Renewable energy

Renewable energy is generated from naturally replenishing sources, such as solar and wind, unlike finite resources like fossil fuels.

Electricity from renewable sources produces little to no emissions, helping to maintain cleaner air and a healthier environment.

By increasing our use of local renewable energy on Nantucket, we reduce our demand on electricity from the grid, which can help lower overall costs for the community, while supporting long-term energy sustainability and resilience.

Increased renewable energy generation will help to “green” the local electric supply and reduce summer peak load and costly capacity charges, resulting in lower electric supply and distribution costs for Nantucket electric ratepayers, specifically those participating in Nantucket PowerChoice.

Your participation advances local renewable energy investments!

Program prices include an extra 0.1 ¢/kWh that directly supports local renewable energy investments.

  • Nantucket PowerChoice directly supports the Nantucket Local SOLAR Rebate Program, which provides up to $10,000 to program participants who install solar on their primary Nantucket properties. To date, the program has provided over $800,000 in financial support for 165 solar installations, adding nearly 1.5 megawatts (MW) of solar power to Nantucket's electric grid.
  • Nantucket PowerChoice purchases RECs generated by the Nantucket High School wind turbine. Our program has purchased 1,726 RECs (the equivalent of 1,726 megawatt-hours [MWh] of electricity) generated by the Nantucket High School wind turbine, greening our electricity supply and contributing $55,600 directly to Nantucket Public Schools.
  • Participants in the PowerChoice Green option do even more. When you choose PowerChoice Green, 100% of your electricity comes from solar projects in New England. Buying solar from New England creates demand for new renewable energy projects on our local grid and supports our local solar industry and the jobs that go with it.

Program renewable energy content detail

  • PowerChoice Standard provides the minimum amount of your electricity from renewable sources required by law.
  • PowerChoice Green provides 100% of your electricity from renewable sources.

Buying renewable energy refers to the purchase of Renewable Energy Certificates (RECs). What are RECs?

Electricity from renewable sources (% of total)

Renewable energy source Power Choice Standard Power Choice Green National Grid's Basic Service
From new, renewable sources in the New England region (MA Class I RECs), required by state law 30% 30% 30%
From new, renewable sources in the New England region (MA Class I RECs), added by Nantucket* – 70% –
Total** 30% 100% 30%

* Under the 2026–2027 electricity supply contract, the renewable energy certificates (RECs) purchased voluntarily over and above minimum state requirements will come exclusively from solar projects in New England.

** In addition to purchasing the renewable energy shown in the table, the program’s electricity supplier is required by state law to purchase renewable energy certificates (RECs) from other sources, including sources that are not new, are renewable but not clean, such as waste to energy, or are clean but not renewable, such as nuclear. This purchase must match 39% of participants’ total electricity use and must be made even if the total amount of RECs purchased exceeds 100% of the electricity used by Nantucket PowerChoice participants.

What does it mean to buy renewable electricity / what are RECs?

Unless you have a renewable energy system, such as solar panels, plugged directly into your home or office, you cannot purchase the specific electricity that is generated by a renewable energy project. The electricity flowing through the grid is a comingled mix of electricity generated by renewable energy projects as well as electricity generated by burning fossil fuels.

As a result, a separate accounting system has been created to keep track of renewable energy and allow it to be bought and sold. That system uses renewable energy certificates, or RECs. Every time a renewable energy project generates 1 megawatt-hour of electricity, 1 REC is minted. That REC can then be sold. Purchasing a REC gives you, and no one else, the right to say you used the electricity from that renewable energy project.

Anyone who wishes to purchase renewable electricity must then purchase 2 things (these two costs are often bundled together, which is why renewable energy costs a bit more):

  • the electricity itself from the grid
  • RECs that equal the amount of electricity they wish to claim as renewable

You can buy as many RECs as you wish

  • You can buy a small number of RECs so you can say that a part of the electricity you use is from those renewable sources.
  • You can buy enough RECs to exactly equal the amount of electricity you use, so you can say that all of the electricity you use is from those renewable sources.
  • Or you can buy RECs that equal more than the amount of electricity you use if you want to build extra demand for renewable energy.

Buying RECs provides an important source of revenue for renewable energy developers. Voluntarily buying more RECs than are required by state law signals to developers that there’s a market for more renewable energy locally and provides a motivator to build more.

Participants in the Nantucket PowerChoice Green option buy enough MA Class I RECs (see below) to equal 100% of the electricity they use.

What are MA Class I RECs?

MA Class I renewable energy certificates (RECs) are from renewable energy projects located in the New England region that began commercial operation after 1997, generate electricity using any of the following technologies, and meet all other program eligibility criteria:

  • Solar photovoltaic
  • Solar thermal electric
  • Wind energy
  • Small hydropower
  • Landfill methane and anaerobic digester gas
  • Marine or hydrokinetic energy
  • Geothermal energy
  • Eligible biomass fuel

Under the 2026–2027 electricity supply contract, the renewable energy certificates (RECs) purchased voluntarily over and above minimum state requirements will come exclusively from solar projects in New England.