Towards the end of 2018, my colleagues and I finished working on a project for the UK Department for Business Energy & Industrial Strategy (BEIS) looking into the ‘Technical Feasibility of Electric Heating in Rural Off-Gas Grid Dwellings’. This was an important project examining the often forgotten off-gas grid sector. The results from this work helped inform BEIS’ response to the call for evidence on the future framework for heat in buildings.
Why off-gas grid homes?
Simply put, there are a lot of homes located off the gas grid. Many of these homes will not be able to benefit from the current concepts around low carbon gas grids and hydrogen.
The Government has committed to “Phase out the installation of high carbon forms of fossil fuel heating in new and existing businesses off the gas grid during the 2020s, starting with new build” in the Clean Growth Strategy. This is driven by the fact that oil boilers have a higher emission intensity than gas boilers [roughly 300 vs 220 gCO2-eq/kWh heat delivered]. Targeting oil boilers is also considered to be a low regrets solution by the government, compared to trying to tackle the >23 million homes currently connected to the gas grid.
How to investigate the technical feasibility for electrifying off-gas grid heating
Using a specially developed housing stock building physics model, we investigated the technical feasibility of installing electric heating on a household level based on thermal and electrical constraints. We also made sure to account for other practical constraints. Costs or economics were not considered – which would of course impact on any scenario.
Figure 2: Electric heating technologies covered in our study for BEIS
In addition to looking at the potential to electrify heating on a household level, we considered the capacity of the low voltage electricity distribution network to accommodate increased electric heating loads.
How many homes could be fitted with electric heating?
The results are very interesting and perhaps not quite what some may have expected! It seems as if most homes off the gas grid are suited to at least some form of electric heating. By adding additional insulation, almost all homes may be suitable for some form of electric heating. In particular, high-temperature heat pumps are suited to a large percentage of off-gas grid homes.
The charts below show the suitability of houses at an individual dwelling level for electric heating.
What about the limitations of the electricity grid?
Technical suitability of homes is one thing, but the electricity networks must also be able to meet this additional load. Using data from a number of distribution network operators, we modelled the ability of the rural low voltage networks to meet the increased loads from heat electrification. The graphs below show what happens when both the technical potential at a house level and the distribution network capacity are taken into account.
The overall limiting factor to the electrification of heat is, therefore, the low voltage network. This limitation is most significant under peak load conditions, such as a 1 in 20 peak winter day. There are however several options available to help reduce the peak demand on the grid. These include measures such as demand response, intelligent controls and energy storage. By using such measures combined with aggregated control systems, we estimate that peak loading on the network could possibly be more than halved - facilitating higher levels of electrification.
For areas where challenges remain with pure electrification, other options exist. These include technologies such as using hybrid solutions and bio-fuelled boilers.
It goes without saying, there are many uncertainties and therefore assumptions that have been made to produce these figures. Perhaps one of the most significant things we did not consider was the cost or economic impact which will, of course, have a very real impact on any future electrification of heat scenario. The rest of the details can be found in the report.
Want to know more now?
The Delta-ee team and I love chatting about all things related to the UK and European energy landscape. Things are changing rapidly and it’s projects like these that put us at the forefront of the evolving new energy space. Feel free to get in contact with me at [email protected] or check out our website for more info.