You are here

RHI Calculator Assumptions

The calculator is designed to give you an idea of what kind of financial returns you might expect from installing a biomass boiler as opposed to a fossil fuel equivalent. It does not cover everything you need to know to make an investment decision. You need to seek expert advice before undertaking a specific project.

Table 1 - Renewable Heat Incentive Tariffs

Boiler Size kW

Tier 1 (£/kWh)

Tier 2 (£/kWh)

199kW or less

£0.083

£0.021

200-999kW

£0.051

£0.021

1000kW or more

£0.01

n/a

Tier 1 cut off to go to Tier 2 is boiler size (kW) multiplied by 1314

Table 2 - Energy, CO2 (as net CO2 equivalents CO2e) and bulk density of selected heating fuels

Fuel

Traded unit

kWh/traded unit

kg CO2e emissions/kWh

Moisture content

Cubic metres per tonne

Average boiler efficiency

Heating Oil

litre

9.8

0.307

 

 

90%

LPG

litre

7.07

0.259

 

 

90%

Coal (domestic)

kg

6.85

0.413

 

 

85%

Electricity

kWh

1

0.617

 

 

100%

Mains gas

kWh

1

0.225

 

 

90%

Wood Pellets

tonne

4680

0.04

10%

1.5

85%

Virgin Woodchip

tonne

3490

0.02

30%

5

85%

Recycled Woodchip

tonne

4090

0.02

20%

6

85%

Stacked Logs (hardwood)

tonne

3490

0.02

30%

2

85%

Boiler Efficiencies - We have used a general estimation for this calculator. Most domestic fossil fuel boiler average efficiencies can be found on the SEDBUK website

Wood energy and bulk density values - We have used figures from The Biomass Energy Centre. We have used approximations for moisture.

CO2 emissions for fuels - We have used figures from the DEFRA Website