DRIVING TOWARD DECARBONIZATION

IT’S NOT JUST CARS: EVERYTHING FROM AIRCRAFT TO TANKERS IS GETTING IN ON THE POST-FOSSIL-FUEL FUTURE.

NO MATTER HOW many new Rivians and Teslas hit the road, some 95% of the world’s energy for transportation still comes from fossil fuels. Transportation accounts for about 30% of global energy use and is responsible for approximately one-quarter of greenhouse gas emissions. But there is no universal solution for decarbonizing the entire transportation sector. From an engineering perspective, trucks, planes, trains, and ships present wildly different challenges. Fortunately, a diverse array of solutions is emerging—and hitting some promising milestones.

Batteries remain the best option for electrifying larger automobiles and present an opportunity for decarbonization at scale. Trucks account for 60% of total U.S. transportation emissions. But the next big challenge is not only electrifying these vehicles but reducing the size of the national fleet. Fluid Truck, for example, offers flexible EVS on demand for commercial deliveries.

For aircraft (9% of U.S. transportation emissions), electrification may play a role—but only in critical niches. Vermont-based Beta Technologies has made significant progress toward commercial certification of its fixed-wing five-passenger EV for short-haul flights, delivering a test vehicle to the U.S. Air Force and building a net-zeroemissions factory to fill orders from customers including Air New Zealand and UPS.

For larger planes and longer flights, says Peter Barrett, founder and general partner at the venture firm Playground Global, hydrogen is key. In 2023, Universal Hydrogen (a Playground portfolio company) flew a successful demo of its modular hydrogen fuel-cell powertrain for existing regional turboprop planes. “Where you have existing airframes,” Barrett notes, “hydrogen fuel cells can give you four times the range and half the weight of batteries.”

Trains, too, are undergoing a hydrogen transition. Hydrogen fuel cell–powered trains can use a similar refueling infrastructure to diesel ones, with comparable refueling times. Last summer, the French multinational manufacturer Alstom demonstrated a first-in–north America hydrogen-powered train, ferrying visitors on a two-and-ahalf-hour trip outside Quebec City and emitting only water vapor.

Shipping (about 3% of global carbon emissions) is also shifting away from petroleum, albeit more incrementally. Maersk’s newest container ship, the Laura Maersk, which arrived in Copenhagen, Denmark, in September, heralds the mega shipper’s move to dual-fuel vessels that can run on either conventional marine fuel or methanol. It’s the first of 25 such ships the company has on order. The use of so-called green methanol for shipping, produced from biomass gasification or from renewable electricity and captured carbon dioxide, could decrease CO2 emissions by up to 95% compared with conventional fuels. And yet another new solution is emerging: green ammonia, which is still energy-intensive to produce. With new techniques, it could be the shipping fuel of the future. —Adam Bluestein