Published on June 10th, 2013 | by April Streeter0
Putting the Bio in Gas
The market for liquefied biogas and compressed biogas for use in transportation is better developed in Scandinavia than anywhere else in the world. Though potential is exponential, and the climate benefits are great, it is still early days for this carbon-neutral fuel.
Residents of Oslo have for months been sorting their food waste into bright green bags, their plastic into blue bags, and the rest of their trash into plain paper sacks. Though many citizens may not know it, those green bags of food trash are to be fuel for a growing number of city buses, turned into liquefied biogas (LBG) for the buses at a small, unassuming-looking plant just a few miles north of the city in Nes, at the Esval Environmental Facility. The Esval plant, commissioned by Oslo municipality and built by Norway’s Cambi AS, employs a thermal hydrolysis process to get more and purer biogas from the city’s waste than conventional digesters. One of the real innovations at Esval, however, is the ability to convert the biogas to liquefied form.
A new era
Esval is not the first biogas plant in Scandinavia to produce LBG – a facility north of Lidköping in Sweden has been running since last year, with a capacity to produce six million liters of LBG annually. Yet both of these plants signify a new era in turning waste into low-carbon transport fuel for the Nordic market.
Sweden has been a leader in producing biogas since the energy crisis of the 1970s, excelling at turning different wastes into power for its combined heat and power (CHP) plants. On the transport side, development has progressed more slowly, and the country made a strategic blunder in 2006, remaining mute when Volvo dropped its interest in producing cars that could run on biogas, in favor of ethanol models. Ethanol, mostly imported became the alternative fuel of choice. By the early years of the 2000s, however, western Sweden had developed a network of filing stations for what it calls “fordonsgas” – compressed natural gas for cars and trucks, to which compressed biogas from waste can be added. This fordonsgas network faltered a bit after Volvo exited the personal gas car market. But 2008 marked a turning point.
“The selling of cars that could run on gas was declining in Sweden by then,” said Anders Mathiasson of Energigas Sverige. “Luckily, along came Volkswagen with the Passat EcoFuel. It was a complete success, and the market has increased rapidly after that.” Volkswagen recently introduced its fourth car to Scandinavia able to run on CNG/CBG, the eco up! In Sweden alone there are now more than 45 000 consumers vehicles that can run on gas, and nearly 2 000 buses.
A fossil-fuel-free transport sector
Coinciding with the upswing in interest for CNG/CBG for personal cars is the development of plants that can also produce LBG. Mathiasson believes LBG is a key component of the Swedish government’s plan to create a ‘fossil-fuel-free’ transport sector by 2030. LBG and CBG, he says, could constitute 10% of the total transport fuel market. The use of these clean biogas alternatives generate just 8 – 15 grams of CO2 emissions per kilometer driven – magnitudes lower than petrol or ethanol. Switching out 10% of diesel and petrol use with biogas use would decrease overall carbon dioxide emissions about 6%, according to Energigas.
Though biogas as a fuel enjoys lower taxes in Sweden, government subsidies haven’t particularly favored facilities’ investing in the technology for conversion of biogas to LBG for motor fuel. However, the plant near Oslo, the plant in Lidköping, and a large-capacity facility being built near Gothenburg by Göteborg Energi all signal that Nordic governments are seeing the potential of CBG and LBG production, not only for their use as nearly climate-neutral fuels, but also as a way to handle food waste streams.
Mathiasson hopes that by this October, when a Swedish task force appointed last year to create a roadmap for getting to the fossil-fuel-free goal makes recommendations, incentives for transport biogas will be clarified. He is rooting for a certificate system, similar to that used in the energy market, for the fuel segment. It would add a small amount to the price of petrol and diesel and serve as a subsidy for biogas.
“As we see it, all the ‘fuels’ used for transport – ethanol, biogas, and electricity – need a model like this,” Mathiasson said.
Petrol: Petroleum-derived fossil fuel that is referred to as ‘gas’ in American markets.
Liquefied natural gas (LNG): Natural gas, generally a byproduct of oil drilling, which is then liquefied for easier transport.
Compressed natural gas (CNG): Natural gas that has been compressed for storage in tanks. It has a lower energy density than LNG because it is not liquefied. More than 15 million ‘bifuel’ or ‘flexfuel’ cars globally can now run on CNG/CBG.
Biogas: Any gas produced from the breakdown of organic matter – food waste, plant waste, sewage, manure – in the absence of oxygen. When biogas (mostly methane) is upgraded and compressed, it is suitable for bifuel cars and buses as a substitute for CNG and sometimes referred to as compressed biogas (CBG).
Liquefied biogas (LBG): When upgraded biogas is subsequently chilled to -163C it is known as liquefied biogas. LBG can be transported easily, and can power heavy trucks with dual-fuel diesel/gas engines.