- LEARN where it comes from
- UNDERSTAND the environmental impacts of using it
- EXPLORE what you can do to reduce your consumption of it
the power behind our lives
It is undeniable that electricity is a necessity of daily life. It is pervasive in everything we do, from running our appliances to lighting our homes to fueling our entertainment and communications with the outside world.
Unlike other resources we consume, however, the true impacts are unseen. When you turn on the stove, you hear the sound of the flame; turning on a tap, cool clear water flows out; but electricity? In many cases, your appliances sit there, connected and using power, without any sign that something is happening.
Tens, hundreds or even thousands of miles away, that power is coming from somewhere. Depending on where you live, your electricity could come from the dirtiest of coal plants, a hydroelectric dam that doesn't contribute to pollution but reduces the native fish that live in a river, or a truly renewable source of energy such as wind or solar power. The impacts aren’t as visible or as local as those from other forms of energy use, but they can be every bit as large. In certain areas of the country, the carbon dioxide emitted by using electricity in the home can exceed that produced by two cars driving 12,000 miles each.
To learn about the environmental impacts of your electric supply and how you can reduce them, read on.
sources of electricity
Most electricity is produced by using some fuel to turn large generators connected to turbines. In the past, this was done either by burning a fossil fuel such as coal or oil to generate steam (which turned the turbine), or turning the turbine using moving water passing through a dam. After World War II, plants employing nuclear reactions and natural gas to produce steam were also built.
More recently, utilities have introduced other ways to generate power. High tech windmills generate electricity in windy areas, and various kinds of solar power plants have been built in sunny areas. Solar electric plants generally come in two types: some that use the heat of the sun to produce steam (and then turn turbines or other generators), and those that directly convert the sun's energy into electricity using photovoltaic cells.
Get more information on solar photovoltaic, or PV
Another option for generating electricity has also emerged: distributed, or self-generation. Through this model, homeowners and businesses install equipment to generate electricity at their own location, and in some cases even sell the excess back to the electric utility. There are many technologies available to do this, but the most common are solar PV, wind turbines, and the use of small natural-gas powered systems called microturbines.
Today, all of these technologies are employed to generate power across the US. Most of our power still comes from the traditional burning of fossil fuels, with the largest amount coming from the dirtiest source, coal (see chart at left)1.
environmental impacts - greenhouse gases
The primary environmental impact of electricity consumption is the production of greenhouse gases that contribute to global warming. In 2004, 40% of the US total emissions of greenhouse gases was from electricity generation2, and 35% of this was from residential use (higher than the electricity-related greenhouse gases from either industrial or commercial use). Doing the math, this means that the electricity that we consume in our houses represents almost 15% of the US total greenhouse gas emissions.
Where you live in the country is the key driver of how much greenhouse gas (primarily carbon dioxide) you create by using electricity. In North Dakota, Wyoming and Kentucky, coal is the primary fuel used in generating electricity. As a result, residents of these states contribute over 2.2 pounds of carbon dioxide for every kilowatt-hour of electricity used on average. Assuming the national average for electricity use of 10,656 kWh a year, a household in one of these states would emit over 10 tons of carbon dioxide per year. For comparison, this is as much as driving a car that gets 20 mpg a distance of 23,000 miles – nearly around the world.
On the other extreme are states like Vermont, Idaho and Washington. These states rely on either nuclear (Vermont) or hydroelectric (Idaho and Washington) power, and on average produce less than 0.3 pounds of carbon dioxide per kilowatt-hour of electricity – less than 15% of that produced by the states mentioned earlier.
The implication is that where you live is the key to deciding whether cutting electricity use should be a prime step in reducing your impact on global warming. To help, Low Impact Living has divided states up into three categories depending on how much power generation contributes to global warming. For reference, the US average across ALL power plants is 1.39 pounds of carbon dioxide per kWh of electricity produced. In a year, the average US household releases as much carbon dioxide using electricity as they would driving an SUV over 12,000 miles.
1 http://www.eia.doe.gov/cneaf/electricity/epa/generation_state.xls
2 http://yosemite.epa.gov/oar/globalwarming.nsf/UniqueKeyLookup/RAMR6MBLNN/$File/06Trends.pdf
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