The case

Ry District Heating Utility provides heat to 95% of households in the Danish towns of Ry and Gl. Ry – a total of 3,450 consumers – with an annual production of 71,000 MWh and a peak load of 22 MW. The utility companies in the two towns merged in 2024 and are now connected by an 8.5 km transmission line.

Previously, Ry relied primarily on wood-chip boilers, while Gl. Ry was heated by a gas boiler. Today, the joint utility’s diverse and flexible energy mix includes an electric boiler, two wood-chip boilers, solar thermal collectors, a groundwater heat pump - and now, four high-efficiency CO₂ heat pumps supplied by Fenagy. Two oil boilers and a gas boiler are kept, but for back-up only.

The system in Ry is designed for maximum flexibility. Heat produced by the heat pumps and the electric boiler can either be fed directly into the district heating network or stored in two large accumulation tanks (5,000 m³ total) when electricity prices are low. In the summer, the solar thermal collectors and heat pumps provide most of the heat for the two towns. In winter, the wood-chip boilers supplement the system.

The shift to heat pumps and flexible electricity consumption has dramatically reduced fossil fuel dependency. As a result, the use of natural gas has been nearly eliminated – cutting CO₂ emissions by an estimated 80–100 tonnes annually. Additionally, the system contributes to grid balancing: the heat pumps and electric boiler can ramp output up or down in real time, helping to stabilise the grid and optimise energy costs.