Posts Tagged ‘energy’


Sweden’s waste incineration plants generate 20 percent of Sweden’s district heating.

When it comes to recycling, Sweden is incredibly successful. Just four percent of household waste in Sweden goes into landfills. The rest winds up either recycled or used as fuel in waste-to-energy power plants.

Burning the garbage in the incinerators generates 20 percent of Sweden’s district heating, a system of distributing heat by pumping heated water into pipes through residential and commercial buildings. It also provides electricity for a quarter of a million homes.

According to Swedish Waste Management, Sweden recovers the most energy from each ton of waste in the waste to energy plants, and energy recovery from waste incineration has increased dramatically just over the last few years.

The problem is, Sweden’s waste recycling program is too successful.

Catarina Ostlund, Senior Advisor for the Swedish Environmental Protection Agency said the country is producing much less burnable waste than it needs.

“We have more capacity than the production of waste in Sweden and that is usable for incineration,” Ostlund said.

However, they’ve recently found a solution.

Sweden has recently begun to import about eight hundred thousand tons of trash from the rest of Europe per year to use in its power plants. The majority of the imported waste comes from neighboring Norway because it’s more expensive to burn the trash there and cheaper for the Norwegians to simply export their waste to Sweden.

In the arrangement, Norway pays Sweden to take the waste off their hands and Sweden also gets electricity and heat. But dioxins in the ashes of the waste byproduct are a serious environmental pollutant. Ostlund explained that there are also heavy metals captured within the ash that need to be landfilled. Those ashes are then exported to Norway.

This arrangement works particularly well for Sweden, since in Sweden the energy from the waste is needed for heat. According to Ostlund, when both heat and electricity are used, there’s much higher efficiency for power plants.

“So that’s why we have the world’s best incineration plants concerning energy efficiency. But I would say maybe in the future, this waste will be valued even more so maybe you could sell your waste because there will be a shortage of resources within the world,” Ostlund said.

Ostlund said Sweden hopes that in the future Europe will build its own plants so it can manage to take care of its own waste.

“I hope that we instead will get the waste from Italy or from Romania or Bulgaria or the Baltic countries because they landfill a lot in these countries. They don’t have any incineration plants or recycling plants, so they need to find a solution for their waste,” Ostlund said.

In fact, landfilling remains the principal way of disposal in those countries, but new waste-to-energy initiatives have been introduced in Italy, Romania, Bulgaria, and Lithuania.

It is also important, Ostlund notes, for Sweden to find ways to reduce its own waste in the future.

“This is not a long-term solution really, because we need to be better to reuse and recycle, but in the short perspective I think it’s quite a good solution,” Ostlund concluded.

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Ta’u Island’s residents live off a solar power and battery storage-enabled microgrid.

by Amelia Heathman

SolarCity was applauded when it announced its plans for solar roofs earlier this year. Now, it appears it is in the business of creating solar islands.

The island of Ta’u in American Samoa, more than 4,000 miles from the United States’ West Coast, now hosts a solar power and battery storage-enabled microgrid that can supply nearly 100 per cent of the island’s power needs from renewable energy.

The microgrid is made up of 1.4 megawatts of solar generation capacity from SolarCity and Tesla and six-megawatt hours of battery storage from 60 Tesla Powerpacks. The whole thing took just a year to implement.

Due to the remote nature of the island, its citizens were used to constant power rationing, outages and a high dependency on diesel generators. The installation of the microgrid, however, provides a cost-saving alternative to diesel, and the island’s core services such as the local hospital, schools and police stations don’t have to worry about outages or rationing anymore.

“It’s always sunny out here, and harvesting that energy from the sun will make me sleep a lot more comfortably at night, just knowing I’ll be able to serve my customers,” said Keith Ahsoon, a local resident whose family owns one of the food stores on the island.

The power from the new Ta’u microgrid provides energy independence for the nearly 600 residents of the island. The battery system also allows the residents to use stored solar energy at night, meaning energy will always be available. As well as providing energy, the project will allow the island to significantly save on energy costs and offset the use of more than 109,500 gallons of diesel per year.

With concerns over climate change and the effects the heavy use of fossil fuels are having on the planet, more initiatives are taking off to prove the power of solar energy, whether it is SolarCity fueling an entire island or Bertrand Piccard’s Solar Impulse plane flying around the world on only solar energy.

Obviously Ta’u island’s location off the West Coast means it is in a prime location to harness the Sun’s energy, which wouldn’t necessarily work in the UK. Having said that, this is an exciting way to show where the future of solar energy could take us if it was amplified on a larger scale.

