With renewable energy sources becoming more popular, could anaerobic digestion offer a viable solution to reducing energy costs?
by Michael Smith (Veshengro)
Much has been said about the more popular ‘green’ energy sources such as solar power and wind. With billions of pounds being poured into the development of these technologies by governments and private investors around the globe, these technologies are well on their way to one day replacing the oil, coal and gas that this planet relies on so heavily. But these are not the only viable options to eliminating non-renewable energy sources. The UK in particular has put together an initiative to increase the amount of energy produced each year from anaerobic digestion.
Put simply, anaerobic digestion is the process by which methane gas is produced when waste is broken down in the absence of oxygen. The technology itself is nothing new. Producers or large amounts of food waste such as farms for example, have been using this method of producing methane gas which can then be burnt to heat houses or power combustion engines for centuries. It is only as recently as 2011, however, that the government has considered AD as an alternative to fossil fuel and has put together an action plan for developing the technology so that it can produce renewable energy on a large scale.
The beauty of AD is that it in effect kills two birds with one stone. Not only is it offer a solution to the problem of finding alternatives to fossil fuels, it also goes some way to solving another increasingly troublesome problem when it comes to the environment; that of waste management. With the population ever on the increase and staggering amounts of food and other biodegradable material being thrown away every year, and landfills growing at an alarming rate, AD at least goes some way to relieving the stress on the environment caused by waste, while actually allowing us to harness the energy produced in the chemical reactions that occur during the decomposition of organic matter.
The Government’s ‘Anaerobic Digestion Strategy and Action Plan’ which was put together in 2011 seeks to put find ways of creating large scale operations that will produce large amounts of renewable energy from sources such as farms and sewage plants that treat biomass in order to produce gas that can then be used to create heat and power, while reducing the amount of waste that is sent to landfill.
By 2020 it hopes to reduce the amount of food waste and slurry that is sent to landfill by instead using it to power the country through the use of AD. It envisions that around 5 megatons of food waste and 20 – 60 megatons of animal waste could be used to create approximately 3.5 terawatts of energy, which is enough to power over 913,000 households annually.
There are still a number of barriers to overcome, including finding the space for new AD plants to be erected and the development of new technology as well as a number of legislative difficulties, however, with the help of incentive such as the Feed-in-Tariff, the Renewables Obligation and the Renewable Heat Incentive, all of which give businesses and industries financial incentives to recycle waste products in order to create renewable energy, anaerobic digestion is becoming ever closer to becoming a viable option.
The thing to remember is that the gas produced by anaerobic digestion (AD) is methane, predominately, which, in fact, is nothing else but natural gas.. the very same stuff that we are drilling for and extracting from the North Sea and other places.
The beauty is that methane can be produced by AD from sewage and from landfills and, theoretically, every single farm, sewage works and landfill site could be an electricity generating plant.
The first Edison power stations were meant to be powered by methane gas from the sewers but the oil industry put an and to that and that by more means than simply being cheap.
Over a sewage plant not far from my home five flares are burning constantly, day and night, flaring off the methane releases. Instead of flaring the stuff off it should be put to use for the flaring, or worse still the simple venting, as done on even the largest landfill in the county, is worse for the environment than burning the gas to generate power.
In addition to AD for the production of electricity we must take also a leaf out of the book of the Swedes and go down the waste to energy route instead of paying them to take out waste that we cannot recycle and burn it in their waste to energy plants.
But that is something where the likes of Friends of the Earth always rant and rave against with statements such as “we need to recycle more”. And while it is true that we still have to get down to recycling more of our waste at least, until such a time that we have an almost zero waste society burning it sanitarily, with the flue gasses being scrubbed, for the production of energy is by far better than dumping the stuff in holes in the grounds, and that aside from the fact that we are running out of said holes in the ground.
Time we got real and used the resources that we have instead of fracking for shale oil and gas and destroying the environment that way.
© 2014
