Question-ID: 1126

ESRS E1 paragraph AR 32 states that ‘when preparing the information on energy consumption required under paragraph 35, the undertaking shall:

(a) only report energy consumed from processes owned or controlled by the undertaking applying the same perimeter applied for reporting GHG Scopes 1 and 2 emissions;

(b) exclude feedstocks and fuels that are not combusted for energy purposes. The undertaking that consumes fuel as feedstocks can disclose information on this consumption separately from the required disclosures;

(c) ensure all quantitative energy-related information is reported in either Mega-Watt-hours (MWh) in Lower Heating Value or net calorific value. If raw data of energy-related information is only available in energy units other than MWh (such as Giga-Joules (GJ) or British Thermal Units (Btu)), in volume units (such as cubic feet or gallons) or in mass units (such as kilograms or pounds), they shall be converted to MWh using suitable conversion factors (see for example Annex II of the Fifth Assessment IPCC report). Conversion factors for fuels shall be made transparent and applied in a consistent manner’.

For further guidance on Heating Values, see the content below.

‘Most fuels are mixtures of carbon and hydrogen and these are the main heating agents. There may be other elements which do not contribute, or contribute only slightly, to the calorific value of the fuel. Both the carbon and the hydrogen combine with oxygen during combustion and the reactions provide the heat. When the hydrogen combines with oxygen, it forms water in a gaseous or vapour state at the high temperature of the combustion. The water is therefore almost always carried away with the other products of combustion in the exhaust gases from the apparatus in which the combustion takes place (boiler, engine, furnace, etc.).

When the exhaust gases cool, the water will condense into a liquid state and release heat known as latent heat, which is wasted in the atmosphere. The heating value of a fuel may, therefore, be expressed as a gross value or a net value. The gross value includes all of the heat released from the fuel, including any carried away in the water formed during combustion. The net value excludes the latent heat of the water formed during combustion. It is important when obtaining a calorific value to check whether it is net or gross. The differences between net and gross are typically about 5% to 6% of the gross value for solid and liquid fuels and about 10% for natural gas.

There are a few fuels which contain no, or very little, hydrogen (for example blastfurnace gas, high-temperature cokes and some petroleum cokes). In these cases, there will be negligible differences between net and gross calorific values.

The derivation of net calorific values for solid fuels is further complicated because they often contain water trapped within the fuel in addition to the water which will be formed from the hydrogen they contain. The reduction in net calorific value as a result of the additional water is uncertain because the dampness of the fuel may vary according to weather and storage conditions.

In summary, the net calorific value of a fuel is the total heat produced by burning it minus the heat needed to evaporate the water present in the fuel or produced during its combustion. Major users of solid fuels, such as power stations, should be able to provide net calorific values based on the monitoring of the electricity generation’ (Source: IEA (2004), Energy Statistics Manual, IEA, Paris, Licence: CC BY 4.0)

There are multiple sources of conversion expressions between HHV and LHV depending on the fuels (coal, NG, biomass, etc.), which can also vary in origin and treatment of fuels in each region. Undertakings are advised to search for appropriate conversion expressions for their particular circumstances.