ABENGOA SOLAR Solar Power for a Sustainable World Past, Present, and Future of Solar Thermal Generation Bruce Kelly Abengoa Solar, Incorporated Berkeley,

ABENGOA SOLARSolar Power for a Sustainable World

Past, Present, and Futureof Solar Thermal

Generation

Bruce KellyAbengoa Solar, Incorporated

Berkeley, CaliforniaJune 2008

22Solar Power for a Sustainable World

ABENGOA Topics

– Solar resource– Solar thermal technologies– Early projects– Current projects– Future plans


ABENGOA Solar Resource

Southwest US, filtered for environmental areas, urban areas, water, and slope < 3%

9,800 TWhe potential

3,800 TWhe US energy consumption


ABENGOA Parabolic Trough

• Type: Glass mirror; single axis tracking; line focus

• Nominal concentration: 80:1

• Heat collection fluid: Synthetic oil

• Peak temperature: 393 C


ABENGOA Central Receiver

Photo by Mike Taylor, SEPA

• Type: Glass mirror, two axis tracking, point focus

• Nominal concentrations: 600 to 1,200:1

• Heat collection fluids: Steam, air, or nitrate salt

• Peak temperatures: 400 to 850 C


ABENGOA Linear Fresnel

Photos taken by Mike Taylor, SEPA

• Type: Glass mirror, single axis tracking, line focus

• Nominal concentration: ~100:1

• Heat collection fluid: Saturated steam

• Peak temperature: ~260 C


ABENGOAParabolic

Trough


ABENGOAParabolic

Trough

• Early projects– Solar Electric Generating Stations (SEGS)– SEGS I and II: 14 and 30 MWe; Daggett– SEGS III through VII: 30 MWe; Kramer

Junction– SEGS VIII and IX: 80 MWe; Harper Lake

• Financed through very favorable combination of investment tax credits, Standard Offers, and PURPA requirements

• All are still in operation


ABENGOAParabolic

Trough• Current projects

– Acciona: 64 MWe Nevada Solar One– Solar Millennium: 50 MWe AndaSol 1

• Nevada Solar One financed through investment tax credit and renewable portfolio standard

• AndaSol 1 financed through Spanish feed-in tariff at ~$0.40/kWhe

• Parabolic trough technology investment to date ~$3,000 million


ABENGOAParabolic

Trough• Future plans

– Spain: 50 MWe; limited by tariff structure– US: 125 to 250 MWe; economies of scale

• Advanced collector coolants– Direct steam generation, and inorganic

nitrate salt mixtures– 450 to 500 C collector field temperatures– More efficient Rankine cycles– Why not yet? → Direct steam generation

has complex controls, and salt freezes





• Early projects– France, Spain, Italy, Japan, and United States– 1 to 10 MWe– Receiver coolants: Sodium; nitrate salt;

compressed air; and water/steam

• Design point efficiencies were close to, but annual energy efficiencies were well below, predictions

• Most suffered from lack of operating funds



• Current projects– Abengoa: PS10 and PS20– US DOE: Solar Two (1999)

• PS10 and PS20: Saturated steam receivers; high reliability, but below-commercial efficiency

• Solar Two: Nitrate salt receiver, thermal storage, and steam generator; high efficiency, but poor reliability

• Technology investment to date ~$1,000 million



• Future plans– Abengoa: Superheated steam;

compressed air; and nitrate salt– SolarReserve: Nitrate salt in South Africa

and US– eSolar: 13 distributed superheated

steam receivers; very small heliostats; central 30 MWe Rankine cycle

– BrightSource: 4 towers; small heliostats; central 100 MWe reheat Rankine cycle



• Why not yet?– Superheated steam: Moderate annual

efficiencies; thermal storage may be impractical

– Compressed air: Complex receiver; small plant sizes; thermal storage may be impractical

– Nitrate salt: Less than perfect operating experience; equipment development must occur at commercial scale, with ~$750 million project investment


ABENGOAPerformance and

Cost

• Annual efficiencies, capital costs, operation and maintenance costs, and levelized energy costs

Parabolic trough

Nitrate salt central receiver



• Annual solar-to-electric efficiencies

14 to 16 percent gross

12 to 14 percent net

• Capital cost

~$4/We without thermal storage; includes project financing, interest during construction, and owner’s costs

~$5 to $8/We with thermal storage



• Operation and maintenance cost

$0.02 to $0.04/kWhe

• Levelized energy costs

$0.14 to $18/kWhe with Southwest US direct normal radiation and 30 percent investment tax credit

$0.35 to $0.40/kWhe with southern Spain direct normal radiation and no financial incentives


ABENGOASalt Central

Receiver• Annual solar-to-electric efficiencies

17 to 19 percent gross

15 to 17 percent net

• Capital cost

~$4/We with minimum thermal storage; includes project financing, interest during construction, and owner’s costs

~$7/We with thermal storage at 70 percent annual capacity factor


ABENGOASalt Central

Receiver

• Operation and maintenance cost

$0.02 to $0.03/kWhe

• Levelized energy cost

For a commercially mature design (which does not yet exist), a nominal 20 percent below that of a parabolic trough project


ABENGOA Future Markets

• Capital investment essentially dictated by commodity prices

• Energy price parity with natural gas combined cycle plant is unlikely

• Solar thermal energy is Much better matched to utility peak

demand than wind

Immune to rapid changes in plant output common with photovoltaic projects


ABENGOA Future Markets

• With 30 percent investment tax credit and property tax exemption, solar energy prices are within $0.02 to $0.03/kWhe of market price referant

• Renewable portfolio standards, plus a modest carbon tax, should provide a commercial, multi-GWe market for solar thermal projects

ABENGOA SOLAR Solar Power for a Sustainable World Past, Present, and Future of Solar Thermal Generation Bruce Kelly Abengoa Solar, Incorporated Berkeley,

Documents

abengoa solar solar

sustainable world abengoa

solar millennium

mwe nevada solar

parabolic trough annual

sustainable world past

commercial efficiency

parabolic trough slide