Unlocking flexibility of hybrid heat pumps

The hybrid heat pump will play an important role in the energy transition from fossil fuels to renewable energy sources. The electrification of heating with heat pumps will put additional stress on the distribution grid (congestion) and may lead to regular local outages. The hybrid heat pump (HHP) is part of the solution as it has the ability to temporarily switch to gas when the load on the distribution grid becomes too high. The flexibility of the HHP can be used by the DSO to perform congestion management. In order to make use of the flexibility offered by the HHP a congestion management architecture is needed. This comprises all the ICT components that are needed to go from the detection/prediction of congestion by the DSO to activating a hybrid heat pump to temporarily fall back on gas. This study presents a high level architecture for the congestion management chain that was also verified in a proof of concept in TNO’s Hybrid Energy System Integration (HESI) lab. The test included 3 different hybrid heat pump models that are currently available on the Dutch market. It was shown in the lab that they can be controlled in a rudimentary way to switch from electricity to gas by making use of the Smart Grid Ready (SGR) interface. Although the SGR interface is not ideal as it does not allow for more advanced forms of flexibility, the good news is that it is already supported by most HHPs available on the market today. Therefore the use of the SGR interface is a good step in the right direction for implementing congestion management. As explained earlier there are also other components required to form a complete congestion management chain. They have been designed to be open and interoperable so that they can be reused for other demand response services that also use the flexibility of a HHP and involve other energy stakeholders such as an aggregator. In the case of congestion management by the DSO this report shows that the smart meter can be used to convey temporary connection limits to the Home Energy Management System of an end user. This smart meter solution is not restricted to a single device and can work just as well with a HHP as with EV, PV inverters, batteries or a combination of these devices. Although the results with the congestion management proof of concept in the lab are very promising, a lot of steps still remain to be taken to scale up the lab results to large operational deployments. For this purpose a timeline is presented that describes the most important steps. A first recommendation is to start congestion management pilots that involve larger numbers of HHPs from which practical lessons learned can be derived. Another important step is to put regulation in place that specifies under which conditions congestion management by a DSO can take place and how end users will have to react to connection limits and what the consequences are of failing to do so. These follow-up steps require urgent action as the number of HHP installations is quickly increasing.