Clean air transport: batteries or biojet or both – but let’s get on with it

March 14, 2019 by Mike Scott

Clean air transport: batteries or biojet or both - but let’s get on with it

by Mike Scott, March 14, 2019

In his last article for Energy Post, Mike Scott looked at how airlines are under increasing pressure to reduce their greenhouse gas emissions rather than offsetting them as they do now. How can it be done? There is no one-size-fits-all solution for the varied size of aircraft and flight distances but that should be no excuse. Battery innovation offers solutions for some cases whilst biojet (aviation biofuel) can fill many of the remaining gaps. Dithering over which is the right path is delaying the deployment of green technologies the sector needs if it is to achieve significant, sustainable GHG emissions reductions and allow us to use aircraft with a clear conscience.

Aviation transport is finally coming under scrutiny because its current share of global emissions – about 2% (3% in EU) – is set to rise sharply in line with business growth while other sectors are actually reducing their emissions. In simple terms, it will start to stick out like a sore thumb. Moves to tackle the issue, including an industry commitment to carbon-neutral growth from 2020, are controversial because the proposed scheme allows airlines to buy carbon offsets from low-carbon projects in other sectors. How to cut emissions at point-of-use is rising rapidly up the agenda.

Electrification

Direct, point-of-use options to cut emissions are limited first of all by the fact that it is much more difficult to use low-carbon technologies such as batteries in aviation than other areas because the more powerful a battery is, the heavier it must be, making them impractical.

Consequently, airlines are facing questions from investors who are concerned that they are not tackling the problem with sufficient urgency. A new study of 20 airlines from the Transition Pathway Initiative shows that none of them has a clear plan for cutting their own emissions after 2025.

Yet, while there is little prospect of electric long-haul aircraft in the foreseeable future, there is plenty that the industry can already do to minimise its impact. Indeed, electric planes are seen as part of the solution – for smaller aircraft and shorter journeys.

A number of companies are working on electric aircraft, from Lilium’s five-person vertical take-off flying taxi to Ampaire’s 19-seater vehicle up to Wright Electric’s plans for a 150-seat aircraft that would be able to make trips of 300 miles or less. Easyjet is planning to fly Wright Electric planes on its short haul European routes from 2027.

It is not just start-ups looking at this space, though. Siemens is working on a number of projects, including the Magnus eFusion electric test plane, the Pipistrel Alpha Trainer and a nine-seat commuter plane being developed by Israeli start-up Eviation. It has also formed a partnership with Airbus and Rolls-Royce to create hybrid-electric propulsion systems for commercial aircraft.

Some people think that hybrid aircraft, with both a battery and a jet fuel engine, will be the first step towards cleaner flying – including Boeing, which has invested in Zunum Aero, which is building a plane that can fly 12 people up to 700 miles, with the aim of becoming fully electric when technology allows.

Biojet

But despite all these initiatives, no-one thinks battery-powered aircraft will be ruling the skies in the next decade or so. A more immediate option is to replace fossil fuel-based jet fuel with biofuel alternatives – also known as biojet. The first flight using biojet fuel was made more than a decade ago. Feedstocks have included jatropha, camelina, algae, brassica carinata, waste vegetable oil and saltwater-loving halophytes. These relatively obscure feedstocks are favoured to ensure that biofuels production does not displace crops from agricultural land or encourage deforestation.

A company called LanzaTech is producing what it calls “next generation ‘advanced’ fuels” by recycling waste industrial gases like those produced from steel making and other heavy industrial processes and turning them into ethanol, which can be turned into jet fuel. Supported by Virgin Airlines, it says that with government support, it could build three plants in the UK by 2025, producing up to 125 million gallons of sustainable fuel per year – enough to provide half the fuel for all Virgin Atlantic’s UK outbound flights and save almost 1 million tonnes of life-cycle carbon.

It adds that “if the technology were rolled out worldwide to the world’s eligible steel mills (65% of all), this alone could produce enough fuel to meet around 20% of the current commercial global aviation fuel demand”. And the technology can be used on oil refineries and agricultural waste as well.

But there is little sign that biofuels or carbon capture fuels are set to displace petroleum-based fuels any time soon, in part because the aviation sector requires exhaustive testing to ensure fuels are safe – it took Lanzatech two years to receive certification for its fuel. However, it’s hard to avoid the suspicion that the lack of progress is also the product of a lack of urgency within the industry. United is leading the pack, having committed to buy 1 million gallons of biofuel a year, which sounds impressive until you discover that its fleet uses 4 billion gallons of fuel annually.

