Powering homes with human waste

Could it power homes?

Solar, wind and hydro-electric power; these are all the forms of renewable energy that generally spring to mind when you think about the need to wean our economies and lifestyles off oil and gas supplies. However biomass, more specifically human waste, could also play a key part in the future of countries' power needs.

In a bid to meet their obligations to make sure that 15 percent of their energy comes from renewable sources, European countries have considered utilising "sewage waste" - an energy source that is as regular and as renewable as they come.

The idea is that by treating human waste, biogas (stop giggling at the back) can be created to power homes. This would be done in the same way that some waste is treated at landfills. Instead of merely being buried in the ground, a lot of waste is naturally broken down by microbes under anaerobic (absence of oxygen) conditions. This decomposition, combined with rainwater filtering through the landfill, results in the production of liquid, called leachate, and gas.

This gas is either burnt off or directed to an on-site energy generation plant, where it is converted into electricity and exported to the grid and this is the same concept that would be used to treat sewage waste.

Any 'solid' waste leftover can be given to farmers as fertiliser...

Europe's gas need

Traditionally Europe gets it gas from Russia and the Middle East, but these supplies are finite and are a constant source of political debate, considering the dependency put on these providers. The North Sea is another source, but one that in recent years is yielding less and less. As such, the need for an alternative source is massive.

The crazy thing is that this is not a new concept: Marco Polo noted the Chinese used covered sewage tanks to generate power in the 13th century, while the idea of biogas was also discussed in the 17th century. In fact, the whole thing has been discussed for years with European countries interesting it providing their own gas sources instead of relying on Russia.

Of course the entire idea would be a much more sensible one than getting biogas from food crops such as rapeseed, considering the food shortage affecting parts of the world. Producing fuel from sewage makes more sense all round.

However, if you can believe it, the amount of waste humans produce may not be enough. According to a 2009 paper by the National Grid, human waste would only produce up to 270 million cubic metres (0.28 percent) of the estimated 97,000 million cubic metres total demand for gas. In an ideal scenario, by 2020, it could provide 629 million cubic metres (0.65 percent) of the total UK gas demand.

Either way, it is an idea that is developing a lot of support on the continent, after all why spend millions treating sewage and then flushing back into the water system when we can use it to power our homes?

Image from The BBC

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