Climate Change and the "Water-Energy Nexus" The dependency of the energy sector on water, and the risks related to climate change

, by  Olivier Petitjean

The energy sector uses huge quantities of water, (almost) irrespective of the source of energy in question. It is therefore vulnerable to the effects of climate change in terms of available resources. And as the case of biofuels has shown, all the proposals for reorienting energy policies need to take into account their potential impacts in terms of water consumption (they are often considerable).

Over and above the obvious case of hydro-electric power, several of the main energy- and electricity-producing methods use a great deal of water, be it for cleaning, cooling or (in the case of biomass energy) for the actual generation of the source of energy. This makes them potentially vulnerable to the effects of climate change and the lack (or over-abundance) of water that can result. All in all, the production of energy could find it is affected in different ways. And as the emblematic cases of biofuels have shown, promoting new energy policies and extending certain branches could prove harmful to water resources.

Potential impacts of climate change on the energy sector

In theory, hydro-electric power output should increase in the regions where rainfall and river flows will also increase. This is the case of Scandinavia and the North of Russia, according to the latest projections made by IPCC. Conversely, there should be a 25% reduction of hydro-electricity output in the South of Europe (Portugal, Spain, Bulgaria) as a result of water scarcity and reduced flows. European hydro-electric production is expected to drop globally. The drop in the flow from the Great Lakes is expected to significantly affect Canadian hydro-electric production at Niagara and on the Saint Lawrence River.

Electricity produced by thermal and nuclear power stations generally requires a lot of water for the cooling process. An Australian study in 2006 calculated that a nuclear power plant required the equivalent of 5 000 swimming pools per year, which is 25% more that for a coal-fired power station. The calculation has been made that producing energy currently represents 20% of non-agricultural use of water in the United States, and this figure could climb to 60% in 2030. Other people maintain that the figures will actually be higher. As the heat wave showed in 2003, abnormal conditions of drought lead to a drop in the flow of water and an increase in temperature (and these conditions could become more frequent with climate change) and this can hinder the working of these power stations and therefore interfere with the production of energy.

Coal and uranium mining - whose products these stations require to work -, generally also use a lot of water, as well as polluting our planet in many places. A lot of the world’s production of aluminium is situated in Iceland, precisely because there is a lot of water available, and energy prices are low. This is also true for extracting oil from the oil sands, such as in Canada.

The production of biomass would also suffer, as would agriculture, from an increased frequency in droughts. Yet in some regions, the rise in temperature, the increase in rainfall or the higher concentration of carbon dioxide in the atmosphere would be favourable to the production of biomass.

Globally, the increased risk of intense rainfall, flooding and the rise of sea level could lead to damage to infrastructure that produces and delivers energy and electricity, and therefore also to a loss in production.

Finally, the changes in temperature could have the effect of substantially modifying seasonal demand for electricity in the countries of the North. With the increase in temperature, there would be less demand for heating in winter, but a greater demand for air conditioning in summer, which is the time of year when some sources of energy are most vulnerable because of reduced water availability.

The counter productive effects of new energy policies concerning water

A negative knock-on effect of the changes in energy policy and the promotion of new kinds of energy might well be the negative impact on water reserves in general as well as on other factors. One effect, where it is possible to increase hydro-electric production by building new dams – quite apart from the many potential social and environmental impacts – is the way the hydrography of whole regions would be modified, as well as the loss of water through evaporation and the aggravation of lack of water downstream.

