ZeroAvia unveils hydrogen fuel cell powertrain for aviation
15 August 2019
In the latest effort to make aviation sustainable and reduce greenhouse gas emissions, ZeroAvia announced advancements in developing a hydrogen-fueled electric powertrain.
The solution aims to deliver the same performance as a conventional aircraft engine, and much lower operating costs. ZeroAvia plans to start supplying its platform to commercial operators and aircraft manufacturers in 2022, initially targeting up to 500-mile regional flights in 10 to 20-seat fixed-wing aircraft.
ZeroAvia prototype shown powering a 6-seat Piper M-Class aircraft, already in flight tests from February 2019.
Using hydrogen produced from local renewable energy is the most practical way to enable zero-emission aircraft of commercially meaningful size on traditional 300 to 500-mile regional missions. It will also be more economical than conventional turbine engines, or even the battery-based systems, on the total cost basis. We calculate the total costs of operating a ZeroAvia aircraft to be close to half of what it costs to fly a conventional turbine aircraft, due to lower fuel input costs, higher powertrain efficiency, and reduced maintenance costs.—Val Miftakhov, ZeroAvia Founder and CEO
ZeroAvia was founded by serial cleantech entrepreneur Val Miftakhov, who is also an avid airplane and helicopter pilot. He previously founded and was the CEO of eMotorWerks, a smart grid electric vehicle charging company acquired in 2017. The core leadership team at ZeroAvia includes alumni from Tesla, BMW, NVIDIA, Zee Aero, Air Liquide, and SystemIQ, as well as other founding members of eMotorWerks.
The company is already flight-testing its powertrain prototype in a Piper M-Class airframe. The Federal Aviation Administration issued an Experimental R&D Certificate to ZeroAvia’s Piper M-Class R&D platform earlier this year.
At a 2-ton takeoff weight and with six seats in a business-class arrangement, it is currently the world’s largest zero-emission aircraft flying without any fossil fuel support, according to publicly available information. The aircraft has completed a variety of test flights, which validated key components and their integration into a complete powertrain system. These tests confirm the company’s fuel economy and maximum power delivery targets.
ZeroAvia is initially targeting 500-mile flights to serve the short-haul and commuter air travel markets, which make up nearly half the commercial flights worldwide. Powered by ZeroAvia powertrains, smaller zero-emission aircraft could achieve similar per-seat economics as today’s large regional jets, allowing economical use of smaller local airports for point-to-point travel with virtually no security lines or delays, and a much more pleasant overall flying experience.
In addition to passenger transport, the ZeroAvia powertrain could have applications across other use cases including cargo, air taxi, agriculture, as well as across the aircraft types, including manned and unmanned fixed-wing, rotorcraft, and more.
Starting in 2022, the ZeroAvia powertrain will offer operators a sustainable option for new aircraft made by established manufacturers where customers already purchase their aircraft. ZeroAvia will lease the drivetrain to customers and provide fuel and maintenance as part of its power-by-the-hour model, in which customers pay only for the hours that they use the drivetrain. This model emulates engine leasing options already popular in the aviation market.
Flight test videos here:
Posted by: Davemart | 15 August 2019 at 03:43 AM
Enviation's Alice 9-seat aircraft is a larger and heavier electric only aircraft with a similar range and is fully battery electric but it is not clear that it has flown yet It was displayed at the Paris Air Show and they have announced an initial customer in the US. I was hoping that it would be shown at the Experimental Aircraft Association's Oshkosh airshow this year but they were not there. Maybe next year with an operating plane.
An interesting problem with a battery electric aircraft is that they do not burn off weight as they fly so they have to land at the same mass as they took off.
Posted by: sd | 15 August 2019 at 06:26 AM
The Alice has to be certified to fly with passengers,
this may be easier.
Posted by: SJC | 15 August 2019 at 06:38 AM
The 6 seater is just the test platform:
' ZeroAvia plans to start supplying its platform to commercial operators and aircraft manufacturers in 2022, initially targeting up to 500-mile regional flights in 10 to 20-seat fixed-wing aircraft.' (ibid)
The bigger and heavier the aircraft, and the longer the flight envelope required, the more the advantage of fuel cells and hydrogen over batteries, as even with the associated tanks and so on they are still way more dense in weight than batteries including losses in coverting hydrogen to electricity also.
Still nowhere near jetfuel of course for really big aircraft and distances of course, but far cleaner.
Posted by: Davemart | 15 August 2019 at 06:39 AM
@SD, that will apply (but to a lesser extent) with Hydrogen fuel cell based aircraft. They will have extra machinery to store and process the H2, and the H2 itself is very light, so they'll still land heavy, not like an ICE plane that has burned off a load of fuel.
