We all know that we face increasing challenges in order to meet our energy needs. With the climate changing, global population increasing, and fossil fuel levels falling, most people agree that renewable energy sources have a major part to play in the coming years. Green energy sources (especially ones that are literally green) must be better than heavily polluting ones such as coal, oil and gas…right?
First, let’s explain what we mean by “biofuels”: these are fuels which have living organisms as their source. While we get fossil fuels from living things which died and decomposed millions of years ago, biofuels use organisms which are around now. Things like algae or oilseed rape are used as the starting point for solid, liquid or gas phase fuels which might be more recognisable to us. There is great interest around their use because of the polluting nature of fossil fuels, as well as the ever-increasing need for cheaper and more sustainable fuel sources.
As a concept there’s nothing new – wood has been burned for thousands of years. The “first generation” biofuels are categorised as those produced directly from crops such as sugar cane and corn, and include ethanol, biodiesel and biogas. Currently, “second generation” biofuels have been produced from different types of biomass such as woody crops or agricultural waste, and more recently biofuels have been produced from algae and are termed “third generation”, although name and definitions sometimes vary. While the source and “generation” may change, the end products are broadly similar.
There are a number of issues associated with the use of biofuels, in particular first generation sources. As the global population increases the amount of food we need to produce also goes up, and because many biofuels are derived from various crops, there is a competing demand on the limited arable land available. As a result, farmers may be encouraged to grow crops for biofuels instead of food, leading to reduced food security and increased prices.
There are also worries around loss of established habitats such as rainforests for biofuels, which has a negative impact on biodiversity especially in fragile ecosystems around the Amazon. Using algae for biofuels instead of land crops may find a way around some of these issues, but as our recent event showed they are not without their own problems – have a look at this article from The Biologist magazine to find out more.