Biomethane, a definitve opportunity for the development of biogas as a mature sustainable process

El biometano, definitiva oportunidad de desarrollo para el biogás como proceso maduro y sostenible

The development of biogas has received very little support in Spain compared to other European countries, especially in the area of agricultural waste. This has repercussions on the potential development of biomethane. Public authorities must, therefore, lend support to issues such as the management of biodegradable waste from the agricultural sector and the establishment of regulations that allow the production and use of biofertilisers from digestate.

EVOLUTION OF BIOGAS

As early as 3000 BC, there are accounts of the Sumerians cleaning organic waste anaerobically and there is evidence that the Assyrians were using biogas to heat water in public baths in 1000 BC.

These two uses of biogas, for both energy and organic waste disposal, define the development and utility of biogas down through history, and these uses survive and coexist to this day.

The 19th century saw the discovery of methane and the beginning of modern biogas use, but the development of fossil fuels, which were much cheaper and had greater volume potentials, slowed the development of biogas.

For decades, biogas was forgotten and used only marginally. After the Second World War, biogas began to be used as a fuel, especially in rural and developing areas. It was not until the 1970s, with the oil crises, that digesters were developed on an industrial scale. These digesters were initially based mainly on sewage sludge.

During the 1990s and, above all, in this century, biogas began to be used on a large scale in countries such as Germany, as a renewable gas, as a system for treating organic waste and reducing greenhouse gas (GHG) emissions and, more recently, as a system for producing biofertilisers

WHAT MAKES BIOGAS DIFFERENT FROM OTHER RENEWABLE FUELS?

The aforementioned historical development clearly highlights the properties of biogas as a sustainable biofuel with unique characteristics, associated, above all, with the biomethanisation production process, which:

  • produces a sustainable biofuel
  • is an environmentally friendly organic waste treatment process.
  • helps to recover the spontaneously emitted methane by capturing it, preventing GHG emissions and improving air quality.
  • depending on the raw materials used, generates a biofertiliser, given that anaerobic digestion preserves nutrients.

Biogas sources, and consequently the feedstock for biogas plants, have traditionally been:

  • Agricultural and livestock waste
  • Sewage sludge
  • Organic fraction of municipal solid waste.
  • Landfill biogas (a source destined to become extinct when the organic fraction can no longer be landfilled).

Depending on the feedstock, biomethanisation results in fuel of different characteristics and properties.

THE GREAT BIOMETHANE OPPORTUNITY

A biomethane plant basically consists of a biogas plant to which an upgrading unit has been to purify the biogas and increase the methane content from around 60% to over 97%.

Despite its countless environmental advantages, the development of biogas in Europe has required impetus and help from the respective public authorities, especially with regard to agricultural and livestock waste, which comes from a sector that has not internalised or has not been able to internalise the costs associated with the treatment of the waste it produces.

For this reason, biogas from livestock and agro-industrial waste has only developed significantly in countries where it has received sufficient aid and incentives from public authorities, which has not been the case in Spain. Just 260 of approximately 20,000 biogas plants operating in Europe are located in Spain, despite the fact that the European Commission considers it to be the country with the third-highest potential.

The development of biomethane has followed a line consistent with the development of biogas. Germany is the country with the greatest development, while it is still an incipient technology in Spain, despite the fact that there are now five plants injecting into the grid.

Published in: #92 FuturENVIRO July – August 2022