Evidence presented by the IPCC and UN Water demonstrate how poor management of freshwater resources can impact economic development and put countries and regions at risk to climate change due to more extreme events and longer term change in precipitation and evaporation. An area that has not received enough attention is the need to secure water for energy production. With the world’s eyes closing in on sustainable development it is critical to discuss innovations related to the green economy that links water, energy and food security and creates added value and jobs. Such solutions will drive human development hand in hand with climate mitigation.
Estimates state that about 1.6 billion people lack access to modern electricity for cooking, lighting and heating. In the area of water, we are familiar with similar gaps related to access to water supply and sanitation. Over the past 20 years there has been substantial progress in many aspects of human development and more people today are healthier, live longer, are more educated and have more access to goods and services than ever before. In spite of this progress in human development there is a persistent “bottom billion” of poor people that are water, energy and also food insecure. To meet the current service gaps for the poorest billion and future demands from growing populations due to economic transformation of societies, global energy consumption is projected to grow by close to 49% by 2035.
Much of this growth in energy demand will be in non-OECD countries, and would as such come with direct effects on climate. Most future energy demand scenarios have a high dependence on fossil fuels, especially coal, in spite of an increasing share of renewable energy in the energy mix. Today only about 13% of primary energy demand is met by renewable energy which in this context refers to hydro, bio, wind, solar and ocean power. Hydropower stands for 86% of the global renewable electric power production with significant potential, especially in developing and emerging economies. Future regional, national and global policy and market signals, in part as a response to climate change, will increase or decrease the share of renewable energy in the mix.
In determining the policies towards decarbonising the energy supply chain, where fossil fuels will still be a key component, a central question will be if this will have an impact on an already constrained water resource? To explore this issue we need to better understand the role of water in energy production.
Water is required to produce energy; for fuel production and power generation and energy is needed to move and clean water through distribution and treatment systems. This link is usually referred to as the “water and energy nexus”. As fresh water resources become scarce at the local, national and regional levels, water will have to be transferred, pumped long distances, or be produced through alternative means, such as energy intensive desalination processes and recycling to meet different demands. In this nexus the information on water use in the energy production chain at the local and regional scale is incomplete. In most fuel extraction, the use of water in refinement processes and power production processes is not accounted for systematically and results vary depending on the methodology used.
The large number of technologies in the energy production chain provides a wide range of water withdrawal and consumption patterns. In general, the production of biofuels is substantially more water intensive than liquid fossil fuels. However, non-conventional fossil fuels such as tar sands, shale gas and hydraulic fracturing are more water intensive than conventional fossil fuels. In the thermal electric power production process most of the water is used for cooling purposes and the abstraction and consumption values vary, depending on cooling technique used.
Hydropower is the most efficient method of large scale electric power generation and has a key role to meet peak demand in power systems thereby allowing for the deployment of other renewable energy technologies. Depending on the location of reservoirs hydropower can consume very small or large amounts of water due to evaporation. Water consumption also varies for different types of solar power technology. Wind power consumes negligible amounts of water.
It should be noted that in the thermal power production process, the actual water consumption is less than the water withdrawn. In general about 5% of the water used in power production for cooling is lost through evaporation and the rest is returned to the recipient. However, water returned has normally higher temperature and altered quality which can have negative environmental consequences. Even if the actual consumption of water in power production is fairly low, water supply needs to be ensured to avoid disruptions to power production processes.
To further explore the question of whether or not water can be a constraint in energy production, we need to improve our understanding of the role of water in our economies. In the water business it is usually claimed that of annual freshwater withdrawals about 70% of the water is used for agriculture, 20% for industry and 10% for municipalities. Depending on the geography of a region and the structure of the economy there are large variations in water withdrawals and use for different sectors. In the European Union and the United States of America about 40% of the water withdrawn is used for energy production with growing demands from industry and for domestic use and decreasing numbers for agriculture. In the Middle East and Central Asia large amounts of water (80 – 90%) is used for agriculture with considerable local variations.
These regional examples demonstrate that water use patterns are different and they are changing because of socio-economic transformations and climate change. It therefore comes as no surprise that the political and economic context behind the allocation of scarce water resources for different purposes, including for vital ecosystem functions, is beginning to shape public policy in various settings. In a context of growing demand for water, the challenge of governing and managing the water resource across political, social, cultural and economic barriers raises several dilemmas of how to prioritise different users.