[NGW Magazine] New gas for Europe's old pipes

This article is featured in NGW Magazine Volume 2, Issue 21

Carbon is the enemy of the Paris Agreement, so grid operators, gas producers and others with an interest in keeping gas in circulation are investing in ways to keep it to a minimum.

Gas from renewable sources is at the forefront of innovation efforts by the established players in the natural gas industry. On October 27, Eurogas, the European gas industry association, hosted its annual conference showcasing pilot projects and new technology covering some of them.

Representatives from Uniper, Sunfire, Statoil, Audi, Greenpeace Energy, and Letang Biogaz shared the floor with members of organisations such as the European Biogas Association (EBA), Climate Action Network, and the European Commission (EC).

Renewable gas was first name-checked at last year’s Eurogas conference, which focused on sustainable innovation. But it hogged the limelight this time. Biogas, hydrogen, and synthetic gas created by renewable electricity are three options for propelling gas into the future – decarbonising heat and electricity while keeping the existing pipelines in business.

These technologies and practices all aim at offsetting the drawbacks of both renewable technology and fossil fuels: gas must be a reliable back up for renewables, but also constantly strive for lower emissions, while remaining cost-efficient and competitive at large scale. This is easier said than done, and European companies want to rise to the challenge.

Although the science for these new methods has existed for a few decades, recent technological, political and economic developments have encouraged innovation to make them commercially attractive and address environmental concerns.

The underlying process of the following technologies is power-to-gas, which integrates renewable electricity in different gas applications. It converts surplus renewable energy into hydrogen gas by rapid response electrolysis which is then injected into the gas distribution network, lowering the concentration of carbon.

Biomethane

Biomethane comes from biomass (fuel crops) or biogas (from biowaste) that has been upgraded to meet the quality standards of natural gas. After this process, it can be injected into the gas grid without any further modification. It can also be used as vehicle fuel. According to the Environment Agency Austria, biomethane can produce between 66% and 97% less greenhouse emissions than normal diesel or gasoline when used as vehicle fuel.

But most important, biomethane – and gas in general – can be stored for a longer time than electricity, whose production and consumption are almost simultaneous. So, if there is too much renewable electricity at a given time, the power can be used to produce biomethane instead, by generating hydrogen (from electrolysis) and converting carbon dioxide into methane. “If every single biomethane plant, and a majority of existing biogas plants were equipped with the power-to-methane process units,” says EBA president Jan Stambasky, “they could provide electricity grid stabilisation services on top.”

Europe’s biogas production corresponds to about 14bn m³/year natural gas equivalent. According to EBA, it could reach 100bn m³/year by 2050, “or more, with political ambition.” Biomethane also has “a 3.5 times higher storage capacity” than hydrogen, they add, and existing biomethane infrastructure “could accommodate up to 382 TWh excess electricity/yr”. This represents around 12% of total electricity generation in Europe – which totalled 3070 TWh in 2015 – although there are limitations: first, excess electricity does not reach that figure; and second, the renewable electricity must be widely spread out. So offshore wind turbines in the North Sea would be unsuitable for working with biomethane plants.

Hydrogen

Hydrogen is another form of converting and storing electricity energy, and can also be fed into the gas grid with small modifications to the infrastructure, as well as being turned into chemicals and fuels by industrial companies and refineries.

Of course, it also emits less greenhouse gases than conventional natural gas. This was a key reason that pushed Norwegian state Statoil to consider converting one of its gas-fired power plants in the Netherlands into a hydrogen-powered plant. “The potential CO2 emission reduction is 4mn metric tons of CO2/year, equivalent to emissions from more than 2mn cars,” it claims.

Swedish utility Vattenfall and Dutch transmission system operator Gasunie are also participating in the feasibility studies, which will determine further progress. The idea is that Norwegian natural gas would be shipped there and then converted into hydrogen onsite to produce electricity. The unwanted CO2 would be shipped back to Norway to be stored in the Troll field in the North Sea, until a business model for using this CO2 can be developed.

Uniper is also working on two pilot plants for storing renewable power in hydrogen form, which it calls “WindGas”. Apart from the traditional method of alkaline electrolysis for producing hydrogen, they are also testing an alternative process, proton exchange membrane (PEM) electrolysis, which can operate at high current densities, lowering operational costs. This is important in systems coupled with very dynamic energy sources such as wind and solar, where sudden spikes in energy input would otherwise result in uncaptured energy.

Synthetic Gas – Audi’s e-gas

To illustrate gas innovation in the transport sector, Audi presented its newest model to use synthetic gas, the A5 Sportback g-tron. The first of such models – the A3 – was launched in 2013. The A5 can run on a choice of “climate-friendly” Audi e-gas, compressed natural gas (CNG) or gasoline. A typical passenger vehicle emits about 4.7 mt/yr of carbon dioxide. According to Audi, the newest A5 g-tron would emit 14 mt throughout its lifetime, down from 38 mt for traditional models.

The brand produces “e-gas” in its own power-to-gas plant in Werlte, Lower Saxony. The process is like the methods commented above: electrolysers powered primarily by surplus green electricity split water into oxygen and hydrogen. In the subsequent methanation process, the hydrogen reacts with CO₂. The result is synthetic methane “Audi e-gas”. The e-gas can be delivered through existing natural gas pipes since it's virtually the same as natural gas.

Clean Energy Package

The big obstacle in the way of the technologies described above is that the market for them is small and the technology very little understood by politicians. Further, it is unknown to the vast majority of the public, which distrusts the energy industry in general. It knows that Europe imports a lot of its gas and doesn’t like it, as pointed out by a member of the audience from the banking sector. The development is still new, and “the need for it still needs to be created”.

On 30 November 2016, the EC presented a package of measures to support the European clean energy transition through innovation. Europe’s joint legislative bodies, the European Parliament and the Council of the European Union, are debating the text and the final draft is expected by mid-2018.

The EBA claims that biomethane is commercially viable if it is exempt of tax and/or granted other financial incentives, as its status as a renewable source of energy is ambiguous. According to the EC, confirmation of this status is currently under way. The EC Energy Directorate’s Mechthild Worsdorfer insisted that "gas from renewable sources is very much supported in the new proposal," in particular by recognising biogas and including a clear definition of what qualifies as renewable gas.

Moreover, the renewable energy guarantee of origin is set to include biogas too, although she did not specify if synthetic gas produced with renewable power would also benefit. The EC will also support these new developments through its Research & Innovation funding programmes, such as Horizon2020 (ending December 2020) and FP9 (Framework Programme) starting 2021.

Is that enough? Not quite. Through Eurogas, the European industry asks for regulations to acknowledge the increasingly important role of storage plants that take excess electricity to conserve the extra power.

All in all, European gas companies have shown their efforts in trying to accommodate cleaner, more efficient practices and technologies, but whether they will be viable at a commercial scale will depend on the results of existing pilot projects and – as always – political and economic support.

Sara Vargas