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.

Renewable 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.

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 distribution networks have been critical in allowing this industry to develop.

The UK’s first commercial BtG plant was located at Poundbury in Dorset, starting production in November 2012. This was followed by two more facilities in 2013 and 24 in 2014. By the end of 2015 there were over 50 plants injecting renewable gas into the UK gas grid. A good example project is at Wyke Farms in Somerset (pictured right), where waste from making cheese is used to create biomethane injected into the gas grid.

According to National Grid, which has been a consistent supporter of BtG: ‘Through injection to the gas grid, biomethane provides a sustainable, flexible and economic solution that could provide a significant contribution to the UK’s heat demand by 2050.’ Meanwhile, the EU Green Gas Grids Project estimates that biomethane from anaerobic digestion could provide around 30 TWh/y by 2030.

Future developments: One way to get higher volumes of renewable methane is for the development of Bio-SNG (biosynthetic natural gas) technology. National Grid is working with Advanced Plasma Power (APP) in a project with £11mn in government funding to develop and build the first plant of its kind to produce renewable methane from waste that is not suitable for anaerobic digestion. APP’s new plant in Swindon will take residual waste – the UK’s largest sustainable source of biomass – and convert it into biomethane using APP’s pioneering Gasplasma® technology.

Together, biomethane and Bio-SNG have the potential to produce 100–150 TWh/y of renewable gas by 2050, if you made use of all available biomass resources. Having its own domestic gas supply would also provide energy security for the UK, reducing reliance on LNG ( which is less environmentally friendly than BtG) imports from the Middle East.

Looking further afield, across Europe, Germany, Switzerland, Austria and France all have biomethane plants connected to their gas grids. According to the latest (2015) report from the European Biogas Association, some 255 plants in Europe were connected to national gas grids in 2014; 165 of which were located in Germany.

France has ambitious development plans for biomethane injection. According to GRDF, which runs the French gas grid, around 400 projects are in the pipeline. France is placing biomethane at the heart of its circular economy, aiming to utilise large amounts of agricultural waste to produce biogas. Plans are for France’s biomethane plants to produce up to 15% of the country’s overall gas requirements by 2030.

The success of BtG is related to the scale and scope of a country’s gas grid. A cold country like the UK, with an extensive gas grid and 20mn central heating systems, has much to gain by developing biomethane. Meanwhile, Sweden is unusual in that it has a limited gas grid and, rather than focus on heat use, it has become the European front runner for compressed biomethane as a vehicle fuel, with around 78% of its 1.3 TWh production fuelling over 50,000 vehicles, according to the European Biogas Association’s 2015 report.

In the UK, there is 6,000 km of high pressure gas grid known as the Local Transmission System (LTS). This is a highly attractive asset when it comes to fuelling trucks on compressed natural gas (CNG). There are no gas leaks from the LTS and a compression plant only requires 10% of the electricity that it would need to compress from a 200 mbar gas grid. The combination of biomethane injected into the grid and CNG from the LTS is encouraging the use of biomethane in transport.

Most recently, CNG Fuels opened a filling station in Leyland, Lancashire, allowing vehicles to fill up on bio-CNG directly from the LTS. The new facility is the first of its kind in the UK and can fuel up to 500 vehicles a day. Waitrose has 35 trucks using this station, with the gas made from food waste at biomethane plants and delivered to Leyland via the gas grid using the REAL Green Gas Certification Scheme to link the source of gas to Leyland. In effect, trucks are being fuelled on food waste. Scania now manufactures a 340 bhp truck that runs on 100% CNG – there is no diesel consumption at all, providing significant benefits in terms of lower fuel cost, lower emissions of nitrous oxides (NOX) and particulates, and reduced noise.

Having established that biomethane is a great solution for decarbonising the gas grid, new challenges lie ahead. The growth of biomethane in the UK has triggered automatic tariff degressions with financial support for biomethane falling to around 5.35 p/kWh from 1 April this year. DECC is currently in consultation regarding the allocation of £200mn of new funding to biomethane projects until 2020 – a key issue under discussion relates to the use of energy crops. The industry is arguing that some crops should be used as part of an overall balanced approach to feedstocks that encourages use of waste as far as possible but in a way that proves an economic option for farmers.

Of the 65 projects that will be injecting gas into the UK biomethane grid by April 2016, a company called Barrow Green Gas is purchasing the biomethane from about half of the sites. This gas shipper, established in 2012 to focus on biomethane, now has around 2 TWh/y of gas contracted, with a focus on supplying the likes of the CNG Fuels filling station at Leyland. The purchase of Green Gas Certificates from Barrow Green Gas is attracting growing interest from large energy users who want to reduce their carbon footprint but who have had no practical alternative to natural gas previously. ●

*The UK’s leading provider of BtG connections