By Lars Gullev, Managing Director VEKS and Chairman of DBDH THE COLUMN
CONVERSION TO RENEWABLE ENERGY MEANS INCREASED DEMAND FOR WELL-FUNCTIONING DISTRICT HEATING SYSTEMS
In this issue of Hot Cool, we focus on "System Integration" in the broader sense.
In recent years we have seen an increasingly focused transition from fossil fuels to renewable energy in both the electricity and the district heating sector. In many countries, an increasing share of the electricity production is now based on the utilization of solar energy in the shape of solar cells and utilization of wind in the shape of large wind farms both off-shore and on land. Since there is often no correlation between the time of production of renewable electricity and the current consumption, there is a need to store the produced electricity. However, this remains a major challenge as the costs of storing electricity on a large scale are very high. Similarly, we also see in the district heating sector that renewable energy in the shape of biomass is gaining ground, just like the utilization of waste heat from the industry becomes increasingly important. In other district heating systems, electric heat pumps ensure that low value energy sources can be utilized in district heating systems. In many district heating systems, there are already today storage options in the form of heat accumulators, which are primarily used on a daily basis to ensure the balance between the district heating production and consumption. However, in recent years, we have seen more and more district heating systems where the heat storage capacity is much larger than to ensure balance on a daily basis. One example is the district heating system in Vojens, Denmark, where 70,000 m2 of solar collectors and a heat storage capacity of 200,000 m3 ensure that almost 50% of the annual heating consumption of Vojens District Heating Company’s customers can be met by renewable energy in the form of solar energy. Thus, we can see that already today the integration of not only the electricity and district heating systems, but also of the production of goods with utilization of waste heat, is taking place.
• In the article "The future of district heating and cooling networks - Intelligent controllers based on machine learning algorithms", we learn how waste heat from flooded mine shafts is used as energy storage for DHC networks. • "New roles of CHPs in the transition to a renewable energy system" - puts focus on the challenges that CHP plants will have in energy systems, in which a large part of the electricity production comes from wind power. • "The smart energy system integrates fluctuating renewable energy" focuses on how the district heating system can be utilized as storage for cheap electricity. • "System integration - Coordination on all levels" puts focus on the need to think across regional boundaries, municipal boundaries and borders between utilities, if we are to ensure an optimal system integration. • "A fairy tale of 100% efficient use of resources - the lifecycle of a citrus fruit from South America to Denmark" emphasizes the fact that a well-functioning district heating networks is a prerequisite for an effective resource utilization. If we are to succeed in the transition of our societies to more renewable energy, it is essential that we ensure well-functioning district heating systems. Without such systems, we will not be able to utilize waste heat from companies on a large scale; we will not be able to store solar heat from summer to winter and we will not be able to integrate the electricity system and the district heating system in the shape of large electric heat pumps, which utilize cheap wind-based power generation. I hope that these articles can be an inspiration to ensure an efficient use of our resources, with well-functioning district heating systems as part of the backbone of future energy systems – PLEASE ENJOY READING.
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