Green buildings (as well as you and I) have the option of buying some or all of their electricity from a green power provider. In this context, green power is renewable energy produced somewhere else and then transmitted to the project site (figuratively). There are dozens of such suppliers in the US, most of which are wholesalers of wind power, some solar power and some biomass, geothermal or low-impact hydro facilities. My own local utility, Tucson Electric Power, sells two packages of GreenWatts power, one 99 % wind and 1% solar, the other 90% wind and 10% solar (at a 20% premium). Tucson Electric Power operates one of the largest photovoltaic (solar electric) power plants in the country, a 5.1-megawatt array capable of producing 7.5 million kilowatt-hours per year of electricity, enough to power 500 Arizona homes.61 I purchase 2,400 kilowatt-hours per year of this power, about 20% of my annual use, for an annual premium of $186, or about 7.75 cents per kilowatt-hour. For commercial users, typical renewable energy premiums are lower, about 2 cents per kilowatt-hour.
In LEED projects, one energy-efficiency point is allowed for purchasing two years' worth of green power from a recognized supplier, provided that the purchase offsets at least 35% of the annual electricity use. The
Center for Resource Solutions' (CRS) Green-e program is used to certify renewable energy sources for the purposes of the LEED credit.62 In 2005 the CRS verified that green power production grew 43% over 2004, to a total of 5.2 million megawatt-hours (5,200 million kilowatt-hours) of renewable energy generation. According to the Center, "Green-e certified renewable electricity products were sold in 48 out of 50 US states, and 215,000 MWh (about 4%) was purchased by companies who contracted to use the Green-e logo to promote their commitment to certified renewable energy."63 In addition to Green-e certified providers, other sources of green power such as Green Tags,64 renewable energy certificates (RECs) and tradable renewable certificates (TRCs) are eligible for LEED project credits if they satisfy the Green-e program technical requirements.
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