It may be that, now the first fuels are starting to be certified for use in aircraft, the process for other feedstocks will speed up, which will help the investment case for building production plants, and that the sector will suddenly scale up rapidly.

In the meantime, work continues on improvements at the margins, from techniques such as more efficient route management and glide landing, and continued lightweighting of aircraft and their components, thanks to composite materials and technologies such as 3D printing, which can produce parts with the same strength while using less material than previously. Other options include increased use of batteries or fuel cells for auxiliary power, more efficient conventional jet engines and measures to reduce drag, such as non-stick coatings that prevent insects from sticking to the fuselage.

All of these things should be seen as a way for the industry to pursue business growth with impunity whereas under the current habit of offsetting carbon – which evidently doesn’t reduce air traffic – emissions will keep rising and the reputation of the air transport industry will suffer as a result. The question as to which technology will mature first seems a dangerous, delaying distraction and while the industry is holding back on both because it’s not sure which will be the winner, we will continue to feel pressured to fly less.

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Renewable jet fuel lands at Schiphol

January 25, 2019 by Mike Scott

Renewable jet fuel lands in Europe

by Mike Scott

January 25, 2019

If you were trying to find a link between fish farms, saltwater plants known as halophytes and mangrove forests, it’s unlikely that renewable jet fuel would be near the top of your list.

Yet these three elements are being combined in a project in Abu Dhabi to develop “a clean, alternative aviation fuel” that has been used for the first time in a commercial flight, from the emirate to Amsterdam. The biofuel made up only a tiny percentage of the flight’s fuel load but is the first step in the initiative’s ambitious aim to create a bioenergy industry that can be sited in arid coastal regions, producing both food and fuel without using land that is needed to grow crops or polluting the oceans.

The project has been developed by the Masdar Institute’s Sustainable Bioenergy Research Consortium (SBRC), a collaboration between Abu Dhabi’s Khalifa University, the emirate’s airline Etihad and its oil company ADNOC. Also on board are Boeing, French aircraft engine maker Safran, GE and German engineering group Bauer Resources.

The fuel is derived from a saltwater-tolerant species called Salicornia, whose seeds produce oil when crushed. But the first, rather unlikely, stage of the process is a fish farm, which will produce local species such as Nile perch, as well as shrimp. The fish farm is based on land rather than in the sea, with seawater pumped into pools where the fish will be farmed.

“The SEAS is a pioneering project – the world’s first desert bionetwork to produce food and fuel from seawater supplies in arid land” Dr Alejandro Ríos, SBRC

Young mangrove plants filter the run-off from the fish farm

One of the main issues for fish farms is what to do with the waste that is produced – in this project, known as the Seawater Energy and Agriculture System (SEAS), the waste from the fish farm is used as a fertiliser and irrigation for the Salicornia. The water will then flow from the halophyte ‘fields’ into mangrove wetlands, which help to clean the water, protect coastlines from storms, store carbon and provide a habitat for marine life and can be used for bioenergy.

“The SEAS is a pioneering project – the world’s first desert bionetwork to produce food and fuel from seawater supplies in arid land,” said Dr Alejandro Ríos, director of the Sustainable Bioenergy Research Consortium.

“This was the first time that ADNOC had ever refined biofuel, so it’s a significant step, even though the process is not that different from refining crude oil,” Rios added. “That is important because it means that they can use the existing infrastructure.”

Clean and better range capability than batteries

The project uses solar energy to power the pumps and the rest of the facility and there is a pleasing circularity to the scheme, which tackles multiple issues, including growing food in desert environments without depleting scarce water resources and making aviation fuel renewable.

This is an imperative because, unlike road-based transport, there is no other feasible alternative to using hydrocarbons, Rios said. “There will be short-haul flights in small planes that will be battery-powered within a few years, but for long-haul the physics just doesn’t work.”

The UAE is keen to establish a leading position among the world’s major oil producers when it comes to reducing its environmental impacts. It aims to derive 50% of its energy from clean sources by 2050, to cut the carbon footprint of power generation by 70% and increase energy efficiency by 40%.

