The annual fuel or electricity consumption under the standard patterns of occupancy and usage is calculated for the following items or functions:
Primary energy factors and CO2 emission factors associated with different fuels are calculated using the data given in Table 12.1 below. Other primary energy or CO2 factors are not used for the purpose of this calculation.
Since fuels must relate to realistic heating systems, it is important that practical combinations of fuel types are used.
The primary energy (renewable and non-renewable) and CO2 emission factors in Table 12.1 account for energy used and emissions released at the dwelling, and also take some account of energy used and emissions released in bringing the fuel or other energy carrier to the dwelling. For example, in the case of electricity they account for energy losses and emissions at power stations. The primary energy and CO2 emissions factors for electricity are updated in line with the agreed methodology and based on the National Energy Balance.
Table 12.1 - Fuel Factors in DEAP
| Fuel | Renewable PEF, (Fp, ren) | Non renewable PEF (Fp, nren) | Total PEF | Emissions (kg CO2 / kWh) |
|---|---|---|---|---|
| Gas: | ||||
| Mains gas | 0 | 1.1 | 1.1 | 0.1838 |
| LPG (propane or butane) | 0 | 1.1 | 1.1 | 0.2136 |
| Oil: | ||||
| Heating oil | 0 | 1.1 | 1.1 | 0.24565 |
| Biodiesel from renewable sources only (7) | 1 | 0.3 | 1.3 | 0.00265 |
| Bioethanol from renewable sources only (7) | 1 | 0.34 | 1.34 | 0.00116 |
| Solid fuel:(2) | ||||
| House coal | 0 | 1.1 | 1.1 | 0.35362 |
| Anthracite | 0 | 1.1 | 1.1 | 0.36627 |
| Manufactured smokeless fuel | 0 | 1.2 | 1.2 | 0.392 |
| Peat briquettes | 0 | 1.1 | 1.1 | 0.377 |
| Wood | 1 | 0.1 | 1.1 | 0.025 |
| Solid multi-fuel | 0 | 1.1 | 1.1 | 0.369 |
| Electricity(3, 8): | ||||
| Delivered |
0 |
1.5 |
1.5 |
0.1685 |
| Electricity displaced from grid(4) |
0 |
1.5 |
1.5 |
0.1685 |
| Electricity exported to the grid |
1.0 |
0 |
1.0 |
0.113 |
| District heating schemes(9): | ||||
| Heat from boilers – waste combustion | 0 | 1.1 | 1.1 | 0.1221 |
| Waste heat from power stations | 0 | 1.05 | 1.05 | 0.018 |
Notes
BER Assessor’s and their clients may notice that dwellings primarily heated by direct or storage electricity will have higher primary energy calculated by DEAP (and hence a “worse” BER than might be expected). There are significant inefficiencies in thermal electricity production (in the generation and transmission of electricity) resulting in a high primary energy factor for electricity.
Also, the DEAP methodology cannot take account of the homeowner’s choice of electricity supplier. As is stated in the DEAP manual, the calculation is an asset rating. This enables the consumer to make a fair comparison between a dwelling’s energy performance and that of other dwellings. For example, if a potential purchaser/tenant of a dwelling were interested in buying/renting a house, the current occupier’s behaviour (including choice of electricity supplier) is irrelevant. Changing electricity supplier does not involve any physical change to the dwelling asset.
The primary energy factor (primary energy required for each unit of delivered energy) and CO2 factor (g/kWh delivered) for DEAP are periodically updated to reflect improvements to grid efficiency and increased renewables on the grid. The DEAP software stores the previous factors and they can be loaded into an assessment for review, but publication of a BER is only possible with the current factors.