Why do we find ourselves needing to store more and more electricity?
My previous article, which you can find here, explores some of the new technologies being developed to store electricity. We have an ever-growing need to store electricity due to our increasing reliance on renewable energy sources. This is because renewable sources can be very erratic: on a windy day, the supply of electricity from wind turbines can outweigh demand, and so we need to find ways to deal with these surplus electrons. This is the very reason why so much research is going into alternate and better energy storage techniques.
What is the problem with storing all the excess electricity we produce?
Despite all the new innovations I discussed in my previous article, storing electricity is still very difficult and expensive. Thus, any other strategy to put excess electricity to good use is always worth pursuing.
One of these strategies is ‘electrochemistry’. Electrochemistry refers to the use of electricity to perform chemical reactions and to create chemicals on demand. Although electrochemistry was the subject of much experimentation as far back as the early 19th century, many scientists are now beginning to realise that it can provide solutions to a number of our problems. One of these is the problem of what to do with surplus electricity.
So, what solutions does electrochemistry offer?
Many chemists dedicate a lot of their time to searching for cleaner ways to make chemicals as part of the global effort to become more sustainable. The global chemical product market is valued at well over $1 trillion, and the majority of these products are produced using additional heat or with another chemical as a catalyst. In contrast, if positive and negative electrodes are dipped into the reaction mixture (this method is called ‘electrosynthesis’), the same chemicals can be produced at a lower cost, and in a cleaner way. It doesn’t take a genius to realise that the problem of surplus electrons and the problem of chemical synthesis can be overcome by a single solution: using any excess energy from renewable sources to produce chemicals more cleanly and on demand.
But what if we don’t want to use up the surplus electricity? Does electrochemistry provide any solutions when it comes to storing energy?
Yes, it does. Another use for the surplus electricity is to obtain hydrogen from water by splitting it from oxygen. The resulting pure hydrogen can then be stored and used as fuel when needed.
As shown in the image above, the idea of using hydrogen fuel cells for transportation is becoming more and more popular due to the fact that the only by-product is water vapour. (It is worth noting that water vapour is actually a greenhouse gas, but it stays in the atmosphere for a much shorter time period than other greenhouses gases which stay lingering in the atmosphere in quantities far higher than they should be, like CO2 and Methane.)
Hydrogen fuel also has implications when it comes to space travel, because our knowledge of electrochemistry means that the presence of ice on other moons/planets could provide a top-up of power.
Does electrochemistry have any applications when it comes to generating electricity?
I think you get the gist of this article by now! The answer, of course, is yes. Electrochemistry refers to the relationship between electricity and chemical processes. We have already looked at how excess electricity can be used to manufacture hydrogen and other chemicals, but as we shall soon see, the relationship also works in the opposite direction: chemical processes being used to generate electricity.
Through research, scientists have found out that microalgae exploit electrochemistry in an ingenious way. As a by-product of all the chemical reactions that take place within them (they are single-celled), they also produce a flow of electrons which can be used to generate a current with the help of a bio-photovoltaic platform. A bio-photovoltaic platform is essentially a biological solar cell. As the algae photosynthesise on the platform, the platform uses the flow of electrons to generate a useable current.
Scientists have also managed to identify enzymes in a specific species of bacteria which are able to break down plastic. If this enzyme is transferred to the algae solution, the microalgae are able to thrive off the molecules from the broken-down plastic while at the same time producing a current.
The implications of this discovery are huge as it addresses two major issues at once: plastic waste and sustainable electricity generation. Microalgae are widely available and so this is a potentially cheap and sustainable solution, which harnesses the power of electrochemistry on a micro scale.