Can Waste Gasification Quell A Future Energy Crisis?
This is a guest post from the BiotechBlog Intern, Fintan Burke. Fintan is a student at the School of Biotechnology at Dublin City University. Do you have a response to Fintan’s post? Respond in the comments section below.
One of the most overlooked but consistent problems facing many governments is waste management. Despite healthy recycling attitudes in both the US and UK, an EPA report showed US total waste production in 2010 was still around 250 million tons, while there are concerns that the UK will run out of landfill sites by 2018.
For many years, the only viable alternative to landfills was incineration. Despite its efficiency over landfill sites (incineration can reduce the waste mass by around 90%), concerns over small energy generation efficiency (estimated at 20-25%) as well as public protest over environmental impact mean incineration can never be a permanent solution.
As public and private sectors are beginning to shift their attention to cleaner, more efficient alternatives to waste disposal, one of the leading candidates is gasification.
Gasification has been with us in various forms since the 1840s. The process involves extracting combustible gases by subjecting dehydrated carbonaceous materials to intense temperatures and reacting the resulting ‘char’ with oxygen and/or steam. Originally coal and wood were used in the process and so bore little difference to incineration. Since the 1970s, however, focus has shifted from using these conventional inputs to biomass.
From this change in focus, several companies have been set up to offer biomass gasification as an effective renewable resource. One such company, Thermoselect, claims that for every 100kg of waste processed, 890kg of “pure synthesis gas” is created for energy generation. Another company, ZeroPoint Clean Tech Inc., is keen to demonstrate gasification’s use in generating renewable gas, heat, water and electricity.
This development has been embraced by both the US and UK governments, welcoming the opportunity to reduce their carbon footprint as well as municipal waste. In April 2011, the US Air Force Special Operations Command invested in a new plasma-based transportable gasification system, with the aim of reducing its waste output by 4,200 tons a year in air bases across the country. Later that year, Britain approved the first advanced gasification plant in the country, with the potential to generate 49 megawatts of renewable energy (enough to power around 8,000-16,000 US households). Some have even speculated that this new technology could be used to spark a boom in hydrogen cell powered vehicles in the future.
Not everyone has embraced the new technique, however. The proposal for a biomass gasification plant in DeKalb County, Georgia was met with protests from locals, fearing carcinogenic emissions. Furthermore, a 2009 report by The Blue Ridge Environmental Defence League warned that gasification shares many similarities with incineration, including the formation of pollutants and greenhouse gasses.
Despite these arguments, the gasification of biomass has several benefits. The high temperatures make them an ideal means of processing bio-hazardous waste from hospitals and the plants themselves occupy very little physical space. As with any emerging technology, however, uptake is cautiously slow. Many of the new plants are in trial stages and it is uncertain whether gasification will have any long-term environmental effects. Should the existent plants prove to be successful, there is no reason to doubt that gasification will become a realistic solution for environmentally sound energy generation.
About the author:
Fintan Burke is a student at the School of Biotechnology at Dublin City University. His main fields of interest include biomedical therapies and recombinant organisms. Fintan may be contacted at firstname.lastname@example.org .