A couple of articles crossed my screen this morning that highlight the unfortunate ways our use of energy and water can interact.

First, in the Bloomberg piece, China Orders Release of Water From Three Gorges Dam to Ease Hubei Drought, we learn hear that rainfall has been so low in parts of China (40 to 50 percent below normal for April and May) that the government has ordered the release of 5 billion cubic meters of water from the Three Gorges Dam. There are over 4 million people and over 3 million heads of livestock under water stress, so this was hardly a step taken on a whim.

The problem, of course, is that this means less hydropower generation (presumably from the Three Gorges generators), which will require China to increase its diesel consumption by 200,000 to 300,000 barrels per day, plus burn some unspecified additional amount of coal. Looking at just the diesel fuel part of that power shift, that’s not only additional oil demand (which caused China to cut its diesel exports by almost half last month, according to this article), but additional CO2 emissions, to the tune of roughly 75,000 to 112,000 tons per day. That’s not a large percentage of China’s emissions, of course. Another 112,000 tons every day for 90 days, for example, adds up to about 10 million tons, which is well under 1% of that country’s 6 roughly billion tons of CO2 emissions per year. Still, at a time when we desperately need to reduce emissions, this kind of fallback to using fossil fuels doesn’t help matters.

The second article is New Scientist’s The climate change threat to nuclear power which focuses on coastal plants being exposed to storms and surges, as well as the thorny issue of cooling nuclear power plants during extreme heat spells.

Heat waves are another serious concern, for two reasons. One, the colder the cooling water entering a reactor, the more efficient the production of electricity. And two, once the cooling water has passed through the system it is often discharged back where it came from in a much warmer state.

During the 2003 heat wave in Europe, reactors at inland sites in France were shut down or had their power output reduced because the water receiving the discharge was already warmer than environmental regulations allowed. Citing “exceptional circumstances”, the French government relaxed the regulations to maintain the supply of electricity. After subsequent heat waves it became a permanent measure during the summer months.

The relaxing of the regulations causes thermal pollution that reduces the ability of aquatic ecosystems to adapt to warmer temperatures. Some may argue these regional impacts are insignificant compared to the global ramifications of climate change, but they illustrate that nuclear power can actually worsen its impact.

There is a human cost too. As the heat wave wore on, French consumers were asked to conserve energy, and exports to some countries, especially Italy, were reduced. While France, which generates over 75 per cent of its electricity from nuclear sources, avoided blackouts, Italy did not. The heat wave caused an estimated 40,000 deaths, around half of them in Italy. These deaths cannot be attributed directly to the failure of nuclear power but energy conservation and blackouts surely made people more vulnerable.

The article also points out that droughts only magnify the difficulty of cooling inland nuclear plants.

As our assumptions about what makes a “good” site for nuclear power plants and other very long-lived pieces of infrastructure are increasingly invalidated, we’ll run into ever more interactions between energy and water (and food and political instability) that will force us to make difficult decisions. Welcome to Planet Triage.