COHEASY: flexibility to balance energy production and consumption

A mismatch between energy production and consumption can lead to a surplus of renewable energy on the electricity grid (congestion) at one moment and an increase in the consumption of grey electricity the next. In both cases, the system is out of balance. Linking the electricity grid to a heat network with heat storage can provide flexibility and reduce imbalances. We call this principle eHeatFlex. The COHEASY project is investigating the opportunities, risks and boundary conditions for eHeatFlex. Working with a focus group ensures that the findings are the best possible match with the market.

Energy storage as a key concept

In the case of solar and wind energy, the production profile and demand are often not balanced. A mismatch between energy production and energy consumption can lead to a surplus of renewable energy on the electricity grid (congestion) at one moment and an increase in the consumption of grey electricity the next. In extreme cases, congestion can even lead to the shutting down of renewable electricity production. Given this background, energy storage is therefore seen as a key concept in robust energy systems. This means that renewable energy sources can be used to the maximum to meet energy demand.

System integration for flexibility: eHeatFlex

Underground heat storage systems provide a better link between and balance for heat demand and supply. They may even help to make the electricity system flexible. At times when there is a surplus of sustainable electricity, electricity is converted into heat efficiently, for example by means of a heat pump. The heat is then stored underground. We call this concept “eHeatFlex”. There are still a lot of questions about practical implementation, such as the role this concept can play. What are the opportunities and boundary conditions for eHeatFlex? How can we quantify the performance or added value of “flexibility” for the heat and electricity system in order to compare performance in different scenarios? We hope to answer these questions in the COHEASY project.

The emergence of Renewable Energy Sources (RES) makes it increasingly important for the electricity grid and consumption to be in a position to cope with rapidly changing production. Flexibility can be achieved with eHeatflex – a link between the electricity grid and a heat network with storage.

Drafting and analysing scenarios

A focus group has been set up to ensure that our solutions match the market as closely as possible. It includes representatives of various stakeholders such as energy suppliers, network operators, engineering firms and energy consultants. We are elaborating two scenarios for underground heat storage and heat pumps, with margins for things like temperature, heat storage capacity and the heat pump, for example. With the focus group, we are identifying the most important yardsticks in these scenarios for assessing the performance of the eHeatFlex concept. That may include looking at costs or carbon emissions, for example.

WarmteStad Groningen

One of the scenarios we are working on comes from our project partner WarmteStad in Groningen. They are currently building an innovative heat plant which will combine the use of residual heat, solar thermal energy, heat pumps and heat storage. With WarmteStad, we are investigating how this complex system can be used in the most sustainable and cost-efficient way. We are sharing the results with the focus group and through other relevant projects.