Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Annual REC purchase cost
$10,000
RECs needed (MWh)
5,000
Price per MWh
$2.00
Cost per kWh (cents)
0.2000
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How to use this
- 1Enter annual electricity use (kWh).
- 2Enter rec type.
- 3Enter or enter your own price ($/mwh, 0 = use type default) ($).
- 4Read your annual rec purchase cost on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
A REC represents the environmental attributes of one megawatt-hour of renewable generation, and buying enough RECs to match your electricity consumption lets you claim market-based Scope 2 emissions of zero under the GHG Protocol, even though the physical electrons you consume come from the regular grid. This calculator converts your annual kWh consumption into the number of RECs needed and prices them at current market rates, which vary sharply by type — unbundled national RECs are cheap, while Green-e certified or in-region RECs cost more, and RECs bundled into a physical power purchase agreement cost more still but carry more credibility with reviewers and rating agencies. Companies use this for RE100 commitments and to compare the cost of REC-based 'green' claims against actually contracting for new renewable generation, which is what additionality-focused frameworks increasingly push buyers toward.
Worked example
Using the values the calculator loads with:
Inputs
- Annual electricity use: 5000000 kWh
- REC type: Unbundled national REC (~$1-3/MWh)
- Or enter your own price ($/MWh, 0 = use type default): 0 $
Results
- Annual REC purchase cost: $10,000
- RECs needed (MWh): 5,000
- Price per MWh: $2.00
- Cost per kWh (cents): 0.2
What each field means
Inputs
- Annual electricity use (kWh)
- The annual electricity use used in the calculation, measured in kWh. Starts at 5000000 kWh so you have a working example on load.
- REC type
- Pick the option that matches your situation — the maths changes per option. Choices: Unbundled national REC (~$1-3/MWh), Green-e certified REC (~$3-6/MWh), In-region/vintage REC (~$8-15/MWh), Bundled PPA-linked REC (~$20-40/MWh).
- Or enter your own price ($/MWh, 0 = use type default) ($)
- The or enter your own price ($/mwh, 0 = use type default) used in the calculation, measured in $. Starts at 0 $ so you have a working example on load.
Results
- Annual REC purchase cost
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- RECs needed (MWh)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Price per MWh
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per kWh (cents)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why are unbundled national RECs so cheap?
Unbundled RECs are decoupled from a specific project's location and vintage year and there's an oversupply relative to demand in most years, especially from older wind projects. That low price is exactly why critics call cheap RECs low-additionality — they rarely fund any new renewable generation, they just relabel existing megawatts.
What does 'additionality' mean and why does it matter for RECs?
Additionality means your purchase caused new renewable generation to exist that wouldn't have otherwise. Cheap unbundled RECs from decades-old hydro or wind projects generally fail this test, while a long-term PPA that finances a new solar or wind farm clearly passes it — which is why RE100 and increasingly CDP scoring reward PPA-linked claims over spot REC purchases.
Does buying RECs actually reduce physical grid emissions?
Not directly and not immediately — the electrons on the grid don't change. What changes is the accounting claim and, if enough buyers demand higher-additionality instruments like PPAs, the long-run investment signal that funds new renewable capacity. Treat REC purchases as a reporting and market-signaling tool, not a physical emissions reduction on their own.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Renewable Energy Certificate (REC) Cost Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/rec-cost
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/rec-cost" target="_blank" rel="noopener">Renewable Energy Certificate (REC) Cost Calculator — RevenueLab</a> (2026).</p>
Source: [Renewable Energy Certificate (REC) Cost Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/rec-cost) (2026).