos needed, low cost O, production needed, US requires major program (see write-up above) High, US requires major program (see write-up above); affordable CO, removal technologies need to be developed and demonstrated

Biomass dispersed Medium, biomass/

source, limited GCC would enhance to 20% when efficiency and CO, co-fired with coal benefit; also genetic engineering to enhance biomass plantations

Lower power plant efficiency yields greater SOx, NOx, fine PM and coal mining impacts, including acid mine drainage. Sequestration could impact groundwater quality//jzg/j

Lower power plant efficiency yields greater SOx, NOx, fine PM and coal mining impacts, including acid mine drainage. Sequestration could impact groundwater quality//îzg/î

Lower power plant efficiency yields greater emissions of sojt, nox, fine PM and coal mining impacts, including acid mine drainage. Sequestration could impact groundwater quality//? zg/î

Reduction in emissions of SOx, NOx, fine PM; fewer mining impacts and residues for disposal or use; however potential eco impacts and excessive water use from biomass plantations/mei/zz/m

(continued)

Table 1.1 (continued)

Current state

2050

Potential environmental

Technology

of the art

Impact

Issues

Technology RD&D needs

impacts/R&D needs

Nuclear power-current

Commercial,

1.0

Plant siting, high capital

Medium, Waste disposal

Relative to coal, reduction in

generation

Pressurized

costs, levelized cost

research

emissions of SOx, NOx, fine

Water Reactors

10^10% higher

PM; fewer mining wastes.

and Boiling

than coal, potential

Small quantities of potent

Water Reactors

U shortages.

and long-lived waste, could

(generation III)

safety, waste and

contaminate small area/high

proliferation

More efficient coal fired

Early commercialization

0.7

Currently maximum

High, new affordable

Small reduction in emissions of

power plants no CCS

of supercritical and

efficiency of 45%,

materials needed to

SOx, NOx, fine PM; fewer

ultra supercritical

yielding 36% less

enhance efficiency to

mining impacts and residues

CO, than current fleet

50-55%

for disposal or use//ow

Coal IGCC with no CO,

IGCC: early

0.7

IGCC: High capital

High, demos on a variety

Small reduction in SOx, NOx,

capture and storage

commercialization

costs, complexity

of coals, hot gas

fine PM; fewer mining

and reliability

cleanup research

impacts and residues for

concerns, only

disposal or use/medium

modest CO,

Geothermal

Early commercialization

0.6

Cost of deep drilling

High, large number of

Potential for water and land

and fracturing.

demos in various

pollution problems at

distance from users

geological formations

geothermal site/medium

Natural gas combined

Commercial, 60%

0.4

Limited by natural gas

Medium, higher

Reduction of SOx, NOx, fine

cycle (new)

efficiency

availability, which is

efficiencies with new

PM; fewer mining impacts

major constraint

materials desirable

and residues. Extraction

R&D could enhance

availability of CH4//ow

Hydroelectric

Commercial

0.4

Capital costs high.

Medium, minimize

Local ecological impacts//ow

(renewable)

potential eco

environmental

disruption, siting

footprint

challenges

Table 1.2 Candidate technologies for CO, mitigation from buildings

Current state

Blue 2050

Technology RD&D priority

Potential environmental

Technology

of the art

impact

Issues

and needs

impacts/R&D need

Heating and

Enhanced energy mgt.

Commercial

2.5

Lack of incentive.

Low/medium priority.

Less fossil fuel and nuclear

cooling

and high efficiency

high initial costs.

incremental improvements

power generation, and

building envelope:

long building

to lower cost and enhance

less on-site fossil fuel

insulation, sealants.

lifetime

performance

combustion, yield reduction

windows, etc.

in coal and natural gas emissions, and nuclear wastes/tow

High efficiency

Commercial

0.8

Lack of incentive.

Low/medium priority.

Same as above

building heating

high initial costs

incremental improvements

and cooling, including

to lower cost and enhance

heart pumps

performance

Solar heating

First generation

0.5

High initial costs.

Medium, focus on

Same as above

and cooling

commercial

availability of low cost efficient biomass heating systems

development of advanced biomass stoves and solar heating technology in developing countries

Appliances

More efficient electric

Commercial

4.5

Higher initial costs

Low/medium priority.

