Take-off with algae in the tank

Environmentally friendly fuels

Researchers in Munich are working hard to develop clean aircraft fuels. In the not-too-distant future, they hope that algae, sunlight and CO2 will provide the energy needed for global aviation.

At dusk in Ottobrunn, the glass structure sparkles like an emerald amid the otherwise generally gray campus buildings. Numerous large basins and the approximately 200,000 LED lamps bathe the laboratory in green hues. The algae being studied here can indeed be seen as precious gems. Their enormous energy content has experts touting them as the "green successors" of "black gold".

When professor Thomas Brück (TU Munich) is at work, he can experience conditions like in Almeria, Spain, or in Chile's Atacama desert. The 1,500 square meter algae research facility, which opened in October 2015, can simulate almost any climate, thanks to the world's largest high-performance LED system. Combining a high-tech air conditioning system and a light sensor on the glass roof that measures the intensity of the natural sunlight, the light output, temperature and humidity can be set to any desired levels.

The objects of this one-of-a-kind research set-up are obliviously floating in a cascading sequence of basins, visible to the naked eye as nothing more than a slimy greenish layer: microalgae. They are the creatures that are made to feel in their LED-radiated basins as if they are in Chile, Spain or Australia. "We want to find out what type of algae thrives best under which climate conditions," explains Brück. With this work, he is actually engaged in fundamental research in aviation.

Professor Thomas Brück (TU Munich) at an algae breeding site in Ottobrunn in the state of Bavaria.

An efficient crop

Although there is little to indicate this at first glance: Brück and his team in the glass building in Ottobrunn are part of a research project funded by Airbus and the state of Bavaria. Under the title "AlgenFlugKraft" ("algae-flight-fuel"), the project's goal is to create an algae-based biofuel to reduce dependency on petroleum-based aircraft fuel.

With algae, they have chosen a plant that is far superior to others in many respects: "Algae does not compete with food production or land use and also grows about 10 times faster than land plants such as maize," says Brück. "But most importantly, they have a higher fat content than almost any other organism."

This is a crucial characteristic because fat is the energy source that will ultimately become a fuel. One hectare of algae has a fat content level about 30 times as high as the corresponding amount of canola or similar land plants. Along with these advantages in terms of efficiency and ecology, biochemical aspects also favor the production of algae-based fuels. Canola oil becomes a solid at -40C°, and bioethanol does not contain enough energy to power an aircraft. By contrast, algae-based kerosene meets all criteria for what is known as a drop-in fuel: it can be used as an aircraft fuel with no further changes or additives.

There are still obstacles to clear, however, before the algae fuel can go into widespread use. The processes for refining the fuel must become significantly cheaper than they would be today. Moreover, for the new fuel to offer true ecological benefits, facilities for growing and refining algae will be needed all over the world. Brück hopes that the first power plants producing algae-based fuel will be operating by 2030. This would reduce C02 emissions from aviation by 30 to 40 percent. The required raw material would then grow in larger basins than the ones now used – and under real sunlight in Spain, Australia or Chile.

Numerous large basins and the approximately 200,000 LED lamps bathe the laboratory of the Technical University of Munich in green hues. © Andreas Heddergott / TUM.
In the 1,500 square meter algae cultivation center, the world's largest high-performance LED array, a high-tech air conditioning system, and a light sensor on the glass roof can simulate almost any climate. © Andreas Heddergott / TUM.