1 John O’Donnell Solar Thermal Power

Electricity: Fuel of GDP

Where Does Electricity Come From?

Heat

Heat Makes Steam

Steam Becomes Electricity Best efficiency at highest temperature Primarily limited by materials

Thermal Power Generation ½ all US potable water used here

It’s not the heat, 40% of heat energy becomes electricity Total heat released is insignificant

It’s not the heat, it’s the CO2 Each molecule of CO2, during its life in the atmosphere, traps 100,000 times more heat than was released when it formed. - Ken Caldeira, Carnegie Inst. Power generation is over 40% of US and world CO2 emissions, and is the fastest growing sector.

100,000 times =

Business As Usual: A Problem

We have a problem

Targets and Methods

SOLAR Primary Resources: Fuel Supply Uranium World energy use R. Perez et al. COAL Oil Gas waves Wind OTEC BIO HYDRO

Solar Thermal Power Now competitively priced in US At $30/ton CO2, economics drives deployment Can deliver 90% of grid power Thousands of megawatts in contract/construction now Needed construction rates achievable US 2006 electricity: 92x92 mi

On Peak Pwr is Most Expensive (and fastest growing)‏ Base Load (coal, nuclear)‏ Intermediate Combined Cycle Peaking GT

Summer peak load growing 2x average use All “peak” load gas-fired Electricity generation fastest growing use of natural gas McKinsey, CERA, Simmons predict doubling++ of US natural gas prices within 5 years Solar Is Strategic and Economical

Solar Thermal Power: 1914

Solar thermal power systems Dish Tower Trough Linear Fresnel Concentrate Sunlight x concentration Track Sun Position daily/seasonally Store Heat Energy Convert Heat To Power Turbine and Stirling Engines Economics Collector Cost Per Area Optical Efficiency Thermal Losses Engine Thermal Efficiency

Factors Driving Cost-Efficiency Engine Efficiency Reflector Field Cost Per Area Thermal Losses  T 4  Receiver Area  Emissivity High Solar Concentration: Materials-limited, cost of precision reflectors and trackers Lower Concentration: Reductions in reflector cost outweigh lower thermal efficiency

Solar thermal power systems Continuous Fresnel Point Line Dish Tower Trough Linear Fresnel Stirling Energy Systems Infinia Abengoa Solar Reserve Brightsource Torresol Solar Millenium Acciona Abengoa Ausra C C C C

Concept of Tower Technology Storage

Dish Engine Link

Trough

Solar Energy Generating Systems (SEGS)‏ 354 MW Solar Electric Generating Systems (SEGS)‏

l Linear Fresnel

177 MW, 1 square mile 28 Carrizo Energy Farm for PG&E in CA; rendering; Online 11/10

Solar Field Costs (Reflector + Receiver)‏ DLR 2007 assessment of solar thermal pwr AQUA-CSP

Variable   Selective Surfaces

Solar Thermal Plant Elements 31

Highly specific design specifications regarding: primary HTF - pressure - temperature - power level - capacity Storage system ONE single storage technology will not meet the unique requirements of different solar power plants Thermal Energy Storage Challenges

Thermal Energy Storage for CSP Plants Status und Development Commercially available storage systems – Steam Accumulator – 2-Tank sensible molten salt storage based on nitrate salts Alternative materials and concepts tested in lab and pilot scale – Solid medium sensible heat storage - concrete storage – Latent heat - PCM storage – Combined storage system (concrete/PCM) for water/steam fluid – Improved molten salt storage concepts – Solid media storage for Solar Tower with Air Receiver (e.g. natural rocks, checker bricks, sand)‏ Future focus for CSP – Higher plant efficiency => Increase process temperature – New fluids: steam, molten salt, gas/air

Steam Accumulators PS10 Saturated steam at 250°C 50 min storage operation at 50% load

Molten Salt Storage – Andasol 1 Ø 38,5 m 14 m 292 °C 386 °C Storage capacity 1010 MWh (7.7h)‏ Nitrate salts (60% NaNO3 + 40% KNO3)‏ Salt inventory t Tank volume m³ 6 HTF/salt heat exchangers

Storage: Meet Peak Demand++ Least Cost per kWh around 14 hrs storage Optimal economics depend on tariff California pays 2x/kWh noon-8pm M-F Spain, others no TOD

Solar Thermal can supply over 95% US Grid Power 11 Mills & Morgan, SolarPACES 2008

Solar Thermal vs Conventional $/MWh

Gerhard Knies, CSP 2008 Barcelona More than 90% of world pp could be served by clean power from deserts (DESERTEC.org) ! Land is not (remotely) a constraint 40 world electricity demand (18,000 TWh/y) ‏ can be produced from 300 x 300 km² =0.23% of all deserts distributed over “10 000” sites

US Solar Resource 100% US electricity 92x92 miles

World Solar Resources 42

High Voltage Direct Current (HVDC) Low-Loss (3%/1000 km)

deserts + technology for energy, water and climate security Sun-belt + technology belt synergies interconnection technology cooperation 44 Gerhard Knies, Taipei e-parl. + WFC /2 CoR White Paper 2007

45 Interstate Highway System HVDC Superhighways Interchanges to today's hubs Stability, Cost, Job Growth, Energy + Climate Security

Can this be done? Give us 100% Clean Electricity within 10 years. 800 GW by GW/yr build! Resource availability Readiness of technology Transmission corridors Cost of power Reliability of supply

US Power Generation 50 yr History 47 Market forces caused 70 GW/yr buildout China building >100 GW/yr Can we build 80 GW/yr? Yes Can

48