Water security at the energy crossroads

December 9th, 2012

Edward Byers, Newcastle University, United Kingdom

Water, sanitation and energy are undoubtedly keystone components of civil infrastructure that enable cities to support populations; they are the foundations of civilisation. The growth of megacities is also rapidly depleting water resources and leading to declining levels of water security across the world. Failure of critical infrastructure services such as water and energy can cripple a city in a matter of hours and leave millions vulnerable.

Yet that which is most dear to us, is now often part of a process of complex interactions before we are able to access it. Energy is used for pumping, transport and treatment of water and wastewater; water is used through most stages of energy production and generation. But most of the resources used are non-renewable, often involve pollution and bring us closer to the planetary boundaries.1 Should we continue developing the interdependencies between energy and water or should, in some cases at least, we be working to decouple these two crucial resources?

In the current system, increasing demands in one usually means increasing demands in the other. But there are alternatives. Hence, water security finds itself at the ‘energy crossroads’ through the multitude of options available for alleviating security issues, options which may use considerably disparate levels of energy. Water security also meets energy at the crossroads in a future that is partly governed by the water-intensity of future energy systems.

Increasingly, water supply options analysis is made with consideration of the energy intensity of exploiting that resource. A variety of capital-intensive options to meet marginal demands may be evaluated, including desalination, wastewater recycling, inter-basin transfers, and increased storage capacity. The uncertainties in the performance and utility of each option may, however, be large. They are driven by the energy sector and stem from variation in demand growth, energy price fluctuation, and dependency on climate-vulnerable water resources. Operational expenditure, the majority of which is usually energy costs, is therefore likely to increase if we are to maintain reliability and service provision. In the UK, raising water quality standards has resulted in a doubling of energy use since the 1990s and is set to rise2; lower river flows during droughts will require more stringent wastewater treatment as receiving bodies will have less capacity to dilute effluent.

The irony is that wastewater has a chemical energy content higher than the energy required to treat it, the former just needs to be harnessed.8 Increasingly, anaerobic digestion (AD) is being deployed around the world in both high-tech and low-tech configurations. Anaerobic digestion is the breakdown of biodegradeable matter in the absence of oxygen and can be used to treat both solid and liquid waste. One of the main byproducts, biogas, consists mostly of methane and can be burnt for electricity generation, heating or cooking. AD applications in developed countries will play a small part towards energy security and low carbon energy supply, whilst flipping the energy balance of wastewater treatment. In less developed countries AD can provide a meaningful step towards proper sanitation and associated health benefits, whilst free biogas used for cooking drastically reduces indoor air pollution, a killer of 1.5 million women and children each year.9 Conversely, seawater desalination and long distance transport and pumping, such as the California State Water Project and the Central Arizona Project, result in roughly 10 times the energy intensity of conventional treatment facilities10 due to the long distances, evaporation losses and changes in elevation.

In many countries, energy is produced by thermoelectric power stations on surface waters abstracting proportions of cooling water far exceeding those taken for public water supply and often matching agriculture (UK: 56%, US: 41%, Europe: 45%). Most is returned, but evaporative losses from cooling towers can reduce this amount by 75%. Energy demands are growing, thermal efficiencies hardly improve (they worsen with Carbon Capture & Storage (CCS)) and the prospects of shale gas and coal with CCS look set to lock electricity supply into another half-century of water-thirsty power plants. Even the fuels used require water for extraction and processing, leading to contamination. In recent years, thermoelectric nuclear and fossil fuel plants in the USA and Europe have faced output reduction and even shutdown due to low river flows and high water temperatures, a problem expected to worsen with climate change.11 But alternatives to water-intensive energy supply exist mostly in the form of some renewables, and more strategic siting of power stations and grid balancing could for example, play crucial roles in increasing not only energy but also water security.

Recent droughts in the United States have highlighted yet again the vulnerability of thermoelectric power stations12 and our dependency on water throughout modern society. Capital investment projects in both sectors lock-in decisions for decades that span considerable uncertainty. Short-term demand reductions can ameliorate the cross-sector risks, but the resource interdependencies will remain.

