Purchasing Carbon Offsets FAQs


Please email Meredith Leigh [email protected] with comments, or to suggest additional questions be added to this list.

What kinds of carbon offsets are available?

This guidance focuses on the voluntary carbon market. Most campuses are not part of a compliance market (such as the California Cap and Trade Program) and all offset purchases are voluntary. While there are many standards that issue offsets through the voluntary market, the most widely used are the Climate Action Reserve (CAR), the Verified Carbon Standard (VCS), the American Carbon Registry (ACR) and Gold Standard (GS). Carbon credits issued through any of these programs can be used to fulfil the Climate Leadership Commitments.

Who verifies the emissions reductions?

When purchasing offsets to cancel a portion of their emissions, campuses should look for offsets that are third-party verified. All credits issued from any of the major carbon standards (CAR, VCS, ACR, GS) will have undergone a robust verification process by an ISO accredited third-party verifier. These credits are also all tracked on registries to ensure emissions reductions are not double counted. Credits from standards not discussed above should be scrutinized carefully to confirm that they have been verified, are the result of a real project, have not been sold or retired previously, and are otherwise legitimate.

What types of projects generate carbon offsets?

Carbon offsets can be generated by any type of project that reduces or eliminates greenhouse gas emissions beyond a business-as-usual scenario. Common types of offset projects include reforestation and improved forest management, methane gas capture and destruction, fuel switching, clean cookstoves, and energy efficiency. There are many more types of projects that can generate carbon offsets however. To get a feel for what project types exist, visit the methodologies page for the standards mentioned above.

What does vintage year mean?

The vintage year refers to the year the emission reduction occurred. Some projects will issue offsets every year, while some will issue offsets in multi-year increments. As a rule of thumb, campuses should look for offsets where the emission reductions took place in a similar timeframe to the emissions they are offsetting. Generally, offsets with a vintage year within 1-3 years of the emissions to be cancelled out are most desirable. Offsets with a vintage greater than 5 years in the past may be considered older, and less desirable.

Where can information about offset projects be found?

Most offset projects are listed publicly, and campuses can visit the standards’ websites for lists of projects. VCS projects can be found through Verra’s VCS Project Database, ACR projects are listed on this registry, and CAR projects are listed here. Gold Standard also provides a list of projects. Keep in mind that some of these projects may be completed and no longer issuing offsets.

Carbon offsets issued through these standards will also have publicly available documentation on the project, emissions reduction calculations, and third-party verification.

How much do carbon offsets cost?

The price of carbon offsets varies widely from <$1 per ton to >$50 per ton. The price depends on the type of carbon offset project, the carbon standard under which it was developed, the location of the offset, the co-benefits associated with the project, and the vintage year. Campuses may obtain a lower price per offset for larger volume purchases. Ecosystem Marketplace publishes yearly reports on the voluntary carbon market, which track information such as average offset prices and total global transactions. Here is the most recent report. The average offset prices are between roughly $3-$6 per ton.

Where are there additional resources?

What are co-benefits?

Co-benefits are positive outcomes from a carbon offset project, beyond  the actual greenhouse gas emissions reductions. Co-benefits may be social, economic, or environmental. Examples of co-benefits include jobs created, health benefits, pollution mitigation (other than carbon), supporting gender equality, renewable energy generation, biodiversity, and education. Co-benefits are often the deciding factor in carbon offset purchases. Many carbon offset developers list the project co-benefits in terms of how they contribute to the UN Sustainable Development Goals.

What companies sell carbon offsets?

There are many types of companies and organizations that sell carbon offsets. Some project owners and developers sell offsets directly to the end buyer; campuses can reach out to contacts listed on project documents to inquire about this. There are also a number of offset providers that serve as intermediaries and can supply campuses with offsets from multiple projects depending on campus needs. These intermediaries may be retailers (that purchase and resell offsets) or brokers (that facilitate transactions but do not own offsets). Below is a list of offset suppliers that can be used as a starting point. There are additional offset suppliers not listed here.

Company Website Company Location Sample Types of Projects
3 Degrees 3degreesinc.com San Francisco, CA Sustainable Forestry, Landfill Gas, Livestock Methane, Industrial Processes

CAR, ACR, Gold Standard

BEF www.b-e-f.org Portland, OR Improved Forest Management, REDD+, Wind Energy, Waste Heat Capture, Landfill Gas Destruction


BlueSource www.bluesource.com Holladay, UT Forestry, Landfill, Ozone Depleting Substances, Coal Mine Methane, Efficient Cookstoves, Transportation, Waste Water Treatment, Fugitive Methane Emissions, Agricultural Methane, Industrial Energy Efficiency, Renewable Energy, Fuel Switching


Carbon Credit Capital carboncreditcapital.com New York City, NY Sustainable Forestry, Biogas, Organics Composting, Renewable Energy

VCS, Gold Standard, Clean Development Mechanism (CDM)

Carbon Fund www.carbonfund.org East Aurora, NY Forestry, Energy Efficiency, Renewable Energy

ACR, CAR, Gold Standard, VCS, CDM

Clear Sky Climate Solutions www.clearskyclimatesolutions.com Missoula, MO Forestry


ClimeCo www.climeco.com Boyertown, PA Nitrous Oxide  Abatement, Composting


Cool Effect www.cooleffect.org Kentfield, CA Grassland Protection, Methane Capture, Nitrous Oxide Abatement, Clean Cookstoves, Renewable Energy, Biogas

CAR, Gold Standard, CDM, VCS

Element Markets www.elementmarkets.com Houston, TX Forestry, Landfill, Ozone Depleting Substances, Coal Mine Methane, Transportation, Renewable Energy, Fuel Switching
Impact Carbon www.impactcarbon.org San Francisco, CA Clean Cookstoves, Fuel Switch,

Gold Standard

Native Energy nativeenergy.com Burlington, VT Renewable Energy, Methane Gas Capture, Land Use, Clean Water

Gold Standard, CAR, VCS

Sterling Planet www.sterlingplanet.com Alpharetta, Georgia Solar panels, wind farms, clean fuels and energy efficiency, tree planting, methane capture, landfill gas recovery
TerraPass www.terrapass.com San Francisco, CA Landfill Gas Capture, Wind, Coal Mine Methane


The Climate Trust climatetrust.org Portland, Oregon Forestry, Grassland Conservation, Livestock Digester