Introduction to Grid-Connected Photovoltaic “Core Principles – Before You Begin”

1. Introduction to Grid-Connected Photovoltaic “Core Principles – Before You Begin”

2. The Basics – Before Equipment • Why Photovoltaic (PV)? • Grid Connected PV Systems – “What they look like” • Separating Hype from Reality – “Understand the difference!” • Who’s Involved – “There are more people involved in all this than you think!” • Terminology – “Process vs. Equipment”

3. Why PV? • Renewable Energy in Support of Traditional Utility Infrastructure • Reduces Load on Grid • Generation at Point of Consumption • Reduces Traditional Energy Dependencies • Environmentally Sound Energy Source • “Locks In” Electricity Cost Up Front • Initial Investment = “Pre-Paid Electricity” • Hedge against Future Electric Rate Increases

4. The Basic System

5. GC PV & The Real World – Separating Reality from Hype • “Solar is THE answer”– Hype. It is definitely “Part of THE energy answer”, but it may not work appropriately for all situations. • “Every kW PV installed produces the same energy as one average Home”– Hype. Just as each person is different, so are our energy needs…. Oh, and the Weather! • “It’s Free Energy” – Hype. The Sun’s energy may be free, but the only “free” way to convert it to something useful is getting a SUNTAN!

6. GC PV & The Real World – Separating Reality from Hype • “It doesn’t matter where you put it because it’s the right thing to do” – Hype. It isn’t “right” if it doesn’t work! • “If the Government just put more money into it it would be fixed in ‘X’ years” –Double-edged hype. They need Justification to continue. Responsible Siting, System Design, & Installations can remove a big part of the “Double Edge” by providing that justification.

8. Sorting It All Out • THERE ARE RULES TO FOLLOW! • “One Size” Does NOT Fit All! • Suitable Site Critical • Electrical Usage • Technology & Equipment • Utility Company • Building Department • Cost • Incentives & Tax Credits • Other?

9. Who is ALL? The “Bank” Environment Neighbors Utility Company Customer Building Department Equipment Manufacturers Contractor Site & Sunshine

10. The Language of PV Pay Attention! Things may not be what they seem and not everybody speaks the same language!!!! • “Equipment” vs. “Process” Terminology • Multiple Technologies & Applications • “Laboratory” vs. “Real-World” • Understand “What you’re buying” • CEC Equipment Lists http://www.consumerenergycenter.org/cgi-bin/eligible_pvmodules.cgi http://www.consumerenergycenter.org/cgi-bin/eligible_inverters.cgi

11. Key Process Related Definitions • DG – Distributed Generation. Electrical generation located at the site of consumption. • Generator – As related to process; Entity owning and operating on-site generation facility. • Grid – Network of Infrastructure for the Generation, Transmission, & Distribution of electricity. Operated by Utility Companies, 3rd Party Providers & Regulatory Agencies. • Interconnection – Parallel connection to the Grid. Requires Utility approval.

12. Key Process Related Definitions • kW– Kilowatt. 1,000 watts. Measurement of Power in terms of Generation Capacity or Load. • kWAC – AC peak power rating of PV system after de-rating factors are calculated. • kWDC – DC power rating of PV system. May be stated in terms of STC (Standard Test Conditions) or PTC (Performance Test Conditions). • kWH – Kilowatthour. 1,000 Watthours. Measurement of Power Generated or Consumed over time. This is “how you buy your electricity” from the Utility Company. (Equal to 1000 Watts continuous for 1 hour or 100 Watts coninuous for 10 hours.)

13. Key Process Related Definitions • kWDC – DC power rating of PV system. May be stated in terms of STC (Standard Test Conditions) or PTC (Performance Test Conditions). • kWH – Kilowatthour. 1,000 Watthours. Measurement of Power Generated or Consumed over time. This is “how you buy your electricity” from the Utility Company. (Equal to 1000 Watts continuous for 1 hour or 100 Watts coninuous for 10 hours.) • Net-Metering– Allows excess energy produced by grid-tied PV systems to flow in reverse, back through the utility meter, and "banked" for later use. Energy generated is valued at “retail”. $$$ value depends on electric service rate of account. Reconciled or “settled” annually in CA.

