Electricity generated from evaporation could power 'most of the United States'

Water evaporating from lakes and reservoirs could generate vast amounts of reliable energy, according to a cross-sector team of scientists.

The potential source could overcome the intermittency of wind and solar energy, the Columbia University researchers said, providing power around the clock.

Although practical experiments have only run in laboratories, the hydrologists and biophysicists analysed weather station data and geographical information from lakes and reservoirs around the US. They claimed evaporation from the water bodies could generate 325GW of power, nearly 70% of the country’s current production.

In the study, the team assumed the use of an efficient new harvesting technology. However, members are already creating possible tools.

Senior author Ozgur Sahin previously developed a machine, known as the evaporation engine, which used changing humidity to prompt bacterial spores to expand and contract, powering a generator.

Generators could tap evaporation power from the water bodies when needed, the team claimed, unlike solar or wind facilities which require expensive batteries.

“Evaporation comes with a natural battery,” said lead author, Ahmet-Hamdi Cavusoglu. “You can make it your main source of power and draw on solar and wind when they're available.”

The technology could also help save water in drought-prone areas, the researchers said. If an energy harvesting process captured half of the water rising from lakes and reservoirs, they estimated it could save 25tn gallons a year in the US, or about a fifth of consumed water.

The study was published in Nature Communications. 

This story appears in the October issue of Professional Engineering.