Photovoltaic Power

John Bothof

John Bothof

Photovoltaic Experience•Ameren Solar Technology Center•Military

NJ ANGHickamLuke AFB

•Doha Qatar:Ex HallStudent Housing

•El Dorado 10MW•Copper Mountain 50MW

Solar Industry

Industry Growth•Grid-connected PV Installations grew 66%. (Q1 2011 vs Q1 2010)•US Grid Connected PV now over 2.3GW.•US Module Production increased 17% from last quarter.•Anticipate Doubling of installations from 2010.•2010 had 60% growth.

Cost Reductions

Increased Energy Demand

United States Net Generation 2009 (Thousand megawatt hours)

3,950331Sales to Ultimate Customers 2009 (thousand megawatt hours)

3,723803

Increase Demand

Photovoltaics

Solar Energy•The energy we get from our sun is the result of nuclear fusion reactions.

•Our sun is made up of hydrogen which is gradually being converted into helium.

•The “waste” from this reaction (derived from e=mc2) is heat and light energy.

Power Content of the Solar Spectrum

Harvesting and Using Solar Energy

TechnologiesDifferent Technologies are used to take advantage of the energy in throughout the solar spectrum.

Photovoltaic Technologies– The direct conversion of sunlight into energy– Converts the energy in the visible spectrum into

electricity.

Solar Thermal Technologies– Use the energy in the “heat” part of the solar

spectrum.

Solar Thermal

Photovoltaics

Flat Plate Collectors

Photovoltaics

Physics

Photovoltaics

Cell • The electronic charges within the doped material create an electric field

across the depletion layer.• When sunlight strikes the cell it can knock an electron out of its atomic orbit• The electric field sweeps the electron towards the top electrodes • The gap or “hole” left by the electron is swept towards the back plate• The flow of charges makes an electric current which powers an attached

electric circuit

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Photovoltaics

Cell Technology

•Crystalline• Mono

• Most efficient• Most Expensive

• Poly• Middle Man

Photovoltaics

Cell Technology

•Thin film• a-Si • CdTe• CIS• CIGS• GaAs

Photovoltaics

Concentrated Solar

Photovoltaics

Ameren Solar Technology Center•Compare Technology Output

• Same conditions• Missouri Weather• Customer Service

Photovoltaic

Ameren Solar Technology Center

Photovoltaics

Tracking•Single Axis

• 25% more kWh•Tilted Single Axis

• 27-32% more kWh•Bi-Axis

• 35 to 40% more kWh

Array

Modules•Series & Parallel Cells•Modules Placed in series are called strings•What is a Panel????

Array

Combiner•Combine Strings in Parallel•NEC required fuse

Array

InverterConverts DC into AC

Array

ARRAY

MODULE

STRING

CELL

Inverter

Combiner

Array

Advances•Manufacturing Standards•Implementation Standards•MPPT Tracking•Balance of Systems•Inverter Improvements

Energy

Solar Power as a Generating SourceReasonsIncreasing Energy DemandEnergy IndependenceDistributed Generation

ChallengesGrid PenetrationCostPermitting Transmission

Energy

Improvements

IEEE 1547– Allow low voltage ride through– Inverters can be Stabilizing– Transmission – Smart Grid– Energy Storage “Arguing with an Engineer is

like wrestling with a pig in the mud, it doesn’t take long to figure out the pig likes it.”

Questions