As we look to stop using fossil fuels, we will need to find alternative ways to boost our economies and lifestyles. Nuclear power, wind power, solar power, and hydroelectricity help us to do so in increasing degrees. However, there are still untapped sources of potential energy.
Look at this: lakes and reservoirs in the United States could generate 325 gigawatts of energy, which would represent 70% of the country's production. Nor would that large untapped source come in the form of more dams, which could cause massive environmental damage. Rather, it would come through harnessing the evaporation of water.
A team of scientists from Columbia University in the US recently published their findings in the journal Nature Communications, arguing that if harnessed, evaporation from water could generate a lot of clean energy. "We have the technology to harness the energy of the wind, water and the sun, but evaporation is just as powerful," emphasizes Ozgur Sahin, a biophysicist who worked on the project. "Now we can put a number on its potential."
Sahin and his team have devised a machine, a so-called evaporation engine. They glued Bacillus subtilis spores onto thin films of tape, so they can control how the spores expand and shrink based on the amount of moisture supplied to them through a shutter. When dry, the spores curl up, causing the tape to contract, just like a muscle contracts. These contractions can be harnessed to generate electricity when connected to a generator.
"Evaporation comes with a natural battery," says study lead author Ahmet-Hamdi Cavusoglu. "You can make it your main source of energy and take advantage of solar and wind power when available."
That said, creating a system to harness the power of evaporation on a large enough scale will pose significant technological and possibly environmental challenges. However, the US team's investigation is a promising new step.