Photo of the week: century old technology meets Kalahri sun

Earlier in the Photo of the Week series, we saw how Vortex Bladeless is offering a radical new way to harvest wind energy. But in the solar energy sector a lot of innovation is going on as well. The Swedish firm Ripasso is building what it claims to be the most efficient solar electricity system. In the South African Kalahari desert, giant parabolic mirrors follow the track of the sun and focus the rays in a small point where it drives a Stirling motor. That’s an invention dating back to 1816, but up to now it has mainly been used in military submarines although it can have much higher inefficiencies than classical combustion motors. It has no exhaust or inlets and works solely on the heating and cooling cycle of an internal fluid. Ripasso took this Stirling motor to South Africa where it is now able to convert solar energy to electricity with an efficiency of 34%, significantly higher than the 23% at best of other solar systems available today. Although it was not easy to convey banks their technology can fulfill its promises, Ripasso has now enough funding to start its first commercial-scale installation.

Ripasso showed that their 100m² mirrors in combination with a Stirling motor can reach an efficiency up to 32% (photo: Jeffrey Barbee)

Ripasso showed that their 100m² mirrors in combination with a Stirling motor can reach an efficiency up to 32% (photo: Jeffrey Barbee)

Sources

Ripasso Energy
The Guardian

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Photo of the week: time for Ocean Cleanup!

We humans are very effective in one thing: ruining all the good things the planet has to offer. On this blog we’ve talked a lot about air pollution and greenhouse gas emissions, but the air is not the only place we use as trash can. Every year millions of tons of plastic debris end up in our oceans. In the so-called Great Pacific Garbage Patch, with an estimated density of plastic of 330 000 parts per square kilometer, debris is brought together by the circular ocean current in the higher Pacific Ocean.

Boyan Slat, now a 20-years old Dutch engineering student, presented an idea to clean up the mess a few years ago. At the time, it got a lot of publicity and with a kickstarter campaign he raised 2 billion dollars in no time. Last week, his ngo the Ocean Cleanup announced a first test system will be deployed in the second quarter of 2016 near Tsushima Island, between Japan and South Korea. Within five years, after other deployments of increasing scale and design updates, Slat plans to deploy a 100 km-long system to clean up about half the Great Pacific Garbage Patch, between Hawaii and California.

With the Ocean Cleanup system, Boyan Slat hopes  to put the sea currents at work to collect garbage (graphic: the Ocean Cleanup)

With the Ocean Cleanup system, Boyan Slat hopes to put the sea currents at work to collect garbage (graphic: the Ocean Cleanup)

Altough many people are excited about the idea, not everyone is convinced the system is going to work. Back in 2014, a very thorough technical and scientific review of Slat’s own feasibility study was published. Besides the enormous technical challenges such a floating device poses to engineers, the Ocean Cleanup seems to aim at collecting the larger plastic debris at the top water layer. In fact, the most harmful are the tiny particles floating in lower water layers that are swallowed by sea animals. How the device will cope with this and other feasibility questions remain largely unanswered until today. Let’s hope the test system in Tsushima will bring clarity on what is possible. In the meantime, we better try to reduce our waste footprint anyway.

Sources

the Ocean Cleanup
Review

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Photo of the week: Recycled printer toner roads

Sydney found a rather creative way to reduce their emissions and waste. The city’s road contractor teamed up with a cartridge recycling company to use printer toner waste to create asphalt. The toner partially replaces the bitumen and fine aggregates used in traditional asphalt production. By using the toner in combination with recycled oil, the production process is 40% more energy efficient. The asphalt is around the same price as the old version. The first streets of Sydney have been paved and now it’s looking forward to the results. Over a few years it will become clear whether this new pavement performs as good (or better) than traditional pavement.

Watkin Street in Newton, Australia, gets a new layer of asphalt made with recycled printer toner (photo: Jamie Williams/City of Sydney)

Watkin Street in Newton, Australia, gets a new layer of asphalt made with recycled printer toner (photo: Jamie Williams/City of Sydney)

 

Source

The Guardian

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Photo of the week: Vortex, wind turbine without blades

Large wind turbines spinning in the background of a magnificent landscape are not such an exceptional sight anymore. But the Spanish start-up Vortex Bladeless proposes a whole new way of generating electricity from the wind, without any rotor. Using the  vortices of wind that flows around the bladeless wind turbine, the asparagus-like structure starts resonating. With a system based on the same principles of an alternator, electricity is generated in a magnetic connection with no bolts or gears. This is one of the biggest advantages of the Vortex since it requires less maintanance and the initial cost is much lower. In addition, on the same patch of land you can put twice as many vortex devices than spinning wind turbines. The Vortex Mini is estimated to produce 4kW, a larger version, the Vortex Gran, is planned to generate at least 1MW.

Prototype of the Vortex , the wind turbine without rotor (photo: Vortex Bladeless)

Prototype of the Vortex , the wind turbine without rotor (photo: Vortex Bladeless)

Sources

Vortex Bladeless
Wired.com

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Photo of the week: NYC’s fleet of eco-friendly street food carts

New York City is looking at several ways to reduce its carbon emissions. The city recently launched a pilot project together with MOVE Systems, an American start-up created to bring the mobile food industry into the 21st century. They’ve come up with the MRV, a food cart with cutting edge technology such as solar panels, batteries and alternative fuels. Nowadays, food carts mostly run on propane gas, both polluting and potentially dangerous in urban environments. The MRV carts are for free for vendors who sign up; the carts are paid for by donations and private funding. Yet, it will take some time before you will see them in the streets of the Big Apple, because the city only gives a limited amount of permits for food carts every year.

The MRV offers a 21th century update for the food carts in NYC (photo: MOVE Systems)

The MRV offers a 21th century update for the food carts in NYC (photo: MOVE Systems)

Sources
The Verge
Move Systems

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Photo of the week: Did Elon Musk just start a new revolution?

Last Thursday, Elon Musk presented the heavily-anticipated Powerwall – Tesla’s scalable battery which Musk believes could revolutionize the way we consume, produce and store energy. The largest barriers today for solar and wind power are the well-known villains: sun doesn’t shine 24 hours a day, nor does the wind blow whenever we would like it to. For years, scientists and engineers are searching furiously for a solution to store renewable energy to match electricity production from renewable sources with electricity demand at every given moment. Batteries, hydrogen storage, compressed air storage… many scenarios are being investigated at the moment and no-one found a decent cost-effective solution, yet. And then came Elon Musk, CEO of Tesla, SpaceX and other ambitious companies. No surprise his keynote last Thursday has been followed with enormous interest.

The Powerwall is a lithium-ion battery starting from 7kWh at 3000$, but is infinitely scalable which means it both targets families and companies. Musk believes Powerwall makes it possible to go off-grid, which means families or companies become fully self-sufficient via a combination of renewable energy generation and storage with one or more Powerwall devices. But what is the real innovation behind the Powerwall? That’s a bit unclear up till now. Besides the fact the battery is cheap thanks to the Gigafactory that will build them, it is still good’ol lithium-ion technology. And going off-grid is easier said than done. Keeping a local grid at the right frequency (50Hz in Europe, 60Hz in US) is not easy. It is vital though for correct operation of computers, domestic electronics as well as industrial machines. For now, it seems people are willing to give it a try: 5 days after Musk’s keynote he announced they reached a total of 38 000 pre-orders.

Elon Musk presenting Tesla's Powerwall

Elon Musk presenting Tesla’s Powerwall

 

Sources

Tesla’s Powerwall official website

The Verge

Watch Musk’s keynote

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