In the U.S., the Public Utility Regulatory Policy Act (PURPA) dictates that electric utilities on the traditional power grid must purchase the excess electricity that renewable energy systems generate.
Net metering is a process by which a single, bidirectional meter spins forward to track the electricity a seller takes from the grid and backward to meter the excess energy they produce. If you've taken out more electricity than you've produced at the end of the month, you'll owe the power provider the retail rate for that excess. However, if you've put in more than you've drawn from the grid, the power provider will pay you the retail instead of the wholesale rate for that excess energy.
RECs are certificates issued by the government establishing ownership of renewable energy. One REC is issued for every 1,000 kilowatt-hours (kWh) of energy funneled back into the grid.
http://www.bayareacensus.ca.gov/counties/SanFranciscoCounty.htm
Total Households in SF 2010 = 345,811
http://www.bayareacensus.ca.gov/cities/Oakland.htm
Total Households in OAK 2010 = 153,791
TOTAL = 499,602
AVG US HOUSEHOLD = 957 kWh per month = 11.484 MW per year
499,602 HOUSEHOLDS TOTAL * 11.484 MW = 5,737.4 GW
EIA Data Browser
https://www.electricchoice.com/electricity-prices-by-state/
https://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a
12.73 cents per kWh average U.S.
17.36 cents per kWh average for state of California
1 GW = 1000 MW 1 MW = 1000 kW
1 MWh = $173.6 AVG.
1 MWh = $332.895 PEAK
1 GWh = $173,000 AVG.
1 GWh = $332,895 PEAK
TIER 1 18.2 cents per kWh base * 1.1813 17.3600 cents
TIER 2 21.5 cents per kWh base * 1.1813 20.5074 cents
TIER 3 27.4 cents per kWh base * 1.5055 26.1355 cents
TIER 4 34.9 cents per kWh base * 1.9176 33.2895 cents