“aviation is responsible for almost 5% of greenhouse gas emissions, and it is growing fast. By 2050, if no action is taken, aviation will have consumed a quarter of the world’s carbon budget” IPCC

Emissions reduction to 2050

At the same time, the need to decarbonise the sector is urgent, particularly in the Middle East. The Intergovernmental Panel on Climate Change says that aviation is responsible for almost 5% of greenhouse gas emissions, and it is growing fast. By 2050, if no action is taken, aviation will have consumed a quarter of the world’s carbon budget. According to Airbus, air traffic in the Middle East region is set to double within a decade. Indeed, aviation is one of the key pillars of the Emirates’ economy, with the country ranking third globally in terms of revenue ton kilometres.

The industry has long been accused of dragging its feet on tackling its environmental impacts, but in 2016, it agreed that any growth in emissions after 2020 will need to be offset through a scheme called CORSIA (Carbon Offsetting and Reduction in Aviation). IATA, the International Air Transport Association, has a target to cut net emissions by half from 2005 levels by 2050.

Zero-cost fuel from upstream fish

But progress has been painfully slow. Although there have been around 160,000 flights using biofuels, with feedstocks ranging from crop residues to algae to municipal waste, no commercial alternative to jet fuel has yet emerged, in part because of the cost.

That is where this project could have a real advantage, because much of the revenue is projected to come from the fish farm, with the aim of producing the fuel itself at zero cost.

But we’re still a long way from seeing commercial quantities of green jet fuel on the market – the pilot project sits on 2 hectares of land near Abu Dhabi’s airport, but Rios says it will need hundreds of thousands of hectares of land to produce commercial quantities of fuel. The next step will be to create a 200-hectare demonstration plant. That is going to take a couple of years at least, and a full-size plant is at least a decade away.

If it can be scaled up, though, the potential is huge – there is no shortage of land available for such projects not just in the Middle East but also Africa and India.

“It’s not about replacing existing aviation fuel, it’s about adding value to the oil and gas infrastructure and producing sustainable aviation fuel for the future,” Rios said.

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Aviation needs a Tesla moment. Rolls-Royce could deliver it

January 18, 2019 by Arasan Aruliah

Aviation needs a Tesla moment. Rolls-Royce could deliver it

by Arasan Aruliah

January 17, 2019

Rolls-Royce is promising to launch an all-electric plane by 2020 that can fly London to Paris, and break the electric aircraft speed record. Is this one-seater the first step towards an airliner that can carry hundreds? The aviation sector needs all the good news it can get as it struggles to find an alternative to kerosene fuel.

The Rolls-Royce project is called ACCEL, short for “Accelerating the Electrification of Flight”. They’re calling this the beginning of the third wave of aviation, and Rolls-Royce wants to be its champion.

The company traces its history back to the luxury car maker established by Charles Rolls and Henry Royce in 1904. Today its jet engines are widely used by the likes of Airbus and Boeing. They are also a major player in the marine and power generation sectors.

The world speed record for an electric plane is in their sights

They’ll need to build the most powerful battery ever built for flight. Yet it has to be light enough to fly, and stable enough not to overheat. And it has to be powerful enough to fly the new plane at 300 mph (483 km/h) and more. That’s because they want the aircraft to break all records and become the fastest all-electric plane in history. By comparison, the current record for an all-electric plane, set by Siemens in 2017, is 210 mph.

ACCEL is partly funded by the UK government and involves a host of partners including electric motor and controller manufacturer YASA and the aviation start-up Electroflight.

YASA’s standard electric motors have been used in several high-performance cars such as the Drive eO PP03, Jaguar C-X75, Koenigsegg Regera, and a Lola Le Mans Prototype converted by Drayson Racing, which set a world electric land speed record in 2013.

YASA workshop

Rolls-Royce wants to think like an entrepreneur

But why would Rolls-Royce partner with a tiny start-up like Electroflight? In an interview with The Telegraph, Rob Watson, director of Rolls-Royce Electrical, explained: “We are a world-class engineering organisation but on an industrial scale, and we’re used to developing gas turbines, so we wanted to see [what happens] if we thought completely differently about an electric propulsion system.” So Rolls-Royce have taken a stake in this small entrepreneurial company to learn a thing or two “[to] see how they go about fixing these problems.” Aviation propulsion certainly needs fresh thinking.

Electric planes are aerodynamically superior

Forget about emissions: electric planes will have a huge design advantage over planes powered by kerosene. The traditional gas turbines have to be hung under the wings on an aircraft to be near the rotating blades, and for safety. That affects the aerodynamics and drag of the design. The electric battery can be placed anywhere in the aircraft. In fact, you can distribute the weight of the batteries across and within the aircraft. This should mean dramatic improvements in the aerodynamic design.

