Alternative Fuels in the Offshore Energy Transition
Alternative fuels dominate much of the discussion around reducing greenhouse gas emissions and promoting sustainability in the ocean industry. Liquefied natural gas (LNG) is currently the most widely adopted and fastest growing alternative to oil for marine vessels. LNG offers a moderate reduction in CO2 emissions and a large reduction in the emissions of harmful regulated pollutants.
Further, increased market supply, decades of technological development, and expansion of distribution infrastructure have made the adoption cost—engine conversion—an increasing attractive investment for offshore operators.
The trends that have spurred adoption of LNG are ongoing, and demand for LNG as a marine fuel is predicted to continue growing through the next few decades. However, if the trajectory of marine regulations continues to trend toward zero net greenhouse gas emissions, the future of low-carbon shipping will likely rely on a new generation of alternative fuels.
THE PROMISE OF HYDROGEN
Hydrogen fuel is fast become a focal point of energetic discussion, speculation, and technological development in the space of alternative fuels. Hydrogen is the simplest molecule that can readily react to release energy. The result is that its emissions are minimal, producing only water vapor and heat and leaving behind no residuals like carbon dioxide or harmful pollutants.
Unlike natural gas, hydrogen itself is not a greenhouse gas, so leaks are not counterproductive to reducing emissions. Hydrogen can be produced with zero fossil fuel input by applying renewable electricity to water through electrolysis, resulting in “green” hydrogen, a term distinguishing this production process from others which do rely on fossil fuels. Hydrogen can be incorporated into or carried by other molecules to create “e-fuels”—a wide range of more complex synthetic fuels including hydrocarbons which can be produced via “green” pathways rather than consuming fossil resources.
THE COST OF CLEAN ENERGY
Green hydrogen and other synthetic fuels are promising, but they all start at a cost disadvantage with fossil fuels for one fundamental reason: we have to collect all the energy they contain, then collect and use significantly more energy to store it in chemical form. For example, green hydrogen production consumes about 5 times the energy content of the hydrogen produced.
Fossil fuels are cheap because the work of producing them from solar energy and geological forces was done for us by nature over millions of years. Our rapid consumption of this energy gift from the past has allowed human civilization to become what it is today, but we must now deal with the side effects of that disproportionate consumption and prepare for a sustainable future once that cheap energy is no longer available. One reality of that future is the real cost of chemical fuels which we will eventually need to pay to continue benefiting from their crucial energy density and transportability.
The other barriers facing hydrogen are similar in nature to those that LNG is currently overcoming. Distribution infrastructure is not yet built; handling it safely is difficult and requires advanced technology and training; ships need new equipment to harness it for power; and the supply of green hydrogen specifically is orders of magnitude lower than its likely future demand.
Overcoming these challenges, along with the intrinsic cost, will require time for technology to mature. Along the way, other hydrogen-carrying alternative fuels may become front-runners, and partially green production methods may be useful for early adoption. In any case, this growth will require coordinated regional and global policy to incentivize early investors and give vessel owners and operators an economic justification for adoption. With ventures starting around the globe, we are already seeing the beginnings of this process, and though barriers remain, the path towards lowering them has been laid out before us.
This story was originally featured in ON&T Magazine's April 2022 issue. Click here to read more.