RHI Calculator

RHI Calculator – Tariff Table

Below is a table showing the payments that are available to commercial Biomass energy users.

Payments are paid for 20 years from installation and index linked annually for inflation.

 Tariff Name

 Eligible Technology

 Eligible Sizes

Previous tariff(pence/kWhth) -up to 31.03.12 New roundedtariff (pence/kWhth) – from04.04.12
Small commercialbiomass Solid biomass incsolid biomass containedin municipal solidwaste (incl. CHP) Less than 200 kWTH Tier 1 7.9 8.3
Tier 2 2 2.1
Medium commercialbiomass 200 kWth and above; less than 1000 kWth Tier 1 4.9 5.1
Tier 2 2 2.1
Large commercialbiomass 1000 kWth and above n/a 1 1


For details on eligibility please see our page RHI Scheme Information

Payments will be paid quarterly against customer supplied heat meter readings.

The payment is calculated by multiplying KWHs used against the capacity of the boiler.

Tier 1 payments are made up to a maximum of 1314 hours (15% of 1 year at maximum boiler output)

Tier 2 payments on all output above 1314 hours

Below are 2 examples to show how the calculations are made.

Example 1: Medium sized office building annual heat requirement 250,000 KWH’s.  Biomass boiler capacity 95KW

Tier 1 payment

Capacity x peak hours x tier 1 tariff

e.g   95 x 1314 x 8.3 = £10,360.88
(Boiler capacity x hours allowed for tier 1 x qualifying rate)

Tier 2 payment

Total energy use (KWH) less KWH paid on Tier 1 paid at Tier 2 Tariff

Total 250,000 KWH less 124,830 KWH x 2.1p = £2628.57

The cost to install a 95KW wood pellet boiler can vary significantly according to site layout, existing plumbing layout and fuel storage capacity. Cost should fall in the range £20,000 – £50,000

The RHI payment of £12989.45 is therefore very significant representing an annual return on investment of between 25 and 50%

There will also be significant extra savings on fuel costs as compared to oil and LPG of around £3000.00/year

Taken together the savings and earnings would total around £16,000/year

Example 2: 4 bedroom house with adjoining 2 bedroom holiday cottage. Annual heat requirement 50,000KWH.Biomass boiler capacity 45KW

Tier 1 payment 45x1314x8.3=£4,907.79

No tier 2 payment as heat used is less than tier 1 limit of 59,130 KWH

The cost to install a 45KW system would fall between £12,000 and £25,000

Fuel saving approx £650 against oil.

Taken together the savings and earnings would total around £5,500/year

Return on investment between 22 and 45%

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