This is just a first step in the emergence of electric planes. Gas turbine technology will remain the propulsion system of choice for the aircraft industry because of the extremely high power density of kerosene, needed to fly hundreds of people thousands of miles. Rolls-Royce’s new single-seater electric plane will use 6,000 battery cells and will have a 200-mile range, enough for a London to Paris flight.

Of all sectors, aviation is struggling the most to transition

Compared to road transport, buildings, marine, and the other major categories, the aviation sector is under the least pressure from legislators to curb its emissions, because of the practical difficulties of finding a power-dense alternative to kerosene. That means aviation’s emissions projections are among the worst. The latest European Aviation Environmental Report states:

Number of flights has increased by 80% between 1990 and 2014, and is forecast to grow by a further 45% between 2014 and 2035.
CO2 emissions have increased by about 80% between 1990 and 2014, and are forecast to grow by a further 45% between 2014 and 2035.
NOX emissions have doubled between 1990 and 2014, and are forecast to grow by a further 43% between 2014 and 2035.

Direct emissions from aviation account for about 3% of the EU’s total greenhouse gas emissions and more than 2% of global emissions. If global aviation was a country, it would rank in the top 10 emitters.

By 2020, global international aviation emissions are projected to be around 70% higher than in 2005 and the International Civil Aviation Organization (ICAO) forecasts that by 2050 they could grow by a further 300-700%.

“Regular production of aviation alternative fuels is projected to be very limited in the next few years, and thus it is unlikely that the roadmap 2020 target will be achieved”

The European Aviation Environmental Report looks at three alternatives to conventional jet fuel: Fuels from hydroprocessing of vegetable oils and animals fats such as Hydroprocessed Esters and Fatty Acids / Hydrotreated Vegetable Oils (HEFA/HVO); Fischer‑Tropsch fuels obtained from biomass (Biomass to Liquid‑BTL); Synthetic iso‑paraffin fuels obtained from the conversion of sugars. But progress is extremely slow. As the report says, “regular production of aviation alternative fuels is projected to be very limited in the next few years, and thus it is unlikely that the roadmap 2020 target will be achieved” for aviation. There is simply no mention of batteries.

Electric aviation needs an EV boost

It doesn’t look good. Then again, electric cars didn’t look very promising when they started on their transition journey, and now they are widely available. Today it’s hard to keep up with the news from car manufacturers of new models and new multi-billion investments.

So before you buy that ticket to your cousin’s wedding across the Atlantic, remember that someone flying from London to New York and back generates roughly the same level of emissions as the average person in the EU does by heating their home for a whole year. Instead, you could wait a couple of years and take a much more eco-friendly and enjoyable trip on an electric plane to Paris. Think of the carbon emissions, the wine, the cheese…

Lightweight carbon fibre car body is also a battery

December 20, 2018 by Matthew James

EXPRESS #3 - December 20, 2018

Lightweight carbon fibre car body is also a battery

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Despite progress in energy storage technology, batteries still make up a significant part of the weight for devices ranging from laptops to cars. But what if the bodywork of the car was also the battery. And what if it was a lightweight carbon fibre. Say hello to the carbon fibre battery car… and aircraft?

Image result for Yen Strandqvist, Chalmers University of Technology

Today carbon fibre is a well known construction material. But researchers have discovered that carbon fibre can also work as battery electrodes.

Dr. Leif Asp

Leif Asp, at Chalmers University of Technology, has led a team of researchers in Sweden, Italy and France to uncover the electrochemical properties of carbon fibres. He says their discovery could one day power vehicles while reducing their weights by as much as 50%. Their report can be found in Multifunctional Materials.

Electrochemical carbon fibre

The structural/mechanical properties of carbon fibres have been well understood for several decades, with a lot of seminal work dating back to the 1980s. The electrochemical properties of newer, but structurally weaker, types of carbon fibres have been known since the late 2000s. However, no-one had looked into how to make carbon fibres that were stiff and strong while simultaneously demonstrating high-performance electrochemical properties.

Researchers studied the microstructure of different types of commercially available carbon fibres and discovered that carbon fibres with small, poorly oriented crystals have good electrochemical properties but lower stiffness. Carbon fibres with large, highly oriented crystals have greater stiffness, but the electrochemical properties are too low for use in batteries.

In other words, high-strength carbon fibres have poor electrochemical performance, and high-performance electrochemical carbon fibres are not strong. A compromise had to be found that allowed for strength of structure, and allowed for the battery power. What surprised Asp was that the compromise was far less than expected. “We now know how multifunctional carbon fibres should be manufactured to attain a high energy storage capacity, while also ensuring sufficient stiffness,” Asp says.