Posted by: mahonj | 15 August 2019 at 08:31 AM
The Eviation Alice is an All-Electric 9-seat passenger plane having 8,000 lbs of battery out of 14,000-lb takeoff weight, having a range of 1,000 km.
Let's consider a hypothetical Fuel Cell alternative to the 8,000-lb of battery, thanks to a recent discovery of a Manganese Hydride complex that can store Hydrogen at 10.5% weight percentage. Given 920 kWh battery capacity which translate to 920 kWh / 22 kWh per kg of H2 = 41 kg of H2. 41 kg divided by 10.5% = 398 kg = 876 lbs.
Needs also 450 kW of fuel cells at 1 kg per kW = 450 kg = 990 lbs.
Total e-storage system weight = 876 + 990 = 1866 lbs. This is very light in comparison to the 8,000 lbs of battery required to travel 1000 km, so wings, tail, and e-motors and inverters can be downsized, result in a lot of weight reduction in airframe weight and motor + inverter weigh. Maximum Takeoff Wt will be around half of current, at around 8,000 lbs, and thus will consume a lot less energy per mile, permitting a total range as far as 1,700 km, which is more in line with petroleum powered planes of this size, and can be refueled almost as fast, and not so slow as with battery recharging.
The waste heat from the fuel cells can be harvested for cabin heating and anti-icing purpose on all forward-facing surfaces, and not wasted at all.
Posted by: Roger Pham | 15 August 2019 at 01:39 PM
Yes, there's a lot to be said for small (6 to 20 pass) FC clean running airplanes including free heat recovery for the pilot/passengers cabins + for free de-icing.
Improved H2 storage and improved FCs will soon allow more range and/or more on board load for larger planes. .
Posted by: HarveyD | 15 August 2019 at 04:01 PM
Not much is reported about the ZeroAvia powerplant, though some details are in the Aviation Week article, "Startup Sees Fuel Cell Future For Regional Aviation” Aviation Week Aug 14, 2019.
ZeroAvia is using a Piper PA-46-350P Malibu Mirage aircraft . The original motor, a Lycoming TIO-540 engine has 260 kW (350 hp, weight 199 kg) will be replaced by a pair of 130-kW electric motors. Note: Siemens eAircraft (now Rolls Royce) has a 260 kW motor -SP260D - that would work. It weighs only 50 kg and runs at 2500 RPM non-geared.
ZeroAvia CEO Miftakhov mentions in the Aviation Week article that "a fuel-cell pack capable of producing 150 kW weighs around 50 kg". This is better than Honda or Toyota (they get around 100 kW for a 50 kg fuel cell), maybe it is the Horizon Fuel Cell which gets about 50% better using bipolar plates. It would be interesting to know.
Also, a 150 kW fuel cell would handle cruise power, however, takeoff and climb would require higher energy outputs. Miftakhov says "the company has had to get creative to overcome this hurdle, insisting that batteries will not be used to provide additional power during such profiles.”
ZeroAvia has some good ideas. It will be interesting to see how they develop.
Posted by: Account Deleted | 15 August 2019 at 04:27 PM
It would be interesting to see the general design; I would think they use a fairly small buffer battery between the motor and FC. If for no other reason to supply emergency power in case of FC problems. This is a good step toward eventually replacing fossil fuel turbines with hydrogen turbines and/or FC/ ducted electric fans on airliners.
In any case this is encouraging.
Posted by: Lad | 15 August 2019 at 04:59 PM
LIPO batteries can output at 20C, you don't need many to climb.
Posted by: SJC | 15 August 2019 at 05:42 PM
Just quoting the AvWeek article about no batteries. It could be SuperCaps which work well with Fuel Cells. In Miftakhov eMotorWerks company that had BMW EV Conversion Kits they used LiPo batteries and are probably using them in the current "FC-free"prototype.
Like to know their creative solution.
Posted by: Account Deleted | 15 August 2019 at 06:52 PM
Thanks for the additional info, gryf.
It would be good to know how they intend to get around peak power considerations.
The fuel cells from Hyundai and Toyota should reach comparable density in their next iteration after 2020.
Since I criticise those who assume that super batteries will come in anytime soon, I am not going to assume that the manganese hydride Kubas-1 storage system for hydrogen will be available.
However the figures work in any case for light and low range aircraft using presently available off the shelf storage technologies, and still provide a very large advantage over battery only solutions for anything except the very lightest and lowest range airdraft, trainers and so on.
Posted by: Davemart | 16 August 2019 at 01:57 AM
You climb 2000 feet per minute for 5 minutes, LIPO is the way to go.
