Electricity network constraints and the 2024 New Build Heat Standard: research

Research looking into the network constraints issues associated with the electrification of heat for domestic new build developments. The focus of the work was on connection costs for these developments, how the cost is defined, and apportioned to the relevant stakeholder.

5 Innovative projects and approaches

European countries are seen as the world leaders of decarbonised heating solutions. In reality they vary greatly with some countries being almost already fully decarbonised, while others are still relatively early in their journey.

Scandinavian countries have been very successful at decarbonising heat. For Sweden, the share of fossil fuels is now below 5%. This has been achieved by removing oil and other fossil fuels for heating in both detached homes and blocks of flats over the past 50 years. Fossil fuel energy has been replaced by both district heating and electricity through resistive heating and heat pumps, which provide up to 75% of the energy demand for heating in buildings. However, critics state that Sweden's burning of waste, which is a source of heat for the district heat networks, has been at the expense of opportunities to recycle. There is also a concern that there is not enough focus on building efficiency.

In Eastern European countries like Estonia, the largest share of heating is derived from domestic biomass where it is regionally produced and widely available at a low cost.

Western and Central European countries have had difficulty decarbonising heat as they have grown reliant on gas networks embedded into their infrastructure. Without biomass or heat networks to rely on the challenge of heat decarbonisation will be difficult, it is expected that countries will turn to electricity or hydrogen as a primary solution.

Zero emissions heating technologies have not yet been deployed at the scale required to meet the world's decarbonisation targets. Deploying them at scale presents new challenges otherwise unseen, including the challenge of network constraints. Innovation projects can provide us with the opportunity to investigate methods of mitigating these challenges.

Innovative projects in the UK and internationally have built experience in the electrification of heat and enhanced understanding about technologies and the effects they may have on the electricity network. A selection of projects is discussed in this section, and each project is described in Appendix A4.

5.1 Identifying and understanding heating solutions

The diversity of housing types, standards of thermal insulation and level of grid connection means that there is no one-size-fits-all solution for heat decarbonisation. Therefore, decarbonising heat needs attention at the local level as well as the national level. The project "Spatial analysis of future electric heat demand" is exploring optimal decarbonisation pathways by creating a geospatial analysis of heat energy demand and providing network impact assessments to identify the least regret network investment options required [11]. It is expected that this could assist in guiding what technology is suitable for individual locations to reduce network investment.

"Heat street" is developing an approach to forecasting energy efficiency measures and low carbon heating solutions. The project plans to use zoning assessments that will help to identify areas that may be particularly well suited to heating electrification so that heat electrification can occur at a faster pace with higher end-user satisfaction [12].

A key barrier to the roll out of decarbonised heating technology is a lack of understanding of the technology and its impact on the network. Electrification of heating using heat pumps was assessed in the "Electrification of Heat Demonstration Projects" that aimed to demonstrate the feasibility of a large-scale roll-out of heat pumps [14]. The projects developed, tested and evaluated innovative products and services that could increase the appeal of heat pumps and demonstrate their technical feasibility. The learning from the project was used to improve awareness across the heating supply chain, raise acceptance and support for the wider deployment of heat pumps in GB. Similarly, the "Flexible Residential Energy Efficiency Demand Optimisation and Management" project investigated the feasibility of hybrid heat pumps on the Western Power Distribution network [15].

There is work being undertaken to build greater understanding of low carbon appliances and technologies and therefore enable more informed, consistent and efficient network design. An example of this is work being undertaken by SPEN and SSEN who are developing ADMD calculators that take more detailed data into account when calculating ADMD for domestic developments including low carbon technologies. These are being shared and published between stakeholders in order to build a consistent approach that is well understood.

The electrification of heating can provide unique circumstances for an electricity network where heating systems will draw an unusually large load when the network is cold starting. In the project "Cold Start", UKPN are building a simulation model to assess how the energy system responds and inform policy and future studies on providing solutions to ensure the power system remains reliable during such events [16].

The project "Electrical Heat Pathways: Looking Beyond Heat Pumps" sought to influence policymakers to give proper consideration to storage heaters in the discussion on heat decarbonisation and ensure that policy does not inadvertently act as a barrier [19]. The project highlights the possibility of commercial arrangements to reward the provision of flexibility and diversity provided by storage heaters.

5.2 Energy management

Energy management solutions use the inherent flexibility of loads to optimise the time that they are used, potentially providing benefits such as reducing overall peak demand, or moving load to times where the grid carbon intensity or the electricity process is low.

Electrification of heating can be used in locations where renewable energy is being curtailed to provide decarbonised heating and reduce curtailment. The project "4D Heat" looked at matching electric heating flexibility with surplus wind power and assessing the cost benefit whilst considering the implications of network constraints in Skye [17]. Key findings were that utilising surplus electricity meant that some consumers could save as much as 18% on their annual home energy bill and 17% of curtailed wind could be absorbed by electric heating systems.

The Northern Isles New Energy Solutions project in Shetland introduced methods of managing the distribution network more effectively [18]. It included, replacing 1,000 homes with modern smart storage heaters with demand response triggers, connecting a 1MW battery and adding an electric boiler to a district heating system associated with a local wind farm. The project allowed the operators to assess the interactions and provide an added level of control for the benefit of the network.

The Maiden Hill case study (see Appendix A2.3) is another example of an energy management project. Increasing the amount of low carbon technologies to be included on site resulted in the maximum demand of the site exceeding the network available capacity, with the costs to release further capacity quoted at approximately £7.5m. In response, the consortium of developers, the DNO, the IDNO and technology providers are investigating using energy management technologies to manage the load to within the existing site capacity by maximising the use of electricity generated on site with solar panels, and managing flexible loads such as hybrid heat pumps and EV charging infrastructure to avoid drawing power at peak times.

5.3 District heating

In the UK, we have limited experience of modern district heating networks. However, there is more experience in other countries such as Denmark where district heating is part of Copenhagen history. It is one of the world's largest, oldest and most successful district heating systems [20]. The heat used is primarily from waste heat released by electricity generation power stations that would otherwise be vented into the atmosphere. The utilisation of this heat supplies 97% of the city with clean, reliable and affordable heating. The primary costs for developers connecting new properties is the pipework to the properties, consideration of heat generation is not required.

An example of a district heat network being developed in Scotland is Queens Quay, Clydebank [10]. The district heating network will utilise the steady temperatures of the River Clyde to supply heat to nearby properties and residents. The water source heat pump will be sized to meet the majority of the heat networks demand and uses back-up conventional boilers for the rare times that the water source heat pumps can't meet the demand. The cost for developers is the heat generation technology and the pipework to the properties but the sizing of the heat pump should keep the overall electricity demand for heating low and with little fluctuation.

ENGIE's harmony project included ground source heat pumps providing heat to 400 flats in eight blocks across two estates in the London Borough of Enfield [21]. The project uses an individual heat generator approach for district heating. Pumps move water round the pipe network, where the water is not artificially heated but instead remains at ground temperature. A "Kensa shoebox" heat pump in each property extracts heat from the ground temperature water and raises the heat provided to 65⁰C so that it can be used for hot water and space heating within the property. The system requires district heating pipework as well as individual heat pump units in each property.


Email: 2024heatstandard@gov.scot

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