In the United States, the increased extraction of natural gas from unconventional reserves is encouraged by the rise in oil prices, and by the attempt to find local energy reserves with a lower rate of carbon emission than oil. The extractive techniques that are used to reach these reserves involve pumping in thousands of litres of water mixed with chemical substances at very high pressure to break up the rock that contains the gas. Part of this contaminated water remains underground. The rest is theoretically recovered, but it is often simply reinjected into the earth. Assessing the pollution resulting from such a process is all the more difficult since the firms involved refuse to publicise the exact chemical composition of the fluids they use, alleging intellectual property reasons. The New York water supplies are among the potential victims of this new technique, as there is a project to drill for gas in this way in the Catskill Mountains, which is where the city gets its water supplies. (In October, 2009, New York State authorities issued a number of rules and conditions to allow such drilling on the state territory, which included the obligation to unveil the chemical compounds used and the creation of a perimeter around the zone supplying water to New York City. Although those rules and conditions have been deemed insufficient by many activists and scientists, the only company in possession of land in the watershed zone has subsequently announced that it gave up any drilling project in this particular zone.)

The programmes of “underground carbon capture”, that have sometimes been presented as a radical solution for reducing greenhouse gas emissions, raises similar issues as far as potential contamination of groundwater reserves that lie near these capture and storage sites is concerned. The Department of Energy of the United States has calculated that there would be a 90% increase in water consumption in the plants and power stations involved in rolling out “clean coal” (power stations using carbon capture techniques) which is the policy of choice of President Obama.

Even solar energy uses a lot of water (used for cooling the installations) that can be in contradiction with the state of the resources in the dry or desert regions where the solar power stations are built. The result of this is that the National Parks Service have placed severe restriction son the authorisations to build new installations in Nevada, or else have encouraged the use of alternative cooling methods that are more expensive (air cooling). In Arizona, the authorities have introduced a programme for converting cotton fields to solar power stations, since the latter still do not use as much water as cotton...


The sector that is the most worrying in terms of wasting water is biofuels. Recent European and American legislation that has set ambitious objectives in terms of the use of biofuels, has come under heavy fire for having overlooked the consequences for food security at global level of there is a massive conversion of land used for food production to energy production. Similar criticism can be made in terms of water. Many countries, starting with China and India, have announced major plans to increase their production of biofuels, which would increase the problems of lack of water that already exist. The quality of water could also be affected due to the increased use of pesticides and nitrates, as has already been observed in the United States, even though the production of biofuels is marginal there.

Depending on the region and the type of biofuel, it requires several thousands of litres of water to make one litre of biofuel. Bioethanols made from maize are grown especially in the United States, and the Chinese authorities plan to quadruple their production by 2020. They use a particularly high amount of water. Recent studies have shown that globally (including transport costs) that ethanol made from maize gives off only slightly less greenhouse gas than oil-based fuels.

All crops grown for producing biofuels should not however be considered as one and the same. There are some alternatives that use less water and fewer chemicals than the bioethanol made from maize that is being promoted by American agribusiness and subsidised by the Federal authorities. Bio-ethanol made from sugar cane in Brazil, (even if it does create other kinds of problems) uses far less water, as it does not require irrigation. In France, producing biodiesel from rapeseed or sunflowers could prove a positive option in terms of economising water, as could bioethanol made from sorghum. Other solutions would be better still for water resources: progress is regularly announced in terms of the production of biodiesel made from algae removed from sewage treatment plants.

There is therefore good reason to fear that the kinds of energy that is being developed as a result of the awareness of climate change, if implemented without due consideration, will have dramatic effects on water consumption. The projects that have been announced by the Obama administration have fortunately led to a certain awareness of the inextricable link between water and energy (the "water-energy nexus"). It is hoped that this will suffice to block the industrial interests and the exclusively profit-focused talk linked to the fight against climate change. A draft law aimed at taking this link more into consideration in political decision-making and energy governance was announced in Congress in early 2009. The planned projects in the United States also include (at least for the moment) rechanneling investments in biofuels to more environmentally sustainable crops than producing bioethanol from maize.

- IPCC Technical Paper « Climate Change and Water ».
- «The Folly of Turning Water into Fuel», Stan Cox, AlterNet, 22 mars 2008.
- INRA report on adapting agriculture to drought (in France).
- For drilling for gas and the consequences on water, c.f. references on the following page :
- «Alternative Energy Projects Stumble on a Need for Water», Todd Woody, New York Times, 29 septembre 2009.

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