Renewable propane and butane using a novel microbial pathway

Dr Sandra Esteves

Professor Sandra Esteves

Researchers at SERC are collaborating with industry to lower the carbon impact of Liquefied Petroleum Gas (LPG).

Liquefied Petroleum Gas (LPG) is comprised of higher alkane gases including propane and butane and is widely used as a fuel in gas cylinders in off-grid locations. These gases are also used as propellant in the aerosol industry and as a feedstock to produce petrochemicals.

Liquefied Petroleum Gas (LPG) plays a significant role in the UK energy system by providing heat and energy to two million off-grid homes and businesses across Britain (UK LPG, 2018). LPG is currently derived through the extraction of natural gas or as a by-product from oil extraction and refining. LPG is either produced at one of the UK’s six oil refineries or is imported.

The UK is likely to fall short of its 2020 Renewable energy obligation of 15% of all energy consumption from renewable sources (30% electricity, 12% Heat, 10% transport). While the UK is expected to exceed the electricity sub target, it has yet to reach halfway targets in both heat and transport. Whilst considerable effort is being made to decarbonise gas grid supplies (such as biomethane and renewable hydrogen), the options to decarbonise off-grid gas users are limited.

A mechanism for the sustainable production of propane and butane is required. The only existing technology uses a by-product from the manufacture of biodiesel which, in the long term, has a limited capacity to fulfil market demand.

Building on their long track record of research into the anaerobic production of methane and hydrogen gas, and more recently in power to gas conversions, scientists at USW have been investigating the potential for producing ethane, propane and butane via microbial pathways.

Wales and West Utilities (WWU) initiated the research with an ESF KESS supported PhD research programme as well as an OFGEM Network Innovation Award, that has demonstrated the concept to produce higher alkane gases using renewable hydrogen and carbon dioxide (the major greenhouse gas) as feedstocks. 

Importantly, the team has identified a pathway through which ethane, propane and butane can be produced through biological means. This has been shown to be capable of producing low concentrations of alkane gases at this early stage, but concentrations are getting close to meeting WWU requirements of 4-10% higher alkane gases for enabling biomethane injection into the natural gas network.

The research team at the University have recently started a new collaboration with Flogas Britain Ltd, a major supplier of LPG in the UK, who has sponsored a further two PhD students through the ESF KESS programme. Over the next three years, the team will be developing strategies to increase the concentrations of propane and butane that can be produced to a level that is industrially relevant. Higher alkane gases production will also be investigated from a wide range of organic feedstocks.

The research has the potential to revolutionise a number of industry sectors. The future of the LPG industry and continuation of the mechanism for providing off-grid fuel gas is dependent on finding sustainable alternatives to fossil based propane and butane. Efforts to reduce the carbon impact of the aerosol industry that provides products that are ubiquitous across the globe are also based on finding sustainable sources of propane and butane gas.

Contact: Professor Sandra Esteves