Heat Network
(Metering and Billing)
Regulations 2014
Guidance for Estimating
Heat Capacity/
Generated/ Supplied
January 2016
Guidance for Estimating Heat Capacity/ Generated/ Supplied
Introduction
The aim of this guidance is to assist heat suppliers in providing information under Regulation 3 of the
Heat Network (Metering and Billing) Regulations 2014, Duty to notify. Specifically, Regulations 3(1)(b)( i), (ii) and (iii). Templates have been made to aid with these notifications; this guidance refers
to questions 17, 18 and 19 in the single notifications template or questions 18, 19 and 20 in the
multiple notifications template.
An associated spreadsheet, the Heat Estimator, has been created with this guidance to further aid
with calculations. Each worksheet in the Heat Estimator corresponds to the numbered methods
described in this document. The Data worksheet is left visible so users can understand which values
are being used.
This guidance has been created in order to support the broadest range of heat suppliers possible, it
does not have to be used in order to comply with the legislation. A more thorough evaluation can be
made but this guide shows an acceptable standard. The NMRO may ask a heat supplier to explain
how values have been determined.
Heat Network (Metering and Billing) Regulations 2014
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Guidance for Estimating Heat Capacity/ Generated/ Supplied
1. Estimated total installed heating/ hot water capacity (kW)
Heat Capacity is the maximum instantaneous output of a heat generator; it is a specification of the
generator. Heat capacity is a measure of power and is measured in kilowatts (kW). Heat generated/
supplied over a time period is a measure of energy and is measured in kilowatt-hours (kWh). For
example if a 20kW capacity boiler ran at maximum capacity for 2 hours then it would generate
40kWh of thermal energy.
Small domestic gas powered boilers range from about 4kW to 20kW, larger domestic boilers may
have capacities up to 70kW. For commercial or industrial use, it is usual to run multiple boilers. If
you have multiple heat generators, the total capacity is the sum of the individual capacities.
Some older boilers will state British Thermal Units per hour (BTU/hour) instead of kW.
1 𝐵𝑇𝑈 ≈ 0.00029 𝑘𝑊ℎ
1 𝐵𝑇𝑈⁄ℎ𝑜𝑢𝑟 ≈ 0.00029𝑘𝑊
(𝐸𝑛𝑒𝑟𝑔𝑦)
(𝑃𝑜𝑤𝑒𝑟)
The Heat Capacity (sometimes called “Maximum Power Output”) is normally printed on the
boiler directly but if not, it will be available in the technical specifications or manual.
Alternatively, a database of heat generator specifications is available here:
http://www.ncm-pcdb.org.uk/sap/searchpod.jsp?id=17,
Note: If your network is shared with another heat supplier, NMRO advises that an
arrangement is made for the primary heat supplier to submit a notification for the
network which encompasses both of the heat suppliers’ information (i.e. total number
of final customers).
If this is not possible, then both parties must make their own notification. In this case,
if you are not the primary heat supplier please enter ‘0’ for the Estimated Total
Installed Heat/Hot Water/Cooling Capacity and leave a covering note including your
primary heat supplier’s name and postcode.
Heat Network (Metering and Billing) Regulations 2014
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Guidance for Estimating Heat Capacity/ Generated/ Supplied
2. Estimated total heat/ hot water generated per calendar year
(kWh)
Heat Generated is the heat input into the network over 12 months (not the amount of fuel being
used).
Please use the table below to determine the appropriate method to estimate heat/ hot water
generated.
Meter fitted on output of Heat
Generator?


Use method:
2.1
2.2
Method:
2.1.
This would be measured by a heat meter placed on the output of the heat generator.
2.2.
If there is no appropriate meter fitted, the heat generated per calendar year can be
estimated through energy put into the heat generator over a year, multiplied by the heat
generator efficiency. This can be done using the Heat Estimator.
Note: If you are not the primary heat supplier and are submitting your own notification, please
enter ‘0’ for the Estimated Total Heat/Hot Water/Cooling Generated and leave a
covering note including your primary heat supplier’s name and postcode.
As an alternative to using the Heat Estimator to estimate Heat Generated per calendar year, the
calculation can be done manually using the appropriate method below. All energy contents and
densities are based on the Higher Heating Value (HHV) also known as the the Gross Calorific Value
(Gross CV).
2.2.1. Natural gas
The Heat Generated by a boiler utilising natural gas will be equal to:
𝐸𝑛𝑒𝑟𝑔𝑦 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 𝑜𝑓 𝑔𝑎𝑠 𝑢𝑠𝑒𝑑 (𝑘𝑊ℎ) × 𝑏𝑜𝑖𝑙𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 (%)
Normally the amount of gas used is measured as energy (kWh) but if only the volume is measured
(m3) then the calorific value of the gas will have to be included:
𝑘𝑊ℎ
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑔𝑎𝑠 𝑢𝑠𝑒𝑑 (𝑚3 ) × 𝐺𝑟𝑜𝑠𝑠 𝐶𝑉 ( 3 ) × 𝑏𝑜𝑖𝑙𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 (%)
𝑚
Heat Network (Metering and Billing) Regulations 2014
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Guidance for Estimating Heat Capacity/ Generated/ Supplied
2.2.1. Natural gas (cont.)