Posted by: SJC | 16 August 2019 at 12:43 PM
It says "largest aircraft flying without any fossil fuel support". 2 rebuttals of that, firstly that is unlikely to happen for this aircraft in the real-world. Operators will probably use a natural gas reformer to obtain the hydrogen on-site at the airport. just like hydrogen-fuelled city busses do. Anything coming in a tanker truck will similarly be derived from natural gas. It is not fossil-fuel-free just like my Tesla is not. It's certainly better, but fuel-cells are not dinofuel-free. They *could* be, but they're not.
Secondly put suitable biofuel in any Jet-A burning aircraft and it is fossil-fuel-free. That has been done already for many much larger aircraft. It's also cheaper to run, because it doesn't have the million dollar fuel cell cost.
Posted by: Floatplane | 16 August 2019 at 01:21 PM
Make H2 from renewable methane, no fossil CO2.
Posted by: SJC | 16 August 2019 at 02:50 PM
I'm inclined to agree with @Floatplane. They'll have all these stories about renewable H2, but they'll end up reforming most of it from fossil methane.
As SJC says, "use renewable methane", but who knows what they'll actually use.
Posted by: mahonj | 16 August 2019 at 03:02 PM
Maximum rate of climb on the Piper Malibu is 1143 fpm. Typically, max throttle to 8000 ft (7 minutes plus), then cruise climb to 25,000 ft. So at least 5 kWh needed.
LiPO batteries would be the standard approach. However, they could be looking at a UK company called Superdielectrics that has a 26 W-hr/kg SuperCap using a contact lens polymer (supposed to reach 50 W-hr/kg this year) which would have energy density competitive to LiPO.
Posted by: Account Deleted | 16 August 2019 at 03:31 PM
I don't think it is productive to be absolute in demands for 'all renewables right now' and so on.
Hydrogen can certainly be produced renewably, as well as a host of other ways such as the 'blue hydrogen' that places like the UK and Australia are developing, where sequestration is the deal as is already done at the million ton level.
But in any case, the other pollutants from present planes are also significant and very damaging, and either battery planes or FCEV ones can ameliorate that.
The ideal should not be the enemy of improvement.
Posted by: Davemart | 16 August 2019 at 03:33 PM
Why would anyone use hydrides at 10.5% H2 by weight when you've got ammonia at 17.8%? That also allows use of an ammonia-burning gas turbine for additional power for takeoff and climb.
I'm surprised that the conversion is a Piper Malibu when the obvious candidate test aircraft would be something like a Queen Air or Aztec. Fuel cells are modular and could be distributed in 2 packages instead of one. The engine nacelles could be downsized and streamlined. For extra efficiency, more motors could be added across the wing span and each propeller made thinner, generating less drag and throwing more air backwards at less ΔV for higher total propulsive efficiency.
Posted by: Engineer-Poet | 16 August 2019 at 05:38 PM
There is more than one metric involved in deciding the optimum strategy.
Hydrogen by weight is just one of them, with how easy or tough it is to get the hydrogen out critical.
And fuel cells are modular, but there is a lot of ancillary equipment including hydration and air flow.
Those kind of ranges of performance and restrictions mean that a range of solutions are available, and don't lend themselves to back of the envelope dismissal of the particular ones chosen.
Posted by: Davemart | 17 August 2019 at 01:35 AM
26 W-hr/kg ...
Do the math,
if you need 5 kWh to climb,
how many kg of supercaps to you need?
With LIPO you can have 260 Wh/kg,
how many kg of batteries to you need?
Posted by: SJC | 17 August 2019 at 05:15 PM
An ideal safer 20+ passenger FC airplane would have 3 smaller FCs and 3 e-motors/props for take-offs and would cruise at less than 50% power or on 2 out of 3 power units during emergencies?
Clean H2 could be made and stored at airports with appropriate electrolysers and REs.
Posted by: HarveyD | 18 August 2019 at 09:57 AM
I am surprised at the claim that fuel cell planes will have lower operating costs than planes powered turbine engines. As far as I know hydrogen produced from electrolysis is still substantially more expensive per unit of store energy than conventional aviation fuel produced from petroleum. I know that significant progress is being made in lowering the costs and improving the durability of fuel cells, but I don't think that the costs of fuel cell/electric motor power trains have yet dropped below those of combustion engines. Conceivably the overall efficiency of the fuel cell/electric motor power train is higher than that of the combustion engine, but I would be surprised if this advantage were sufficient to lower the overall operating costs. Certainly no one is making this claim in the more advanced technology of fuel cell buses.
Posted by: Roger Brown | 19 August 2019 at 09:03 AM
Piper M-Class airframe...
M600 rate of climb 1500+ fpm
Posted by: SJC | 19 August 2019 at 01:35 PM
Fuel: Piper M500
...based on 40 gph on 500 NM trip segments
Includes climb, cruise and descent fuel.
H2 from renewable methane beats $200 per hour fuel cost.
Posted by: SJC | 19 August 2019 at 01:53 PM