Solar & battery
Solar Net Metering Calculator
Works net metering, where the tariff rather than the physics decides the value.
Result
Net metering rules are set state by state and utility by utility, and many have moved from full retail credit toward avoided cost or net billing. Grandfathering terms vary and are rarely permanent. The factors here are illustrative bands, not your tariff.
Get a Free Business AuditHow the calculation works
Production exported and energy imported, valued at the tariff's respective rates, netted over the billing period the tariff specifies. The two variables that matter are the export rate and the netting period, and both are set by the utility tariff rather than being general features of solar.
What moves the number
- The export credit rate under your specific tariff.
- The netting period, whether monthly, annual or instantaneous.
- Whether excess credits carry forward or expire.
- Fixed and demand charges that continue.
Where this one goes wrong
Full retail net metering is no longer the general case, and several states have moved to crediting exports at avoided cost or a separate export rate, which changes the economics substantially and favours self-consumption and batteries over maximum production. Terms also vary by vintage, so a customer connecting now may be on different terms from a neighbour who connected earlier. Read the actual tariff that will apply.
Before you quote
- Read the specific tariff that will apply to your interconnection.
- Check the netting period and whether credits expire.
- Confirm whether existing customers are on different terms.
Questions
About this calculator
Is net metering the same everywhere?
No. It is a utility tariff, and terms differ by state, by utility and by the vintage of the tariff. Several states now credit exports at avoided cost or a separate export rate rather than full retail, which changes the economics considerably.
What is the netting period?
The interval over which exports and imports are offset, which may be monthly, annual or close to instantaneous. A shorter period captures less value from production that does not coincide with use, which makes it as important as the rate itself.
Do credits carry forward?
It depends on the tariff: some carry excess credits forward indefinitely, some reconcile annually and some expire. Where credits expire, oversizing a system produces nothing, which makes this a sizing question rather than a detail.
The formula
value = self-used kWh x retail + exported kWh x retail x credit factor
Put this calculator on your site
Free to embed. Paste this where you want it to appear. It stays up to date automatically because it loads from BDEVY.
Please keep the attribution line. It is the only thing we ask in return.
How to use this calculator
- Annual production (kWh). Enter your own figure; the page starts at 9,200.
- Annual consumption (kWh). Enter your own figure; the page starts at 11,400.
- Share used as it is generated (%). Enter your own figure; the page starts at 40%.
- Retail rate per kWh ($). Enter your own figure; the page starts at $0.16.
- Credit scheme. Enter your own figure; the page starts at Full retail net metering.
The result updates as you type, so you can try a figure, see what it does to annual value of production, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Annual production (kWh) | 9,200 |
| Annual consumption (kWh) | 11,400 |
| Share used as it is generated | 40% |
| Retail rate per kWh | $0.16 |
| Credit scheme | Full retail net metering |
What comes out
| Result | Value |
|---|---|
| Annual value of production main result | $1,472 |
| Exported | 5,520 |
| Value of exports | $883.20 |
| Value of self-consumption | $588.80 |
| Lost against full retail credit | $0 |
Production is worth $1,472 a year: $588.80 used directly and $883.20 exported. Against full retail credit you are $0 a year worse off, which is why self-consumption matters more every year.
How sensitive the answer is
Holding everything else steady and changing only retail rate per kwh, this is what happens to annual value of production. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Retail rate per kWh ($) | Annual value of production |
|---|---|
| $0.08 | $736 |
| $0.12 | $1,104 |
| $0.16 example above | $1,472 |
| $0.24 | $2,208 |
| $0.32 | $2,944 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Annual production (kWh)
- A number, between 0 and 5000000, starting at 9,200.
- Annual consumption (kWh)
- A number, between 0 and 5000000, starting at 11,400.
- Share used as it is generated (%)
- A percentage, between 0 and 100, starting at 40%.
- Retail rate per kWh ($)
- A money amount, starting at $0.16.
- Credit scheme
- Choose from Full retail net metering, Avoided cost, about 40% of retail, Net billing, about 25% of retail.
What the results tell you
| Result | What it is |
|---|---|
| Annual value of production | The headline result. A money figure. |
| Exported | A number. |
| Value of exports | A money figure. |
| Value of self-consumption | A money figure. |
| Lost against full retail credit | A money figure. |
A design still needs a site visit
Output and sizing figures use the assumptions you enter, not measured irradiance, shading or roof orientation at your address. Real production depends on all three, plus inverter behaviour and local interconnection rules.
Keep going
Related calculators
Estimating is the easy part
The jobs you never hear about cost more than the ones you mis-measure. BDEVY builds the marketing, systems and automation that bring them in.