The volume of gas used will be measured by a gas meter on the system or taken from an
accurate bill.
The gross calorific value of the natural gas depends on its methane content, typically around
97%i, this would equate to about 10.91kWh/m3 ii or 0.3089kWh/ft3
The boiler efficiency should be found on the technical specifications of the boiler, it would
be expected to be around 85% iii for a modern condensing boiler.
2.2.2. Oil
The Heat Generated by a boiler utilising heating oil will be equal to:
𝑘𝑊ℎ
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑜𝑖𝑙 𝑢𝑠𝑒𝑑 (𝑙) × 𝐺𝑟𝑜𝑠𝑠 𝐶𝑉 (
) × 𝑏𝑜𝑖𝑙𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 (%)
𝑙


The gross CV of oil will be about 10.88kWh/litre iv v
An oil burning boiler efficiency should be found on the technical specifications of the boiler.
Older boilers will have efficiencies of around 70% and new condensing oil fired boilers have
efficiencies of about 92% vi
2.2.3. Solid Fuel including Biomass and LPG
The Heat Generated by a boiler utilising solid fuel will be equal to:
𝑘𝑊ℎ
𝑀𝑎𝑠𝑠 𝑜𝑓 𝑓𝑢𝑒𝑙 𝑢𝑠𝑒𝑑(𝑘𝑔) × 𝐺𝑟𝑜𝑠𝑠 𝐶𝑉 (
) × 𝑏𝑜𝑖𝑙𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦(%)
𝑘𝑔


The gross CV of the biomass will depend on what fuel is being used. Common solid fuels and
their associated specific energies are detailed in the table below. vii
Fuel
Gross CV
kWh/kg
Domestic wood
4.14
Wood pellets
4.64
House coal
8.36
Anthracite
9.53
LPG
13.72
A solid fuel boiler efficiency is expected to be around 80% viii
Heat Network (Metering and Billing) Regulations 2014
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Guidance for Estimating Heat Capacity/ Generated/ Supplied
2.2.4. Biogas
The Heat Generated by a boiler utilising biogas will be equal to:
𝑘𝑊ℎ
𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑔𝑎𝑠 𝑢𝑠𝑒𝑑 (𝑚3 ) × 𝐺𝑟𝑜𝑠𝑠 𝐶𝑉 ( 3 ) × 𝑏𝑜𝑖𝑙𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 (%)
𝑚


The gross CV of the biogas depends on its methane content, typically around 60 and 68% for
household waste and agrifood respectively. This would equate to about 6.42kWh/m 3
(0.1818kWh/ft3) for biogas from household waste and 7.28kWh/m3 (0.2061kWh/ft3) for
biogas from agrifood.
Biogas boilers are expected to about 75-90% efficient.ix
2.2.5. Electricity
The Heat Generated by an electric boiler will be equal to:
𝐸𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑢𝑠𝑒𝑑(𝑘𝑊ℎ) × 𝑏𝑜𝑖𝑙𝑒𝑟 𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦(%)


Electrical energy used will be measured by an electricity meter on the system.
The boiler efficiency should be found on the technical specifications of the boiler, it would
be expected to be around 90-100% x
Heat Network (Metering and Billing) Regulations 2014
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Guidance for Estimating Heat Capacity/ Generated/ Supplied
3. Estimated total heat/ hot water supplied per calendar year
(kWh)
Heat Supplied is the total amount of heat used by the customers of the system per calendar year. It
should be lower than the Heat Generated due to the heat losses between the generator and the
final customers.
Please use the table below to determine the appropriate method to estimate heat/hot water
supplied per calendar year.
Individual meters fitted
for each final customer?




Good knowledge about
network efficiency?



