There is an invention that can replace coal powered plants in generating energy. It is renewable, passive, could potentially generate more than 325 gigawatts of electricity, but might cause a change in local climate.

One other advantage of these evaporation engines is that they can continue to generate power even after the spores die. Since the individual units are small, they can also be easily setup as long as there is a way to transmit the power.

The technology, however, does not exist yet; it is a bold idea that scientists and researchers are exploring at length. It’s called an “evaporation-driven engine” and makes use of bacterial spores to generate energy.

The spores are on the surface of water, like lakes and water reservoirs, and are connected to a tiny power plant. Movement from the spores’ expansion and contraction due to the absorption and release of air moisture drives tiny engines, which then convert the movement to electrical energy. It has been estimated that an 8 cm x 8 cm (3.15” x 3.15”) of water surface with a tiny evaporation engine can generate 2 microwatts (µW) of electricity, with a burst of up to 60 µW.

Steam Engine and an Evaporation Engine

The key takeaway is that after doing the math, it is found would take a big surface area to generate a sizable amount of energy. On the plus side, it is not dependent on the sun nor wind, and the energy produced does not fluctuate. Since there is no intermittency of power generation, there is no need for batteries to store energy for off-peak hours. Another upside is that the spores decrease the evaporation rate, which would increase the surface water temperature. This increase can further add to the energy being generated by the evaporation engine.

While the energy produced is relatively small, it can scale up given enough surface area. This is where some concerns would come in. With an evaporation engine power plant covering a large lake, the ecosystem could be changed both by the surface devices, as well as the rise in temperature. In addition, it will also change the aesthetics of the place.

Dam reservoirs would be ideal locations for these power plants, as most dams have significant surface areas. The plant can also share distribution and transmission networks with the dam.

The engineering and the design of the actual device has yet to be created. In order to be viable, it has to generate more energy, and the fabrication of the equipment has to be as cheap enough to be economically feasible.

Looking Deeper at the Potential of Evaporation Engines

A research team from Columbia University created the study on the evaporation engine, and published it in Nature Communications, a peer-reviewed scientific journal. It was co-authored by Dr. Ozgur Sahin, an associate professor of biological sciences and physics at Columbia University. The team from Columbia was also able to power a small car with the use of the bacterial spores and the evaporation engine. Prior literature was from the Massachusetts Institute of Technology (MIT) Technology Review which computed the output of these power plants.

One other advantage of these evaporation engines is that they can continue to generate power even after the spores die. Since the individual units are small, they can also be easily setup as long as there is a way to transmit the power.

In regard to the nature of the power plants, it would take a lot of water surface area to totally replace coal powered plants. However, even small plants, or a small number of evaporation plants, can go a long way towards a renewable energy independence. Once the technology for this bold idea can be developed and refined, it should provide better economies of scale and improved actual production levels.

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