Which electricity tariff is best for solar panels?

It depends on your usage, whether you import or export more. The article below will help you understand what to look for.

Choosing the right electricity tariff for solar panels will get the most out of your system.

Just as important to choosing which electricity tariff to use is shifting usage into "free" and off-peak times. Below is a summary table of the article below.
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Solar generation Vs electricity usage per year	Imports \| Exports	Difference between imports & exports	Tariff advice
4500 Vs 4500 kWh	2925 \| 2925 kWh	0 kWh	Minimise differential between export/import prices: Octopus Outgoing & Off-peak
9000 Vs 4500 kWh	2250 \| 6750 kWh	- 4500 kWh	Maximise export payments: Octopus Flux/E.On – electricity bills should be negative.
4500 Vs 9000 kWh	6075 \| 1575 kWh	+4500 kWh	Minimise import cost. Shift usage into the day, choose the tariff with the lowest average electricity cost.

How much will your solar panels generate and how much electricity does your home use?

The first thing to know is how much energy will your solar panels generate per year? and how much electricity will your home use per year?

Solar generation 4500 kWh per year | Electricity usage 4500 kWh per year

In this scenario, which electricity tariff should be used with my solar panels?

No battery

Assuming no change in behaviour, you will consume 35% of your solar generation.

Imports: 2925 kWh
Exports: 2925 kWh

Imports and exports are roughly the same over the year therefore your best tariff is the one with the smallest difference between exports and import prices (on average).

Electricity tariff advice:

Exports: Octopus Outgoing or similar for export payments (15p-16.5/kWh).

Imports: The lowest off-peak rate without a peak rate as you have no battery.

You should look to shift usage into the middle of the day and heavy usage overnight - shifting usage will be just as important as choosing the right electricity tariff for your bill.

With a battery

The same advice applies, bring down your average cost per kWh by shifting usage. If export payments earn more than the off-peak rate - you should charge your battery to full every night (especially if it's sunny) to maximise the energy exported to pay for off-peak imports.

Solar generation 9000 kWh | Electricity usage 4500 kWh

No battery

Assume 50% electricity usage covered by solar.

Imports: 2250kWh
Exports: 6750 kWh

Exports are the most important so your focus should be the export rate. No battery means no peak usage electricity tariffs.

Electricity tariff advice:

Choose the highest export tariff you can find (E.On at 16.5p or Octopus Flux). Use the export credits to pay for imports - your bill should be negative in this scenario.

With a battery

We wouldn't advise getting a battery in this scenario if reducing cost is the goal. Using the grid as a battery, export payments paying for energy when you need it.
If you do have one - use it to maximise exports by switching to an off-peak tariff, charge to 100% every night, especially when sunny. Your bill should become even more negative.

Octopus unplugs MCS certification

Source: eFIXX Youtube. Octopus has enabled non MCS solar installations to access their export payments.

NICEIC and NAPIT already certify and assess their electricians for competence which includes solar PV so is this change an obvious one?

Always use a fully qualified electrician.

Solar generation 4500 kWh | Electricity usage 9000 kWh

No battery

Assume 65% of generation is consumed.

Imports: 6075 kWh
Exports: 1575

Your imports are the most important, it's unlikely you'll be able to shift that much usage unless usage is high due to having an electric car. If you have an EV, switch tariffs to an off-peak EV tariff such as Octopus Intelligent. If you do not have an EV and your high usage is mainly daytime use, switch to the lowest flat rate you can.

No battery means no peak time electricity tariffs.

Export tariff - Octopus Outgoing or similar fixed 15-16.5p/kWh export rate.

With a battery

Charging overnight at off-peak rates to supplement the solar with cheap off-peak energy is the best approach. Export tariff remains the same.

To calculate how large your battery should be take your estimated imports (6075 kWh) and divide by 365 = 16.6 kWh

This is the largest battery size we would recommend. Larger than this and the return on investment drops sharply.
If you have an electric car, which explains the high usage, you may not need a battery.