Solar Photovoltaic Systems Neal M. Abrams, Ph.D. Department of Chemistry SUNY ESF March 7, 2012
Electricity Use and Demand
A Focus on Energy Use! 1.8x10 12 Watts (continuously)! 6x10 9 persons! 3 100W light bulbs per person! U.S. 25% of total! 15 100W light bulbs per person! 36 kwhr/day/person Solar energy 1% Conventional hydroelectric power 45% Geothermal 5% Wind energy 2% Biomass 47% U.S. Energy Consumption
Where are the people? Where is the power? nasa.gov
Current Supplies U.S. Energy Information Administration Annual Energy Review 2009
How Where much are the do we watts? need? Area required for all US electricity production (~100 x 100 miles)
Matching the Need! A 1 kilowatt (1,000 watt) system will generate nearly 1,000 kilowatt hours (kwh) per year of energy in cloudy climates! Average consumer utility bill:! 10,000 kwh/year! Reduce your load!
The Magic in the Panel
The Magic in the Panel! Photons in sunlight hit the solar panel and are absorbed creating a dc source! An array of solar panels converts solar energy into usable DC electricity.! Inverters convert the DC to 60 Hz AC to feed for on grid! Power goes to a charge controller to charge batteries for off-grid e- Cover glass anti-reflective coating front contact n-layer p-layer back contact
Anatomy of PV cell Cover glass e- anti-reflective coating front contact n-layer p-layer back contact
PV System Components! Array Set of PV cells that typically sit on a roof or a pole! Inverter Converts PV DC voltage to AC voltage with very low loss! Batteries Provide backup power for off-grid use! In a net metering system, batteries can still be used for backup power! Electric meter Connects the PV array to the grid to support net metering.! Can spin backwards!
Required Components On Grid! The solar module! Inverter (which translates direct current power to alternating current)! Associated wiring and support structures Off Grid! The solar module! The battery (for energy storage)! The battery regulator (also known as a charge controller),! Attachment structure and associated connections! Wiring
On Grid! The solar module! Inverter (which translates direct current power to alternating current)! Associated wiring and support structures Sunny Boy inverter ETM solar
Off Grid! The solar module! The battery (for energy storage)! The battery regulator (also known as a charge controller),! Attachment structure and associated connections! Wiring ETM solar
Going off-grid Batteries! Rechargeable batteries are most effective energy storage solution! Remaining PV production capacity can be used up by the electrochemical conversion process of the battery.! Battery storage capacity is rated in ampere hours! Most PV systems use lead acid batteries. Nickel cadmium batteries are newer and have very high reliability. Charge Controller! Used to prevent over- and undercharging of the battery.! Typically necessary if the peak charging rate of the solar module is more than 1.5% of the battery ampere hour capacity.! The quality of the regulator is a key factor in the reliability of the overall system. Aligns the depth of discharge with the battery temperature and the rate of discharge.! Monitoring current and voltage throughout the system is important for safety and overall system performance.
Anatomy of a PV Installation
Silicon the benchmark
The Solar Benchmark 32 %! Silicon cells most mature, most developed! 80-90% market share new Apple data center, NC
Photovoltaic types and benefits! Silicon! Single crystal silicon (c-si)! Multicrystalline silicon (mc-si)! Amorphous silicon (a-si)! Thin-film (10-20% market share)! Silicon! Cadmium telluride, CdTe! Copper indium gallium diselenide, CIGS! Very efficient in diffuse light conditions! Dye-sensitized
Efficiency: How high? 35 32.0 % Efficiency 30 25 20 15 10 5 25.0 20.4 16.7 26.4 19.4 16.7 10.1 10.1 10.4 5.2 0
PV development nrel.gov
PV Production Payback! Current silicon PV technology requires 4 years to generate the energy required to produce it.! Newer generation PV cells require only 2 years. Alternatives! Other semiconductors: GaAs, GaInP, CdTe, CIGS! Thin films and amorphous cells! Solar concentrators! Dye-sensitized
Costs and Benefits
Growth! Market is growing! The US on-grid market increased to 914 MW in 2010, a growth rate of 101% over the prior year.! California s share dropped from 51% of the on-grid market, down from 30%, as New Jersey s and Arizona s market sizes soared.! Led the market for >1 MW system sizes with a 31% share! Chinese manufacturers grew their share from 11% to 37% of the US market. (39,000 miles 2 )
The Growing Solar Industry The solar market grew 20% in 2009, in spite of the economic downturn! 1,000,000 900,000 800,000 Silicon Thin film kw of shipped modules 700,000 600,000 500,000 400,000 300,000 200,000 100,000 0 Source: Solarbuzz Year
Module Pricing $7.00 $6.00 $5.00 Cost per watt $4.00 $3.00 $2.00 $1.00 $0.00 Year
Other issues People, places, and politics! Building infrastructure! Permits: Electrical and structural! Neighborhood restrictions! Beauty and the bulb! Finding installers! Maintaining incentive programs
Light, people, and politics! Sunniest place in Germany has 1250 kwh/m 2 per year! Syracuse has 1358 kwh/m 2 per year (horizontal average)! Germany: 8800 MW of PV! USA: closing in on 1000 MW of PV! Germany has 2.47 times as much area of land and water as NY! Population of Germany: 82,422,299! Population of NY: 18,976,457
Is it worth it??? nyserda.cleanpowerestimator.com/nyserda.htm
True Market Drivers (current)! Early adopters! Perceived benefit! Feel good, go green
Getting the Job Done! PV installations require NABCEP certification for NY state incentives, $1.50/watt, max $10,500! NABCEP certified programs offered locally! Federal tax incentives do not require NABCEP certification! Permits required for! Structure! Electrical connection Your Name Here
Is PV the complete solution? Advantages! Vast, renewable, free fuel source! No emissions, no combustion, no radiation! Low operating costs! No Moving parts! High reliability Disadvantages! Diffuse fuel source! High installation costs! offset by financial incentives! Poor reliability of system components (inverters, etc.)! Lack of efficient energy storage! Modular! Point of use capability
Our Ever Leaking Sun When there s a HUGE solar energy spill, we just call it a nice day!