Definitions

The list below includes terms frequently used when discussing aggregation, electricity, and renewable energy.

Basic Service

When your electric utility, Eversource, is also your electricity supplier, you have a service called Basic Service. The Basic Service price is the price Eversource uses to calculate the Supply portion of your electric bill. Eversource’s Basic Service prices change seasonally. If you sign a contract with an electricity supplier on your own or you participate in an electricity aggregation, such as Lexington’s Community Choice Program, Eversource will continue to deliver your electricity, but they will no longer be your electricity supplier, so you will no longer have Basic Service.

Clean electricity

Clean electricity is electricity that is generated by a renewable energy resource that does not generate pollution or emissions, such as the sun or the wind, and not by burning fossil fuels like gas, oil, or coal.

Electricity delivery (sometimes referred to simply as delivery, and also as distribution)

This term refers to the service of delivering electricity to you through poles and wires, and also to the maintenance of that electricity delivery infrastructure. Electricity delivery charges appear on the Delivery portion of your electric bill. Electricity Delivery charges do not include the cost of the electricity itself. Those charges appear on the Supply portion of your electric bill.

Electricity supplier

An electricity supplier is a company that buys electricity on your behalf. The price that your electricity supplier charges appears in the Supply portion of your electric bill. In Massachusetts, you can choose who your electricity supplier is:

Your electric utility, Eversource, can serve as your supplier. In that case, you have Basic Service. Eversource buys electricity for you and uses their own Basic Service price to calculate the Supply charge on your electric bill.
You can select an electricity supplier on your own. In that case Eversource only delivers electricity to you, and they use the price provided by your electricity supplier to calculate the Supply charge on your electric bill.
Your municipal government can establish an electricity aggregation and, with that program, your Town can select an electricity supplier for you, as with Lexington’s Community Choice Program. In this case, Eversource only delivers electricity to you, and they use the Lexington’s Community Choice Program price to calculate the Supply charge on your electric bill.

Electricity supply (sometimes referred to simply as supply)

This term refers to the electricity that is delivered. Electricity Supply charges appear on the Supply portion of your electric bill. Your electricity Supply charge is calculated by multiplying the amount of electricity you use (in kilowatt hours) by a price. Your electricity Supply charge does not include charges for the delivery of the electricity or for the maintenance of electricity-related infrastructure. Those charges appear on the Delivery portion of your electric bill.

Green electricity

Green electricity is electricity that is generated by a renewable energy resource, such as the sun or the wind, and not by burning fossil fuels like gas, oil, or coal.

Renewable energy

Renewable energy is energy generated by sources that can be renewed as opposed to sources that can be used only once, such as fossil fuels. Under Massachusetts state law, a variety of resources qualify as renewable. The main sources of renewable electricity are solar, wind, and small hydroelectric projects. Renewable electricity is electricity that is generated by renewable energy projects and is sometimes referred to as “green” or “clean” electricity. Renewable energy sources do not create air pollution or emit the gases that cause climate change.

Renewable energy certificates (RECs)

RECs are a method of keeping track of renewable electricity. One REC is minted for every 1 megawatt-hour of electricity generated. RECs are tracked in a central database known as the NEPOOL GIS (generation information system). Electricity customers who wish to be able to say they are purchasing renewable electricity from the grid can pay for RECs in addition to paying for the electricity they use. Purchasing RECs gives an electricity customer the right to say they have used the electricity generated by renewable energy systems. Once a REC is purchased, it is then retired so that no one else can purchase it and lay claim to having used the same renewable energy.

Renewable portfolio standard (RPS)

The RPS is a minimum amount of renewable energy that is required by law in the electricity sold in a state by the utilities and other electricity suppliers. Massachusetts has an RPS, as do many other states. An RPS specifies both the amount and type of renewable energy that must be included. Because of the Massachusetts RPS, all electricity sold in the state includes a minimum amount of renewable energy. Massachusetts also has an APS, an alternative portfolio standard, which requires that all electricity include a minimum amount generated by alternative energy sources, which are typically highly efficient but not renewable. Read more on the Massachusetts DOER website.

Opt down

To opt down within Lexington’s Community Choice Program is to change to a program option with less renewable electricity or a lower price.

Opt out

To opt out of Lexington’s Community Choice Program is to leave the program and instead receive your electricity supply from a competitive supplier or through Eversource’s Basic Service. You have the right to participate in the program for as long as you like and to opt out at any time with no penalty or fee.

Opt up

To opt up within Lexington’s Community Choice Program is to change to a program option with more renewable electricity or a higher price.

Utility

In Massachusetts, an electric utility is an electricity delivery, or distribution, company. Electric utilities do not generate electricity, but instead purchase it on your behalf, if you are not already using a competitive supplier. They are responsible for delivering electricity. You have no choice in your electric utility as they have geographic monopolies. In Lexington, your electric utility is Eversource.