Less fossil fuel and nuclear

appliances

and lack of information to the consumer

incremental improvements to lower cost and enhance performance

power generation, yields reduction in coal and natural gas emissions, and nuclear wastes//ow

More efficient lighting

Commercial-

Lack of incentive

Medium, LED and OLED

Same as above; however.

systems

fluorescent

given higher initial costs

technology needs further development with aim of lowering initial cost

mercury content of fluorescent bulbs could cause health and environmental problems/merf

Reduce stand-by losses

Commercial

Lack of incentive

Low

Less fossil fuel and nuclear power

from appliances.

from vendors and

generation, yields reduction in

computer

lack of knowledge

coal and natural gas emissions.

peripherals, etc.

from end-users

and nuclear wastes//ow

Table 1.3 Candidate technologies for CO, mitigation from mobile sources

Technology

Current state of the art Issues

Key enabling technologies

RD&D needs

Vehicles Improvements:

current internal combustion engine components

Non-engine

Improvements: current vehicles; tires, A/C, light materials Hybrid electric vehicles (HEVs)

Plug-in hybrid electric vehicles (PHEVs)

Full performance electric vehicles (FPEVs)

First generation: commercial

First generation: commercial

First generation: commercial

Developmental

Developmental

Lack of customer incentive major problem; trend to larger vehicles in US and recently Europe counterproductive Lack of customer incentive major problem; trend to larger vehicles in US and recently Europe counterproductive Higher costs (about $3000), "light" hybrids not as efficient as full hybrids, some newer models yield power over mileage benefits Battery cost and lifetime key issues. Also requires low C electric generation to maximize carbon reduction benefits

Battery cost, storage capability and lifetime key issues. Also requires low C electric generation to maximize carbon reduction benefits

Batteries: near term nickel metal hydride; longer Term: lithium Ion

Batteries: Near term nickel metal hydride; longer term: lithium ion

Batteries: longer term: lithium ion

Medium, transmission and drive train improvements

Medium, lower weight construction, improved tires and more efficient A/Cs

Medium/High, minimize incremental cost, mostly battery related, and enhance efficiency

High, intensive R&D necessary to upgrade battery performance, lifetime and ability to allow deep cycling and rapid charging

High, intensive R&D necessary to upgrade battery performance, lifetime and ability to allow deep cycling and rapid charging

Fuel cell electric Developmental vehicle (FCEV)

Fuels Ethanol from sugar Commercial

Biodiesel and other Developmental fuels from biomass; thermo chemical processes

Biodiesel from First generation:

vegetable oil commercial

Ethanol from grain/ Commercial starch, e.g., com

Ethanol from Early developmental biomass/lignose cellulose;biochemical process

Fuel cell costs and fuel cell stack life; also hydrogen production and storage, safety and lack of infrastructure

Limited by land capable of high sugar yields, e.g., sugar cane

Developmental, yet potentially high production and lower cost via gasification/Fischer-Tropsch synthesis

High costs, low yield from oil crops, limited waste cooking oils, low S a positive Limited by grain supply; high costs, energy intensive production Inability to convert wide range of biomass types, high production costs, dispersed biomass source

H2 production:

lower cost low C processes H2 Storage: high pressure storage, and liquefied gas storage; both appear expensive Fuel cells: need to increase power per cell

High, breakthrough RD&D needed to develop cost competitive, long lived fuel cells. Hydrogen production and storage RD&D also needed

Medium, develop sugar cane cultivars with higher yield and more frost tolerance High, major RD&D

needed to develop and demonstrate viable technology for biomass feedstock Low

High, breakthrough RD&D needed to develop lower cost generally applicable process(es)

Table 1.4 Candidate CO, mitigation technologies for industrial sources (impact in Gt/year)

Blue 2050

Potential environmental

Technology

Current state of the art

impact

Issues

RD&D needs

impacts/R&D need

CO, capture and storage

Early development

4.3

Applicability limited to

High, major

Lower process efficiency

large energy-intensive

program

yields greater

industries, including

with long

air. water and

fuel transformation

term demos

land impacts per

processes; key

evaluating

product produced.

questions: cost, safety.

