Water as an energy source

Can we power our devices with water? Innovative ways of potentially using water to generate energy are currently being researched.

Big dams, which use the force of running water to spin turbines that generate electricity—currently provide about 16% of the world’s energy needs*. But the potential to use water for power goes beyond hydropower. It’s an area spurring increasing amounts of research.

Hydrogen fuel cells

Hydrogen is a highly efficient way of storing energy—hydrogen fuel cells are much lighter than the batteries needed for electric cars, and refueling takes just a few minutes. Additionally, when hydrogen is transformed into energy, the waste-product is just pure water. However, hydrogen itself is not easy to obtain; the process of splitting water into hydrogen and oxygen requires massive amounts of energy, and getting hydrogen from fossil fuels, like natural gas, produces carbon monoxide and carbon dioxide.

Researchers are thus attempting to find new ways to produce hydrogen from water without using more energy than the fuel cell later produces.

Micro fuel cells

Swedish startup MyFC is working to commercialize a fuel cell that creates hydrogen by making water molecules react with a special salt-mixture contained within the cell. So far, the company offers a product similar to an external battery, but using swappable fuel cells to charge phones and computers.

Wave power

Tidal turbines are similar to wind turbines, except that instead of sitting above ground, they are situated 100 feet below the surface of the ocean. In the same way that wind spins the blades of wind turbines (generating energy), tidal currents cause underwater turbines to swivel and spin between 7-15 times per minute, generating power in the same way.

One advantage that tidal power has over wind power is predictability: companies that operate them can predict how much energy they will generate every 15 minutes over the next 25 years. Even if it is still expensive—at two and a half times more than wind power: some countries are investing heavily to reduce the cost of prodction. Drawing power from the ocean currents is a major part of Scotland’s plan to become 100% powered by renewable energy in the future.

Hydropower

Hydropower is the world’s largest source of renewable energy, and provides roughly 16% of the world’s electricity. There are three main types of hydroelectric plants:

  • Run-of-river plants: These generate electricity by using the constant flow of a river. As such, the amount of electricity they produce varies substantially over the course of a year.
  • Reservoir plants: This type of hydroelectric plant stores water in a reservoir, which allows operators to generate electricity when needed, and to adjust the plant’s output, by opening and closing the gates that control the amount of water that runs over turbines. Large reservoirs effectively function as giant natural batteries; the water they contain can be understood as potential future energy.
  • Pumped storage plants: When electricity supply exceeds demand, most hydroelectric plants use the extra electricity to pump water from lower reservoirs to upper reservoirs. That way, when demand increases, they can release the water back through the turbines to generate additional electricity.
*https://www.iea.org/topics/renewables/hydropower/