With rising sea levels, the decreasing size of polar icecaps, the steady rise in atmospheric temperature, and a hole in the ozone layer, climate change is not to be ignored. Besides trying to be better individually, through the increased use of public transport/walking/cycling, decreasing our carbon footprint, and increased efforts toward recycling, what is science doing to harness new, ‘clean’ energy?
I’m sure you’ve all heard of/seen solar panels and wind farms dotted around the country, however, wave energy and nuclear energy are amongst other forms of renewable energy used today. These resources are great on the surface, generating renewable energy, and on a small-scale they’re wonderful, providing energy for small businesses, homes and even schools. However, the technology is still not quite advanced enough to maximise and store all the power it could harness from sources such as the sun. So, while technology advances and plays catch up, what else can science do?
There have been plenty of news reports on other renewable energy sources, one of which is biofuel. Biofuel is not as new as you may have thought, in fact, biofuel has been around since the invention of cars. It was upon the discovery of huge amounts of underground petroleum which enabled petrol and diesel to be used as widely as they have been, considering the resource was readily available. Biofuels, by definition, are made from dead plants and other matter. Therefore, petrol and diesel are also biofuels as they were made by the burial of dead plants and matter, the difference is they were created over millions of years and are therefore not renewable: fossil fuels. Today’s biofuels are created from plants and crops currently grown. Whilst the crops grow, they can soak up atmospheric pollution during photosynthesis, and when burnt for fuel, do not release more harmful gases than they have recycled during their growth. Biofuel is created using chemical reactions, such as fermentation, and heat. Follow this link if you want to learn more: Biodiesel production.
But, does the process of making biofuel use up too much energy for it to be a worthwhile process overall? In fact, much of the energy used in biofuel production is from coal and natural gas. Are the crops therefore better used as a food source than a fuel source?
So, is there a way to use a natural resource to create energy which does not require more power to make than it would produce? A well known scientific rule (The First Law of Thermodynamics) could lead to this successful research: “energy is not created nor destroyed, it is only transferred, or changed from one form to another” (for example, when a light bulb is switched on, light energy is produced, but in turn, so is heat energy). So what has potential energy that is going to waste? Well, waste, quite literally.
An avenue under current exploration, is the use of waste from water treatment plants: the power of your poo! It is a renewable resource which, at the moment, is not used once it leaves us…until now. It is possible to harness the potential energy which our poo holds by a process called anaerobic digestion. Microorganisms such as bacteria conduct anaerobic digestion which is the degradation of biodegradeable chemicals like sugar (glucose) in an oxygen free environment. This process releases energy as a byproduct as the microorganisms digest the waste.
Is this really a viable energy option, and could it be used globally? Currently Oslo, Norway, uses poo power to heat the city’s homes! And before you ask, no, it does not make your home smell. Raw sewage releases heat energy, and this energy alone can be channelled into the hot water pipes of homes, reducing energy bills as it is all recycled from waste! In South East Asia, Africa and farms in Australia, poo power has been used for a while to heat homes and businesses. Even here in the UK, chicken poo has been used to generate electricity and heat for 350 homes.
Currently in the UK, Yorkshire Water is trialling various poo power methods to lower energy bills, and the country’s carbon footprint. They are now successfully running an entire sewage works in Bradford on poo power, saving £1.3 million/year in energy bills, whilst lowering their carbon footprint by 9,000 tonnes! It takes a lot of poo to create this power though. The site claims that 100,000 people’s poo is required to generate enough energy to power 500 light bulbs. However, when the resource is so readily available and not going to be running out anytime soon, how about we all do our bit for the planet and use our poo?
Fossil fuel image from: https://www.tes.com/lessons/Q5oW22tSZy43vw/sedimentary-rock-and-fossil-fuels