Where fuel goes, water cannot follow: impact of energy demand on water consumption

Water has rarely been a more valuable resource. The drought in California has crippled farmers' ability to meet food demands and motivated citywide reductions in water use. Water tables in countries from the United States to India are depleting faster than their recovery rates because industries must tap freshwater aquifers deep below the surface. Growing global consciousness of this scarcity has birthed noble conservation efforts. Californians are uniting to voluntarily reduce water use for domestic, everyday activities like showers, laundry, and dish-washing. Golf courses have stopped using fresh drinking water to maintain lawns. These concrete actions to reduce direct use are of critical importance to ensure future generations have access to safe, clean drinking water.

Water, however, is not only consumed as a primary resource. Industries such as energy and agriculture all require water consumption to create and transport their goods. The water-energy connection is particularly important to investigate because of the energy industry's comprehensive use of water, from extracting gas through fracking to powering coal-fired plants using steam turbines. How much water does energy production require and how do changing energy policies in response to global warming help or hurt water conservation efforts? These are the questions asked by Holland et al in a recent study¹ that examined the connection between energy demand and availability of freshwater resources (known as the water-energy nexus). Their answers illuminate the differences in how water and energy resources can be transported, which impact where and when water scarcity will arise.

The transport problem

Across our entire civilization, we use only 10% of all freshwater reserves, however a huge mismatch exists between where these reserves are located and where we want to use them.^2,3 The energy industry requires substantial quantities of water, but policy decisions usually treat water extraction and energy production as separate problems. This split has become especially apparent in the context of global warming. To reduce greenhouse gas emissions, power generation alternatives like hydroelectric and biofuels are gaining popularity, but these are water-intensive technologies that often detrimentally affect water supplies.⁴ Thus, water and energy production must be considered concurrently and policy regulating one must consider the other.

Resources in the energy sector, like oil or natural gas, move along a long supply chain spanning the entire globe. Oil ripped from the ground in Saudi Arabia is transported across the Atlantic Ocean to US refineries, then towed along US highways to local gas stations. In contrast, water transport is much more energy-intensive and less feasible because it is heavier than gas or other energy resources. Some estimates predict that transported water through pipelines across Australia would be 100-200 times as expensive as bulk water used near its source.

This ease of energy but not water transport creates a drastic geographical disconnect between the regions responsible for water and fuel input for a given type of energy production. Water is a local resource whereas energy can come from anywhere (up to a point). What does this mean for consumption, demand, and the potential for scarcity?

Water from around the world

Holland et al explored this water-energy connection by determining the freshwater consumption used in the gas, electric, and oil industries for countries across the globe, taking into account all uses along the supply chain from raw extraction to final distribution. Energy data came from the Global Trade Analysis project that records economic transactions between countries. Data about water came from WaterGAP, which follows freshwater consumption in a variety of industries covering agriculture and energy production. For each, consumption of water or energy resource was recorded on a 0.5 by 0.5 degree grid across a map of Earth. This is the first study of its kind to take such a comprehensive and global look at the water-energy nexus.

Given the global scale of the project, the study reports a tremendous amount of data about energy production in different countries and how it connects to water use. I'll focus on a few highlights:

1) General freshwater consumption. The energy industry only accounts for 1-2% of all water use (agriculture dominates with 92% of all use). This energy slice may seem small and insignificant, but this use is highly localized at extraction sites (fracking) or power generation (coal-fired power plants) and therefore can have high environmental costs in local regions. Therefore, a key component of understanding the water-energy connection is to pay attention to small regions within regions where scarcity may arise, likely close to fuel extraction.

2) Water consumption by fuel type. Across the world, electricity requires four times as much water (measured in annual volume consumed) as petroleum production and 20 times more compared to gas production. However, petroleum uses the most freshwater (56%) far from the source of demand. This means that, if US consumers are the demand endpoint, 56% of the water used to produce that oil was consumed outside the US. In contrast, electricity and gas outsource only 9-19% of water consumption. This likely attests to the fact that only a few specific regions in the world dominate oil production - the Middle East and North Africa, for example - that then send the oil to all corners of the world.

3) US and China consumption. One of the most surprising findings related to differences in freshwater consumption by US and China. Seventy five percent of all water used for energy production in the US was originally sourced outside the country, diversified across many other countries. In contrast, only 22% of water consumption connected to Chinese energy production occurred outside Chinese borders. In general, the US relies more on the Middle East than China.

4) Water scarcity. The physical shortage of freshwater is known as first-order water scarcity. Overlap between regions of high first-order scarcity and freshwater consumption are localized in India, Pakistan, the southwestern US, and northern China. This is bad enough, however a more insidious form of shortage known as second-order scarcity applies to countries where poor governance, lack of effective policy, or socioeconomic factors like public health threaten availability of freshwater resources. Perhaps most unsettling, the study found a substantial overlap between regions with high freshwater consumption and second-order scarcity. For example, regions of India and Pakistan , in particular, showed high consumption of water that ends up being used for US energy demand. These regions also exhibit high second-level scarcity due to booming populations that strain resource availability for many citizens.

Policy implications

So what does this all mean for policy-making? First, it highlights the globalization of fuel production and its impact on other resource use. The energy industry has well-developed means of transportation to make oil and coal (and gas to a lesser extent) a global commodity. Water cannot follow this same economic logic, and therefore the energy industry as a whole can only be considered partially globalized. As resource extraction further diminishes local water resources in regions like the Middle East and India, it is the local populations that will suffer most due to the energy demands of developed countries. From this point onward, any policy is incomplete if not considering water (and other local) resources when describing the energy economy.

Interestingly, countries driving demand have varying patterns of freshwater consumption. In particular, the United States diversifies the water consumed for its energy production across many countries, whereas China relies on its own water use. This means that China must deal with greater pressure to manage its own water resources well as its population and energy consumption grows.

Finally, developing countries already threatened by second-order scarcity are especially vulnerable to excessive freshwater consumption used in the globalized energy industry. Therefore, water-energy policy should focus on improving irrigation and water conservation methods in these areas so that they can continue to meet the water needs of local citizens while also providing the economic benefit of providing energy to other countries. Much more research must be done to understand how these water pressures affect local communities in India, Pakistan, and the Middle East, as this is one of the first studies to shine light on the problem.

Global warming is the popular international buzzword, especially with the climate talks this month in Paris. And it should be! But the energy sector does not just create carbon dioxide; its use of critical resources like water must also be assessed in greater detail so policies can take into account all external costs. Those communities caught in the crossfire of large consumption and weak water management will pay the highest price if this water-energy connection is ignored.

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