Up to half the UK's homes could be heated with gas made from waste food or sewage, according to research by the National Grid.
The Telegraph 2 Feb 09;
The analysis suggested biodegradable waste could be used to make biomethane to be injected into the gas grid, which would help achieve targets to source 15 per cent of all energy from renewables by 2020.
The study by Ernst and Young for National Grid also said that in the longer term, biogas could be used to provide up to half the country's domestic gas heating.
Currently a small amount of biogas is produced from landfill and sewage plants but is burnt to produce electricity, and National Grid believes piping the gas to homes would be more efficient.
The study said the £10 billion costs of delivering renewable gas compares reasonably with the provision of other types of renewables, such as wind power, and the unit cost of the gas would be similar to other "green" energy sources.
It would also provide the country with greater energy security to use waste products generated in the UK to provide gas as North Sea supplies of natural gas tail off.
Biogas, which is already being produced and injected into gas grids in Europe, is made through anaerobic digestion of wet waste such as sewage or manure, or through gasification of drier waste or energy crops.
Janine Freeman, head of National Grid's sustainable gas group, said: "Biogas has tremendous potential for delivering large scale renewable heat for the UK but it will require Government commitment to a comprehensive waste policy and the right commercial incentives.
"Biogas has benefits on so many fronts," she went on.
"It is renewable and could help to meet the target of 15 per cent of all our energy coming from renewable sources by 2020.
"It provides a solution for what to do with our waste with the decline in landfill capacity and it would help the UK with a secure supply of gas as North Sea sources run down."
The report said there would be no insurmountable technical difficulties in delivering biogas, and with an extensive gas grid in the UK there would be little need for major new infrastructure development.
National Grid said the main hurdle would involve getting commercial incentives for waste to be turned into biomethane for injection into the gas grid rather than electricity.
A spokeswoman for the Department of Energy and Climate Change said: "Government set out its policies on recovering energy from waste in its Waste Strategy 2007.
"Further work is taking place in the context of our Renewable Energy Strategy to establish what potential might exist for biogas injection to the gas grid."
'Green' gas could help heat homes
Roger Harrabin, BBC News 2 Feb 09;
Gas from waste could heat almost half the homes in the UK, according to a new report from National Grid.
It says obtaining more gas from waste will help cut carbon emissions, improve energy security and compensate for the shortage of landfill sites.
Renewable gas from landfill sites and sewage works provide 1% of the UK's gas at present.
Today's report says an extra £10 billion investment could increase that to between 5 and 18%.
The cost would be similar to that of other forms of renewable energy.
'Over-optimistic'
It says biogas could deliver up to two thirds of UK renewable energy targets by 2020. Critics believe the report is over-optimistic and seeks to capitalise on National Grid's control over the UK's gas pipelines.
Today's report will contribute to the growing debate about heat, which produces 47% of the UK's CO2 emissions - much more than electricity or transport. The government will soon launch a consultation on a heat strategy.
Renewable gas is currently obtained through anaerobic digestion (microbes) or by super-heating waste to drive off the gas. The report says both these processes create much less pollution than incineration.
Renewables subsidies mean renewable gas is currently used to generate electricity. But the report says this is much less efficient than using the existing gas grid to pipe the gas to heat homes.
The report says there are no insurmountable technical or safety barriers to delivering the gas, as the technology is already used in many other countries.
The key to delivery is government policy, including:
* A commercial incentive for producers to inject "green" gas into the grid rather than generating electricity
* A strategy to ensure each waste stream goes to the most appropriate technology to maximise energy recovery and recycling
* A change in the rules about the amount of oxygen allowed in gas pipes
* Continued support for research and development of renewable gas.
"As we look forward to 2050," the report says, " it is important to recognise that delivering 80% emissions reductions is going to require a very sizeable contribution from heat which only renewable gas is able to deliver without significant inconvenience to consumers and other residents of the UK."
Lower bills
National Grid says the beauty of renewable gas is that it utilises existing infrastructure. Competing technologies like combined heat and power, or CHP, require new pipes to deliver the heat.
The report says instead of transporting wood chips by lorry to be burned in CHP plants it would be more efficient to gasify the wood chips and then transport the gas.
Renewable gas is slightly less powerful than gas from fossil fuel but the report says consumers could be compensated through lower bills.
Critics point out that reliance on renewable gas locks the UK into a high-waste economy when the government is urging people to waste less.
Gas heating also allows less flexibility than electric heating which allows the heat in each room to be programmed easily.
Methane leaks could also be damaging - the greenhouse gas is more than 20 times more powerful than CO2.
Graham Meeks from the Combined Heat and Power Association said: "Renewable gas has an important role to play in the decarbonisation of the economy, but on its own it is no panacea. The low carbon agenda needs another silver bullet like a hole in the head.
"Any suggestion that this could displace the need for technologies such as district heating is extremely unhelpful. In fact district heating and CHP are the perfect complement to renewable gas production."
