Naturgy Energy S A : and Greene develop the first Spanish technology plant to convert solid industrial waste into renewable gas

Naturgy and Greene are collaborating on a project to produce syngas biomethanation for injection into the distribution network or for use in mobility.

The innovative aspect of this project, unique in Spain, resides in the type of waste from which the bio-synthetic natural gas is obtained. A thermal process totally transforms the dry waste materials, contributing significantly to the circular economy by giving a second life to this type of difficult-to-process waste.

If the joint venture is a success, Spain will become Europe's leader in low-emissions bio-synthetic natural gas production by valorising energy from rejected streams of industrial and urban waste, providing a new method of generating low-carbon gas.

According to Naturgy's innovation manager Jesús Chapado, "the company is aware of the global challenge presented by the fight against climate change, which is why we prioritise having an innovation-based strategy to transform and steer the business toward the energy transition to help address the social and environmental challenges facing humankind. This project takes it towards these objectives and is a great opportunity to lead the development of a technology that will enable the generation and marketing of a new, zero-emissions energy vector that will help to address the serious problem of waste management in urban and industrial centres".

According to Greene CEO Juan José Hernández, "we have reached the point where, thanks to our technology, we can offer sustainable solutions to the significant global problem of waste by giving it a new purpose, generating biomethane, among other circular products, and obtaining a more sustainable energy source without having an environmental impact that exacerbates climate change. The biomethane produced with our technology is, on the one hand, the source of the waste because, in this project, we eliminate waste currently destined for incineration or landfills. It should be remembered that there is a far greater volume of this type of waste than wet waste, which opens a new opportunity to create bio-synthetic natural gas on a large scale and in almost unlimited quantities. In addition, as no digestate is produced during the process, the problem of managing it is eliminated".

Project stages

During the development phase -which includes the laboratory and experimentation stage and the design, assembly and operation of a pilot plant- the partners will research the conversion of syngas to low-emissions bio-synthetic natural gas through a biological fermentation process that maximise biomethane concentration and reduces syngas conditioning requirements.

This includes building and operating a renewable biomethane pilot plant in Elche (Alicante) with a processing capacity of 10 kg/h of waste to produce 2.4 kg/h of high-purity biomethane (over 95%).

After this, the industrial-scale plant with a processing capacity of 45,000 tons of waste annually will start operating to produce around 6,200 tons a year of high-purity synthetic bio-natural gas (over 95%).

Naturgy is committed to renewable natural gas as a circular energy for a decarbonised future

With a specific strategy already underway, Naturgy is committed to innovating to make renewable gas a reality, so much so that the company has spearheaded biomethane injection into the Spanish gas distribution network, having been the first to do so at its Butarque plant, contributing to developing a gas that offers great opportunities in renewable energy in the country.

To date, Naturgy has pioneered the development of biomethane production plants and owns two of the six now injecting biomethane into the Spanish gas distribution network: the Mixed Renewable Gas Unit (La Coruña), which produces biomethane from wastewater, and the Elena plant (Cerdanyola del Vallès, Barcelona) that produces biomethane from solid municipal waste. The company has another plant under construction that will inject biomethane into the distribution network during the second half of 2023. This is the Vila-sana (Lleida) plant, which will produce biomethane from farm and livestock waste.

In 2020, Naturgy included ambitious renewable gas objectives in its strategy for Spain and an action plan that is already underway. The company expects to produce ~1 TWh of renewable gas (biomethane and green hydrogen), with a development model based on multi-sector collaboration and partnerships.

On the other hand, through its gas distributor Nedgia, it is boosting the grid injection of biomethane produced by other developers. It has pinpointed 170 projects in Spain that could materialise in the short term, with a capacity of more than 7 TWh/year (equivalent to the consumption of 1,400,000 homes).

In the future, the commitment to renewable gases will be completed by developing green hydrogen projects. Naturgy has been researching the development of hydrogen for years and is working on developing large production hubs. Special attention is paid to converting coal-fired thermal power plants in Just Transition zones.

About Greene

Greene was established in 2011 and now has more than 60 employees and backing from investors at Moira Capital. The company provides the market with mature, efficient technology that covers the need to manage and eliminate waste in different areas such as municipal solid waste (MSW), industrial waste, biomass and sludge from water processing, among others. Greene's plants dispose of waste, are energy self-sufficient and, as a result of the gasification process, produce high-value-added circular products such as biofuels, biogas, synthetic waxes, pyrolytic oils and others.