Our ancestors discovered water as an energy source thousands of years ago. Water wheels are already known from ancient Mesopotamia. Modern man has built even more efficient models and thus generates electricity. We can also generate, capture and use energy by damming water, but so far hydroelectric power generation in Germany has only accounted for a small share of 8.2 percent. Let’s keep going, we can do better! Researchers have now found a new approach to blue energy that has enormous potential.
In 2009 the Statkraft power station in Norway shut down
Wherever fresh and saltwater mix, energy is released. This has been known for a long time and has led to numerous attempts to harness this power in the past. One idea is to separate the two types of water with a membrane and capture the energy as the water travels through that tissue. In 2009, a Norwegian opened a small power plant called Statkraft based on this principle. Unfortunately, it only gathered enough energy to heat a stovetop. To supply a city of 30,000 people, it would have to be the size of a football stadium. The project was called off.
2.6 terawatts of electricity can be generated at estuaries
Researchers from Rutgers University (US) have now developed a new BNNT membrane based on nanotubes. If this membrane were used in all estuaries in the world, 2.6 terawatts of electricity could be generated per year. This corresponds to the energy production of 2,000 regular nuclear power plants. The only question is what the energy shortage means for the sea.
Another project comes from Stanford, the scientists there reported on in 2019 in the journal ACS Omega. They developed a battery that they alternately filled with seawater and freshwater. No membrane is used here, the electrically charged salt particles flow back and forth between the two electrodes and deliver their energy. Such batteries are used in sewage treatment plants whose water flows into the sea. In a model project, it was possible to operate the associated system with the generated electricity. Comparable batteries could cover about three percent of the international energy demand.
A huge untapped resource of renewable energy«
Blue energy power plants operate independently of wind and weather. They can occur anywhere freshwater naturally flows into the sea — or at sewage treatment plants. “Blue energy is a vast and untapped source of renewable energy,” writes an author of a Stanford study. Let’s see what can be done.