While electric vehicles score a lot of press as we search for less carbon-intensive public transportation, finding alternatives to diesel-fueled buses could go a long way to lowering our carbon footprint. Electric buses are a large part of this equation, but considering all the sewage municipalities generate, biomethane is another source of energy that can help wean us away from fossil fuels. Last week the first bus in the United Kingdom made its maiden voyage, powered by yes, biomethane from human poop and food waste.
The 40-seater Bio-Bus made a trip from Bristol Airport to the famous historic city of Bath. It runs off of biomethane gas generated at Bristol’s sewage treatment plant, operated by GENeco. The company was the first in the UK to churn local sewage into a steady stream of reliable fuel. GENeco says the bus can run 186 miles (300 km) on a full tank of gas while producing 30% fewer emissions than conventional diesel buses. Bath Bus Company, which is contracting the bio-bus, expects as many as 10,000 passengers to travel on this route monthly.
This pilot project in Bristol, which started in 2010 by experimenting with a “bio-bug” that could run seamlessly off of biomethane, sums up why this fuel is a reliable one for bus fleets. Just take a look at the numbers. Each tank of gas takes the waste five people flush down the toilet annually. Considering Bristol’s population is over 420,000, there will be no shortage of feedstock to power a larger fleet of these buses.
In fact, GENeco’s general manager claims the Bristol sewage plant could produce enough methane to power 8,500 homes annually. Of course, consumers will have to get over the scatological base of their fuel. Not many people want to be reminded that the gas they might be using to cook their breakfast could be based on what they flushed down a few days earlier. Nevertheless, with fossil fuel prices always volatile and with nations focused on reducing their greenhouse gas emissions, waste-to-energy will be an important source of power in the coming years.
Logistically, the use of biomethane is also a natural for bus fleets. In the case of Bristol, the anaerobic digester that converts sewage into gas generates 17 cubic meters of biomethane a year has been integrated into the city’s gas grid. A fueling station was built adjacent to the sewage plant, which will allow buses to refuel regularly and then continue their next round of rides.
While reducing greenhouse gas emissions and Bristol’s carbon output—timely considering the popular coastal getaway has been designated as Europe’s Green Capital for 2015—biomethane from waste also can help take care of another challenge confronting cities. With diminishing landfill space a pesky problem in Britain and the European continent, converting human waste and food scraps into energy also skirts incineration and dumping waste into a landfill—the latter of which allows methane, one of the most potent greenhouse gases, into the atmosphere. The Bristol sewage plant alone treats 75 million cubic meters of sewage waste and 35,000 tons of food waste a year.
Hence lies even more potential for biomethane in the UK. Charlotte Morton of the Anaerobic Digestion & Bioresources Association said, “GENecos Bio-Bus is an excellent demonstration of biomethane’s unique benefits; decarbonizing areas other renewables can’t reach. A home generated green gas, biomethane is capable of replacing around 10% of the UKs domestic gas needs and is currently the only renewable fuel available for HGVs (heavy goods vehicles).”
The use of biomethane is already established elsewhere in Europe. Sweden, for example, has long been a leader in converting sewage into transportation fuel. Over 36,000 trucks, 1,500 buses, and 500 heavy-duty trucks crisscross the southern part of the country and can easily refuel thanks to a network of 130 public fueling stations. Five years ago, Oslo, Norway rolled out a fleet of 80 buses running off of biomethane and has recently launched a project that turns food waste into transport fuel. France and Germany are also boosting their biomethane capacity.
The quest to turn poop into pep for vehicles is hardly new. Who would not want to profit off of a resource that for ages was considered to have no value? Many start-ups have focused on converting algae that feeds off of sewage into fuel. Researchers have also explored ways to generate transport fuel from animal waste, a noble effort considering factory farms are often responsible for creating algae blooms in coastal areas. Millions have been spent on this effort, including by the Spanish energy company All-gas, which hoped to create a reliable stream of energy from waste harvested from sewage. But what stands out about this project in Bristol is that it is converting waste right at the source, essentially turning a sewage plant into a co-generation facility. Should the Bristol project prove successful, look for city planners to look at it as a model for killing two birds with one stone: sustainable fuel and waste diversion.
Image Credit: GENeco
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