Finding the right mix of RES technologies for your DHC system
Replacing fossil heat generation with RES is in many cases a challenge and requires a thorough analysis of the locally available resources. Often a single high capacity fossil heat generation unit needs to be substituted by several heating plants based on a mix of RES technologies.
The main heat generation technologies for RES DHC available today are:
biomass in heating or CHP plants
Biomass is the predominant RES for heat production in many countries. Its use in heat-only and CHP plants is based on the combustion of wood-chips from forestry and from wood industry, wood pellets or straw.
biogas and biomethane CHP
Mid-size DHC systems are often based on gas motors or turbines using natural gas. Biogas and Biomethane, often produced by fermentation of biomass and organic waste, can increase the RES share of such gas-driven DHC systems.
deep geothermal heat
Deep geothermal DHC plants extract heat from deep natural water reservoirs. Depending on the depth and the temperature of the reservoir, the heat is used for electricity production and / or DHC.
large-scale solar thermal
Large ground-mounted solar collector fields can deliver RES heat to DHC systems at temperatures of up to 100 °C. Solar district heating plants are ideally suited to cover the full summer load of the DHC network or, in combination with large heat stores, also higher shares.
For more information, you can find it in the solar district heating info package for cities and towns.
heat pumps using low-temperature waste heat or shallow geothermal heat
Heat pumps move heat from a lower to a high, more useful temperature level, in most cases driven by electricity. In DHC systems they enable the use of low-grade waste heat and the use of excess RES electricity.
power-to-heat systems (P2H) based on RES
In regions with high shares of fluctuating RES electricity generation from wind turbines and PV, excess RES electricity can be integrated into DHC networks, by heat pumps or electric boilers, preventing curtailment.
waste heat based on RES
The use of locally available waste heat e.g. from industry has an enormous potential. Waste heat at useful temperatures can be directly applied for DHC. Low-grade waste heat can be upgraded through heat pumps.
