Heart Aerospace, the ES-Thirty Electric Regional, and the Battery Wall That Forced the Pivot No Aviation Startup Wants to Make

Heart Aerospace pivoted from a fully electric 19-seat regional aircraft to a 30-seat hybrid-electric design in 2022, after battery energy density failed to keep pace with what real-world regional operations demand. The decision - abandoning a concept that had attracted over 300 conditional orders from major carriers - is the clearest illustration yet of where electric aviation actually stands, versus where the industry hoped it would be.

Why Regional Aviation Was the Target

Heart Aerospace was founded in 2018 in Gothenburg, Sweden, by Anders Forslund. The company’s focus was never urban air taxis or short city hops. From the beginning, the target was scheduled regional service - the routes connecting smaller communities to national networks, the flights that make rural hospitals reachable and keep isolated economies from being severed from the cities they depend on.

Hundreds of small airports across the United States have lost scheduled service over the past two decades. The core problem is operating economics: a conventional turboprop burning jet-A on a 150-mile segment simply cannot generate enough revenue to cover its costs when a route moves 40 people a day. The margin requires either volume or subsidy, and neither is reliable.

What the ES-19 Promised

The original aircraft concept, the ES-19, was a 19-seat all-electric regional with a target range of roughly 200 kilometers on a single charge. Its layout resembled a conventional twin-turboprop commuter - straight wing, two propellers - but electric motors replaced the turbine engines and battery packs replaced fuel tanks.

On paper, the numbers fit a real slice of the market. Thousands of city pairs in Europe and North America fall within that 200-kilometer window. The ES-19 promised near-zero direct emissions, substantially lower maintenance costs (electric motors have no hot section inspections, no combustion chamber erosion, and far fewer moving parts), and operating economics that could challenge conventional turboprops on short hops.

The aviation industry’s response was serious. By 2021, United Airlines had placed conditional orders for 100 aircraft. Mesa Air Group added another 100. Air Canada and Braathens Regional Airways also placed conditional orders. The total order book climbed past 300 aircraft - not the kind of interest that comes from a slide deck alone. Major carriers run real technical analysis before signing anything.

The Battery Wall

The problem was never the electric motor. Electric motors convert electrical energy into mechanical output at efficiencies above 95 percent. A turbine engine, in the best case, converts roughly 40 percent of fuel’s chemical energy into useful shaft power. The electric propulsion case is genuinely strong.

The problem is energy storage.

Jet-A fuel contains roughly 12,000 watt-hours of usable energy per kilogram. Liquid hydrocarbons are among the most energy-dense portable fuels ever found - a fact that made aviation possible in the first place. The best lithium-ion battery cells available today store somewhere in the range of 250 to 300 watt-hours per kilogram at the cell level. When those cells are built into a flight-ready battery pack - with thermal management, structural housing, battery management electronics, safety containment, and all certification-required hardware - the real system-level energy density drops to roughly 170 to 200 watt-hours per kilogram.

That is a gap of more than 60 to one between jet fuel and a deployable battery pack.

The electric motor’s efficiency advantage partially offsets this. But even accounting for that edge, a battery-powered aircraft is still operating at a fraction of the specific energy that conventional fuel provides.

There is a second, structural penalty. A fuel tank gets lighter as the flight progresses - a turboprop burning fuel on a 200-mile leg arrives at its destination meaningfully lighter than when it departed. A battery pack weighs exactly the same whether it is fully charged or fully depleted. Every kilogram of battery is carried from takeoff to landing regardless of how much energy remains in it. That dead weight compounds as the mission lengthens.

When the Margins Collapsed

For the ES-19 at 19 seats and 200 kilometers, the battery math worked - under favorable conditions, with careful weight management. But the margins were thin.

Airlines asked the obvious operational questions. What about segments of 230 or 250 kilometers? What about cold-weather operations, where lithium-ion performance can drop 20 to 30 percent as temperatures fall? What about a headwind day that adds 15 minutes to block time? What about the reserve requirement when a diversion is necessary?

The margins that looked acceptable in the design case eroded quickly once real-world operational variability entered the picture.

Meanwhile, battery development wasn’t moving fast enough. Energy density improves every year - the gains are real - but they are incremental, roughly 5 to 8 percent annually in a good year. To double the energy density of current packs, which is what a pure-electric regional aircraft would need to meaningfully expand its mission capability, requires a minimum of 10 years, assuming the underlying chemistry breakthroughs arrive on schedule.

Heart Aerospace ran the numbers and acted.

The ES-30: Engineering Around What Exists

In 2022, Heart Aerospace cancelled the ES-19 and announced the ES-30 - 30 seats, hybrid-electric architecture, and a fundamentally different philosophy about bridging the gap between what batteries can do today and what regional aviation actually requires.

