Green electricity sources generated from renewable sources are sent to the grid. The percentage of green electricity available on the grid constantly varies. On a no wind or a cloudy day, for example, less green energy is being generated. Due to these variations the percent of available green electricity may have been 12 percent yesterday and 4 percent today. The percent green can also varies based on where you are on the grid. Your neighbor that has signed up for 100 percent green energy is getting the exact same percent green energy as you are. The difference between the amount of green electricity that is currently available and 100 percent green is accomplished by purchasing Renewable Energy Certificates.
According to Wikipedia Green credits are:
Renewable Energy Certificates (RECs), also known as Green tags, Renewable Energy Credits, Renewable Electricity Certificates, or Tradable Renewable Certificates (TRCs), are tradable, non-tangible energy commodities in the United States that represent proof that 1 megawatt-hour (MWh) of electricity was generated from an eligible renewable energy resource.
These certificates can be sold and traded or bartered, and the owner of the REC can claim to have purchased renewable energy. According to the U.S. Department of Energy's Green Power Network, RECs represent the environmental attributes of the power produced from renewable energy projects and are sold separate from commodity electricity. While traditional carbon emissions trading programs promote low-carbon technologies by increasing the cost of emitting carbon, RECs can incentivize carbon-neutral renewable energy by providing a production subsidy to electricity generated from renewable sources. It is important to understand that the energy associated with a REC is sold separately and is used by another party. The consumer of a REC receives only a certificate.
In states that have a REC program, a green energy provider (such as a wind farm) is credited with one REC for every 1,000 kWh or 1 MWh of electricity it produces (for reference, an average residential customer consumes about 800 kWh in a month). A certifying agency gives each REC a unique identification number to make sure it does not get double-counted. The green energy is then fed into the electrical grid (by mandate), and the accompanying REC can then be sold on the open market.
By purchasing green energy, customers will support currently available renewable resources as well as help the development of new renewable resources. By making simple choices, we can contribute to the reduction of pollution, and together we can make a difference.
Not only will you feel better about your contribution to saving our planet, there are many widespread benefits of green energy.