Renewable gases as an opportunity in the fight against the climate emergency

Renewable gases, understood as those that can be used to generate energy and come from renewable raw materials or sources, could serve to reduce 35 million tons of CO2 if Spain develops its full production potential in this field. That is, the CO2 emitted by the entire fleet of passenger cars in one year or that absorbed by the country's entire forest area in 2017. All in all, it would mean saving more than 10% of the greenhouse gas emissions projected for the year 2030.

Biogas, synthesis gas, and hydrogen are the three types of existing renewable gases. All of them have characteristics that allow them to be converted into methane and, therefore, be injected into the natural gas network. In fact, if these three renewable gases were exploited to their maximum potential in Spain, they would allow covering 65% of the current natural gas demand. "Provided that their development is decisively promoted without further delay," conditions the industrial engineer and emeritus professor of Environmental Engineering at the Universitat Politècnica de Catalunya (UPC), Xavier Flotats. If not taken to its maximum potential, in the least optimistic scenario, it would be equivalent to a quarter of the current demand.

"Although Spain still has a way to go, our country has notable potential in this area, fundamental for achieving climate change control objectives," Flotats argues. For its development, decisive policies are needed to incentivize its use and implementation.

If biogas, synthesis gas, and hydrogen were exploited to their maximum potential in Spain, they would allow covering 65% of the current natural gas demand

In addition to reducing CO2 emissions, the use of renewable gases will also facilitatethe integration of the gas and electricity systems. This is a clear advantage since, in a context of decarbonization and progress towards electrification, there are uses that cannot depend on electricity, especially in industry, as it is necessary to be able to store energy and not consume it immediately, which is why the use of natural gas is preferred. In this case, if natural gas can be replaced by renewable gas, the impact on the environment would be reduced, since the former is a fossil fuel and pollutes more.

The integration of both systems also means that the two energy sources are complementary. This implies that electricity can be converted into natural gas and vice versa, exploiting the virtues of each according to the context. Thus, energy could be stored and production and consumption decentralized, increasing the efficiency of the system.

Another advantage that the implementation of renewable gases can bring is greater control of many waste products that are not currently controlled and pollute, considering that biogas comes from organic waste and synthesis gas from forest waste. In turn, the production of renewable gases can also allow the rural development of those areas that have suitable waste for conversion. Finally, it will promote energy self-sufficiency, reducing dependence on external energy sources and promoting local production.

Spain's position regarding Europe

If the development of renewable gases in Spain is compared to the rest of Europe, it stands out that in Europe there are more than 540 biomethane production plants installed ---biogas from which CO2 has been removed to be used for energy---, while in Spain they do not exceed twenty, among those that are operational or in pilot phase. Specifically, 66% of the plants are located in three countries: Germany, leader with 50% of European production, the United Kingdom and Sweden. In countries such as France, Italy, the Netherlands or Denmark, measures have been approved to boost their development.

Hydrogen is one of the renewable gases with which Spain can lead the European market. The potential for green hydrogen production is 1,750 TWh/year thanks to the country's geographical and climatic conditions, which is equivalent to eleven times the current natural gas consumption (160 TWh/year), excluding that used for its generation.

In Spain, biomethane production plants do not exceed twenty, compared to the more than 540 plants installed in Europe.

These estimates place it as the country with the greatest hydrogen production potential in all of Europe, according to the Institut d'Investigació en Energia de Catalunya (IREC). "Spain is a well-positioned country in Europe to produce renewable hydrogen at a competitive cost and export it to other European Union countries," according to IREC experts. "Spain's renewable energy production potential is above 3,000 TWh/year, an order of magnitude higher than current electricity consumption and about 30 times the current production of renewable energies," they state, "which means there is capacity for hydrogen production."

Depending on its origin and production process, there is gray hydrogen (the one mainly used today in industry and produced with non-renewable materials), blue (produced by incorporating CO2 capture technologies), and green or renewable (renewable and emission-free option, produced by electrolysis, from water and electricity from renewable sources).

First injection of renewable gas into the gas network

One of the first experiences with renewable gases in Spain has been led by Naturgy, becoming the first company to inject renewable gas from a landfill into the national gas distribution network. The renewable gas plant from which it did so is located in the Parc de l'Alba in Cerdanyola del Vallès, next to an urban waste landfill, from which biogas is generated, from which CO2 is removed to be able to use it for energy.

After an investment of 2.2 million euros, this biomethane plant was launched last June, in a testing phase. Currently, it has already surpassed this initial period and will gain capacity to produce energy, with the forecast that it will reach its maximum, of 12 GWh/year of biomethane, by next year, according to the technical manager of Biomethane Projects at Naturgy, Ignasi Mallol. This is equivalent to the annual consumption of 3,200 homes. That is, it will be able to avoid the emission into the atmosphere of 2,400 tons of CO2/year, an amount equivalent to planting some 5,000 trees.

The Naturgy renewable gas plant in Cerdanyola del Vallès will be able to avoid the emission into the atmosphere of 2,400 tons of CO2/year, an amount equivalent to planting some 5,000 trees

Part of the biomethane generated at this plant will be used for sustainable mobility, thanks to the supply contract that Naturgy has signed this month with Aquaservice. The water distributor, which will be the first in Spain to use this gas in its last-mile delivery fleet, will avoid the emission into the atmosphere of up to 350 t CO2/year, which is equivalent to removing 53,000 vehicles from circulation in a city for one day.

The Cerdanyola del Vallès project, along with others that Naturgy is developing in Spain, respond to its objective that, by 2050, all gas circulating through its networks will be of renewable origin. To this end, it is digitizing its distribution infrastructure with an eye on the massive entry of renewable gases and is analyzing biomethane and hydrogen projects worth 4,000 million euros within the framework of European funds.

Another experience with renewable gas that has taken place in Catalonia is the Life Methamorphosis project, in which the Catalan Energy Institute (ICAEN), the Barcelona Metropolitan Area (AMB), the L'Hospitalet City Council, Aqualia, FCC Medio Ambiente, Naturgy and Seat have participated. This initiative explores technologies that also allow the recovery of organic waste generated in both urban and rural environments and convert it into biomethane.

Within the Life Methamorphosis project, Naturgy has transformed slurry from an agri-food plant located in Porgaporcs, near Lleida. The renewable gas obtained can be used to fill the tank of vehicles with gas consumption engines or to be injected into the natural gas network, as in the case of Cerdanyola del Vallès.