The war in Ukraine and the resulting sanctions and supply disruptions have sent many importers of Russian natural gas scrambling for alternative sources — and reinforced many countries’ commitments to home-grown renewable energy.
Natural gas has long been considered a transition fuel and renewable natural gas (RNG) is being pushed as a potential step forward in the low-carbon energy drive.
RNG is an inherently local source of energy, often coming from waste and the agriculture sector, and can utilise current natural gas infrastructure.
The multiple ways to produce and use renewable gas, known in some forms as biogas or biomethane, make it a diverse option for the energy transition and energy security, advocates say.
RNG cannot be considered a truly “clean” fuel. Depending on how it is made and how it is used, renewable gas can still produce high levels of greenhouse gas emissions.
Nevertheless, many regions are addressing opportunities in renewable gas with a variety of approaches suited to their energy needs.
In response to the conflict in Ukraine, the European Commission released its REPowerEU plan to drastically reduce Russian oil and gas imports by the end of the year.
The plan says renewable gas could replace 3.5 billion cubic metres of Russian natural gas this year and 35 Bcm per annum by 2030, or some 22% of Russian gas imports.
To do so, however, Europe would need to add 5000 new renewable gas plants to the 20,000 in operation — a target European Biogas Association chief executive Harmen Dekker says is “ambitious, but definitely realistic”.
“I think a lot of things need to happen policy-wise to make sure this is going to happen,” Dekker says. “However, I think we are on the right track.”
Germany, he notes, developed 6000 renewable gas production plants in the nine years from 2005 to 2014.
But Dekker says European politicians are currently more focused on hydrogen rather than renewable gas incentives.
“Everybody in Europe is now embracing biomethane,” he tells Upstream. “But for some reason, politicians are still a bit hydrogen-minded, even though [hydrogen] cannot fill the full demand.”
Much of Europe’s renewable gas is used for heating and light transport, although Dekker says there is potential for it to grow into the heavy-duty vehicles and maritime sectors.
One common source of renewable gas in Europe is non-food cover crops, which are harvested and put through an anaerobic digester.
The remaining materials created from the process are injected back into the ground to restore the soil and eliminate the need for mineral fertilisers.
Coming from a time when crop-based renewable gas was debated due to its potential competition with food, this process changes the equation and actually benefits farming.
Cover crop feedstock relies on a suitable agricultural environment, something that Dekker says Asia can seriously benefit from.
“I’m jealous of the Asian region because they have the best climate to make sustainable biomethane,” Dekker says.
While government incentives for RNG are scarce in most of the region, Japan released a New Energy Strategy ahead of last year’s COP26 that includes plans to inject up to 1% of renewable gas into the urban distribution network by 2030, and 90% by 2050, law firm Allen and Overy reports.
The energy-poor country imports over 90% of its primary energy supply, making renewable gas a prime opportunity for Japan to increase local energy production.
Its feed-in tariff system requires power companies to buy electricity from certified renewable sources at a fixed rate to create stability in the sector and incentivise investment.
In 2019, Japan had 221 digesters in operation, totalling 85 megawatts of capacity. The amount is small compared with Europe’s numbers, but the country is still early on its renewable gas journey.
In the US, California’s Low Carbon Fuel Standard, which offers credits to producers for replacing conventional vehicle fuel with low-emission alternatives, has spurred RNG development in the state, specifically in production from dairy farms.
But the incentives only extend to transport uses, making most other RNG applications uneconomic, says Sahar El Abbadi, a postdoctoral researcher at Stanford University.
At least three-quarters of renewable gas produced in California is now used for transportation.
The incentives have helped establish a renewable gas market and infrastructure, but even with a more sustainable production method, renewable gas will still produce greenhouse gas emissions when it is burned.
There are other uses for renewable gas that could be carbon neutral or even carbon negative, El Abbadi says.
Her research has explored the potential use of renewable gas to create methane-eating bacteria that can be used as a replacement for fish meal.
Other research has looked at the use of such bacteria in creating bioplastics that are less damaging to the environment.
“If we scale up RNG infrastructure and focus on applications that have really high leak rates, then that is very concerning to me,” El Abbadi says.
“We want to make sure that applications that we’re using would not increase life-cycle emissions of methane.”
For sustainable uses of RNG to be commercially viable, however, incentives such as the Low-Carbon Fuel Standard must not exclude types of production or use that could bring even more environmental benefits, El Abbadi says.