• Seawater dam for renewable energy
    Deni Williams via VisualHunt.com / CC BY

Renewable energy of the future: Seawater

There’s no doubt about it, global warming is a real, and growing crisis. While some are choosing to ignore the signs and the information given to them, others are looking towards a move into renewable and clean energy. A few researchers at Osaka University have found a way to make renewable energy that utilizes one of the largest resources on earth, seawater.


Solar energy is a major source of renewable energy. However, how can we use solar energy when the sun is hiding? One answer is to turn solar energy into chemical energy that can be used as fuel. By doing this conversion, it can be stored and moved around. Hydrogen (H2) is a potential candidate for the conversion. It can be produced by splitting water molecules (H2O) using a process called “photocatalysis”. Photocatalysis is when sunlight gives energy to another substance which then acts as a “catalyst”. A catalyst speeds up the rate at which a chemical reaction happens. Photocatalysis occurs all around us, sunlight hits a plant’s chlorophyll (a catalyst) in their plant cells, which allows to them produce oxygen, and glucose which is a source of energy!

However, as the researchers noted in their paper, “the low solar energy conversion efficiency of H2 production and the storage problem of gaseous H2 have precluded the practical use of H2 as a solar fuel.”


Enter hydrogen peroxide (H2O2). As American Energy Independence notes, “Hydrogen peroxide, when used to produce energy, creates only pure water and oxygen as a by-product, so it is considered a clean energy like hydrogen. However, unlike hydrogen, H2O2  [hydrogen peroxide] exists in liquid form at room temperature, so it can be easily stored and transported.” The problem was that the previous way to make hydrogen peroxide used photocatalysis on pure water. Pure water is as clean as it gets. With the amount of pure water used in the process, means that it isn’t a feasible way to create sustainable energy.

Here’s where seawater comes in. Given what seawater is made up of, the researchers used it in photocatalysis. The result was an amount of hydrogen peroxide that was high enough to run a hydrogen peroxide fuel cell (a fuel cell is like a battery, only it needs a continuous stream of fuel to run.)

This method of creating hydrogen peroxide for fuel is a budding project with room to grow. There is still the question of cost-efficiency, and using it on a larger-scale, rather than just as a fuel cell. One of the researchers involved, Shunichi Fukuzumi, was noted in an article saying, “In the future, we plan to work on developing a method for the low-cost, large-scale production of H2O2 from seawater,” Fukuzumi posits, “This may replace the current high-cost production of H2O2 from H2 (mainly from natural gas) and O2.” 


Taking one of the Earth’s largest resources and using it to our advantage in the form of energy could be considered, in my mind, one of our greatest achievements. Given how much seawater we have, it would result in cheaper energy for all. We would also be able to reduce our carbon emissions immensely, should most major countries and corporations look to make the shift from fossil fuels and other non-renewable energy sources toward a seawater energy source.

As it was mentioned earlier, pure water is a by-product of hydrogen peroxide when used to make energy. So there is even the possibility of being able to re-use this water for consumption and other applications. With some countries right now not having access to clean water, as well as efforts on how to effectively move and manage freshwater, seawater may be the answer.

Of course, there is the other side of the story of using photocatalysis on seawater. If this method is to be used on a global-scale, what will be the impact on marine life? There is no doubt that oil rigs out on the sea will be a slow process to phase out. As well, it is important to consider the amount of space that might be needed for these photocatalyic machines. What happens to the territory, or the survivability of marine life? These questions will surely be taken into account, and the optimism should be there that there will be a way to make sure our sea friends will be alright.

Forecasted start year: 
2018 to 2025
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