In its current state, the energy sector poses unacceptable risks to the public water supply and agriculture sectors that must be addressed with robust decisions that encompass sustainability, security of supply and affordability. Whilst the challenges facing each sector of the water-energy-food nexus are great in themselves, decision makers must recognise the win-win-win opportunity that is presented by tackling them together, elegantly summed up by Wangari Maathai, “Our planet is finite, our fates are intertwined, our choice is clear – stand together or fall divided.”13

References:

1. Rockström, J., Steffen, W.L., and 26 others (2009), “Planetary Boundaries: Exploring the Safe Operating Space for Humanity”, Ecology and Society 14 (2): 32.

2. Council for Science & Technology (2009), ‘Improving innovation in the water industry: 21st century challenges and opportunities’, Council for Science & Technology, available online at: http://www.bis.gov.uk/assets/cst/docs/files/whats-new/09-1632-improving-innovation-water-industry.

3. Water UK (2010), ‘Sustainability Indicators 2009/2010’, Water UK, London, available online at: http://www.water.org.uk/home/news/press-releases/sustainability-indicators-09-10/sustainability-2010-final.pdf.

4. Perrone, D., Murphy, J. & Hornberger, G.M., (2011), ‘Gaining perspective on the water energy nexus at the community scale.’ Environmental Science & Technology, 45(10), pp.4228-34.

5. Water Reuse Association (2011), ‘Seawater desalination power consumption’, Water Reuse Association, available online at: http://www.watereuse.org/sites/default/files/u8/Power_consumption_white_paper.pdf.

6. Sampson, D.A. & Gober, P., (2007), ‘The central Arizona water-energy nexus?:WaterSim 3.5.5’, Global Institute of Sustainability, Arizona State University, available online at: http://sustainability.asu.edu/docs/symposia/symp2009/Sampson_Gober.pdf.

7. EEA, (2010), ‘Water abstractions for irrigation, manufacturing industry, energy cooling and Public Water Supply: early 1990s and 1997-2007’, European Environment Agency, available online at:http://www.eea.europa.eu/data-and-maps/figures/water-abstractions-for-irrigation-manufacturing-industry-energy-cooling-and-public-water-supply-million-m3-year-in-early-1990s-and-the-period-1997.

8. Heidrich, E.S., T.P. Curtis, and J. Dolfing (2011), ‘Determination of the Internal Chemical Energy of Wastewater’, Environmental Science & Technology, 2011, 45(2), pp.827-832.

9. World Health Organization (2006), ‘Fuel for life. Household Energy and Health’, World Health Organization, Geneva, available online (23/08/12) at: http://www.who.int/indoorair/publications/fuelforlife.pdf.

10. Water Reuse Association, (2011), ibid.

11. van Vilet, M. T. H., Yearsley, J. R., Ludwig, F., Vögele, S., Lettenmaier, D. P., Kabat, P. (2012), ‘Vulnerability of US and European electricity supply to climate change’, Nature Climate Change, 1546 Advance Online Publication, 3 June 2012. DOI: 10.1038/NCLIMATE1546.

12. Eaton, J., (2012), ‘Record Heat, Drought Pose Problems for U.S. Electric Power’, National Geographic News, available online at: http://news.nationalgeographic.com/news/energy/2012/08/120817-record-heat-drought-pose-problems-for-electric-power-grid/.

13. Maathai, W., (2010), ‘Cancun must be about more than climate change’, The Guardian, available online at: http://www.guardian.co.uk/commentisfree/cif-green/2010/nov/26/cancun-climate-change-conference.

Edward Byers is a Ph.D student at the School of Civil Engineering & Geosciences at Newcastle University in the UK. His research focuses on infrastructure transitions in the water-energy nexus for the UK. He is affiliated with the Infrastructure Transitions Research Consortium and the Tyndall Centre for Climate Change Research and can be contacted at e.a.byers@ncl.ac.uk.

The views expressed in this article belong to the individual authors and do not represent the views of the Global Water Forum, the UNESCO Chair in Water Economics and Transboundary Water Governance, UNESCO, the Australian National University, or any of the institutions to which the authors are associated. Please see the Global Water Forum terms and conditions here.