The ES-30 retains the electric motors and the battery pack. It adds a turbogenerator - a compact turbine engine running not to drive propellers directly, but to spin a generator producing electricity. On segments within battery range, the aircraft operates primarily on battery power. When the mission demands more energy than the batteries can provide, the turbogenerator runs, burning conventional fuel to extend range.

The result: battery-only operation to roughly 200 kilometers on a full charge, and hybrid operation extending practical range to approximately 400 kilometers. The architecture also provides meaningful redundancy - losing the turbogenerator still leaves battery power available, and the failure modes don’t compound.

In interviews following the announcement, Forslund was direct: the physics are unambiguous. If you want to serve the regional market with current battery technology, you need a bridge. The hybrid is that bridge.

The Certification Advantage Nobody Talks About

A fully electric transport-category aircraft enters unmapped regulatory territory. EASA and the FAA are still writing the frameworks for certifying novel electric propulsion systems in this size class. Battery pack separation requirements, energy storage certification standards, and emergency procedure logic for electrical energy failures are all being developed in real time, concurrently with the aircraft programs trying to meet those standards.

The ES-30’s turbogenerator makes the aircraft considerably more familiar to existing certification structures. The electric propulsion elements remain novel, but the overall system architecture maps more cleanly onto frameworks regulators already know how to apply. When a company’s funding runway is finite and the path to revenue service must be as short as possible, that regulatory legibility is a meaningful structural advantage.

Where Heart Aerospace Fits in the Broader Landscape

MagniX, based in the Seattle area, has focused on high-power electric motors for existing airframes. Their eCaravan - a modified Cessna 208 Grand Caravan with an electric motor replacing the conventional turbine - flew in 2020 at Moses Lake, Washington, proving the platform concept. But the eCaravan is a technology demonstrator, not a product ready for regional network operations.

Ampaire has pursued hybrid-electric modifications of existing airframes, including demonstration flights in Hawaii showing the hybrid concept functioning under real revenue conditions. Their approach avoids clean-sheet certification entirely, but is constrained by original airframe geometry and capabilities.

Eviation Aircraft has developed the Alice, a nine-passenger all-electric commuter with a flying prototype and serious conditional orders from Cape Air. All-electric, targeting the shortest regional segments - but nine passengers represents a different commercial proposition from 30 seats. The route economics scale differently.

Heart Aerospace’s deliberate targeting of the 30-seat class reflects where regional network economics begin to work for underserved communities. Below 20 seats, economics push toward air taxi or on-demand charter models. Above 40 seats, the competition is the bottom of the narrowbody jet market. Thirty seats, at the range the ES-30 can cover, is the specific intersection where a hybrid-electric aircraft can make the commercial case for restoring scheduled service to communities that have lost it.

The Noise Factor

One advantage that doesn’t appear in performance tables but matters enormously for community acceptance: an electric motor driving a propeller at lower tip speeds is significantly quieter than a conventional turboprop. For routes serving smaller communities where airports sit close to residential areas, the ES-30’s noise signature is a genuine operational advantage - the kind that turns a local zoning board from an obstacle into a supporter.

What This Means for Pilots

The honest timeline for ES-30 commercial service is initial EASA certification by the end of this decade, with revenue service to follow. That target has already moved from earlier projections and may move again. Certifying a hybrid-electric transport-category aircraft is genuinely difficult work, and parts of the regulatory framework are being written alongside the development program.

For pilots, the type rating for a hybrid-electric regional will introduce concepts with no direct analogue in conventional turboprop training. Energy management takes on a different character when you are actively monitoring battery state of charge and turbogenerator output alongside conventional aircraft performance. Emergency procedures branch differently depending on whether you have lost the turbogenerator, lost a motor, or encountered a battery management issue - these are separate abnormal procedure trees, not variations on the same engine failure drill.

Regional carriers building training pipelines for these aircraft will need instructors genuinely comfortable at the intersection of electrical systems knowledge and traditional regional operations. Pilots who invest early in understanding electric and hybrid-electric powerplants will have a meaningful advantage when conditional orders become actual deliveries.

Key Takeaways

Heart Aerospace cancelled the all-electric ES-19 in 2022 after battery energy density failed to support reliable real-world regional operations, pivoting to the hybrid-electric ES-30
The fundamental problem is energy storage: jet-A delivers roughly 12,000 Wh/kg; a flight-ready battery pack delivers roughly 170–200 Wh/kg - a gap exceeding 60 to one
Battery energy density improves 5–8% per year; doubling current pack density requires a minimum of 10 years of continued development
The ES-30’s hybrid architecture - battery-only to ~200 km, hybrid to ~400 km - is engineered around what battery technology actually delivers today, not projections
The turbogenerator addition also provides a significant certification advantage, mapping more cleanly to existing regulatory frameworks than a fully novel all-electric design
Pilots pursuing careers on these platforms will need to master energy management and parallel failure mode trees that have no direct equivalent in conventional turboprop training