Umweltbundesamt
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Climate change will increase the demand for cooling energy. At the same time, the energy supply is particularly affected by extreme weather events. These can lead to a shortage of cooling water, disrupt supply chains for fossil fuels and cause damage to the power grid.
As a result of higher temperatures, the need for cooling increases in buildings and production facilities, but also in the transport and storage of goods and merchandise. If cooling is provided by air-conditioning systems, this is associated with a greater demand for electricity.
In the period from 2008 to 2016, an increase in final energy consumption of almost 36 percent was observed for space cooling. The future development of cooling energy demand depends primarily on the type of cooling systems. While active cooling systems such as air conditioning systems contribute to energy consumption, passive cooling measures such as ventilation cooling or sun shading systems offer energy saving potential. In general, however, an increase in the number of air-conditioning systems and the associated higher electricity demand can be assumed.
Bottlenecks in energy supply in Germany due to the higher cooling energy demand are not to be expected. This is mainly because the share of cooling energy is relatively small in relation to the total energy demand.
Thermal power plants such as coal, nuclear, gas and steam power plants need cooling water to generate electricity. In the combustion process, only about 40 per cent of the energy is converted into electricity. The remaining energy is converted into heat, which is released either into the air or into the water. The cooling water is usually taken from flowing waters, into which it is then heated and reintroduced. When water levels are low and water temperatures are high, the power plants' electricity production may be throttled or temporarily stopped.
Low water levels can restrict the availability of cooling water and reduce the efficiency of power plants. When water temperatures are high and water levels are low, the withdrawal and discharge of cooling water into water bodies may be restricted due to environmental regulations.
Dry periods and heat have increasingly led to a shortage of cooling water in the past. For example, several power plants had to curtail their output due to the heatwave in summer 2018. However, a threat to the German electricity supply due to the curtailment of individual power plants is not apparent.
Indicator from the monitoring on the DAS: Ambient temperature-induced power reduction in thermal power plants
For the fossil energy sources hard coal and lignite as well as oil and natural gas, the delivery of the respective primary material is a prerequisite for reliable electricity generation. The transport takes place either via roads, railways or waterways or via pipelines. Delivery failures primarily affect power generation from gas and coal.
Supply chains for fossil fuels can be interrupted if transport via railways, roads and inland waterways is restricted due to storms, heavy rain or flood events. Gas and oil pipelines that run underground are rarely affected by climatic influences. Low water events can also restrict the navigability of inland waterways, affecting the transport of energy sources such as oil and coal. The transport of hard coal via inland waterways was already affected by prolonged low water in the summer of 2015. In order to avoid supply bottlenecks, shifts from inland waterway vessels to rail were necessary in some cases.
Restrictions in the energy supply result in particular from interruptions in the power supply via distribution and transmission grids. These can occur when the grid infrastructure is damaged by heavy rain, floods or storms. High temperatures also deteriorate the transmission capacity of high-voltage lines. In the case of underground cables, dryness in the ground can lead to heat not being able to dissipate and energy distribution becoming congested.
In addition to interruptions, grid fluctuations in the distribution and transmission grids can also affect the reliability of the energy supply. Grid fluctuations mainly result from changes in the yields of wind and photovoltaic plants.
Indicator from the monitoring on the DAS: Weather-related power supply interruptions
Demand for heating energy: The demand for heating energy will decrease. However, cold winters and thus periods with higher heating energy demand may occur in isolated cases in the future.
Yield reduction/increase for photovoltaic systems and onshore and offshore wind energy systems: Changes in yields are currently only expected to a small extent. The yield of photovoltaic systems is mainly influenced by high temperatures, while wind speeds are too high for wind turbines.
Lack of reliability of energy supply: Extreme weather events can cause interruptions and grid fluctuations in the energy supply and thus impair the reliability of the energy supply.
The UBA’s motto, For our environment (“Für Mensch und Umwelt”), sums up our mission pretty well, we feel. In this video we give an insight into our work.
