District heating ensures faster green conversion. District heat- ing is already driving the green transformation of space heating.
When a district heating company switches to renew- able heat production, it immediately affects the heat consumption of all district heating customers. This happens, for example, through an ongoing replace- ment for greener and more efficient plants and fuels. It does not require an investment or conversion on the part of the individual heating customer, which is also why the conversion can go faster via district heating. District heating has the potential to implement the green transition quickly and as part of an overall integrated solu- tion. District heating has a better seasonal match with power pro- duction from wind and solar and less strain on the electrical system. This means less need for network extensions and seasonal energy storage. There is less need for expansion of the power grids at both transmission and distribution levels. Here, it also contributes positively that the district heating’s heat pumps can often be connected to a strong point in the electricity grid. Faster daily fluctuations in the power system are also handled better with electrification via district heat- ing than with individual heat pumps and electric heating. High energy efficiency in district heating and lower electric- ity consumption in winter save investments for the estab- lishment of additional green power production. Only district heating’s large heat pumps can utilize heat sources such as excess heat, cleaned wastewater, ground- water, geothermal energy, and seawater. These energy sources are locally available, provide diversity in the energy supply, and do not fluctuate like wind and solar energy. Summary District heating is synergistic with wind power and delivers good sector integration. If the green conversion of the heating sector is to be cost-effective for society, district heating must be chosen as the driver instead of individual electricity-based solutions. District heating provides access to flexibility and storage on both a seasonal and hourly/daily level, which benefits both power and heating systems. District heating’s heat pump or electric boiler does not deliv- er this alone. Good sector integration comes from the overall combination of the district heating infrastructure, large heat pumps, good heat sources, electric boilers, other heat produc- tion, storage, and intelligent operation.
Figure 3: Denmark’s energy consumption for electricity and heat, respectively, in 2018 (Source: Danish Energy Agency)
be stored in large heat storages as Pit Thermal Energy Storages (PTES)
District heating’s electricity consumption has smaller season- al fluctuations than that of electric heating or individual heat pumps and thus fits better with electricity production from wind turbines. Generally, space heating does not fit well with power production from solar cells, but district heating does fit better than individual heating. Comparison of consequences - types of electrification Sometimes, you come across the idea that heating in Den- mark should be completely electrified. However, this is far from the most efficient solution, neither technically nor financially.
Why not?
The answer is partly given in Fig. 3, which shows the total Danish electricity and heat consumption in 2018. The heat demand is almost 100% larger than the electricity demand, and the figure clearly illustrates how a complete conversion to electricity-based heating is not realistic with the power system we have today. As the report and the arguments below illustrate, partial elec- trification via district heating will provide a much better syner- gy. Basically, the green conversion of electricity and heating is about creating cost-effective and robust systems that benefit the overall economy of society and customers. Here, renewable electricity from wind turbines and solar cells is not a goal in itself but a means on equal terms with other renewable energy sources, energy efficiency improvements, district heating infra- structure, technology development, and digitalisation. Why district heating goes best with green electricity Of the three ways of using electricity for heating, the district heating solution uses the least electricity. It is most compatible with a green transition, where power production from the sun and wind plays a major role. Below are several arguments for why electrification of space heating is better via district heating and? gives a more effective green transition compared to individual electric heating and heat pumps.
For further information please contact: Lars Gullev, lg@veks.dk
30 HOTCOOL no.6 2024
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