14. Key Process Related Definitions • PV Production – Electricity generated by a PV System. May be stated in terms of kW (Point in time power) or kWH (Power produced in a given period of time). • Production Based Incentive – (PBI) Distribution of incentive funds based on actual kWH production of PV system. Not yet effectively deployed in the US. Stay tuned! This is where it “all” has to go if it’s gonna work for the future…

15. Key Process Related Definitions • PTC – Performance Test Conditions. Testing standard for modules that was developed to more closely represent conditions likely to be found in the field. 1000 W/M2, 20°C Ambient Temp. (AKA – PVUSA Test Conditions) • STC – Standard Test Conditions. Laboratory testing standard for modules. 1000 W/M2, 25°C Cell Temp. “Nameplate Rating” of Module or Array. Manufacturers advertise and sell modules based on this value. (AKA – Peak Power Rating)

16. Key Equipment Related Definitions • AC – Alternating Current. Form of electricity supplied by Utility Company. • DC – Direct Current. Form of electricity generated by PV modules. • Combiner – Circuit Termination Equipment that connects multiple PV Source Circuits, generally in Parallel. Has fuses or breakers for overcurrent protection of individual circuits.

17. Key Equipment Related Definitions • Disconnect – Switch. Turns electrical circuit on & off. • Inverter – Converts DC to AC. • Module – An individual assembly of PV cells. Often called a “panel” by unfamiliar folks. • Panel – A Mechanically connected assembly of Modules.

18. Key Module Specification Related Definitions Pay Attention! Things may not be what they seem and not everybody speaks the same language!!!! • Voc – Open Circuit Voltage at STC. • Vpeak – (Vmpp) Voltage at Maximum Power Point at STC. • Isc – Short Circuit Current (Amps) at STC. • Ipeak – (Impp) Amperage at Maximum Power Point at STC.

19. Key Module Specification Related Definitions Pay Attention! Things may not be what they seem and not everybody speaks the same language!!!! • Max Power – (Wpeak) Watts at STC. • Max DC Short Circuit Current – Maximum Array Isc at STC. • UL 1703 – Standard for establishing safety related suitability of “flat plate photovoltaic modules”.

20. Key Inverter Specification Related Definitions Pay Attention! Things may not be what they seem and not everybody speaks the same language!!!! • DC Voltage Range – Minimum to Maximum DC Voltage Input for the Inverter to operate. Array must be electrically connected to provide voltage in this range. • Output Power – Rated AC output capacity in Watts. • AC Voltage Range – Minimum to Maximum AC Voltage Input for the Inverter to operate. Grid Voltage. • Efficiency – Efficiency of the DC-AC conversion in terms of watts. Ratings are based on “X” % of capacity.

21. Key Inverter Specification Related Definitions Pay Attention! Things may not be what they seem and not everybody speaks the same language!!!! • Maximum Input Current – Maximum current of the Array at Max Power Point. • Max DC Short Circuit Current – Maximum Array Isc. • UL 1741 / IEEE 929 – Standards for establishing suitability for Grid Connection of the Inverter.

22. Key Secondary Component Related Definitions • BOS – Balance of System. Equipment & hardware required to build a PV system other than Modules & Inverters. • AC Disconnect – Switch in the AC Circuit. Disconnects AC source from Inverter. May be integral or external to Inverter. Multiple AC Disconnects are often required. • DC Disconnect – Switch in the DC Circuit. Disconnects DC source from Inverter. May be integral or external to Inverter.

23. Key Secondary Component Related Definitions • PV Meter – Generation meter. Measures output of PV System over time. AKA – REC Meter • Rack – Framework supporting and mechanically connecting Modules.