There’s something in the brew in biogas, that brew being biomethane. As the world strives for a more diversified energy mix, renewable energies like biofuels and biogas are coming to the fore.

Sustainability is driving the utilisation of natural resources such as biomass, the products and potential of which is unlocked through anaerobic digestion (AD).

AD is a natural process whereby plant and animal materials (biomass) are broken down by micro-organisms in the absence of oxygen. Many different forms of biomass exist and can be used, from food waste to manure, and crops or crop residues in-between.

Although the exact composition of biogas depends on the type of feedstock it is derived from, it generally comprises around 60% methane and 40% carbon dioxide (CO2), as well as traces of other contaminant gases. This enables biogas to be used for two means of energy generation; it can either be combusted to provide heat or electricity, or can be upgraded to biomethane (pure methane) through the removal of other gases. The purified product can then be injected into the mains gas grid or used as a road fuel, reducing both the use of fossil fuels and the release of greenhouse gas emissions.

Biogas is burgeoning, globally. Its use is rapidly growing around the world and especially in Europe and a particular strand of this movement, biomethane, appears to be of growing interest to the industrial gas community.

As described earlier, biomethane is a purified form of renewable biogas that meets pipeline natural gas quality specifications and can be distributed and sold by injection into existing pipeline gas utility pipelines. It can also be used as a carbon-neutral compressed natural gas (CNG) vehicle fuel for vehicles including refuse trucks, heavy duty transportation trucks, transit buses and passenger cars.

Air liquide biogas spridlington ©james bastable

Source: Air Liquide / James Bastable

To meet these pipeline specifications, biogas must be put through a process whereby the methane present is separated from the CO2 and hydrogen sulfate that makes up the bulk of biogas – leaving behind an almost pure biomethane gas. This is largely achieved through biogas upgraders that process biogas and concentrate it to the same standards of fossil natural gas, removing CO2, water, hydrogen sulfide and other particulates.

SIAD S.p.A claimed a couple of ‘firsts’ in Italy, when it brought on-stream a new CO2 and biomethane plant in the country in July 2017. It is the first ‘carbon negative’ plant in Italy, meaning it does not release any emissions into the atmosphere, and also the country’s first industrial plant capable of producing CO2 and biomethane exclusively from the treatment of the organic fraction of municipal solid wastes (OFMSW).

The technologically-advanced plant breaks biogas down into its two main components; CO2 and methane. It is understood that the CO2 produced is used for industrial purposes, whilst the methane will be put into Italy’s national network. The biogas upgrading plant was created by SIAD’s subsidiary Tecno Project Industriale (TPI) and delivered to post-consumer plastic recycler Montello S.p.A.

A Tier One industrial gas player making great strides forward in biomethane is Air Liquide. The company has three new biomethane production units since the beginning of 2018, doubling its biomethane production capacity.

Air Liquide is developing technologies and expertise that cover the entire biomethane value chain and currently operates a total of 10 biomethane production units worldwide. Its production capacity stands at 60 MW, which comes to 500 GWh for a full year of production. To date, Air Liquide has rolled out more than 60 bio-NGV stations around the world.

The company announced the three new units in April 2018, located in the US (Walnut, Mississippi), France (Cestas, near Bordeaux), and the UK (Northwick, near Birmingham). The Cestas unit was inaugurated in June 2018, enabling the production of biogas from organic matter of farm origin and its purification into biomethane. This energy injected into the natural gas grid supplies a new multi-energy station that distributes, in particular, bio-NGV (Natural Gas for Vehicles). This clean non-fossil fuel reduces fine particulates emissions by 85%, CO2 emissions by 90%, and noise pollution by up to 50%.

The new biomethane production unit in the US is located in the Northeast Mississippi Landfill (NEML) site, and was inaugurated in July. Air Liquide was joined by stakeholders, local officials and members of the community at a ribbon cutting ceremony for the grand opening of the plant in Walnut, which purifies household waste gas provided by the landfill and converts it into a renewable natural gas that is re-introduced back into the energy grid to provide renewable energy for surrounding communities.

Michael Graff, Executive Vice-President and Executive Committee Member of Air Liquide S.A., and Chairman & CEO of American Air Liquide Holdings, Inc., said, “Air Liquide is committed to providing reliable, secure and sustainable energy solutions for our customers and global society, and we firmly believe in the power of renewable energy as a cornerstone of this energy transformation. We are proud to offer innovative and sustainable technologies that strengthen this commitment across the US.” The plant is the first large-scale unit built by Air Liquide in the US.

Air Liquide has invested around €100m ($123.4m) in different projects in biomethane production over the course of the last four years and clearly believes in its potential. François Darchis, Senior Vice-President and member of the Air Liquide Executive Committee supervising Innovation, said of this market in April, “The commissioning of these new biomethane production units, whether in the US or in Europe, illustrates the strong growth in new markets related to the energy transition.”

“In transforming the biogas produced by waste into biomethane using its patented separation and purification technologies, Air Liquide contributes to reducing greenhouse gas emissions and improving air quality.”

At another end of the spectrum, industrial gas equipment provider and pioneer iGas Technology Solutions, member of the Industrial Gas Project House (IGPH), is also active in the biomethane business and completed another successful Bio Methane PRS (Pressure Reduction System) installation in the UK last year.

Ian Davies, Managing Director for IGPH, discussed biomethane at the British Compressed Gases Association’s (BCGA) 2018 annual conference, and underlined the potential for this green energy in the UK. With an ever-growing demand for environmentally friendly, alternative energy, Davies’ presentation explored the viability of biomethane as one of these potential sources and commented, “The UK produces more than 62 million tonnes of manure per year which is about 40 KW hours per tonne. Forecast electricity generation from this source from 2020, is somewhere between 3,000 and 5,000 GW.”

Carbon dioxide and green gases

Future

Back in summer 2014, the UK-based Anaerobic Digestion & Biogas Association (ADBA) described biomethane as a vitally important part of our energy future and urged its long-term deployment.

Almost five years on, and with imperative carbon emission reduction targets to meet and an energy sector striving for diversification, could anyone really doubt this call to action?

Like the escalation in LNG, the utilisation of AD systems for biogas production and the purification technology for biomethane will only increase as energy security becomes more apparent. For the gases industry, again mirroring the synergies in (distributive) LNG, as time passes we can see the crossovers into the biogas business growing – a trend that will surely continue in the years ahead.

And at a time when the European CO2 supply chain has been so notably exposed to fragilities, biomethane could also present an opportunity for CO2 supply diversification – if its sourcing from essentially waste product can be stomached by end-users in the food and beverages sector, for example.