CHARTS: How Power Generation Threatens Water Supplies, And Climate Change Threatens Both

CREDIT: Shutterstock


CREDIT: Shutterstock

The United Nations’ World Water Day 2014 is this Saturday. In its honor, the International Energy Agency is releasing its latest analysis of the intersection between the world’s power generation and its water use.

The numbers are pretty bracing.

Of the world’s freshwater supplies, 70 percent are locked up in the ice caps and glaciers, and almost another 30 percent are underground and hard to reach. Only about 0.3 percent is actually on the surface and easily accessible.

Of that measly 0.3 percent, only 11 percent goes to municipal uses, including direct consumption by humans. Seventy percent goes to agriculture and farming, and 11 percent goes to industrial uses. That last figure includes power generation, and it’s the intersection of energy and water with which the report is concerned.


CREDIT: International Energy Agency

Water is consumed at nearly every stage of energy production, especially when it comes to fossil fuels. It’s used in the hydraulic fluid in oil and natural gas fracking; it’s pumped into oil and gas wells to enhance recovery; it’s used to cut and suppress dust in coal mines; it’s used to wash coal before it’s burned; it’s used to make the slurry in which coal ash is stored after it’s burned; huge amounts are pulled in by coal, natural gas, and nuclear plants, both to cool things down and to generate the steam that spins the turbines; huge amounts are also consumed in the agricultural sector to produce biofuels; much smaller amounts are used for similar purposes for solar plants and concentrated solar power setups; and of course it’s stored in reservoirs for hydropower generation.

This also brings up the difference between withdrawal and consumption. Water that’s merely withdrawn for energy production is eventually returned to its source. Water that’s consumed is not. And the ranges of withdrawal and consumption are generally quite higher for nuclear and fossil fuel power than for wind or solar photovoltaics.


CREDIT: International Energy Agency

As of 2010, global water withdrawals by the energy industry stood at 583 billion cubic meters (BCM), and consumption stood at 66 BCM. Under current policies, IEA projects consumption will increase 85 percent by 2035, or over 120 BCM. Withdrawal will increase to 790 BCM. Under much more aggressive attempts to cut carbon emissions, IEA sees withdrawal barely rising at all by 2035 to, 600 BCM. But consumption would still double.

Water that’s consumed still eventually becomes drinkable again, as it’s returned to the Earth’s surface via the water cycle. But that takes time. And water that’s merely withdrawn and returned to its source can still be polluted — either directly by the processes it’s used in, or indirectly by emissions and discharges from burning fossil fuels (especially coal). Withdrawn water can also be unnaturally warm when it’s returned, which can damage local ecosystems.

That’s a problem because parts of the world are currently hurting for water. Most of China and South Asia’s water resources are already “vulnerable,” India’s and some of Africa’s are “stressed,” and other parts of Africa are already suffering “absolute scarcity.” These areas are home to much of the world’s poorest and most vulnerable populations.


CREDIT: International Energy Agency

IEA projects water consumption to double or more in both India’s and China’s energy sectors by 2035 — and that’s under its “New Policies” scenario, which is more optimistic than the “Current Policies” one. Withdrawal increases in both countries as well.

Finally, there’s climate change: water sources become less reliable as higher temperatures drive more precipitation and evaporation: snowpack goes down, which hurts freshwater supplies; higher surface water temperatures can make power plant cooling more difficult; and floods and sea level rise threaten freshwater supplies with contamination.

The result is a kind of double ratchet effect: as climate change makes freshwater harder to come by, traditional fossil fuel power will become more difficult to produce, less reliable, and more costly. At the same time, as long as that use by the fossil fuel industry continues, it will make drinking supplies for humans even more scarce than they would be with climate change alone.

The rather obvious solution to all three problems — climate change, power generation, and drinking supplies — is to get as much of the world’s power from renewables as possible.