Aviation electrification got a jolt this week when United Airlines and partner Mesa Airlines said they each plan to buy 100 19-seat regional electric airplanes from Heart Aerospace. Moreover, United's venture capital division, Mesa and Bill Gates-funded Breakthrough Energy Ventures led a $35 million fundraising round for the Swedish startup. Heart Aerospace says it will start delivering the 19-seat all-electric ES-19 to airlines in 2026.
Heart Aerospace is far from alone. There are more than 200 electric airplane development programs today, according to consulting firm Roland Berger. The majority are air taxis or personal airplanes. A couple dozen programs are regional aircraft. A handful of companies are even developing large commercial airliners with room for 100 or more passengers.
Electric commercial aviation is coming on faster than expected, and the pace seems to only be picking up. There is substantial work to do involving a big cast, including airplane makers, aerospace suppliers, battery makers, the aviation regulators, airports—and utilities. Yet, it is absent from utilities' transportation electrification plans.
Economics and emissions are the two factors driving electric aviation's development.
Air travel produces about 2 percent of global greenhouse gas emissions, according to the Air Transport Action Group. An analysis published in January in the academic journal Atmospheric Environment calculated that aviation accounts for 3.5 percent of anthropogenic climate change. The United Nations expects aviation's carbon emissions to triple by 2050, The New York Times reported in 2019. It is no surprise the industry is under pressure to cut emissions.
Commercial aviation is an intensely competitive market, and airlines look to shave costs wherever they can. Electric airplane proponents say they will cut operating, maintenance and fuel costs for airlines. Those economic benefits will, in turn, make it cost-effective for airlines to increase regional air travel, connecting smaller cities and oftentimes avoiding more congested hub airports. It is similar, albeit on a much smaller scale, to airlines using Boeing's more cost-efficient 787 to open new long-haul routes that were unprofitable with previous generation jetliners.
Generally, electric aircraft can be classified by three attributes: range, propulsion and size.
Range: Currently, most development work is being done either on air taxis or electric vertical takeoff and landing (eVTOL) aircraft that fly trips usually less than 50 miles. Next are regional aircraft that typically fly routes between 50 and 500 miles. Beyond that are large commercial aircraft flying short-haul routes; they would replace single-aisle jetliners such as a Boeing 737 or an Airbus A320 flying between Portland and San Francisco.
Propulsion: Airplane makers are developing all-electric, hybrid-electric or turbo-electric aircraft.
Size: Size and range usually are closely linked. Air taxis seat a handful of passengers. Next are small regional aircraft that seat up to 30 passengers. Larger regional planes have room for around 100 passengers. Beyond that are large commercial aircraft, which include everything from a 737 to the behemoth Airbus A380. None of these categories have firm definitions.
Most electric airplane development programs are air taxis or regional turboprops. On the other end of the spectrum, Wright Electric is developing its Wright 1, a 186-seat electric airliner with 2 MW electric motors. The company says the plane will start flying paying passengers in 2030. Most industry experts say it will be closer to 30 years before large commercial electric aircraft are viable.
Perhaps the most important specification for electric flight is batteries' energy density, measured in watt-hour per kilogram, commonly abbreviated as Wh/kg. Jet fuel's energy density is about 12,000 Wh/kg, compared to about 250 Wh/kg for commercially available lithium-ion batteries.
Batteries with 350 Wh/kg energy density could be commercially available by 2030, enabling all-electric, short-range, 30-seat aircraft, according to NASA's conservative projections, according to Aviation Week's executive editor Graham Warwick and France Bureau Chief Thierry Dubois.
Electric propulsion in commercial aircraft faces "a discouraging number of challenges" that could limit the technology to short-haul routes, such as Seattle to Portland or San Francisco to Los Angeles, Warwick and Dubois wrote. Even so, it has "the potential to change the air transport industry."
New chemistries are improving battery energy density. One company pursuing lithium-metal batteries, Cuberg, has received money from the California Energy Commission, the Department of Energy and Boeing.
Safety and discharge capacity also are key attributes of batteries for electric aviation, noted a paper presented at the Electrochemical Society's 2020 conference.
Electrifying aircraft could "considerably amplify electricity demand requirements at airports," according to a 2018 case study by researchers at the University of Illinois at Urbana-Champaign.
The study estimated that electrifying regional flights to and from Chicago's O'Hare International Airport could more than triple its annual load. However, the authors project that daily charging demand would ramp up around 6 a.m. and rise and fall over the day, topping out at about 20 MW depending on average energy density of batteries and with no pronounced morning or evening peaks.
However, it will be 15 years or more before small electric aircraft are common sights on airport tarmacs. International consulting firm ICF projects 3,300 electric commercial aircraft by 2035.
By then, mid-mile flights with up to 15 passengers "will be commonplace," said Roei Ganzarski, CEO of electric engine maker magniX and executive chairman of its sister company, electric airplane manufacturer Eviation. MagniX is based in Everett, Wash., home to Boeing's biggest assembly plant. Eviation is a few miles north in Arlington, where it is building the Alice, an all-electric nine-passenger airplane.
"We're not talking about CGI graphics; we're actually assembling [the Alice] at Arlington Municipal Airport," Ganzarski told Clearing Up.
The plane is expected to take its first flight this year, with Federal Aviation Administration certification and deliveries to airlines in 2024. The turboprop Alice is powered by two magniX electric motors with a 1 MWh battery system capable of two hours of flying time. That gives the plane a range of around 400 miles.
Increasing load at airports is not a major roadblock, he said.
Eviation and magniX currently are focused on selling to air carriers primarily serving smaller markets, not replacing a 40-passenger de Havilland Canada Dash 8 flying in and out of O'Hare. (MagniX is collaborating on a hydrogen-fueled conversion of a Dash 8 Q300, which seats about 50 flyers.)
"The idea of electric aviation is to connect smaller airports, so one or two [DC fast] chargers per airport should be enough," he said.
Very small airports might not even need chargers. Instead, a truck can haul a charging trailer to the airport. The trailer could recharge off the airport at a charger for heavy-duty trucks.
Nonetheless, "it's going to be a heavy lift" for utilities, he said. "Even if a utility doesn't step up, airports can create their own microgrid to charge airplanes."
Early engagement with utilities will be key to developing electric aviation in the state, according to a 2020 study by the Washington State Department of Transportation.
"The increased electric infrastructure needs of electric aircraft will also need to be balanced with other new landside electric demands including transportation and heating and cooling" at the airports, the study states.
"We're still trying to get our arms around what the [aviation] industry is looking for," said Arif Ghouse, airport director at Paine Field in Everett.
The airport, which has regional commercial air service and is home to Boeing's Everett assembly plant, is drafting a new master plan to chart its course for the next couple decades. Making room for electric aviation will certainly be in the plan, Ghouse told Clearing Up.
Paine Field officials have had "very high level" talks with Snohomish County PUD about increased demand from transportation electrification, he said.
Electric aviation is nowhere on the radar for most utilities. Two of the biggest utilities in the Northwest, Portland General Electric and PacifiCorp, both said it is not part of their current planning.
Snohomish PUD is further along than most.
"We're in the early stages of examining electric aviation from a load perspective," said Brian Booth, the PUD's senior manager for rates, economics and energy risk management. "We don't know enough to play with the numbers yet, but it's on our horizon and has been discussed as part of our scenario planning effort."
"Short-distance flights are considerably less fuel efficient than long-distance flights and battery size is a big cost constraint, so we'd expect e-planes to hit shorter, regional flights first," he said in an email. "Paine Field has a proportionately high number of these flights (Portland and Boise come to mind) and could be a good location for exactly these kinds of planes to come in."