The project was funded by the American Samoa Economic Development Authority, the Environmental Protection Agency and the Department of Interior, whilst the microgrid is operated by the American Samoa Power Authority.

http://www.wired.co.uk/article/island-tau-solar-energy-solarcity

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

A new superthin material can cool buildings without requiring electricity, by beaming heat directly into outer space, researchers say.

In addition to cooling areas that don’t have access to electrical power, the material could help reduce demand for electricity, since air conditioning accounts for nearly 15 percent of the electricity consumed by buildings in the United States.

The heart of the new cooler is a multilayered material measuring just 1.8 microns thick, which is thinner than the thinnest sheet of aluminum foil. In comparison, the average human hair is about 100 microns wide.

This material is made of seven layers of silicon dioxide and hafnium dioxide on top of a thin layer of silver. The way each layer varies in thickness makes the material bend visible and invisible forms of light in ways that grant it cooling properties.

Invisible light in the form of infrared radiation is one key way all objects shed heat. “If you use an infrared camera, you can see we all glow in infrared light,” said study co-author Shanhui Fan, an electrical engineer at Stanford University in California.

One way this material helps keep things cool is by serving as a highly effective mirror. By reflecting 97 percent of sunlight away, it helps keep anything it covers from heating up.

In addition, when this material does absorb heat, its composition and structure ensure that it only emits very specific wavelengths of infrared radiation, ones that air does not absorb, the researchers said. Instead, this infrared radiation is free to leave the atmosphere and head out into space.

“The coldness of the universe is a vast resource that we can benefit from,” Fan told Live Science.

The scientists tested a prototype of their cooler on a clear winter day in Stanford, California, and found it could cool to nearly 9 degrees Fahrenheit (5 degrees Celsius) cooler than the surrounding air, even in the sunlight.

“This is very novel and an extraordinarily simple idea,” Eli Yablonovitch, a photonics crystal expert at the University of California, Berkeley, who did not take part in this research, said in a statement.

The researchers suggested that their material’s cost and performance compare favorably to those of other rooftop air-conditioning systems, such as those driven by electricity derived from solar cells. The new device could also work alongside these other technologies, the researchers said.

However, the scientists cautioned that their prototype measures only about 8 inches (20 centimeters) across, or about the size of a personal pizza. “We are now scaling production up to make larger samples,” Fan said. “To cool buildings, you really need to cover large areas.”

The scientists detailed their findings in the Nov. 26 journal Nature.

http://www.livescience.com/48942-cooling-buildings-without-electricity.html

A team of solar thermal engineers and scientists at the Energy Centre in Newcastle have used the ample sunlight flooding their solar fields to create what’s called ‘supercritical’ steam – an ultra-hot, ultra-pressurised steam that’s used to drive the world’s most advanced power plant turbines – at the highest levels of temperature and pressure EVER recorded with solar power.

They used heat from the sun, reflected off a field of heliostats (or mirrors) and concentrated onto a central receiver point to create the steam at these supercritical levels. The achievement is being described in the same terms as breaking the sound barrier, so impressive are its possible implications for solar thermal technology.

Put simply, the temperature of the steam they created (570° C) is about twice the maximum heat of your kitchen oven – or around the point where aluminium alloy would start melting. And the accompanying pressure (23.5 megapascals) is about 100 times as high as the pressure in your car tyres, or roughly what you’d experience if you were about 2 kilometres under the surface of the ocean.

That’s all impressive in itself. But when you take into consideration that this is the first time solar power has ever been used to create these ‘supercritical’ levels on this scale – traditionally only ever reached using the burning of fossil fuels – the real worth of this achievement begins to sink in.

Solar thermal, or concentrating solar power (CSP) power plants have traditionally only ever operated at ‘subcritical’ levels, meaning they could not match the efficiency or output of the world’s most state of the art fossil fuel power plants.

Enter the Advanced Solar Steam Receiver Project. To prove that solar thermal technology can match it with the best fossil fuel systems, they developed a fully automated control system which predicts the heat delivered from every mirror (or heliostat), allowing them to achieve maximum heat transfer, without overheating and fatiguing the receiver. With this amount of control, they were able to accurately recreate the temperature and pressures needed for supercritical success.

So instead of relying on burning coal to produce supercritical steam, this method demonstrates that the power plants of the future could be using the zero emission energy of the sun to reach peak efficiency levels – and at a cheaper price.

Thank to Kebmodee for bringing this to the attention of the It’s Interesting community.

http://csironewsblog.com/2014/06/03/our-solar-team-sets-a-hot-and-steamy-world-record/