Potential Large Scale Solutions

Global strategy consulting firm Roland Berger predicts that if other industries de-carbonize in line with some projections, aviation could account for up to 24% of global emissions by 2050 unless there is a significant technological shift.

They identify three options:

  1. sustainable aviation fuels (SAFs)
  2. electric aircraft: Hydrogen fuel cell (HFC) aircraft could offer a “true zero” solution for GHG emissions as the only output of fuel cells is water vapour. Studies indicate that hydrogen fuel cell aircraft would be 20-40% more efficient than hydrogen combustion designs. Could benefit from the rapidly developing electric powertrain supply chain.
  3. hydrogen propulsion through hydrogen combustion in a modified jet engine, less disruptive to current operational systems

The March 2020 Roland Berger study identified five key barriers to hydrogen technology
1. A redesign of much of the aircraft, from the propulsion system to fuel storage.
2. Advancements in light-weighting storage tanks and cryogenic cooling systems, in order to take advantage of hydrogen’s high energy density.
3. A significant ramp-up in “green” hydrogen and/or carbon capture and storage (CCS) to increase the share of emissions-free hydrogen production.
4. Hydrogen infrastructure improvements in fuel delivery to airports and airport refuelling.
5, A reduction in the price of production methods for “green” hydrogen in order to compete with kerosene on a cost basis.

The full report has on page 19 a very useful comparison of the relative merits of using hydrogen for combustion and fuel cells.

Looking forward  they forecast: " the emergence of three different technological segments of aircraft with different sizes and ranges."
1. smaller aircraft with shorter ranges will likely become all-electric, with battery gravimetric densities expected to achieve the minimum thresholds to cater
for these missions.
2.  larger, long-haul aircraft can be expected to have to rely upon Sustainable Aviation Fuels (SAFs), as all-electric, hybrid-electric or hydrogen solutions will face
gravimetric and volumetric power density challenges at the required weights and ranges.
3. between these two extremes, regional and narrowbody/Middle-of-the-Market aircraft will likely be the battleground where hydrogen will compete against hybrid-electric.

They conclude: "Executives making investment decisions on future propulsion technologies should thus seriously consider allocating resources to explore the potential of hydrogen technology, diversify their technology risk, and help overcome the barriers to hydrogen propulsion.


Carbon Capture DAC & CCS

Direct Air Capture can be used to pump CO2 underground and store it permanently underground. It is also possible that captured CO2 can be used to create aviation fuel.

January 11 Carbon capture and storage is a costly “distraction” that cannot be relied on to help meet climate targets, according to research published by Global Witness and Friends of the Earth Scotland said reliance on CCS, to decarbonise the energy system, was “not a solution” to global warming. The research was undertaken by the Tyndall Centr at Manchester Victoria University.  They concluded that "CCS deployment is likely now too slow to participate substantively in this part of the transition. Concerns about residual emissions from capture and fuel supply stages of fossil fuel CCS for power and hydrogen in the context of constrained carbon budgets suggest a limited role is possible in the energy system post 2030 where 2050 net-zero targets exist."  Full Report 

Global Witness and Friends of the Earth Scotland said that this research proves that " CCS has a “history of over-promising and under-delivering”. The FT reported that "CCS was first developed in Norway in 1996 but there are only 26 commercial projects in operation globally, none of which are in the UK or EU. To date most carbon capture has been used to extract difficult-to-reach oil. Stuart Haszeldine, Professor of Carbon Capture and Storage, School of Geosciences, University of Edinburgh wrote in a letter to the FT  26 January "either the oil industry can co-operate and develop CCS today to counteract their hydrocarbon production, or the taxpayer will have to ban fossil fuel extraction and develop CCS in a panic in the 2040s."

Dec 10, 2020 United Airlines announced that they plan to be 100% green by reducing its greenhouse gas (GHG) emissions by 100% by 2050. They plan to advance towards carbon neutrality by committing to a multimillion-dollar investment in revolutionary atmospheric carbon capture technology known as Direct Air Capture. Scott Kirby, United's chief executive officer. said "These game-changing technologies will significantly reduce our emissions, and measurably reduce the speed of climate change – because buying carbon offsets alone is just not enough. Perhaps most importantly, we're not just doing it to meet our own sustainability goal; we're doing it to drive the positive change our entire industry requires so that every airline can eventually join us and do the same." Rather than simply taking a conventional approach to decarbonization by relying solely on the purchase of carbon offsets, United intends to make a multimillion-dollar investment in 1PointFive, Inc., a partnership between Oxy Low Carbon Ventures, a subsidiary of Occidental (NYSE:OXY), and Rusheen Capital Management. 1PointFive's mission is to curb the rise in global temperatures by physically removing carbon dioxide (CO2) from the air using Direct Air Capture technology licensed from Carbon Engineering. more

June 2o20 the International Energy Agency reviewed progress on DAC.
The CO2 can be permanently stored in deep geological formations or used in the production of fuels, chemicals, building materials and other products containing CO2. When CO2 is geologically stored, it is permanently removed from the atmosphere, resulting in negative emissions. There are currently 15 direct air capture plants operating worldwide, capturing more than 9 000 tCO2/year, with a 1 MtCO2/year capture plant in advanced development in the United States. In the SDS, direct air capture is scaled up to capture almost 10 MtCO2/year by 2030. This is within reach but will require several more large-scale demonstrations to refine the technology and reduce capture costs. more