Renewables
BTG
Biogas comes of age
John Baldwin, Managing Director of CNG Services,* takes a look at what’s happening in the biomethane-to-grid (BtG) sector in the UK and further afield.
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CNG Fuels recently opened a filling station located near to junction 28 on the M6 in Lancashire, UK, allowing vehicles to fill up on bio-CNG directly from the gas grid – the first of its kind in the UK Source: National Grid
enewable gas is now a reality, decabonising the gas grid. The biomethane-to-grid (BtG) market came of age in 2015 as the UK added a further 23 BtG connections, bringing the total to 50 nationwide. As a result, for the second year running, the UK has been the fastest growing – and the biggest – BtG market in the world. In 2012, just 300,000 therms of biomethane was being injected into the UK’s gas grid. However, when all planned projects are completed by mid-2016, this will rise to around 120mn therms/y. That will bring annual ‘green’ gas production in the UK to 3.5 TWh/y – representing around 240,000 tonnes of LNG that the country won’t need to import from the Middle East or four 60,000-tonne LNG tankers not needing to dock at domestic ports.
34 Petroleum Review | May 2016
A critical issue Gas has a vital role to play in the UK energy mix. There are no easy alternatives to the gas grid and central heating, reflected in the fact that changes to the Renewable Heat Incentive (RHI) reduced support for small-scale biomass and solar thermal technologies whilst increasing funding for biomethane which can be injected directly into the grid. There have been some attempts to introduce heat pumps into the market, but they have been generally unsuccessful due to lack of space for ground source pumps and cold air temperatures for air source models. Given the lack of alternatives it is no surprise that the UK Department for Energy and Climate Change (DECC) is on record as saying: ‘Biomethane-to-grid is a key renewable technology that has the potential to make a significant contribution to the UK’s 2020 renewable energy commitments.’ What is BtG? So, what exactly is BtG? Biogas is gas produced from organic waste in an anaerobic digester (AD); it is then cleaned and upgraded to
become biomethane. Biomethane is produced from renewable biomass such as organic waste, sewage, agricultural residues or energy crops. A number of AD plants had been built in the UK prior to 2010, mostly on sewage treatment works. These plants produced biogas used to generate electricity, for which they received a government subsidy – as one was available for renewable electricity at that time. However, the absence of use for waste heat from electricity generation created a business case for biomethane injection into the gas grid. In 2010, the Renewable Energy Association was successful in lobbying for the Renewable Heat Incentive to include biomethane, which gave investors the confidence to commit to producing biomethane for injection. Another piece of the jigsaw was overcoming the technical challenges presented by cleaning (removing hydrogen sulphide, H2S) and upgrading biogas (removing 45% carbon dioxide, CO2) in order to safely inject it into the gas grid. The cooperation and support of the gas