Her Majesty's Biogas
With natural gas production and landfill capacity declining, the U.K. is looking at converting waste to biogas and synthesis gas for heat, power, and fuels on a large scale
Meanwhile, landfill capacity has also been declining. A common sight in London is a Thames River barge laden with rubbish-filled containers destined for landfills elsewhere.
Alongside minerals, waste is among the two major types of freight cargos delivered to the wharves in greater London, according to an April 2007 report by Adams Hendry Consulting Ltd. titled "Assessment of Boatyard Facilities on the River Thames." The report says one major waste disposal company employs 200 people and operates a fleet of six purpose-built tugs and 47 container barges to transport more than 600,000 metric tons of waste by river each year. This is despite the fact that the Waste Strategy employed by the
Department for Environment, Food and Rural Affairs has managed to decrease the total waste delivered to landfills by one-fifth from 80 million tons to 65 million tons between 2000 and 2006, according to DEFRA's waste strategy progress report for 2007-'08. Londoners now recycle 20 percent of their waste and send the rest to landfills or incinerators at rates of 57 percent and 22 percent, respectively.
DEFRA's efforts to reduce, reuse and recycle are in support of the U.K.'s Climate Change Act, which became law Nov. 26, 2008, and which sets targets to reduce greenhouse gas emissions in the U.K. by 80 percent of the 1990 level by 2050 and to reduce carbon dioxide emissions 26 percent by 2020. DEFRA's efforts also support actions at the European Union level, including the EU Landfill Directive, which aims to reduce the amount of biodegradable municipal waste sent to landfills by 35 percent of the 1995 level by 2020.
"Local authorities in the U.K. all collect green waste for compost, but they have an obligation to divert as much biodegradable waste as possible from the landfill and so food waste is the next key element that needs to be captured and treated," says Jeremy Jacobs, managing director of the Association for Organics Recycling, a trade organization for the biological waste management industry in the U.K. "Some will capture that with the green waste, but most of the work that is being done shows that collecting food waste separately gives you better capture rates and better participation by householders. [Also], you've got back-of-the-store wastes from the major supermarkets and you've got processors who are dealing with food waste all of the time who have the opportunity to provide significant volumes of this material consistently."
DEFRA's efforts also support the EU's goal of sourcing 20 percent of its total energy from renewable sources by 2020. For the EU's goal, the U.K. will need to increase its share of renewable energy from 1.5 percent in 2006 to 15 percent by 2020. The U.K. is expected to publish its renewable energy strategy this year.
Energy From Waste
To help the U.K. lessen its dependence on natural gas and to reduce the amount of waste being sent to landfills, National Grid, an international utility that delivers gas and electricity to households in the territory of Great Britain and the northeastern U.S., commissioned Ernst & Young to look at the potential for using anaerobic digestion and gasification in the U.K. to produce biogas and synthesis gas. The report found that up to half of the country's domestic gas heating could be generated from manure, sewage, food waste and wood waste. The January 2009 report, titled "The Potential for Renewable Gas in the U.K," has been delivered to the U.K.'s Department of Energy & Climate Change.
"After we published the report, the phones were red-hot with waste companies and local waste management authorities contacting us," says Isobel Rowley, press officer for National Grid. "It certainly rang a bell."
According to the report, a small quantity of biogas, approximately 1.4 billion cubic meters, is currently being produced in the U.K. from landfills and sewage plants. For the most part, the biogas is being used to generate electricity at a 30 percent efficiency rate.
Jacobs says since BERR announced in June 2008 the department's intentions to change how many Renewables Obligation Certificates it will award to renewable electricity producers based on the technologies they use, more companies are looking at using anaerobic digestion or gasification to earn double ROCs beginning in April 2009. "The appetite is greater now than it has been in the past because of the financial incentives," Jacobs says, "and also because the price of energy has been extremely volatile. [In the current financial climate], proving the bankability of these projects is absolutely imperative; I think that the double ROCs will provide that. People who have been skeptical in the past now say that this is something which makes sense and payback is fairly quick."
However, instead of using these technologies to generate electricity, National Grid says it would be more efficient-as much as 90 percent efficient-to scrub biogas and syngas to pipeline specifications and to inject the gas into the gas network, a practice already being deployed in Germany, France and Austria, and also by National Grid in Staten Island, N.Y.
"Because we are basically running out of landfill, a lot of local authorities are looking at tying up long-term contracts for their waste disposal. Our concern is that it doesn't all just go for incineration or for electricity generation, but that a good portion of it actually goes for biomethane, which we feel is a more efficient use of it," says David Pickering, development manager in National Grid's Sustainable Gas Group.
The company says as much as 50 percent of the U.K.'s residential gas demand could be met with renewable energy if every person and business in the U.K. sorted and directed their waste to anaerobic digestion and gasification plants throughout the country.
In London, a city that will host the Olympics in 2012, Dow Jones Architects LLP and the professional services firm Arup Group prepared a report for the Greater London Authority titled "Rubbish In-Resources Out: Design Ideas for Waste Facilities in London" that includes conceptual designs for anaerobic digestion and gasification facilities within the city.
The report supports London's municipal waste management strategy, first published in 2003, that envisions that by 2020, 85 percent of the city's waste will be managed within the city, up from 60 percent currently. The architects estimate that 328 hectares (811 acres) of land within the city will need to be utilized for 297 facilities, including 25 anaerobic digestion units and 11 gasification plants and supporting infrastructure. The architects suggest the facilities should be "bold and visible," like little Wren churches built for practicing the renewable energy religion.
