Geothermal heat is not just another renewable option; it’s the stable heart of a modern, decarbonised district heating network. By securing the base-load with geothermal, cities can build more resilient, efficient, and climate-friendly heating systems.
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What is base-load in heating?
In energy systems, base load refers to the steady, constant demand that exists more or less day and night, year-round. For district heating, base-load heat is what keeps the system running when someone takes a shower at 6 a.m. or turns up the thermostat in winter – it’s the heat needed to keep the network stable and buildings comfortable at all times.
A reliable base-load source is essential because it provides security of supply and reduces the need to ramp up or down other heat sources.
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Why geothermal is the perfect base-load
Geothermal district heating is uniquely suited to supply base-load heat because:
- It runs 24/7 – Geothermal energy is available day and night, in all seasons.
- Output is predictable – Unlike solar or wind, geothermal is not affected by weather, climate, or season.
- It has low operating costs – Once built, geothermal plants have minimal operational expenses, making them economical for continuous operation.
- It’s low/no-carbon – Operating with (near-)zero emissions when powered by renewable electricity.
These qualities make geothermal heat ideal as the backbone of renewable district heating supply, with other sources – like solar thermal or waste heat – layered on top for peak demand.
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How base-load geothermal works in practice
In a typical setup, geothermal provides a steady baseline output that meets most of the network’s year-round demand.
- In winter, this base-load is supplemented by peak-load units (biomass, biogas, or waste heat).
- In summer, geothermal alone may cover the entire demand, including domestic hot water.
This approach allows utilities to run peak-load boilers far less often, reducing both emissions and fuel costs.
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Case studies of geothermal as a base-load
- Paris Basin, France – Geothermal plants provide most of the year-round heating, with other sources used only during peak winter demand.
- Munich, Germany – The city’s strategy to supply a large share of its district heating from geothermal by 2040 hinges on geothermal’s base-load capability.
- Xiong’an, China – Geothermal delivers constant heating to the network, with large-scale heat pumps adjusting supply temperature seasonally.
- Reykjavik, Iceland – Almost all heat demand is covered by geothermal base-load, with minimal backup required.
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Benefits for system planning and costs
Using geothermal as a base-load source helps district heating operators:
- Reduce reliance on fossil fuels – Lowering both carbon footprint and fuel price volatility.
- Improve network efficiency – Steady base-load operation avoids frequent on/off cycling of other units.
- Enhance investment stability – Long-term contracts for geothermal heat supply provide predictable pricing.
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A stable foundation for the green transition
As cities aim for net-zero heating, the need for dependable, renewable base-load sources will grow. Geothermal district heating offers exactly that — clean, constant energy that can anchor the transition while integrating seamlessly with other renewables.
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