large number

sequestration could

efficacy

of geological

impact groundwater

formations

quality//j/g/j

to evaluate

efficacy, cost

and safety

Motor systems

Commercial

1.4

For most industries not

Medium; lower

Reduction in coal emissions:

a major cost, lack of

costs and higher

Sox. NOx. PM and

expertise for some

efficiencies

resides//ow

industries

desirable

Enhanced energy

Commercial

Enhanced fuel

Developing countries

Low

Potential reduction in

efficiency: existing

efficiency.

can have low energy

air emissions, water

basic material

total 2.3

efficiency due to lack

effluents and wastes/tow

processes

of incentive and/or

expertise

Steam systems (required

Commercial

For most industries not

Low

Reduction in coal emissions:

for many industries)

a major cost; lack of

Sox. NOx and PM and

expertise for some

residues//ow

industries

Materials/product efficiency

First generation: commercial

Cogeneration (combined heat and power)

Enhanced energy efficiency: new basic material processes

Fuel substitution in basic materials production

Commercial

Developmental to Near-commercial depending on industry

Commercial

Feedstock substitution in Commercial key industries

Little incentive to minimize the CO, "content" of materials and products; life cycle analyses required

Limited by electric grid access that would allow the ability to feed electricity back to grid also high capital costs New, innovative production processes require major RD&D and would need reasonable payback to replace more C intensive processes

Natural gas substitution for oil and coal can be expensive Biomass and bioplastics can substitute for petroleum feedstocks and products, however cost high and availability low

Medium, conduct life cycle analyses of key materials and products with the aim of minimizing CO, "content" Low

Potential reduction in air emissions, water effluents and wastes, depending on substitute material /medium

Reduction in coal emissions: Sox, NOx and PM and residues/tow

Medium/High,

Develop and demonstrate less carbon intensive production processes for key industries Low

Potential reduction in air emissions, water effluents and wastes, depending on new process!high

Unclear, environmental studies useful/high

Medium, develop affordable substitute feedstocks and products based on biomass

Unclear, environmental studies useful, depends on feedstock and process/high

Major reductions can result from lower emissions both on the generation side and on the user side as a result of lower usage via enhanced end use efficiency. Table 1.1 presents a summary of major generation options that offer significant opportunities for CO2 mitigation. They are presented in the order of highest potential for CO2 mitigation consistent with the IEA Blue scenario. Included in this and the subsequent tables are the IEA projected CO2 savings for each technology in Gt of CO2 in 2050 for the Blue scenario. Also included is information regarding potential environmental issues assuming wide scale deployment of the given technology, and the relative priority of environmental characterization and risk management research to understand and minimize these problems. Priority judgments were based on the potential magnitude of the environmental impacts and the relative availability of information on the magnitude and the mitigation potential of such impacts.

Key generation technologies include nuclear power, natural gas/combined cycle, and three coal combustion/capture technologies - Integrated Gasification Combined Cycle (IGCC), pulverized coal/oxygen combustion, and conventional pulverized coal - all with integrated CO2 capture and underground storage. Figure 1.29 illustrates the major components of each capture technology. IGCC technology is the primary focus of the U.S. RD&D program. But this technology requires complex chemical processing and pure oxygen for the gasification process, and it cannot be readily retrofitted to existing plants. Oxy-combustion systems also require pure oxygen for combustion but are less complex and have the potential for retrofitting existing plants. CO2 removal via scrubbing, adsorption, or membrane separation is conceptually simple and inherently retrofittable but is at

Post Combustion CO2 Scrubbing

IGCC: Pre-combustion CO2 removal

Oxy-Fuel (Coal/oxygen) Combustion n2, o2, h2o n2, o2, h2o

Post Combustion CO2 Scrubbing

IGCC: Pre-combustion CO2 removal

Oxy-Fuel (Coal/oxygen) Combustion

Afib With Rvr Algorithm
Fig. 1.29 Three key technologies capturing CO2 from coal-fired power plants

Carbonation Reactor

Fossil Fuel Combustion Facility

Fossil Fuel Combustion Facility

CO2 Generation

Dry Na-Based Sorbent Technology

Carbonation Reactor

Sorbent Transfer

Decarbonation Reactor

Water Condenser

Water

Carbonation: Na2C03 + H20 + C02 ^ 2NaHC03 Decarbonation: 2NaHC03 ^ Na2C03 + C02 + H20

CO2 Separation

CO2-Free Stack Gas

Stack

CO2 Sequestration

Fig. 1.30 RTI's Dry carbonate process for CO2 capture an early development stage; commercial amine scrubbers use large quantities of energy for sorbent regeneration and are expensive. Figure 1.30 schematically depicts a promising CO2 capture technology under development by Research Triangle Institute (RTI). The Department of Energy has sponsored small pilot testing at EPA's Office of Research and Development's (ORD) Multi-pollutant Combustion Research facility. Early pilot testing results showed high CO2 capture and efficient sorbent regeneration.