Nationally, the cost to build the infrastructure to support using anaerobic digesters and gasification plants to produce enough biogas and syngas to satisfy 50 percent of the demand in the U.K. is £10 billion ($14 billion), National Grid says, or about £100 ($140) per megawatt-hour, which the company says is similar to the cost of generating electricity using off-shore wind towers.
The key to building a biogas and syngas industry in the U.K. is government policy and regulation, National Grid says. Producers must be given a commercial incentive to inject gas into the grid rather than use it to generate electricity. National Grid proposes a "biomethane injection incentive" which would provide enhanced returns to producers when biogas or syngas is injected into the grid rather than used to produce electricity.
"We're working closely with DECC, which published a consultation paper back in February called the ‘Heat and Energy Saving Strategy' for the U.K., which is about providing the right incentives for a whole raft of energy conservation measures, in particular, heat. [The consultation] specifically mentions biomethane as a contributor to the renewable energy mix. We'll be responding to that consultation positively," Pickering says.
"Presently, the playing field is somewhat tilted against renewable heat technologies and toward renewable electricity technologies," Pickering continues. "One of the things that we've argued for is this thing called the renewable heat incentive, [which will be determined] by April 2011 at the latest. We're hoping to get some kind of reasonably firm indication from the government on the level of the incentive well before then so that projects can take it into account."
The "Heat and Energy Saving Strategy," published jointly by DECC and the Department for Communities and Local Government, lays out the U.K. government's vision for actions that should be taken through 2020 for "de-carbonizing" the way Brits heat their homes and businesses. The strategy is a request for input from the British people, which closed May 8.
"It is clear that without financial support, renewable heat will not be forthcoming on the scale we need," the strategy says. "We already provide such support for renewable electricity and renewable transport fuels."
The government says it plans to provide the incentive to all eligible renewable heat producers at all scales, from household- to industrial-scale generators. However, because renewable heat technologies vary widely in the amount of financial support they require to make them attractive, the renewable heat incentive will be applied differently for various technologies. The incentive amounts will be shared for consultation later this year. The incentives will be funded through a levy on fossil fuels used for heating.
In addition, National Grid says policies need to be in place to direct wet and dry wastes to appropriate facilities for conversion to energy. Finally, gas network owners who control the pipeline must be provided with incentives to connect the pipeline to biogas and syngas resources.
National Grid says the government must continue to support research and development to improve biogas and syngas production and upgrade technologies.
Meanwhile, the U.K. government is working on policies to support biogas production through anaerobic digestion. In February, DEFRA published shared goals for the anaerobic digestion industry in the U.K., which is supported by farmers, technology providers, supermarkets, water and energy utilities, waste handlers, and the food products industry, as well as government officials and regulators. A DEFRA task group will develop an implementation plan for the shared goals, which are to make anaerobic digestion an established technology in the U.K. for converting food waste to biogas, including both post-consumer food waste and industrial food waste. This includes a pledge from the Food and Drink
Federation, the voice of the food and beverage industry in the U.K., to send zero food and packaging waste to landfills by 2015. DEFRA's Milk Roadmap includes establishing anaerobic digesters at 30 dairy farms by 2010. For the farming sector in general, anaerobic digestion will be used to process food waste, crop residues and energy crops, in addition to manure. The ultimate vision is to have 1,000 farm-based anaerobic digesters in place by 2020. The implementation plan will include recommended regulations for encouraging growth in the use of anaerobic digestion.
To kick-start anaerobic digestion in the U.K., DEFRA is working with the Waste & Resources Action Program, a private nonprofit organization backed by government funding from England, Scotland, Wales and Northern Ireland, to construct three to six anaerobic digestion demonstration plants under the £10 million ($14 million) Anaerobic Digestion Demonstration Program, which is being jointly funded by DEFRA and BERR through the Environmental Transformation Fund.
WRAP has set aggressive targets for turning waste into energy. The program wants to divert 8 million metric tons of waste using anaerobic digestion and other approaches, with the goal of providing government, businesses and consumers with £1.1 billion ($2.2 billion) of economic impact by 2011. WRAP's business plan for 2008-2011 includes developing a market for the solid digestate produced from anaerobic digestion. To this end, WRAP and The Environment Agency have developed a draft Quality Protocol, applicable for England and Wales, for the collection, storage, transport and use of digestate. The draft protocol was published in January and will be reviewed by the European Commission's technical standards committee this year.
"[The protocol] provides confidence in the market," Jacobs says. "If you're going to be using digestate in the future, you need to be sure that it meets a standard. It also means that this material will be a product-and not a waste-and so when it is spread to land, waste regulations don't apply. It makes use of the digestate or the liquor fraction much easier for the processors."
Renewables obligation certificates, the proposed renewable heat incentive and the quality protocol for digestate will help to bring more anaerobic digester projects for converting food waste into biogas to fruition in the U.K. However, space and financial considerations will continue to be stumbling blocks.
"We live in a small, crowded island in the U.K.," Jacobs says, "and we have the issue around finding sustainable markets for digestate. I think planning is important in speeding up delivery of projects, because it seems to take an awfully long time to get anything built in this country.
"They say a green waste composting facility takes 12 to 18 months and an industrial composting facility maybe two years and above," Jacobs continues. "I suspect an anaerobic digestion facility would not be dissimilar. It should be quicker than that, because we need significantly more infrastructure to comply with our landfill directive obligations and our diversion targets."
Ryan C. Christiansen is a Biomass Magazine staff writer. Reach him at firstname.lastname@example.org or (701) 373-8042.