100% renewables means 95% less water consumption for conventional power generation

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A global energy system based on a 100% share of renewable energy would be cleaner, cheaper and better equipped to fight climate change, but it would also help reduce water consumption from conventional power generation by more than 95%.

This is the main conclusion of new a new study that was recently published in Nature Energy. The research team behind the study includes Christian Breyer, professor of solar economy at Finland’s Lappeenranta University of Technology.

According to Breyer and his colleagues, solar PV withdraws and consumes between 2% and 15% of the water that coal and nuclear power plants use to produce just 1 MWh, while for wind this percentage ranges from 0.1% and 14%.

“In this regard, renewable energy represents a viable solution as it couples almost zero greenhouse gas emissions with very low to negligible water demand for power generation,” the researchers said.

The study is based on data collected from 13,863 thermal power plants above 50 MW in size, with an aggregate capacity of 4,182 GW. That represents approximately 95.8% of the world’s total thermal power generation capacity, the researchers said. Their best policy scenario, based on the LUT Energy System Transition modeling tool, was developed to assess water consumption for thermal and nuclear power generation for the 2015-50 period.

In 2015, the United States was the largest consumer of water for conventional power generation, with a 35.7% share, followed by China at 31.5%. If the best policy scenario is implemented by 2030 – which would mean that a huge number of nuclear and fossil fuel-based plants would be decommissioned – water usage could be reduced by 75.1% compared to 2015 levels, the researchers claimed.

“During the analyzed period, 1,797 GW of new gas power plant capacities are scheduled to commission globally, from which 1,365 GW are open cycle units and 432 GW are combined cycle units. For this reason, in 2050, water withdrawals are projected to remain large in the territory from the northeast to the south of China, South Korea, Benelux countries, central regions of Russia and Iran,” the researchers stated.

By 2050, however, the water consumption of the world’s power plant fleet could be decreased by 97.7% and water withdrawal by 95.1%, if the best policy scenario becomes reality. The water that would be not used for power generation could then be diverted into food production or aquatic ecosystems.

“Thus, the results of our research can potentially help in further studies on global food security to achieve a sustainable water-energy-food nexus,” the researchers said.

The researchers also identified the world’s rivers that are the most affected by water withdrawal. For all of them, the team has indicated how water stress could be reduced or mitigated by 2050.

“We show that the depletion of water resources caused by the water-energy nexus can be mitigated by transitioning to an electricity supply based on renewable energy,” they concluded.

According to a recent report by LUT University, solar may become the cheapest and largest energy source by 2050, with an impressive 68% share of global power generation. In the electricity sector, PV is also expected to become the largest and cheapest source, increasing its share from 32% in 2030 to 73% by 2050, with wind power falling from 43% in 2030 to 20% over the same time frame. The report predicts that PV will reach an installed capacity of 34.8 TW worldwide by 2050, while wind will hit 4.6 TW.