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Monday March 24, 2014 MYT 12:00:00 AM
Monday March 24, 2014 MYT 10:47:55 AM
Water scarcity: Children collect drinking water from a tube well in the village of Murkata in Morigoan district in Guwahati. With an annual monsoon, India does not lack water, but it struggles to preserve water due to poor storage and distribution systems. — AFP
World Water Day 2014 focuses on the deep-rooted relationship between water and energy.
Saving energy is saving water; saving water is saving energy – that is the message which the United Nations wants to drive across.
Both are closely inter-linked and interdependent, in what it calls the “water-energy nexus”. Energy has different forms, and water is crucial to produce, transport and use all forms of energy to some degree, and these activities have different impacts on water resources. On the other side of the equation, water is used in extractive industries to produce fuels such as coal, oil, gas and uranium.
The 2014 World Water Development Report underlines how water-related issues and choices impact energy and vice versa. For example: drought diminishes energy production, while lack of access to electricity limits irrigation possibilities. It notes that roughly 75% of all industrial water withdrawals are used for energy production.
The report stresses the imperative of coordinating political governance and ensuring that water and energy prices reflect real costs and environmental impacts.
Tariffs also illustrate this interdependence: if water is subsidised to sell below cost (as is often the case), energy producers – major water consumers – are less likely to conserve it. Energy subsidies, in turn, drive up water usage.
The UN predicts that by 2030 the global population will need 35% more food, 40% more water and 50% more energy. Already today 768 million people lack access to improved water sources, 2.5 billion people have no improved sanitation and 1.3 billion people cannot access electricity.
Water-Guzzling Energy sources
Conventional energy generation requires considerable water supplies, particularly for cooling for nuclear and thermal energy, and reservoir storage and driving turbines for hydroelectricity. Power generation is particularly sensitive to water availability and several power plants have been forced to shut down due to lack of cooling water or high water temperatures.
Thermal power generation accounts for roughly 80% of global electricity production and is responsible for half of all water withdrawals in the United States and in several European countries. Several factors determine how much cooling water is needed by thermal power plants: the fuel type, cooling system design and prevailing meteorological conditions. However, efficiency is often the main factor that drives water requirements: the more efficient the power plant, the less heat has to be dissipated, thus less cooling is required.
Biofuels, while touted as a more environment-friendly option to conventional fossil fuels, can also exert pressure on water supply.
The report predicts that even a nominal increase in biofuel demand (say 5% of road transport by 2030, as predicted by the International Energy Agency) can push up the water demand by as much as 20% of the water used for agriculture worldwide.
Biofuels now represent only 0.8% of global final energy consumption but this contribution will grow rapidly. If bioenergy feedstock is produced on irrigated lands, then the potential impact of biofuels on water resources is of major concern.
In terms of renewable energy, solar power, depending on its type, can use little water (as in the case of solar photovoltaic). On the other hand, concentrated solar power uses five times more water per unit energy than a gas-fired thermal power plant or two times more than a coal-fired plant.
Wind power uses a negligible amount of water but has other limitations. Geothermal energy has been reported to use and consume less water than other electricity generating technologies, though actual water requirements are variable and dependant on site conditions. While the water is generally reinjected to the reservoir, co-production of water and energy offers interesting opportunities to energy- and water-scarce countries.
Energy To Water Supply
On the other side of the nexus, about 8% of global energy generation is used for pumping, treating and transporting water to various consumers. Water, being dense, requires much energy to move it. Globally, the amount of energy used for irrigation is directly related to the huge amounts of water pumped. In addition, water and water treatment processes can require a lot of energy, though this is dependent on the contamination and treatment technology. Moreover, different levels of treatment are required depending on the use. For example, drinking water for municipal systems typically requires extensive treatment and once it becomes wastewater it requires treating again before it can be discharged to the environment.
Growing demand for limited water supplies puts increasing pressure on water-intensive energy producers to seek alternative approaches, especially in areas where energy is competing with other major water users (agriculture, manufacturing, drinking water and sanitation services for cities) and where water uses may be restricted to maintain healthy ecosystems.
With industries being major water and energy consumers, a green economy will be contingent to the greening of the industrial sector, one that is more resource efficient and has cleaner production. The UN says emphasis has to be placed on increasing the water use efficiency in energy production – essentially producing more kWh per drop of water. This will require a policy environment in which economic and social incentives are offered to promote water use efficiency and protect freshwater ecosystems. The world cannot continue to ignore or escape the strong link between water and energy. – UN
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Environment, Environment, ecowatch, World Water Day, water-energy nexus
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