This is typically due to the type of generation tied to the REC. REC’s sold locally are more likely to be solar or wind, while national REC’s are more likely to be less sustainable forms.
The type of generation also influences REC value. Solar RECs are usually the most expensive and sought after, followed by wind. In many cases, Solar RECs, or SRECs will be created by State Government’s to allow organizations to access specific tax carve outs for Solar & Solar related projects. For more information on SRECs check out this article from the EPA:
State Solar Renewable Energy Certificates
Next is biofuel, energy produced from renewable natural gas (RNG) or biomass like wood chips and landfill gas. “Any source” is the least expensive option, but is most likely landfill gas or trash-burner RECs, which are the least sustainable and might not look good on your report.
Green-e certified RECs are also more valuable, as they meet certain quality requirements:
- proof that the energy source is a renewable generator connected to the grid
- it is less than 15 years old
- has been properly tracked and retired (once purchased, RECs are retired so they aren’t accidentally double-counted).
As Vice President of Renewables Origination & Partnerships at Transparent Energy, David Braun, says, the most important thing to understand is why you’re buying RECs: “Want to support local renewable projects and job development or impact the environment in your area? Pay more for an in-state REC. Want to green your energy purchase at the lowest cost? Consider buying low-cost National RECs. Looking to highlight your greening efforts in your corporate sustainability report? Shop the market for RECs tied to the kind of renewable projects you want to align your brand with and trumpet to your investors, employees, and other stakeholders.”