Harnessing the Energy from the SunUsing inertially confined thermonuclear energy to power our lives

Jacob AndersonUniversity of Maryland

SASS, Nov. 12, 2008 2

Ideas

How much solar energy is there? How can we collect the solar energy to do work for

us? Photovoltaic power Concentrating solar power Solar heating, cooking, cooling, and more.

How much is this going to cost me?

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How much solar energy is there?

Family of four living in bay area.

90 m2 apartment uses ~250 kWh per month Solar power in bay area:

~200 W/m2

What are the requirements for us to go solar?

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How much solar energy is there?

Every hour enough solar energy reaches the surface of the earth to meet the energy demands of the entire world for a year.

The sun is the thermonuclear power plant in everyone's back yard, but far enough away that nobody cares.

Converting that energy to work for us is the trick.

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Solar energy working for us

Solar energy conversion falls into 3 major categories. Photovoltaic power Concentrating solar

power Solar heating, cooking,

cooling and more.

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Photovoltaic power cells

Electrical generation based on the photoelectric effect.

Several configurations Flat plate photocells Concentrating

photovoltaic cells (CPV)

Various PV cell materials Silicon (Si) copper indium

diselenide (CIS) cadmium telluride

(CdTe) gallium arsenide (GaAs)

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Flat plate cells

Large area of active material. The more area the more sun you absorb.

Can be installed without solar tracking mechanisms. Can use diffuse solar radiation, i.e. cloudy days. Typically 15-20% efficiency.

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Concentrating Photovoltaic cells

Use optical mirrors and lenses to focus the light onto a small PV cell.

Need sun tracking mechanism.

Little diffuse capture. Use higher efficiency

PV cells, ~35%.

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Characteristics of photovoltaic technology Advancing efficiency. CPV needs less active

cell area. Provides more power on

hot sunny days when demand is typically higher.

Produces DC power which must be run through inverter.

After installation, they are very low cost.

Flat-plate needn't have moving parts.

Possible to recycle out of service modules.

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Concentrating solar power

Using the sun to heat a working fluid to produce steam to drive a turbine to produce electricity.

Three types dish reflector linear reflectors power tower

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Dish/engine concentrators

Typically 3 to 25 kW. Uses an engine, usually a Sterling, to produce

power. Solar tracking required

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Linear concentrators

Long linear reflectors.

Can be combined with thermal storage to provide power at night, etc.

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Power towers

Reflectors aim to a central tower.

Can also be combined with thermal storage to provide power at night.

Also combined with conventional fossil fuel power generation.

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Thermal storage

Concentrating solar power has the advantage of using the sun to provide thermal energy not directly to electricity.

The thermal energy can be stored in the form of molten salts for use to generate power when there is no sun for hours maybe even days. The storage as been shown to be ~99% efficient

You can also build hybrid power stations that use conventional fossil fuels to provide the heat when there is no sun.

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Other solar related activities

Solar heating and water heating. Solar cooking

Solar refrigeration Solar desalination Solar industrial process heat

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Cost comparisons

Figuring out the cost is not always straight forward.

LEC =

Pnt=1

It+Ft+Mt

(1+r)tPnt=1

Et(1+r)t

² LEC = Average lifetime levelised electricity generation cost

² It = Investment expenditures in the year t

² Mt = Operations and maintenance expenditures in the year t

² Ft = Fuel expenditures in the year t

² Et = Electricity generation in the year t

² r = Discount rate

² n = Life of the system

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Levelized Cost – CA (2007 USD)http://energyalmanac.ca.gov/electricity/levelized_costs.html

MW MW MW

500 102.19 10.22 0.25 143.61 14.36 50 75.85 7.58

550 103.52 10.35 2 70.05 7 50 73.66 7.37

800 96.36 9.64 25 118.72 11.87 0.75 1030.5 103.05

100 599.57 59.96 25 111.15 11.12 15 424.84 42.48

Small Simple Cycle 50 647.28 64.73 Biomass - IGCC 21.25 123.66 12.37 63.5 277.3 27.73

200 236.12 23.61 Biomass - LFG 2 56.11 5.61 1 704.98 70.5

575 126.51 12.65 0.5 97.34 9.73 15 518.89 51.89

Advanced Nuclear 1000 118.25 11.83 2 114.66 11.47 Wind - Class 5 50 84.24 8.42

Hydro - In Conduit 1 52.84 5.28 0.03 182.41 18.24

Hydro - Small Scale 10 138.74 13.87 0.25 123.66 12.37

DollarsPer MWh

CentsPer kWh

DollarsPer MWh

CentsPer kWh

DollarsPer MWh

CentsPer kWh

Conventional Combined Cycle (CC)

Biomass - AD Dairy

Geothermal - Binary

Conventional CC - Duct Fired

Biomass - AD Food

Geothermal - Dual Flash

Advanced Combined Cycle

Biomass Combustion - Fluidized Bed Boiler

Ocean Wave (Pilot)

Conventional Simple Cycle

Biomass Combustion - Stoker Boiler

Solar - Concentrating PVSolar - Parabolic Trough

Advanced Simple Cycle

Solar - Photovoltaic (Single Axis)

Integrated Gasification Combined Cycle (IGCC)

Biomass - WWTP

Solar - Stirling Dish

Fuel Cell - Molten CarbonateFuel Cell - Proton ExchangeFuel Cell - Solid Oxide

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Levelized cost – Australia (2006 AUD)

Technology TechnologyNuclear 40-70Gas: combined cycle 37-54Coal 28-38Gas: combined cycle + CCS 53-93Coal: IGCC + CCS 53-98Small Hydro power 55

64-106 55Open-cycle Gas Turbine 101Solar thermal 85Hot fractured rocks 89Biomass 88

120

Cost (AUD/MWh)

Cost (AUD/MWh)

Coal: supercritical pulverised + CCS

Wind power: high capacity factor

Photovoltaics

http://en.wikipedia.org/wiki/Levelised_energy_cost

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References

DOE Solar - http://www1.eere.energy.gov/solar/technologies.html DOE renewables - http://www.eia.doe.gov/fuelrenewable.html California - http://energyalmanac.ca.gov/electricity/index.html LEC - http://en.wikipedia.org/wiki/Levelised_energy_cost NREL - http://www.nrel.gov/learning/re_solar.html CPV - http://www.solfocus.com/Primer.php Solar cooking - http://solarcooking.org/plans/funnel.htm