The data speaks for itself and the conclusion is clear: natural gas and other fuels based on methane cannot be the solution to solve the climate problem caused by shipping. If this sector really wants to fully decarbonize in line with the Paris Agreement, it must not continue down this path.
It’s more, natural gas has an even worse climate impact than current liquid fossil fuels. Betting on natural gas will lead to the generation of stranded assets and also exacerbate the severity of climate change.
Natural gas is a fossil fuel that is extracted from the ground. It is made up mostly of methane molecules (CH4), which produces CO2 when burned. Methane is also a greenhouse gas in its own right, 36 times more potent as a GHG than CO2 in a 100-year perspective (or 87 times more powerful in a 20-year perspective). Therefore, its release into the atmosphere causes more climate change than its combustion.
Natural gas is “gaseous” under normal conditions of temperature and atmospheric pressure. To facilitate its transport and storage, it is usually liquefied at freezing temperatures (-160Cº), which gives rise to liquefied natural gas (LNG).
LNG ships perform worse in terms of total GHG emissions than those that use conventional fuels. Indeed, LNG is a fossil fuel and is often presented by the hydrocarbon industry and its associates as a bridge fuel towards decarbonisation. However, many studies, such as those of the world Bank, show that it has only marginal benefits for the climate compared to existing marine fuels such as very low sulfur fuel oil (VLSFO), the dominant marine fuel today.
LNG-fueled ships are often portrayed as less damaging to the climate than they actually are. The trick behind these claims about the supposed positive impact of LNG use on the climate is that they only consider direct CO2 emissions from LNG combustion, ignoring the impact of methane leaks and leaks into the atmosphere. Methane often leaks from natural gas pipelines during transportation or escapes from engines when incomplete combustion occurs. The combination of CO2 emissions and methane leaks / leaks throughout the entire life cycle of the fuel, that is, from production to combustion in the ship’s engine (analysis well-to-wake), makes natural gas / LNG more harmful than fossil diesel used in shipping.
What about bio-based alternatives, like biomethane or bioGNL? The problem with these is that they are insufficient to replace natural gas in homes, much less to satisfy the growing demand of maritime transport.
Another argument from the promoters of LNG is that investments made in LNG infrastructure should be considered future-proof, as they could be reused when their bio-based substitutes, such as biomethane or bioGNL, come into play.
However, the data indicate that there will not be sufficient capacity to produce biomethane sustainably in sufficient quantities to meet the fuel needs of shipping. It could only provide a small fraction of what is needed for this sector. This is because the amount of sustainable waste feedstocks available to produce biomethane (also known as advanced biofuels as defined by RED II) is extremely limited. Based on the analysis of the International Council on Clean Transportation (ICCT) on sustainable biomethane production capacity in Europe, Transport & Environment (T&E) has calculated that biomethane would not be enough to meet the needs of European domestic demand, which already depends on natural gas for heating and cooking in homes Not to mention creating a new demand for shipping that traditionally did not use natural gas for propulsion. For this reason, betting on biomethane produced from waste to replace the future demand for LNG for ships seems doomed from the start.
Methane can also be produced synthetically by combining green hydrogen from electrolysis with CO2 captured directly from the atmosphere through industrial processes (also known as direct air capture or DAC). This is known as electro-methane or e-methane (also known as e-CH4). When e-methane is burned, it obviously emits CO2, but it is considered carbon neutral because the CO2 emitted was captured from the atmosphere in the first place; therefore, it is not additional but circular. E-methane is sometimes called e-LNG.
Unlike biomethane, e-methane could theoretically be produced on a large scale. Because all that is needed is green hydrogen and CO2 captured from the atmosphere, and both can be plentiful. Furthermore, e-methane is compatible with the current LNG infrastructure and with ships powered by this fuel. The problem, however, lies in the production costs of e-LNG compared to other green alternatives, such as the direct use of green hydrogen or green ammonia (which in turn is produced from green hydrogen). The decarbonisation of EU shipping via e-methane would cost industry tens of billions of euros more than the direct use of hydrogen or green ammonia. Therefore, e-methane does not appear to be a profitable long-term solution and therefore, it would not be viable either.
Fortunately, there are many operational and technological options that can be applied to achieve a sustainable reduction in GHG emissions from ships. In the first place, measures to increase the efficiency of the engines, the propellers and the design of the boat itself. Second, other operational efficiency measures, especially reducing sailing speed, are very important in reducing energy consumption and emissions and can be taken immediately. The integration of all these measures together with others, such as wind support systems for navigation, would save significant amounts of fuel and therefore reduce emissions.
Another excellent idea is to establish zero-emission requirements for ships in berth so that they connect to the electrical system of the ports (Shore-Side Electricity, SSE). This is a very technically advanced solution and can be deployed in most cases. It is the simplest and probably the cheapest option to fully decarbonise ship dock operations, which alone account for 6% of EU maritime transport emissions, and also to eliminate air pollution, which negatively affects the health of the inhabitants of nearby cities.
As for the larger ships, on long transoceanic voyages, the most sustainable solution is in green hydrogen and e-ammonia. The latter presents the cheapest e-fuel option for maritime transport, with better performance than e-LNG.
There is a growing consensus among the world’s largest shipyards that e-ammonia could be the “closer alternative to an ideal fuel” for maritime transport. Although their energy density is lower than that of e-hydrocarbons and e-alcohols, such as e-diesel, e-methanol or e-methane, the total cost of operation of ocean vessels with e- Ammonia appears to be the lowest, even when the indirect costs of lost space are taken into account.
This, however, does not mean that other electrofuel alternatives are not technically feasible. For example, the shipping companies DFDS and Viking Cruises intend to build a ferry and cruise ships of compressed hydrogen and liquid, respectively.
LNG-powered ships or port infrastructure are not physically compatible with hydrogen or ammonia. Thus, public support for LNG for shipping would cause a lock-in effect, while making the transition to truly sustainable and scalable alternatives such as renewable electricity, e-hydrogen, and e-ammonia difficult.
Unfortunately, the European Commission, in its legislative package “Fit for 55”, has included a proposal for the Alternative Fuel Infrastructure Regulation (AFIR) that includes a mandate to develop a fossil LNG bunkering infrastructure in European ports, thus employing public money in technologies that would block the deployment of truly sustainable alternatives and would make us depend on this fossil fuel.
Let’s hope that Spain opposes this and that, in the “Fir for 55” negotiations, it supports the setting of binding targets that facilitate a rapid, large-scale deployment of e-ammonia and green hydrogen for maritime transport, in addition to the operational and technical efficiency options that we discussed earlier.