by Eamon Keane
“Before the world’s fossil fuels are finally exhausted, it is likely that their extraction will require an unimaginable amount of water”
“When measured in calories, the energy market is twenty times the food market. So if governments would replace only 10% of global energy consumption with first-generation biofuels, they in the same stroke would double agricultural water withdrawals”
“The share of biofuels in total use of coarse grains is projected to increase until 2015, reaching 13%”
“The area currently under cultivation is 1.5 billion hectares, so if all that extra land could be used it would represent an increase of one-third. In fact a lot of it either should be left alone for environmental reasons or would be too expensive to farm.”
Given the above quotes, it is a wonder that most energy outlooks pay only cursory attention to the interrelationship between water, food, energy and climate. Signs of stress in the water-food-energy complex are visible in the record high food prices, dropping water tables and the need for cooling in power plants is on vivid display in northern Japan. Do you know how/if it will affect your investments? Maplecroft’s water security index shows nearly the entire Middle East and North Africa, the origin of much of the world’s oil, as under extreme risk of water scarcity. There’s a nice graphic in the World Economic Forum’s Global Risks 2011 which highlights some of the water-food-energy interactions in Figure 1. I’ll try to concisely address them in this series.
Figure 2 shows the water required to extract and refine energy, while Figure 3 shows the energy required to make different forms of electricity. The water needed in primary extraction of oil, gas and coal is not that significant, however it depends on local availability. For instance in China’s Shaanxi Province, the coal reserves cannot be tapped due to lack of water. The plan is to desalinate sea water and pump it uphill for 600 km: “We need water, and the sea can provide it”.
The oil industry uses some 220 mb/d of water for enhanced oil recovery, for an average of about 3 mb/d water per mb/d oil. This is about 0.3% of global water use (4,500 bn m3/year or 77,500 mb/d). In some cases this will be the reinjection of the water cut, however where steam injection is used, the quality is required to be higher. For fossil fuel extraction, the issue is not the absolute volume of water but the environmental pollution that inadequate environmental care can cause. An estimated 12,000 miles of waterways are adversely affected by abandoned coal mines in the US. Shale gas uses relatively low volumes of water, but a few cowboy fraccers could lead to the contamination of rivers or groundwater and so close regulation is required.
The elephant in the energy-water nexus is biofuels, with irrigated corn requiring up to 100,000 litres per GJ. Converted to oil, this is an impressive waste of 3687 mb/d water per mb/d of oil equivalent, or 4.8% of the world’s water consumption. This is the number one reason why first generation biofuels are doa once governments recognise water constraints.
Power generation uses significant quantities of water. Due to the massive volumes of water used in open loop cooling in old designs of nuclear and some fossil fuel power plants, in 2005 41% of American water abstraction (withdrawal from a water source) was used to cool power plants. The operation of open loop nuclear plants requires this steady flow of water, or else they must shut down. Only 3% of US water is actually consumed by power plants, the rest returned to rivers slightly warmer. Hydro plants evaporate large quantities of water/MWh. New power plant designs can significantly reduce power generation water consumption through a range of technologies, such as hybrid cooling systems. This has significantly reduced the water requirement of the 100 MW Tonopah solar tower plant in Nevada that recently got the go-ahead, with water consumption a key constraint.
Part 2 will look at the food-water nexus.