The strength v battery trade-off

In the study, the types of carbon fibre with good electrochemical properties had a slightly higher stiffness than steel, whereas the types whose electrochemical properties were poor were slightly more than twice as rigid as steel. Those trade-offs look well within the bounds of possibility for car and aircraft construction.

The results suggest a promising outlook for using carbon fibre car bodies that also act as the car battery. Although the battery performance itself does not compare with state of the art car batteries, the resulting overall weight reduction could mean the carbon fibre battery car will one day outperform the traditional EV car.

Collaborating with car manufacturers

However Asp points out that it can be difficult to make these benefits apparent to commercial car manufacturers. Their people tend to work specifically on one function at a time: energy storage, or car bodies, but never bring the two problems together. It’s difficult to get them to see it as a single problem, and fix it.

“The key is to optimize vehicles at system level – based on the weight, strength, stiffness, and electrochemical properties,” Asp explains. “That is something of a new way of thinking for the automotive sector, which is more used to optimizing individual components. Structural batteries may perhaps not become as efficient as traditional batteries, but since they have a structural load-bearing capability, very large gains can be made at system level.” Nevertheless, the researchers are now collaborating with car companies.

And aviation companies too! Asp explains that for the aviation industry, it may be necessary to increase the thickness of the carbon fibre composites to compensate for the reduced stiffness of the structural batteries. But this would, in turn, also increase their energy storage capacity – another positive trade-off for aircraft that must spend long hours in the air before they can recharge.

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Carbon zero flight propulsion is here! But the “ionic wind” aircraft only weighs 2.3 Kg

December 13, 2018 by Express Editor

EXPRESS #4 - December 13, 2018

Carbon zero flight propulsion is here! But the “ionic wind” aircraft only weights 2.3 Kg

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Aviation has been given a free pass in the fight to reduce carbon emissions. That’s because lifting hundreds of tonnes into the air, cost-effectively, with renewable fuels is unviable for the foreseeable future. But what if someone invented an aircraft with no propellers or jet engines, just a blue glow out the back like something out of Star Trek. Long believed impossible, or at least impractical, that technology is now real. The “ionic wind” aircraft is here.

MIT aerospace engineer Steven Barrett led a team in a nine-year research effort to design, build and fly an aircraft propelled by “ionic wind”. The engine generates enough thrust to propel the plane over a sustained, steady flight.

But the aircraft weighs only about 2.3 Kg, and has a 5-meter wingspan. The fuselage of the plane holds a stack of lithium-polymer batteries, which is the cause of its main problem: weight.

The team flew the plane a distance of 60 meters (the maximum distance within the gym they did the tests in) and found the plane produced enough ionic thrust to sustain flight the entire time. They repeated the flight 10 times, with similar performance.

Barret expects that in the near-term, such ion wind propulsion systems could be used to fly less noisy drones. Further out, he envisions ion propulsion paired with more conventional combustion systems to create more fuel-efficient, hybrid passenger planes and other large aircraft.

The science

“Ionic wind” is also known as electro-aerodynamic thrust: a physical principle that was first identified in the 1920s and describes a thrust that is produced when a current is passed between a thin and a thick electrode. If enough voltage is applied, the air in between the electrodes can produce enough thrust to propel a small aircraft.

Barret’s aircraft carries an array of thin wires, which are strung like horizontal fencing along and beneath the front end of the plane’s wing. It requires no moving parts.

Once the wires are energised, they attract and strip away negatively charged electrons from the surrounding air molecules, like a giant magnet attracting iron filings. The air molecules that are left behind are newly ionized, and are in turn attracted to the negatively charged electrodes at the back of the plane. As the newly formed cloud of ions flows toward the negatively charged wires, each ion collides millions of times with other air molecules, creating a thrust that propels the aircraft forward.

The inspiration: Star Trek

The team is not shy to admit their inspiration comes partly from the movie and television series, “Star Trek,” which they watched avidly as children. They were particularly drawn to the futuristic shuttlecrafts that effortlessly skimmed through the air, with seemingly no moving parts and hardly any noise or exhaust.

But it’s still out of reach for now. What’s holding them back is the weight, and insufficient currents flowing through the wires. So once again it’s over to the battery sector (and possibly the superconductor wire engineers) to make it work for airlines. Sometime this century, we hope.

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