Grid-Connected Solar PV Systems

1. Grid-Connected Solar PV Systems Shawn Murphy September 29, 2011

2. Outline • Solar Photovoltaics • Electricity Generation, the CEC and PUC • Silicon Solar Cell production • Technical challenges of grid-tied solar • Grid-tied issues • Permitting and Rebates • Net Metering • Design issues • Solar Engineering as a Career • General class recommendations • Training on solar PV

3. Conventional Energy Generation

4. Electricity Storage There is no good way to store electricity Batteries Peak energy is more expensive and more polluting Energy produced during high demand periods is more valuable

6. The CEC and the PUC • California Energy Commission • Founded early 70’s • CEC goals • Generate power using alternative means • Generate power during peak hours • Public Utilities Commission • Regulate public utilities like PG&E, SCE and SDG&E • Tells utilities what they can charge for electricity • Decoupled utility profits from electricity generation

7. Solar Photovoltaic Panels Similar process as semiconductor manufacturing. Conventional silicon still dominates market

8. Monocrystalline Silicon Poly or multicrystalline Silicon

9. On-Grid Solar Much simpler than battery-based system. Grid serves as free, infinitely-large, no-maintenance battery System sizing not as crucial Can be designed to maximize yearly annual electricity generation. Does not have to be optimized for winter production. Can operate at much higher voltages, saving power losses.

23. Grid Connected Solar PV Meets the state’s goals • CEC goals • Generate power during peak hours • Generate power using alternative means • Grid connected solar photovoltaic • Maximum generation during sunny summer days • Distributed generation • Uses existing spaces • Very quick deployment

24. Technical Issues with Grid-Connection Power Quality Safety Connection to Existing Equipment

25. Grid Connected Solar How do you keep track of the power? How much do you pay for the power? How do you take into account when the power is produced? How do you determine the rebate amount? How do you incentivize grid-connected solar at the proper amount over time? How often do you read the meter? Who inspects the system?

26. Net Metering & Interconnection One single meter that spins forward and backwards. Meter can take into account time of use rates Annual true-up Minimum monthly meter fee, $4 to $13, charged by utility

27. Rebates and Incentives • Tax Credits and deductions • 30% FITC • MACRS depreciation • Various state tax breaks • Renewable Energy Credits • State Rebates • California Solar Initiative • Declining schedule – based on expected performance

28. Economic EvaluationSolar Offsets Electricity Use • Must know how much a customer is paying for electricity • How do you compare one-time cost of a solar system versus the value of lower electricity bills in future years? • Engineering economics • Payback • Net Present Value • Internal Rate of Return

36. Recommended Classes • Engineering Economics • Accounting • Technical Writing • Public Speaking • Engineering Statistics • Computer Drafting/ CAD • Google Sketchup • Autocad • Solidworks • Pro-E

37. More Solar resources • PG&E Energy Center • Diablo Valley College • Private classes • Solar Living Institute • Solar Power International • Semicon – Intersolar SF July