The aviation industry’s attempts to go green are getting a boost from an unlikely place: carbon-neutral jet fuel pulled from thin air.

That may seem far-fetched, but it’s a concept that engineers at the Swiss Federal Institute of Technology (ETH) have not only proved experimentally, but apparently proven again at scale. Even better, the fuel created by the process is allegedly a drop-in alternative to fossil-derived aviation fuel that can be used without changes to storage or distribution infrastructure.

Here’s how the system works:

Synthesizing kerosene pure enough to be used as jet fuel from thin air isn’t even a new concept. We know it can be formed from something called synthesis gas, or syngas, which is a mixture of hydrogen and carbon monoxide.

Crucially, the goal of this particular project is to produce a clean, carbon-neutral form of syngas that doesn’t create additional emissions. According to the researchers, the best way to do that is with solar energy.

For their test-scale unit, the researchers built an array of 169 sun-tracking reflectors that focus approximately 15kW of solar energy at a 16-inch aperture on a tower-mounted solar reactor. According to the researchers, the solar energy directed at the reactor “corresponds to an average solar concentration ratio of approximately 2,500 suns, with a peak above 4,000 suns.”

Inside the reactor, temperatures reach approximately 1,500°C (2,732°F), which is hot enough to split captured carbon dioxide and atmospheric water vapor to form syngas. As it cools, the syngas flows out of the reactor to a gas-to-liquid unit that processes it into kerosene.

According to the researchers, the syngas produced by the reactor has selectivity, purity, and quality high enough to make it suitable for Fischer–Tropsch synthesis, which turns liquid syngas made from hydrogen and carbon monoxide into hydrocarbons we can use to fly planes.

The system isn’t the most efficient – only managing a 4.1 percent solar-to-syngas efficiency. Still, project lead and ETH engineering professor Aldo Steinfeld told IEEE, 4.1 percent is a record for thermochemical fuel production.

The test-scale project didn’t use any heat capture technology, meaning that 4.1 percent record should be easily beaten. If heat capture technology were added to a future iteration of the facility, efficiency rates could reach as high as 20 percent, the researchers claimed.

Jet fuel that begins life as air and captured carbon, the researchers explained, is completely carbon-neutral because the fuel only produces as much carbon dioxide as went into its manufacturing.

[…]

Source: Pull jet fuel from thin air? We can do that, say scientists • The Register

Wave Swell Energy’s remarkable UniWave 200 is a sea platform that uses an artificial blowhole formation to create air pressure changes that drive a turbine and feed energy back to shore. After a year of testing, the company reports excellent results. New Atlas reports: As we’ve discussed before, the UniWave system is a floating device that can be towed to any coastal location and connected to the local energy grid. It’s designed so that wave swells force water into a specially designed concrete chamber, pressurizing the air in the chamber and forcing it through an outlet valve. Then as the water recedes, it generates a powerful vacuum, which sucks air in through a turbine at the top and generates electricity that’s fed into the grid via a cable. As a result, it draws energy from the entire column of water that enters its chamber, a fact the team says makes it more efficient than wave energy devices that only harvest energy from the surface or the sea floor.

[…] A 200-kW test platform was installed last year off King Island, facing the notoriously rough seas of Bass Strait, which separates the island state of Tasmania from the mainland of Australia. There, it’s been contributing reliable clean energy to the island’s microgrid around the clock for a full 12 months. The WSE team has made a few live tweaks to the design during operation, improving its performance beyond original expectations. “We set out to prove that Wave Swell’s wave energy converter technology could supply electricity to a grid in a range of wave conditions, and we have done that,” said WSE CEO Paul Geason in a press release. “One key achievement has been to deliver real-world results in Tasmanian ocean conditions to complement the AMC test modeling. In some instances, the performance of our technology in the ocean has exceeded expectations due to the lessons we’ve learnt through the project, technological improvements and the refinements we have made over the course of the year.” “Our team is excited to have achieved a rate of conversion from wave power to electricity at an average of 45 to 50% in a wide range of wave conditions,” he continues. “This is a vast improvement on past devices and shows that the moment has arrived for wave power to sit alongside wind, solar and energy storage as part of a modern energy mix.”

The King Island platform will remain in place at least until the end of 2022, and the company is now gearing up to go into production. “Having proven our device can survive the toughest conditions the Southern Ocean and Bass Strait can throw at it, and deliver grid compliant electricity, our priority now shifts to commercializing the technology,” said Gleason. “For Wave Swell this means ensuring the market embraces the WSE technology and units are deployed to deliver utility scale clean electricity to mainland grids around the world.”

https://www.youtube.com/watch?v=PD5fXCW-yKc

Source: Blowhole Wave Energy Generator Exceeds Expectations In 12-Month Test – Slashdot