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Real Prospects for Energy Efficiency in the United States
TABLE F.3 Electricity Used Annually by a Typical Home and Generated by a 500 Megawatt Power Plant
A Typical Annual Use
D Electricity Use in Units of 1 Million Homes
1 typical home
1 million typical homes
Typical power plant (½ GW × 5,000 hours per year)
are roughly proportional to primary energy, although the cost per Btu would vary among fuels.
Using Table F.2 (Primary Energy)
With respect to the use of Table F.2, suppose one learns that low-energy (low-E) windows are saving 1 quad per year (1 quad = 1015 Btu, or 1 quadrillion Btu), which is about 1 percent of total U.S. energy use. One can use Column C of Table F.2 to divide by 1 million cars.
Similarly one could calculate 5 million equivalent homes or 38 power plants avoided.
Using Table F.3 (Electricity)
Suppose one learns, however, that the 2001 refrigerator standard will save 30 billion kWh, or 30 TWh, annually. In this case, Table F.3 indicates that a typical power plant sells 2.5 billion kWh per year (or 2.5 TWh), so it can be seen that as a result of the standard 12 power plants are avoided. Likewise, according to Table F.3, 1 million homes use 12 TWh, and so the standard has freed up electricity to supply 2.5 million homes.
But as is noted above, for every 100 Btu of electric energy, homes use another 50 Btu of fuel, so there has not been enough energy and pollution saved to offset 2.5 million homes, but only about 1.7 million.2
This 1.7 million home offset can be checked by converting 30 TWh to trillion Btu (using the grid’s heat rate of 10,500 Btu/kWh) and then using Table F.2.