Renewable Energy — Helping Us Avert a Water Calamity
Renewable energy sources like wind and solar are touted for their positive and remedial effects on air quality and climate change. But there is an equally compelling and less appreciated rationale for renewables — they mitigate the risk of catastrophic global water shortage, and this is why.
About 84% of the U.S. electricity is produced from coal, natural gas and nuclear energy combined. Some 45% of our water — 73% of that amount fresh water — is used to cool the power plants that generate this electricity. This use of water for energy (W4E) is a threat to future generations and our way of life.
We can’t carry on the same way, and expect a sustainable world. Producing electricity for a typical U.S. house requires 615 gallons of water when that electricity is generated from nuclear sources, 200 gallons from coal, 185 gallons from biopower, and 114 gallons from natural gas.
Renewable sources slash these numbers dramatically. Typical U.S. house electricity production requires 16 gallons of water from concentrated solar — generating solar power with mirrors and lenses that focus solar thermal energy into a small area — and 7 gallons from geothermal. Water usage for wind power and solar photovoltaic — converting the solar radiation in sunlight into electricity via photovoltaic cells in solar panels — are even more negligible.
By investing in wind turbines and solar energy, we are taking care of our climate and protecting our water resources. Renewable energy helps reverse our relentless march toward a water calamity. So, renewables have major benefits: (i) save water, (ii) mitigate Co2 emissions and, it has another big benefit, (iii) it creates more jobs than natural gas, coal and nuclear combined. In 2016, solar and wind created 24 jobs versus 1 job for gas/coal/nuclear combined for each GWh in the production of electricity. As the consequences of climate change become more severe, droughts, hurricanes and flooding will become stronger and more frequent, and water shortages will be more widespread. These upheavals will spur a massive migration of people from water-deprived regions to those with water — geopolitical tensions could be another legacy of non-renewable energy.
The World Bank estimates that agriculture accounts for 70% of water withdrawals globally, and that agricultural output will need to expand 60% — and water withdrawals 15% — to feed 10 billion people by 2050. The international organization adds that, by 2025, about 1.8 billion people will already be living in regions or countries of absolute water scarcity.
We should be generating energy from clean, renewable sources, and not rely on water for energy. This will allow us to not only cleanse our air and lessen the impact of climate change, but to repurpose our water usage to the growing of food. This will help to ensure a sustainable future for a growing population, and the 821 million people in the world today — one in nine — that the World Food Programme says go to bed on an empty stomach every night.
by Luciano Castillo, Kenninger Chair Professor of Renewable Energy & Power Systems, School of Mechanical Engineering, Purdue University
