Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
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- Focus on quality not slowing innovation, says GKN April 18, 2024
- Boeing defends 787, 777 against whistleblower charges April 17, 2024
- Dissecting Boeing CEO’s statement next new airplane will cost $50bn April 15, 2024
Bjorn’s Corner: Why e in ePlane shall stand for environment, Part 19. ICAO CORSIA.
April 24, 2020, ©. Leeham News: Before we wrap the series about technologies that can help us reduce the environmental footprint of air transport, we describe what the ICAO emissions scheme CORSIA is, its goals, and comment on its importance.
Figure 1. The world’s CO2 emissions increased at a fast pace until today. Source: Wikipedia.
The CORSIA emission scheme
ICAO is the UN agency that manages the agreements around international air transport. It’s also active in rules and conventions around environmental issues for air transport. As its charter is agreements for international air transport, any ICAO emission scheme can only be for this part of our air transport system. Any domestic air transport environmental schemes must be handled by the local state.
ICAO got its 193 members to agree to an aspirational goal of a “carbon neutral growth from 2020” for international aviation at its general assembly 2013. In 2016 the measures to achieve this goal were collected under the name CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation).
Implementation of CORSIA shall start next year and it’s voluntary for states to participate until 2026. It foresees the use of the technologies described in our low hanging fruit to achieve the goals. But it realizes this will not be enough to reach “carbon neutral growth from 2020” and therefore adds a carbon trading scheme to offset any higher CO2 load from international aviation.
It couldn’t, of course, envisage a worldwide virus pandemic virtually stopping air transport during 2020, thus the 2020 CO2 emissions are not useful as targets for CORSIA. CORSIA has a further goal of reducing CO2 emissions to 2005 levels by 2050, but how to get there is not described at present.
CORSIA is criticized for not being ambitious enough by many groups, but what is the point in such criticism? It’s an agreement voluntarily adhered to by states covering 85% of international air transport. Those who haven’t joined are Russia and India, but all other key states are in.
Summary
CORSIA is a key framework for how the aviation world can attack the issue of a global CO2 problem. It’s critical to support it and get it going, with its limitations and faults. Because then we have a base. Without it, we have nothing, and the efforts to control air transport’s environmental load disintegrates into local schemes infected by political agendas. This will achieve nothing but political infighting.
As I’ve argued, electric hybrids don’t really bring us forward:
https://www.airbus.com/newsroom/stories/our-decarbonisation-journey-continues.html
https://www.rolls-royce.com/media/press-releases/2020/24-04-2020-our-sustainability-journey.aspx
Bjorn
“Amongst the many great achievements from E-Fan X has been the generator – about the same size as a beer keg – but producing a staggering 2.5 MW. That’s enough power to supply 2,500 homes and fully represents the pioneering spirit on this project.”
Still I would have liked to see a 2MW electric fan in operation as all the other projects are fairly simple motor and propeller.
Dear Bjorn, The price estimates of drop in replacement carbon neutral fischer-topsch jet fuels seems to range from EUR$0.70 to abut EUR$1.40 per Litre. The lower range would be possible right now using biogas. This would seem to be nearly 3 times the price of current jet fuel. What do think the impact of these price increases would be on airfares and airline economics?
“Amongst the many great achievements from E-Fan X has been the generator – about the same size as a beer keg – but producing a staggering 2.5 MW. That’s enough power to supply 2,500 homes and fully represents the pioneering spirit on this project.”
Still I would have liked to see a 2MW electric fan in operation as all the other projects are fairly simple motor and propeller.
Sadly E-fan X has been jointly cancelled by Rolls Royce and Airbus as a result of the impact of COVID-19. The Siemens developed cryogenic motor had a power to weight ratio of 10kW/Kg. I imagine that the Rolls Royce University of Nottingham generator had at least the same P/W ratio. It was cooled by oil and super critical CO2. I’m not sure of the impact of the heat exchangers.
This means gearboxless power transmission can be achieved for 5kW/Kg. Much lighter than a gas turbine engine.
The 5 kw/kg figure is for power conversion, shaft power into the generator to shaft power out of the motor, with about 15% conversion losses. It doesn’t include power conversion from fuel. If the fueled turboshaft weight is added, it drops to about 2 kw/kg. If the weight of batteries is added for hybrid operation, it’s well below 1 kw/kg.
Modern turbofans achieve 10 to 12 kw/kg for the full conversion process, fuel to propulsion.
I’m sure COVID greatly reduced the funding available for this research, but as Bjorn has been telling us, it still had a very long way to go to be practical.
If the figure of 10kW/kg for a gas turbine were correct the overall P/W ratio would be a little better than 2kW/Kg? (which is still better than any piston engine) ie 1/(1/10+1/5) = 3.33kW/Kg but your figure of 2kW/Kg seems about right. This is still much better than a piston engine ever was.
All of the major car makers have a fuel cell vehicle approaching market. Bosch say the Platinum usage in a Fuel Cell Car will be no more than a Diesel car. Toyota have the compressed hydrogen fuel cell car called MIRAI on the market right now and BMW are cooperating with them and it is said fuel cell is now already cheaper than the electric car.
On that basis I argue that the fuel cell powered aircraft with cryogenic or superconducting motors and cabling is as likely as the fuel cell powered car. The efficiency of the fuel cell ameliorates the problem of a large cryogenic hydrogen storage. I also note that the MIRAI collects large amounts of condensed water from its exhaust into a reservoir. It occurs to me that the issue of water emissions into the stratosphere could be dealt with by simply condensing and collecting it releasing it at low altitude.