An emerging solution to aviation carbon emissions?

The concept of flygskam (flight shaming), coming from northern Europe, arises from concerns about the impact of carbon emissions from our travel on the planets climate. In a world where some seem determined to ignore the threat of climate change, choosing to fly responsibly is something each of us can do. Even some airlines are promoting it. Two recent breakthroughs in energy development hold the promise of a solution.

For a country such as New Zealand, on the outer edge of nowhere, the rise of this movement is recognized as a threat to the national airline and to the New Zealand tourism industry. Forward thinkers such as Air New Zealand chief executive Christopher Luxon see the biggest challenge for the airline industry coming in the next 20 or 30 years as other industries de-carbonised – making aviation’s relative contribution even greater.

The Current State

Current measures to address this issue range from the airlines reducing their own footprint, through to measures such as moving to more efficient aircraft and removing the cartage (and expense) of providing newspapers in airport lounges. However, while incremental gains in efficiency add up, the volume of air travel is increasing at a higher rate, meaning the proportion of global emissions  from aviation is likely to increase. Although travelers often offset their travel by purchasing carbon credits, this is not a complete solution.

Need for Radical Solutions

Radical solutions are necessary.  Development of future fully electric aircraft to replace the domestic turboprop fleet is an obvious point to start, given New Zealand’s variety of routes and renewable supplies of electricity. The aircraft are not in service yet, but manufacturers are responding to demand by developing concepts for potential new aircraft.  It takes many years for an aircraft to go from concept to commercial service, so this is a long term solution. Once available, shorter hops may be the first to be electrified, with others following as battery technology improves and range expands.

Air New Zealand regional operations account for around 40% of the airline’s carbon emissions. What about the other 60% for long haul?  A central problem with long haul is range.  Carbon-based aircraft fuels are energy dense, allow quick refueling and enable amazing range. The current record for the world’s longest commercial flight is a Qatar Airways’ 14,200km non-stop service from Auckland to Doha. Qantas is proposing to test and introduce a 17,000km, 19 hr service direct from Sydney to London.

Trials have been held with plant derived aircraft fuels, such as the jojoba. Blends are used for some commercial services and partial mixes with low proportions of bio-fuel are available at several airports. As fuel comprises over 75% of airline operating costs, a price 2-3 times fossil fuel has limited uptake.

By Kenneth Bosma – Seeds on a Female Jojoba Bush, CC BY 2.0,

Biofuels

Aviation bio-fuels derived from agricultural wastes are particularly attractive on ethical grounds. This has led to commitment to invest of hundreds of millions of dollars for plants in California and Amsterdam. Given the environmental pressures on the industry, we expect in time this method will become more common and hopefully cheaper.

If plants are thought of as a means of converting carbon dioxide, water and sunlight into carbon fuel-stock is it possible to cut out the plant stage and to develop an artificial means of achieving the same outcome? This is the basic idea behind a series of studies funded by the European Union since 2011. The researchers report the production of a cup-full of aviation fuel using carbon dioxide and water feed stocks, powered by direct sunlight in a reactor. This is an encouraging start, but overall progress appears to be slow. This may suggest difficulties in scaling up the process.

Direct Synthesis of Fuels

A less direct but more simple approach is to decouple the solar energy and chemical reaction processes. Recent articles by the American Academy for the Advancement of Science in the Journal Science, suggest a possible way forward. One outlining a process using carbon nano-tubes that claims to convert water and carbon dioxide directly into fuels. Although the technology has yet to be proven, a $150,000 USD grant from the famed start-up incubator, Y-Combinator, has been used to build a demonstration pilot plant the size of a large refrigerator. We will soon know if this technology works, and if not, it may inspire others.

A subsequent issue of Science reported another incremental but equally important milestone: the cost of supplying electricity in California by solar with battery back-up is now less than the cost of fossil fuel. As illustrated in the chart below, the cost of solar photo-voltaic plants has fallen exponentially over the years.

This tipping point – where costs of PV fall below fossil fuels – has been long-predicted as battery technology improves. The tipping point is now and the effects are evident.

The fact that three major US coal miners have filed for bankruptcy since May 2019 illustrates the futility of clinging to outmoded methods of energy generation. This is a pattern of human history: where fuels have been outmoded by new developments before they run out. Most of the coal and remaining petroleum will likely stay in the ground – where it needs to if we are going to address the threats of climate change.

Summary

• continuing incremental improvement of aircraft efficiency
• acting responsibly by jettisoning what we don’t need – such as unnecessary travel or physical newspapers
• utilising biofuels created from agricultural waste
• creating fuels from thin air using cheap renewable electricity

Flygskam need not lead to the demise of the New Zealand tourism industry. However, in the words of Chris Luxon, “You’ve got to start that journey now”.