Find out how much energy you currently use.
Before you buy clean energy, it's important to first reduce your electricity use as much as possible, at home and at work. There are many easy things you can do right now to become more efficient and reduce your energy consumption, and you should do those first.
Once you've gone on an energy "diet" and reduced your usage as much as possible, you can buy clean energy from resources like wind, solar, geothermal, and biomass for the rest. The first step is finding out how much you currently use—this can be most easily done by looking at your monthly statement from your utility or electric service provider. Your monthly electricity usage will usually be expressed in kilowatt-hours (KWh). Nationwide, the average monthly household use for residential customers is typically a little more than 900 kWh (see the U.S. Energy Information Administration’s Frequently Asked Questions – Electricity page for more information), but can be more in summer and winter months when air conditioners and heaters are in use.
For Step 1: Get an idea of your annual electricity use by multiplying your monthly kWh by 12. To get a more accurate figure that accounts for seasonal changes, refer to your statements from all of last year. Once you have your yearly electricity usage, you know how much clean energy you need to buy.