Globally, domestic aviation was responsible for emitting 287,000,000 tonnes of carbon dioxide in 2010, according to an IPCC report. Looking at this in more detail, a Boeing 737 would burn approximately 5 tonnes of jet fuel on a 2 hour flight, resulting in 15 tonnes of carbon dioxide emissions.
Unfortunately, mass-market adoption of zero-emission electric aircraft (battery electric or hydrogen fuel cell electric) is not likely to occur anytime soon. Primary reasons for this are:
- The energy density of jet fuel is around 30 times higher than current lithium-ion batteries after accounting for efficiency gains of electric drives over jet engines.
- An aircraft requires around 3 times as much power during the initial takeoff and climbing period as it does during the cruising period. Lithium ion batteries currently have relatively low power densities, meaning that these batteries will need to be sized for this power potentially resulting in additional weight.
- Aviation certification of any new aircraft generally takes a long time. When you then add in the additional safety concerns around lithium ion batteries or hydrogen storage, this certification process could be lengthened.
These challenges should not stop us from planning and working towards a future with electric aviation in 10 / 20 / 30 years’ time. Generally, technological advancements do not happen overnight and people who wait for them to occur miss out on the economic windfalls that they can bring. Just look back at the history of the computer and today’s value of those visionary companies.
One reason to be optimistic about electric aviation is the speed of innovation in battery technologies. Since 2010, the energy density of lithium ion batteries has tripled and is expected to continue to improve. This is making battery electric airplanes more viable. When you couple the significant reduction in operating costs with this increasing viability, there is cause for excitement.
Electric aircraft will require major changes to airport infrastructure and operations, manufacturing, supply chains, maintenance infrastructure and operations, airline capital plans and operations, and training. Therefore to realise the future economic and environmental returns of zero-emission electric aircraft, now is the time to start planning as these types of changes don’t happen overnight. This planning needs to include:
Assessment of electric aircraft technologies
- Analyse the energy demands for different sized regional aircraft (starting with small planes that carry 3-12 passengers). Calculate the hypothetical battery pack and hydrogen fuel tank sizes required for these aircraft along with associated weights and volumes. Assess the practical flight time and distance limitations based on battery and hydrogen tank requirements. Do this for current and future technology based on expected improvements.
- Analyse the demand and utilisation of these aircraft in different service roles (charter, scheduled charter, business travel, regional airline service).
- Review constraints to develop electric aircraft and the parties involved.
Case studies:– A Vancouver (Canada) company, Harbour Air, is developing an electric seaplane for short haul flights in partnership with magniX, which is a Washington based company. One of the biggest concerns Harbour Air has at the moment is the certification and they plan on working with both Transport Canada and the FAA.
– Airbus demonstrated the performance of the E-fan that crossed the English Channel in 2015. While the production of this aircraft has been cancelled, the Department for Business, Energy and Industrial Strategy (BEIS in the UK) has announced an investment of £255 million to develop greener flight technologies.
Assessment of the infrastructure required to support electric aircraft
For battery electric aircraft this includes:
- An analysis of the benefits and challenges of the different charging technologies and standards.
- Analysis of battery storage, which has the benefit of providing local power supply, which minimises the stress on the power system and therefore reduces operational costs.
- In addition to battery storage, a battery swap model should be assessed. This model allows high utilisation of the aircraft, decreased battery degradation due to slower charging rates and is easier to logistically implement relative to cars because aircraft routes are limited and defined.
- Analysis of peak electricity demand of charging a battery electric fleet, which may result in costly capital upgrades to the electrical network and can be a large contributor to the operational cost. Battery storage and smart charging strategies would flatten the electricity demand and optimise the capital and operational cost.
Hydrogen fuel cell electric aircraft, would require an analysis of the production, supply, storage and dispensing infrastructure for hydrogen. One potential option is to build electrolysis plants at the airport to produce and supply hydrogen.
Hydrogen fuel cell electric aircraft have two main advantages over battery electric aircraft:– The energy density of hydrogen is approximately 240 times more than current lithium ion batteries, which means that hydrogen electric aircraft can be built with a longer range.
– Hydrogen refuelling time is much quicker than battery charging times, which means that hydrogen electric aircraft can have higher utilisation.
Assessment of the Environmental Impacts
- Assess the relative reductions in greenhouse gas (GHG) emissions accounting for energy requirements and the carbon intensity factor of the energy source. Depending on the energy source, it will likely be very beneficial for local air pollution and overall greenhouse gas emissions.
- Assess the reduction in noise pollution of an electric aircraft relative to a conventional aircraft. As noise from an electric engine is significantly lower than a jet engine, it is expected to have a large reduction in community level noise.
Assessment of the economic development potential
The introduction of electric aircraft will create new opportunities in the aviation space as well as potential new opportunities in other markets. Like electric cars, this new technology will bring new types of jobs such as:
- On-board electric and power system manufacturing.
- Aircraft maintenance.
- Infrastructure construction and maintenance.
Also, as operational costs will likely be cheaper, it may open opportunities for a new customer segment looking for rapid short haul trips to avoid taking their vehicle. In addition to the direct economic impact, increased airport traffic has a strong indirect economic impact in areas such as restaurants, hotels, tourism, mobility services, etc.
Assessment of the education and workforce development required
The maintenance of electric aircraft will require new skills and knowledge relative to conventional aircraft maintenance. These include the checking and assessing of battery safety, performance and health; knowledge of battery management and control systems; assessment and maintenance of electric motors; etc.
Zero-emission electric aircraft will be part of the future of flying. Due to the long lead time to realise this future, now is the time to start planning to be at the forefront of this technology and industry. Governments and organisations should be identifying specific and measurable goals for the years 2030, 2040 and 2050. They should then be developing agile roadmaps to ensure these goals are met.