For the rural village of Herrup, with 150 households located outside Holstebro, a local 3 MW wind turbine could effectively operate in combination with simple and low-cost electric heating in the village homes. Each household would install solar panels on their rooftops.

The nearby district heating plant in Haderup is equipped with a large electric heat pump and a gas engine, which the utility had planned to decommission due to its limited operating hours. However, an integrated dualist production system at the Haderup plant — combined with electrically heated homes in the surrounding rural area — could make effective use of the gas engine, which could be refurbished and operate for many more years.

System concept for the integrated project:
When the rooftop solar panels and the wind turbine generate electricity, power is supplied to the electrically heated homes via the grid, and any surplus from solar and wind is absorbed by the heat pump at the Haderup district heating plant.

When the rooftop solar and wind turbine are not producing power — and there is a heat demand in Herrup’s electric-heated homes — there will typically also be a heating demand in the town of Haderup. In such cases, the gas engine at Haderup is started: its waste heat covers the town's district heating demand, while the electricity from the engine is used to power the electric heating in Herrup via the grid.

With 400 electric-heated households — matching the 800 kW capacity of the gas engine — the overall system economics become highly favorable. The electrically heated homes, equipped with heating systems costing less than DKK 10,000, would benefit from very low heating prices, while also contributing to reduced district heating costs in Haderup.

Actual and practical simulations demonstrated that more than 80% of the electricity used for heating in the homes in Herrup could come from wind and solar, with less than 20% needing to be generated by the gas engine in Haderup.