On average, a house fueled by natural gas is responsible for about one-third fewer greenhouse gas (GHG) emissions than a comparable all-electric home.
Why? Let’s take a look at what’s called the full fuel cycle, which accounts for how much energy is retained – or lost – from an energy source until its final use in your water heater, oven, or home heating system. With the full fuel cycle in mind, natural gas’s direct use comes out as a winner in the energy efficiency race. For example, by the time you turn on an electric appliance, up to 68 percent of the original fuel’s energy value has been lost. That means the full fuel cycle efficiency is about 32 percent. By contrast, a natural gas appliance’s full fuel cycle efficiency is about 92 percent – a substantial difference. More efficient use of fuel means less energy loss and less that needs to be produced, which reduces GHG emissions.
The graphic illustrates the efficiency of natural gas and electricity on a full fuel cycle basis for 100MMbtu (100 million British Thermal Units). A Btu is a measure of the energy content in fuel expressed by the heat required to raise the temperature of one pound of water by one degree Fahrenheit at a specific temperature and pressure. One Btu equals 252 calories, 778 footpounds, 1,055 joules, or 0.293 watt-hours. One cubic foot of natural gas contains about 1,027 Btus.