Zeroing in on Zero-Carbon Fuels
Bridging the timeframe between 2023 and 2040 will require interim propulsion solutions that undoubtedly involve the internal combustion engine.
COP27, the 2022 United Nations Climate Change Conference that took place in Sharm El-Sheikh, Egypt, over a two-week span in November, helped bring global attention to the need for significant reductions of climate emissions stemming from transport sectors. Notably, the climate summit saw the United States and at least nine other nations sign a global MOU pledging to support a path to 100% new zero-emission medium- and heavy-duty vehicle sales by 2040, with an interim goal of at least 30% new sales by 2030.
Twenty-six countries on four continents now have signed the global MOU, which is co-led by the Netherlands government and CALSTART’s Drive to Zero program. Subnational governments such as California, Québec, and Telangana in India also have endorsed the initiative, as have private-sector companies including Scania, Nikola, Proterra, Lightning eMotors, Ballard and Eaton.
Electrification is at the heart of achieving the MOU’s goals. The plan involves targeting “first-success markets” where electrification works now – segments such as buses, terminal tractors, and trucks for short regional delivery. From there, the goal is to expand technology development and implementation to other on-highway, off-highway and marine sectors as components mature, volumes grow, and costs decrease.
But bridging the timeframe between 2023 and 2040 will require interim propulsion solutions that undoubtedly involve the internal combustion engine. For applications where electrification can be particularly difficult to implement, such as long-haul trucks and heavy-duty off-highway equipment, low- and zero-carbon fuels are receiving a lot of attention.
Kohler, for example, plans to achieve its ICE decarbonization strategy via investment in alternative fuels, such as HVO (hydrotreated vegetable oil) and hydrogen, as well as hybridization to reduce engine size requirements and operating emissions.
MTU also is focusing on sustainable fuels such as HVO and e-diesel for use in rail, power generation, marine, construction, agriculture and mining industries. The engine maker is partnering with Neste to use its fuel produced from 100% renewable raw materials. Neste plans to increase total production capacity of renewable products to 5.5 million tons by the end of 2023, up from its current annual production capacity of 3.3 million tons.
“Since May 2022, Rolls-Royce has approved MTU diesel engines for Power Generation for renewable diesel (also known as HVO) and other EN15940 fuels,” said Michael Stipa, VP stationary strategy, business development and product management for the Power Systems division of Rolls-Royce. “The tests we have done show an up to 90% greenhouse gas reduction, up to 80% less particulate emissions and an average of 8% nitrogen oxides reduction. All our tests revealed full performance without modifications to the engines.” With synthetic diesel fuels of the EN15940 standard, CO2 emissions can be reduced by up to 100% compared to fossil diesel, he added.
Liebherr, too, sees the combustion engine having protracted relevancy thanks to hydrogen fuel. “How can you bring a combustion engine to zero emissions? From our point of view, we have a lot of simulations that show hydrogen is a possibility to accomplish this. Especially with green hydrogen, we are directly zero-emissions,” said Ulrich Weiss, Liebherr’s managing director for the construction and development of combustion engines.
But convincing the regulatory community that hydrogen ICE is a zero- or near-zero emissions technology is a challenge. “Through our engagement with the regulatory agencies, it’s not being missed but it does need to be addressed,” Tim Frazier, VP of research and technology at Cummins, said at the 2022 SAE COMVEC conference. “Hydrogen ICE technology has the capability of being certified to the lowest emissions standards on criteria emissions [PM, NOx, CO, HCs] and then coupled with zero tailpipe emissions. It seems that we should really be emphasizing that as a solution. We’re in the development of those engines now.”
Low-emissions hydrogen is vital as a fuel or feedstock for decarbonizing fuels, a recent Clean Air Task Force blog post emphasized. Synthetic fuels use hydrogen as a feedstock and biofuels require hydrogen for desulfurization. To maximize its climate benefit, hydrogen must have low GHG-intensity (i.e., electrolysis using low-carbon electricity, gas reforming with very high rates of carbon capture and storage, very low rates of methane emissions in the natural-gas supply chain, minimal venting/flaring, etc.), the blog stated.
A number of OEMs and suppliers are working to help increase the supply of clean hydrogen. Nikola, for example, recently announced a collaboration with KeyState Natural Gas Synthesis to create Pennsylvania’s first low-carbon hydrogen production value chain, which includes full integration of commercial carbon capture and storage. Once the site is operational in 2026, KeyState plans to supply Nikola with up to 100 metric-tons per day of low-carbon hydrogen, which can supply fuel for up to 2,500 Nikola Tre FCEVs.
As decarbonization efforts progress, electrification may be the endgame for many vehicle types, but for harder-to-abate applications, low- and zero-carbon fuels will be a vital pathway to zero emissions.