Good knowledge
about customer
consumption?
Use method:
3.1
3.2
3.3
3.4


Method:
3.1.
This would be the sum of the metered consumption of each final customer for the
year. A table is available in the Heat Estimator to facilitate this.
3.2.
If no appropriate meters are fitted but you have good information about the
expected efficiency of your network, the Heat Supplied per calendar year would be
approximately:
𝑯𝒆𝒂𝒕 𝑮𝒆𝒏𝒆𝒓𝒂𝒕𝒆𝒅 𝒑𝒆𝒓 𝒚𝒆𝒂𝒓(𝒌𝑾𝒉) × 𝑬𝒙𝒑𝒆𝒄𝒕𝒆𝒅 𝑵𝒆𝒕𝒘𝒐𝒓𝒌 𝑬𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 (%)
This can be done using the Heat Estimator. The expected network efficiency should
include heat and head losses in pipes to the buildings and throughout the
buildings; this will vary depending on the size of the network, size/location of
pipes, insulation, ambient conditions, maintenance etc.
3.3.
If you do not have good information about the expected network efficiency, the
expected annual consumption of each property on the network should be
summed. A table is available in the Heat Estimator to facilitate this.
3.4.
If you do not have good information regarding the efficiency of your network or
the consumption of the properties on the network, use the energy demand
benchmarks laid out in Assessing the cost effectiveness of individual metering:
Energy Demand benchmarks. This can be done using the Heat Estimator.
Heat Network (Metering and Billing) Regulations 2014
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Guidance for Estimating Heat Capacity/ Generated/ Supplied
As an alternative to using the Heat Estimator to estimate Heat Supplied per calendar year, the
calculation can be done manually using the method below.
The energy demand benchmarks are laid out in Assessing the cost effectiveness of individual
metering: Energy Demand benchmarks . Benchmarks are based on space heating and hot water
demand; it is assumed that 21% of overall heating demand is attributed to hot waterxi.
The estimated Heat Supplied for a domestic property is the sum of the annual domestic energy
demand of each property on the network from Table 1. The consumption for each domestic
property is categorised by age and type, this is then adjusted by regional weather correction factors
from Table 3.
Example: A block of 6 flats built in 1965 in North East England (+11%)
8,653𝑘𝑊ℎ × 6 𝑓𝑙𝑎𝑡𝑠 × (1.0 + 0.11) = 57,629 𝑘𝑊ℎ
The consumption for each non-domestic property type is categorised by use and floor space on
Table 2, then adjusted for regional weather correction (this should be applied to only the proportion
of the benchmark related to degree days).
Example: A general office (fossil-thermal prorated to degree days= 55%) in East Anglia (+4%) with a
floor space of 90m2
120
𝑘𝑊ℎ
× 90𝑚2 × (1.0 + (0.55 × 0.04) ) = 11,038 𝑘𝑊ℎ
𝑚2
Note: Energy Demand Benchmarks will not be appropriate for all networks, if method 3.4
produces a higher heat supplied value than heat generated, please revert to using method
3.2.
Heat Network (Metering and Billing) Regulations 2014
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Guidance for Estimating Heat Capacity/ Generated/ Supplied
i
http://www.biogas-renewable-energy.info/biogas_composition.html 24/02/2015
ii
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/447648/DUKES_2015_Anne
x_A.pdf 18/08/2015
iii
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/424254/heat_networks.pdf
26/03/2015
iv
http://physics.info/energy-chemical/ 03/06/2015
v
http://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html 18/08/2015
http://www.which.co.uk/home-and-garden/heating-water-and-electricity/guides/how-to-buy-the-best-
vi
boiler/oil-boilers/ 03/06/2015
vii
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/447648/DUKES_2015_Ann
ex_A.pdf 18/08/2015
viii
http://www.energysavingtrust.org.uk/domestic/content/our-calculations 24/02/2015
ix
Peter Frost and Stephen Gilkinson, 27 MONTHS PERFORMANCE SUMMARY FOR ANAEROBIC DIGESTION OF
DAIRY COW SLURRY AT AFBI HILLSBOROUGH, June 2011
x
xi
http://www.energysavingtrust.org.uk/domestic/content/our-calculations 24/02/2015
http://www.energysavingtrust.org.uk/domestic/saving-water 10/11/2015
Contact Details
Enforcement Authority
National Measurement & Regulation Office
Stanton Avenue
Teddington
London
TW11 0JZ
Enquiry Telephone: 020 8943 7227
Website:
www.gov.uk/heat-networks
Email:
heatnotifications@nmro.gov.uk
Enquiry System:
www.rohs.bis.gov.uk/enquiry.aspx
End of Document
Heat Network (Metering and Billing) Regulations 2014
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