RECs vs. Carbon Offsets: What’s the Difference?
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You can play an important part in caring for the environment with every energy choice you make. Simple changes to your habits like switching to energy efficient lights and appliances can help reduce the energy you usebut if you want to do more there are other ways to help. Renewable energy certificates (RECs) and carbon offsets are two additional options to consider.
To get started, you will want to understand the differences between RECs vs. carbon offsets and how they work to contribute to a cleaner environment. Then consider how these options might best work for your situation.
What are Renewable Energy Certificates (RECs)?

Renewable energy certificates, or RECs, support renewable energy generation capacity. A REC is a market-based instrument used for tracking and accounting. A REC is used to distinguish the electricity generated by a renewable energy resource.
When a wind or solar farm delivers energy to the grid, the power system operator measures the megawatthours provided. A tracking system then issues a REC to certify the source and amount of clean energy provided to the grid. The RECs can then be sold to customers who prefer clean, renewable energy.
Why purchase Renewable Energy Credits (RECs)?
RECs are a way to account for renewable energy usage and provide a tracking mechanism, particularly where specific clean energy plans are not available. For organizations that operate in many states or that operate on different energy grids, RECs provide consolidated documentation of clean energy usage.
Individuals and organizations buy RECs to support renewable, clean energy.
Individuals who are interested in lowering their reliance on fossil fuels, can do so by buying RECs.
The motivations are similar for small businesses and other organizations, who may have voluntarily decided to meet sustainability goals and lower Scope 2 emissions, which are the greenhouse gases created by a supplier, such as their electric company. For organizations that operate in many states or that operate on different energy grids, RECs provide consolidated documentation of clean energy usage.
As a customer who purchases a REC, you incentivize clean energy producers to commit to invest in renewable power generation. Customers active participation demonstrates there is a market for clean energy products and you reduce your carbon footprint. Its's a win-win. Plus, by using clean energy, you reduce your carbon footprint. It’s a win-win.
What are carbon offsets?

Another tool for reducing your carbon footprint and supporting a cleaner environment is purchasing carbon offsets. Like a REC, a carbon offset is a legal accounting and tracking instrument.
However, there is a difference between RECs and carbon offsets: a carbon offset represents a reduction of one ton of carbon dioxide (or equivalent) in the atmosphere, either by removing it from the atmosphere or by preventing emissions. A carbon emissions offset is created through various activities, such as:
- Capturing landfill gas or methane released during mining for use in generating electricity.
- Reclaiming land and planting trees that absorb carbon dioxide.
- Using biogas digesters to convert manure on farms into usable methane.
- Adopting regenerative agricultural practices like no-till planting and limited use of pesticides and synthetic fertilizers.
A variety of organizations, such as Verra Verified Carbon Standard (VCS), validate carbon reduction programs and issue carbon credits for carbon removed from the atmosphere. They are an instrument for offsetting the air pollution created.
Why purchase carbon offsets?
Individuals and organizations use energy for more than running homes and businesses. That is where carbon offsets come in.
When you commute to work, fly to a vacation, buy a product that takes energy to manufacture or ship and generate trash, your carbon footprint increases. The same is true for businesses. The inputs to their products, shipping, employee commutes, business travel and waste management also all count toward their carbon footprint.
To offset greenhouse gas emissions, individuals and organizations can buy carbon offsets. Reforesting land, investing in renewable energy projects and capturing methane at landfills are all examples of activity that either remove greenhouse gasses from the atmosphere or preventing ghg from reaching the atmosphere..
How big is your carbon footprint? Figure out the amount of carbon offsets to buy using this carbon footprint calculator from the EPA.
6 differences between RECs and carbon offsets
Understanding carbon offsets vs. renewable energy certificates is the first step in deciding which choice or combination of choices works best for your situation. Here are the key carbon offsets vs. RECs differences:
1. Unit of measurement
RECs vs. carbon offsets are measured differently. RECs are measured in megawatt hours of clean energy produced. Carbon offsets are measured in metric tons of carbon dioxide removed from the atmosphere.
2. Purpose
Another difference between RECs and carbon offsets is why they were created. The purpose of a REC is to give energy users a way to choose to buy clean energy and to reward clean energy producers financially. The reason carbon offsets were created was to provide a financial reward for investments that remove carbon from the atmosphere.
3. Source
Another RECs vs. carbon offsets difference is where they come from. RECs are created when renewable energy from solar, wind, geothermal, biomass, and hydropower is sent to the grid. Offsets are created when a project avoids or reduces greenhouse gas emissions from the air.
4. Consumer claims
When talking about making a contribution to a cleaner environment, it helps to be clear in what you say. Using REC vs. carbon offset interchangeably contributes to the confusion. A REC is a way to buy clean energy. An offset makes up for the emissions you produce through activities that remove those emissions from the air.
5. Greenhouse gas reporting
When you write or read corporate reporting on the use of carbon offsets vs. renewable energy certificates, each should be separately listed. When you see mention of “net” emissions, you are looking at the greenhouse gases a company produces minus the carbon offsets they buy. When you see “scope 2” emissions, you see the greenhouse gases a company generates from using power from fossil fuels, not clean energy represented by RECs.
6. Additionality testing
Additionality is another way of saying that carbon offsets need to be generated by projects that go over and above the normal operational activities of companies. Organizations that certify offsets want to make sure that the emissions claimed really do represent a genuine metric ton of reduced atmospheric greenhouse gases, so they conduct additionality testing. RECs, on the other hand, are metered at the source and don’t need to prove additionality.
Choosing between RECs and carbon offsets—which is better?
Individual energy customers and small businesses can choose between RECS vs. carbon offsets, or both. They are not only for large corporations. Both are valuable if you are looking for ways to reduce your carbon footprint.
If you want to commit to clean power and support renewable home energy options, RECs are a great choice.
If you want to focus on reducing co2 and greenhouse gases in the atmosphere, buying carbon offsets for the pollution you create can make a difference.
The importance of minimizing your carbon footprint
If you care about the environment, minimizing your carbon footprint will help. Constellation is here to help you do more than improve your energy efficiency. We provide residential customers in specific electric distribution service areas with access to renewable energy through the purchase of renewable energy certificates, which are sourced from wind and/or solar power generators within the United States.
Whether you want to use carbon offsets vs. RECs, Constellation has great options for you and the environment.