MIT [4] conducted an in-depth study of coal in a carbon-constrained world and concluded that: "... CO2 capture and sequestration is the critical enabling technology that would reduce CO2 emissions significantly while also allowing coal to meet the world's pressing energy needs." They concluded that current research funding is inadequate and "what is needed is to demonstrate an integrated system of capture, transportation, and storage of CO2, at (appropriate) scale."

With the exception of wind power, renewable technologies are not projected by IEA [7] to have major mitigation impacts for the ACT scenario in the 2050 time frame. In the case of solar generation, both photovoltaic and concentrating technologies are currently prohibitively expensive. However, the Blue scenario assumes major improvements and cost reductions for both solar technologies, allowing them to play a major role in low carbon power generation before 2050. For biomass, major utilization is projected to be limited by its dispersed nature, its low energy density, and competition for the limited resource in the transportation sector.

An important factor that must be taking into account when considering a major restructuring of the power sector is the importance of water availability, needed for cooling and various unit operations and processes. Water supply in some regions could be compromised by climate change and scarce supplies would have to be shared with municipal, industrial, and agricultural users.

The author rates RD&D needs in the power generation sector critical, especially in the area of CCS and for the next generation of nuclear power plants. All three capture technologies described above warrant aggressive RD&D programs. The author concurs with MIT [4], that there are too many uncertainties with regard to IGCC to limit RD&D focus to that technology alone. Therefore, more emphasis should be placed on pulverized coal/oxygen (oxy-fuel) combustion, and high efficiency pulverized coal with CO2 flue gas capture technology. Underground sequestration will be needed for each of these technologies and is in the developmental stage, with extraordinary potential. However, there are a host of economic, environmental, safety and efficacy questions that can only be resolved through a major program with a particular focus on demonstrations for the key geological formations most applicable to the greatest potential storage capacity.

An example of an important sequestration environmental issue is the potential of such operations to adversely impact drinking water sources. While CO2 itself is not toxic, it could change subsurface geochemical conditions in such a way that toxic metals, such as arsenic, could be released into groundwater. In addition, impurities in the captured CO2 stream could also impact drinking water quality. Because of these potential impacts and the likely large areas of the subsurface impacted by such sequestration if applied on a wide scale, this issue should be given a high research priority.

MIT [4] estimates that three full-scale CCS projects in the United States and ten worldwide are needed to cover the range of likely accessible geologies for large-scale storage.

For the next generation of nuclear reactors, the technology is quite promising and could start making a major impact by 2030. However, there needs to be a number of successful demonstrations to allow for resolution of remaining technical problems and to instill confidence in the utility industry that the technology is affordable and reliable, and to the public, that it is safe.

Given the resource, environmental and sustainability challenges associated with fossil fuel and nuclear power generation technologies, it would be highly desirable to generate all required electricity from affordable renewable resources. Therefore, major technological development efforts, should be focused on enhancing performance and reducing costs for wind power, both on-shore and offshore, and both solar generation technologies.

It should be noted that subsequent chapters discuss power generation mitigation in more detail: Chap. 2: Coal and Coal/Based Power Generation, Chap. 4: The Role of Nuclear Power: No Free Lunch, Chap. 5: Renewable Energy: Status and Prospects. Note that further consideration of the environmental implications of emerging technologies is discussed in Chap. 12: Potential Adverse Impacts of Greenhouse Gas Mitigation Strategies. Also, recognizing the importance of timely mitigation in the rapidly growing economies, Chap. 11 analyzes the climate change mitigation challenge unique to China, India, and Mexico. It is titled, The Role of Technology in Mitigating GHG Emissions from the Power Sector: the Case of China, India, and Mexico.

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