1. Boxborough and Littleton Solar Program Training 5/15/15 Arnie Epstein – “Solar Coach” Stow Solar Challenge arnold.epstein@comcast.net

2. Solar in MLP versus IOU Communities

3. MLP’s versus IOU’s Areas serviced by MLP’s can’t participate in Solarize Mass Unless your MLP opts in to the RET MLP’s policy for residential and commercial solar is different From IOU’s IOU solar policy set by the state IOU’s serve 85% of the state’s population From each other Each MLP can set their own solar policy Hudson Light & Power’s policy is different from Littleton Light Differences Financial options – leasing and PPA’s may not be allowed Credit for electricity fed back to the grid Net metering or other policy. Hudson Light & Power doesn’t offer net metering Rebates and rebate requirements – if any Don’t anticipate “special” treatment for a community solar initiative Participants in Stow Solar Challenge treated the same as any other solar installation by our utility.

4. Solar PV Basics

10. Good Site A good site should be 80% of optimal or better Optimal: 42 degrees tilt, 180 degrees azimuth, no shade from 9:00 AM to 3:00 PM Optimal about 1.2 kilowatt-hours per watt of solar per year. A good site can have a wide variation from optimal High tilt 91% of optimal: 65 degree tilt, optimal azimuth, no shade West facing 92% of optimal: 42 degrees tilt, 130 degrees azimuth, no shade

11. Solar Panels Standard: Canadian Solar 250 watt IsoPhoton 250 watt (US Made) 10/25 Year warranty Standard Power Density: ~14.2 watts per ft 2 17.75 kWh/ft 2 /year High efficiency: Sunpower 327/335/345 US Company 25/25 Year warranty High Power Density: >18.6 watts per ft 2 25.1 kWh/ft 2 /year

12. Roof Attachment

13. Inverters – Convert DC from Panels to AC String inverters Convert the output of a number of panels Typically mount near electrical panel Cost somewhat less Shade on one panel can impact performance of all panels connected to the inverter Shorter warranty – usually 10 years Microinverter One per panel Mounts on railing under panel Shade on one panel will impact only that panel. Longer warranty – 25 years More difficult to replace.

14. Snow on Panels Just leave it Snow slides off panels before rest of roof Not usually a significant loss of output – winter sun Last winter was an exception Weight of snow and panels Concern when large sheets slid of panels Some residents had snow cleared

15. Solar During Power Outage and Solar Storage During power outage, solar system will automatically disconnect To insure no power on grid during repair Very few grid connected residential solar systems include storage Expensive No financial advantage if net metered

16. Common Adders

17. Financials and Incentives

18. Now is the Time to Install Solar 30% federal tax credit expires at the end of 2016 Unlikely a new federal tax credit will be as generous SREC and net metering policy is likely to change Net metering task force report submitted Very unlikely existing installations will be impacted – “grandfathered” For Littleton and Boxborough net metering policy determined by Littleton Light. But may be influenced by net metering policy at state level SREC policy determined at state level. Discounted pricing from community solar program Lock in cost of electricity

19. Additional Financial Benefits of Solar $1,000 Mass tax credit 20 year property tax exemption Increased property value Accelerated depreciation for commercial sites

20. SRECs Solar Renewable Energy Certificate Electricity utilities in Massachusetts are required to secure a portion of their electricity from solar generators. An SREC represents the “solar” aspect of the electricity that was produced NOT the electricity itself. SRECs apply to all solar production, including electricity you use and electricity sent to the grid. SREC’s are sold to utilities so they can meet their solar requirement

21. SREC Value SREC’s can be sold quarterly for a period of 10 years (40 quarters). An SREC is 1,000kWh of solar generation. A 5,000 Watt system = ~5-6 SRECs per year. The value of the SREC is determined by the market. The supply is determined by the number of solar installations. producing SRECs in MA. Utility SREC requirement increases each year (about 30%) following a formula that takes into account previous year’s supply. Currently working under SREC II Somewhat lower price than initial SREC program (SREC I) Value has continued to be strong – well over $200 per SREC

22. How do SRECs work? At contract you up with an SREC broker (aggregator). Install production meter. Receive a check in the mail every 3 months, for 10 years, for your solar generation. First check is about 7 months after the system goes live.

23. Net Metering Credits generated when system is producing more than is being used on- site “Meter runs backwards” Receive credits at full retail rate of electricity.

24. Financials A number of variables Price of installation Siting of solar panels Price of electricity Price of SRECs Utility policy for electricity fed back to the grid Tax credits Terms of loan – if any Price of SRECs and electricity outside of installers control Installer will not guarantee ROI Many installers will guarantee minimum production

25. Example Assumptions 5 kW system $3.50 per watt system cost Good siting No loan $200 SREC Net metering $0.11 kWh with 3% annual increase 7 year payback

26. More Information Sustainable Stow site http://sustainablestow.org/stow-solar-challenge/ Stow Solar Challenge facebook page https://www.facebook.com/stowsolarchallenge Email arnold.epstein@comcast.net