Tagged: solar

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: 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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Photo of the week: Solar eclipse challenges Germany’s grid

Seen as a bad omen by old cultures, the solar eclipse last Friday was enough reason to make some people worrying. Germany, highly reliable on solar energy generation, faced a serious challenge. The country has around 37gigawatts installed photovoltaic capacity -a typical nuclear reactor is 1gigawatt. In a timespan of 75 minutes, solar power output of 21.7 gigawatts dropped to a low point of 6.2 gigawatts. When the eclipse was over its apec, the output increased again with 15 gigawatts, according to TenneT (one of the four transmission net operators in Germany) this is triple the usual rate. This effect was enlarged because the eclipse started in the morning when insolation (amount of sun rays falling on earth’s surface) was not so high, but ended around 11:30 AM when insolation is much higher. The whole effect was amplified because of the bright weather that day. Thanks to careful preparations, the German grid didn’t experience any problems. They put alternative power sources including coal, gas, biogas, nuclear and hydroelectric energy pumped from storage in action to fill in the gap. Some big industrial facilities such as aluminium plants, which are very energy intensive, temporarily lowered their demand. The solar eclipse was a unique test which is relevant for all of us, since we’re going towards more sustainable energy generation which make us more vulnerable to changes in nature. But there’s nothing to worry about -the German engineers have shown we can handle it.

The solar eclipse on March 20th posed a serious challenge to the German electricity grid (graph: Opower)

The solar eclipse on March 20th posed a serious challenge to the German electricity grid (graph: Opower)

Sources

DW
GreentechMedia

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Facts and figures: solar power is booming

Despite the political insufficiency to address the climate challenges of our time – debating endlessly about whether climate change is engraved by human activity or not – solutions are here today and they’re working. The IPCC has calculated the global “carbon budget” we can spend until 2050. If we want to stay under the 2°C temperature rise, which is generally accepted as the tipping point to unleash feedback loops in our climate system, we can only burn fossil fuels for another 17 years at the current rate (see blue scenario on graph below). It’s obvious we need to shift to renewable solutions, now. Luckily there are more and more investors who seem to have noticed this. Get ready for some nice facts and figures about the solar photovoltaic power industry. Unless otherwise stated, all graphs are produced by the Renewable Energy Policy Network for the 21st century (REN21) and published in their global status report 2014(more…)

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Photo of the week: The Desolenator

The Desolenator turns dirty water into clean drinking water solely by solar energy (photo: Desolenator)

Desalination of water usually is an energy-intensive and expensive process. The Desolenator is aiming to change that: it’s a cheap and easy-to-use solution to produce clean drinking water in regions where water scarcity is a problem. With the sun as only driving force, this piece of engineering is able to produce up to 15litres of clean water a day – enough for cooking and drinking of a small family. Not only salt water but also contaminated and dirty water can be transformed. The contaminated water is first heated up by the sun until it reaches boiling temperature, then electricity generated by the soler panel is used to boil it further and to vaporize the water. The condensed vapor is safe to drink. The Desolelanor has a price tag of 450$ but the team is working hard to get the price down so it becomes affordable for families who lack access to clean water. CEO Janssen: “… [water scarity, red.] will get worse—by 2025, close to 3 billion people will deal with water scarcity daily. We want to give them something that’s an affordable, family-sized device.”

Find out more: desolenator.com

Sources:

FastCoexist

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