For countries such as the United Kingdom and others in Europe, the decarbonisation of homes and buildings is a key step towards meeting the Paris Agreement and its intent to contain the rising temperatures globally.
In the UK, for example, homes contribute approximately 20% of the national carbon emissions, primarily through heating. Thus, the move to low carbon heating will be critical. In part this will occur with lower carbon generation, but new low carbon heating technologies and more efficient operation of heating systems also can support the containment of carbon emissions.
In addition, there is the potential of such systems, including both water heating and space heating systems, to serve as electricity storage and provide services to the grid. However, although domestic water heaters have long been used as an easily implementable low-cost option for utility demand management, there has been limited focus on this storage potential, which also offers another route to enabling consumer participation in the market.
RealValue for energy storage
In order to get a handle on this potential the RealValue project was launched in mid-2015 by a consortium of utility, energy service, industrial and academic partners led by the major Irish heating and household supplier Glen Dimplex.
The three-year project, which was supported from the European Union’s Horizon 2020 programme, has involved demonstrations of smart electric thermal storage systems (SETS) in over 750 diverse properties across sites in the three countries, Ireland, Germany and Latvia. The properties, both domestic and non-domestic, also were equipped with smart plugs, sensors, smart meters and gateways. In Germany, a ’retrofit’ solution to enable advanced control of traditional storage heaters also was developed within the project and rolled out in around 25 properties.
The gateways, connected to the internet, linked the heating appliances to an aggregation platform to interpret the available flexibility. This information was then transmitted to a cloud optimisation engine integrated with the electricity grids in each country, allowing an understanding of the current and future wholesale prices and other network constraints. An optimised charging schedule for each appliance was then calculated and passed through the gateways to be activated, providing load balancing services.
Market potential of thermal storage
Among the findings from the project, the capacity value of SETS is of a similar scale to the potential for system operating cost savings, i.e. less conventional plant capacity is required when SETS are deployed over direct resistance heating.
Smart control of the SETS devices simultaneously reduces charging costs of the devices while improving the thermal comfort of the end user. It also has potential to manage congestion on the distribution network.
Deployed at scale SETS devices can have a significant impact on power system operating costs, providing savings of up to 3% compared to direct resistance heating. Through load shifting and reserve provision, SETS devices facilitate more efficient power system scheduling, reducing wind curtailment and power plant cycling.
SETS deployment is deemed to be particularly valuable in future scenarios where fuel and carbon prices are high or very high shares of variable renewable generation are achieved. Moreover, the system value of SETS is generally expected to increase in the future, with rising fuel costs and penetrations of variable renewable generation. However, the potential value SETS deployment can realise will be impacted ultimately by the adoption of other flexibility solutions and the development of technologies in competing markets such as heat pumps.
“RealValue has proven the value for small scale energy storage and we look forward to building on the results,” says Rowena McCappin, Project Director at Glen Dimplex Heating and Ventilation
Impact on the grid
Along with a strong focus with new learnings on customer engagement, the project brochure notes that RealValue has generated valuable learnings in terms of impact on the grid, in particular in Ireland where both the transmission and distribution system operators EirGrid and ESB Networks were participants.
For example, it has facilitated an appreciation of the dynamic nature and flexibility of SETS in comparison with traditional storage heating and an understanding and appreciation of the new demand profile associated with the technology. It also allowed the development and demonstration of grid-friendly control architectures to ensure SETS technology can fully utilise existing network capacity without forcing electrical system uprates.
“The project has been instrumental to the development and appreciation of future technologies and services required by a DSO,” says Cristina Coleman Kenny, Smart Networks Engineer at ESB Networks.
Similarly, John Young, Senior Engineer at Eirgrid, adds: “The project has increased understanding of the type of role such small-scale storage technology will play in the future and what we as system operator may need to do to both enable and respond to it.”
Looking to the future, while flexibility markets are emerging in some countries in Europe, key at this stage is their wider development, which is coming with the Clean Energy Package but may differ across countries and regions.