Electricity prices are rising and more and more people are becoming concerned about what the future holds for energy security. What is responsible for these increases? Higher water temperatures and reduced river flows, in both Europe and the United States. A new study shows that even more worrisome is the drop in production or temporary shutdown of various thermoelectric power plants, which also trigger higher prices. The study, published in the journal Nature Climate Change, was funded in part by two EU projects: WATCH and ECLISE. WATCH ('Water and global change') received almost EUR 10 million under the 'Sustainable development, global change and ecosystems' (SUSTDEV) Thematic area of the EU's Sixth Framework Programme (FP6) and ECLISE ('Enabling climate information services for Europe') is supported under the Environment Theme of the EU's Seventh Framework Programme (FP7) to the tune of EUR 3.4 million.
Researchers in Austria, Germany, the Netherlands and the United States estimate that the supply of electricity will be disrupted even further, with thermoelectric (nuclear or fossil-fuelled) power-generating capacity dropping to between 6% and 19% in Europe, and between 4% and 16% in the United States in the period 2031–2060. The main problem will be insufficient cooling water. Current data show that thermoelectric power plants provide 78% and 91% of electricity to Europe and the United States, respectively. The researchers believe more than 90% cuts in thermoelectric power production will, on average, increase by a factor of three.
According to the researchers, the thermoelectric power sector is one of the biggest consumers of water compared to other water-use sectors. They said that while the majority of this water is 'recycled', the power plants depend on consistent volumes of water, at a particular temperature, to ensure the power plants do not get overheated. So higher water temperatures and reduced water availability, which are triggered by increasing ambient water temperatures associated with climate change, are putting even more pressure on the supply of power.
Power plants that depend on 'once-through cooling' are particularly vulnerable, while recirculation (cooling) towers are less so. Water from rivers, lakes and even the sea is pumped by these plants for cooling. The water then gets back to its source, often at temperatures that are higher than when the water entered the plant. So another problem emerges: downstream thermal pollution.
'Higher electricity prices and disruption to supply are significant concerns for the energy sector and consumers, but another growing concern is the environmental impact of increasing water temperatures on river ecosystems, affecting, for example, life cycles of aquatic organisms,' said Michelle van Vliet of the Research Centre at Wageningen University in the Netherlands.
Strict environmental standards over how much water is withdrawn and the temperature level of the water discharged from power plants are currently in place but conflicts emerge between environmental objectives and energy production when warm periods are coupled with low river flows.
Reducing dependence on freshwater sources and replacing them with saltwater could help, said co-author Pavel Kabat, formerly of Wageningen University and now head of the International Institute for Applied Systems Analysis (IIASA) in Austria.
'However given the life expectancy of power plants and the inability to relocate them to an alternative water source, this is not an immediate solution but should be factored into infrastructure planning,' said Professor Kabat. 'Another option is to switch to new gas-fired power plants that are both more efficient than nuclear- or fossil fuel- power plants and that also use less water.'
A total of 96 power plants (35 in Europe and 61 in the United States) were evaluated in the study.