Chapter 2: Ambition & targets
Our ambition is for a heat networks sector that:
- delivers affordable clean heat supporting delivery of emission reduction and fuel poverty targets
- develops local supply chains and attracts new public and private investment
- contributes to the development, and operation, of an integrated and resilient energy system
Targets to 2027 and 2030
The 2021 Act sets statutory targets for the amount of heat to be supplied by heat networks, requiring the combined supply of thermal energy by heat networks to reach 2.6 TWh of output by 2027 and 6 TWh of output by 2030. This is 3% and 8% respectively of current heat demand . As heat networks can provide heat to homes, workplaces and industry the targets could be met with a range of outcomes in terms of the numbers of these types of buildings and processes that are connected.
The targets are broadly equivalent to 120,000 and 400,000 average gas using homes being connected to heat networks for 2027 and 2030 respectively. Multi-building heat networks are generally anchored around large non-domestic buildings, which account for a significant portion of the heat supplied. As such it is anticipated that the number of homes connecting to heat networks up to 2030 will be lower, with a significant proportion of connections being to non-domestic buildings, which are more suitable as anchors and early customers of heat networks. The number of domestic connections would be expected to rise once heat networks are established and being further developed.
Box 1: What is an anchor load?
Buildings with a large, reliable and long-term demand for heat, often with a stable and constant use profile, can act as anchors for a developing district heating network. Examples include hospitals, swimming pools and high-density housing. These anchor loads allow such district heat networks to operate efficiently and provide the potential to extend the network to smaller existing heat users in the area.
The First National Assessment identified a maximum of 13.73 TWh/yr of heat demand that could be supplied by heat networks, under stringent conditions requiring a high density of heat. As shown in Table 1, the First National Assessment found that over 80% of identified heat demand in zones was attributed to non-domestic buildings. It also found that over 65% (an estimated 9.30 TWh/yr) of the total identified heat demand in zones could be attributed to anchor loads alone.
|Number of properties
|Heat demand (TWh/yr)
Note: Unattributed property type includes buildings that could not be identified as either domestic or non-domestic from the data held.
To further illustrate the impact that the number of non-domestic buildings connecting to heat networks has on the number of domestic properties required to connect we have developed a series of simple scenarios, based on the outputs of the First National Assessment (see Chapter 1). They each assume a proportion of anchor loads, other non-domestic properties and domestic properties connect across potential zones identified in the First National Assessment.
The scenarios are intended to be illustrative only and are not a statement of ambition. Real world deployment will be guided by detailed heat network zoning, feasibility studies and business case development.
Table 2 below shows three scenarios, all capable of meeting the 2030 heat network target. Across all three scenarios there is a high number of non-domestic connections. These connections are important as they help to ensure a more balanced load throughout the course of the day helping to ensure efficient network operation.
In reality, as noted above, the type and number of buildings connecting will be dependent on detailed feasibility studies and business cases. It is likely that the number of residential properties connecting will be higher. Initially this will be guided by the Local Heat and Energy Efficiencies Strategies (LHEES) and Heat Network Zones designated by local authorities.
|Number of properties connected
|Heat demand (TWh)
|A (Anchor loads + 60% of flats)
|B (Anchor loads + 30% of all domestic properties)
|C (Anchor loads + 70% of buildings with heat demand in interval [250 - 500) MWh/yr + 60% of flats)
Note: "properties" refers to the number of properties of that type identified within a potential zone as identified in the First National Assessment. Scenarios do not have connections in the same number of potential zones, nor do they have connections in all potential zones identified under the stringent conditions.
Future target setting
The 2021 Act requires Scottish Ministers to set a target for 2035, in addition to the 2027 and 2030 targets. Respondents to the Draft HNDP consultation suggested a number of wider considerations in setting the 2035 targets including progress toward the 2027 heat networks target as well as toward wider heat decarbonisation targets including energy efficiency. Respondents also raised concerns that by 2030 the best opportunities for heat networks may have been taken.
We will consult on a proposed 2035 target in early 2023, which will be informed by the First National Assessment of Potential Heat Network Zones (see Chapter 4) and work carried out to develop LHEES. We will set the 2035 target by 1 October 2023. Chapter 7 sets out how we intend to measure the targets set and to begin to improve monitoring of these.
Contribution to emission reduction targets
Emissions reductions as a result of expansion and development of heat networks will vary depending on:
- the buildings they supply, including whether they are existing or new, and whether the heat network is replacing existing fossil fuel heating systems and
- the heat source(s) of the heat network the building connects to.
As set out in the Heat in Buildings Strategy and Chapter 3 below, from the point that the heat network legislative framework is in place, new heat networks, and any additional heat plant for extensions of heat networks, will need to be powered predominantly using low and zero emissions sources of heat such as heat pumps or sources of surplus or waste heat. Therefore, we would expect them to generate significant emissions savings, beyond those from gas-fired networks often using CHP which under the current system may be installed. To provide an example of this, assuming that heat pump powered heat networks replaced 6 TWh of heat from individual gas boilers in homes the savings are broadly estimated to be 1.1 MtC02e per year in 2030. Scenarios (as above) where a high proportion of the heat is provided to non-domestic properties broadly estimate emissions savings to be between 1.18 and 1.19 MtC02e per year in 2030.
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