Water for energy and energy for water
The inter-linkages between energy and water have always been known. For generating energy on a large scale as in thermal power plants, large amounts of water are required. In steam turbine plants, the dynamic pressure generated by expanding steam is used to turn the blades of a turbine. Once water has gone through this cycle, it is cooled and condensed back to water and then reheated to drive the turbines again.
All thermal generation plants, whether they are powered by coal, oil or natural gas require huge amounts of cooling water. Nuclear reactors require the most water for cooling. Hydropower production requires water directly for driving turbines. In short, energy-generation by conventional methods is heavily dependent on water for its functioning.
Take the reverse case – energy needed for water supply. Huge amounts of energy are needed for pumping water at various stages of supply, whether it is water from the underground aquifers, rivers or any other source. Treating water needs energy and distributing it to consumers also needs energy.
Says Prof Asit Biswas in the recently released Asian Water Development Outlook: “It will become increasingly important for planners and policy makers to concurrently consider water and energy policies, especially in terms of their symbiotic relationship: each affects and is affected by the other.” He predicts that the inter-linkage between energy and water sectors will only intensify in the future.
Years ago, the practice of subsidizing energy for farmers was started by many governments in order to give a boost to agriculture. This resulted in farmers pumping more groundwater than needed, which eventually led to a steady decline of water levels and in the process, many public electricity boards suffered heavy financial losses. This could have been avoided if the inter-linking of water and energy sectors had been taken into account.
“The current and past practices of formulating policies in one sector without adequate consideration of and coordination with policies in other sectors will increasingly become costly, inefficient and unsustainable,” argues Prof Biswas.
Another important development is the growing demand for biofuel production. The contribution of biofuels to energy supply is expected to grow fast but not much attention is being paid to its impact on water resources. It will have to be seen whether the biofuels such as bioethanol and biodiesel will be watered by rains or irrigation, before calculating the impact on water resources. Prof Biswas warns that the non-point pollution caused by pesticides and fertilisers used for biofuel production on water bodies would also have to be taken into account by policy-makers.
China and India are already hard-pressed for water on account of being the world’s largest producers and consumers of many agricultural commodities. Now, both these countries are planning to boost biofuel production. In rainforest regions such as Indonesia also, the forests are already being cleared to make way for biodiesel plantations.
Add to this the spectre of global warming which is going to alter the patterns of rainfall and temperatures all over the world and will make the energy-water linkage even more complex.
No one can predict what is going to happen in the future. But it is certainly possible to study, research and plan various alternatives as well as we can.