For a Carbon-Free Future, Renewable Gas May Be Key

Natural gas is widely seen as the transition fuel to decarbonize the energy sector, but renewable gas is gaining momentum to take on that role.

Renewable gas is a catchphrase mostly for hydrogen, the most common chemical element on the planet. Hydrogen can be injected into a gas pipeline network for use in heating homes, fueling cars, and generating power, making it cheaper and greener than drilling, extracting, and piping gas.

The Next Step

World energy leaders are looking at hydrogen as the next step after gas in the shift away from fossil fuels, said Thorsten Herdan, Germany's director general of energy policy, at a meeting of G20 energy leaders in Argentina in June, according to Oil Review Middle East.

The private sector is also taking a look at hydrogen. At the 2017 World Economic Forum in Davos, Switzerland, 17 big businesses formed the Hydrogen Council to research ways to integrate hydrogen into energy systems.

"We are convinced that hydrogen, and more particularly renewable hydrogen, will play a major role in the next phase of the energy transition," Isabelle Kocher, CEO of the French multinational electric utility company ENGIE, said in an interview on the Hydrogen Council's website; ENGIE is one of the founding members of the Hydrogen Council. She continued: "By that I mean that we go beyond decarbonizing electricity production, and strive to decarbonize all the uses of energy: transportation, industry, heating, and cooling."

Cutting Emissions

The desire to reduce carbon emissions is driving a boom in building renewable power generation capacity. The International Energy Agency (IEA), a Paris-based organization, forecasts a 43 percent surge in renewable electricity capacity between 2017 and 2022.

Technological advances are lowering renewable generation costs, allowing wind and solar farms to compete with more traditional power sources. This helped increase renewables' share of the primary energy mix to 3.6 percent in 2017 from 3.2 percent the previous year, according to BP's 2018 Statistical Review of World Energy.

Still, the share of fossil fuels has remained above 80 percent since 1980. If power systems around the world are to reduce this, then they must find new generation sources beyond wind and solar, Jane Burston, managing director of the Clean Air Fund, a UK-based think tank, wrote in Global Agenda, a publication of the World Economic Forum.

"We cannot . . . keep asking for more from technologies that have proved successful to date," she wrote of solar PV, onshore wind, and energy storage and EVs, stating that it's "unlikely we can squeeze more out of these three technology areas than is currently projected."

A New Source of Energy

Hydrogen can make a difference as a new source of energy by working in tandem with wind and solar.

Those renewables are intermittent, meaning they're not available all the time, such as when the wind dies and the sun sets. Coal, gas, and nuclear power plants provide a reliable baseload supply, or the minimum supply required to meet demand, leaving renewables to meet the spikes in consumption, or peak-load demand.

The rapid increase in renewables has raised concerns about future supply if baseload capacity fails to expand with demand.

Energy storage technologies, such as lithium-ion batteries, are emerging as an increasingly cost-competitive option to improve the reliability of renewables over longer periods. These batteries store surplus output, such as from a solar farm during the day, to be dispatched at night. However, until energy storage is more widely adopted, power systems will require a renewable-balancing generation source.

This is where natural gas and hydrogen come in. Natural gas has long been a tried-and-true balancing resource, but carbon-free hydrogen is emerging as another intriguing option.

Splitting Water

While hydrogen can be made from fossil fuels, renewable gas is based on electrolysis, or the use of electricity to split water into hydrogen and oxygen. This process produces no pollutants to make hydrogen.

The challenge for years, however, has been how to make electrolysis more economically viable, given that the process uses a large amount of energy.

An emerging solution is to use excess output from the renewables boom. When demand is low or power lines are congested, renewable assets must be shut down, leading to lost output and revenue. With electrolysis, a wind park can avoid these shutdowns and use its excess power to make hydrogen, a process known as power-to-gas. The product can then travel through existing pipelines as pure hydrogen or be mixed with gas to supply power plants.

"Hydrogen offers a solution to the intermittence problem of renewable energy sources because power-to-gas is currently the best massive storage solution for surplus energy production," ENGIE's Kocher said.

"If you want to get to 100 percent renewables, hydrogen could play a key role," Claire Curry, an analyst at Bloomberg New Energy Finance, said. "You could have natural gas plants, but that would, of course, not be 100 percent clean."

Early Developments

Projects are emerging. A German utility has started producing hydrogen from excess wind power for transport over existing pipelines. Japanese electronics maker Toshiba has teamed up with Tohoku Electric Power to build a hydrogen plant that will generate 10 MW of power from the sun and other sources and produce 900 metric tons of hydrogen per year from water for storage and use in fuel-cell cars, starting in 2020.

This is just the start, according to Pierre-Etienne Franc, vice president of advanced business and technologies at French industrial gas maker Air Liquide.

The next decade will be for hydrogen "what the 1990s were for solar and wind," he told Bloomberg New Energy Finance. "It's a real strategic shift."