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NRC Opposes European Moves to Tighten Nuclear Safety Post-Fukushima

Nuclear power plants’ reactor pressure vessels (RPVs)—the massive steel jars that hold a nuclear plant’s fissioning fuel—face incessant abuse from their radioactive contents. And they must be built with extra toughness to withstand pressure and temperature swings in the event of a loss-of-cooling accident like the one that occurred at Fukushima in 2011. As the triple meltdowns at Fukushima Daiichi showed, the next layer of defense against a nuclear release—the so-called containment vessels—can not be counted on to actually contain molten nuclear fuel that breaches the RPV.

Nuclear safety authorities have recently discovered weaknesses in several RPVs, and their contrasting responses suggest that the ultimate lessons from Fukushima are still sinking into international nuclear power culture—especially in the United States, where the Nuclear Regulatory Commission (NRC) is resisting calls to mandate tougher inspection of RPVs.

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Drought May Force California’s Water System Into the 21st Century

As California withers in its fourth year of extreme drought, Governor Jerry Brown has ordered a mandatory 25 percent cut in water consumption in the coming year for the state’s local water supply agencies that serve urban areas.

Although the current order is short term, it could ultimately help transform how California’s city dwellers use water, especially in terms of how data and analytics aid in conservation.

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New Ultrafast, Long-Lasting Aluminum Battery

A new kind of flexible aluminum-ion battery holds as much energy as lead-acid and nickel metal hydride batteries but recharges in a minute. The battery also boasts a much longer cycle life than today’s battery technologies.

The battery’s low cost, long cycle life and stability are appealing for grid-scale storage, says Hongjie Dai, a professor of chemistry at Stanford University. The technology could also be developed to power wearable devices. Dai and his colleagues reported the details regarding the new device in the journal Nature.

Aluminum-ion batteries are an attractive alternative to lithium-ion batteries for a few reasons. For one, aluminum is abundant and hence cheap. It is less reactive, which would mean safer, less-flammable batteries. In a video, the researchers drill into the batteries and they continue working for a while without catching fire. For the same reasons, many teams are also working on alternatives to lithium batteries that feature potassiumsodium and manganese.

Delving into chemistry, aluminum has three valence electrons compared to lithium’s one. So charge-discharge reactions transfer three electrons per atom, which means an aluminum battery could pack almost three times as much energy as its lithium-ion counterpart, and in a smaller, lighter package.

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Storing Solar Energy: A great idea caught on contested ground

Adding energy storage to sites with rooftop solar power generation offers a range of potential benefits. A battery can help smooth out solar’s inherently variable supply of power to the local grid, and even keep buildings powered during blackouts. Consequently, power-conversion innovators are developing a host of new products designed to reduce the cost and improve the efficiency of integrated solar-storage systems. 

Some analysts project a boom in the co-location of solar and energy storage. GTM Research, for example, foresees that co-located PV and storage will grow from $42 million in 2014 to more than $1 billion by 2018. However, the market is moving slower than it might thanks to a little-discussed regulatory roadblock in the United States.

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Costa Rica Runs on Renewables For 75 Days

Costa Rica has been coasting on nothing but renewable power since the start of 2015, according to news from the Costa Rican Electricity Institute (ICE).

The study found that during January, February, and at least the first half of March, the nation’s grid has been running on mostly hydropower, with geothermal, wind, biomass, and solar rounding out the power generation mix. Costa Rica has not had to use any of its oil reserves for electricity.

Heavy rainfall has allowed four hydropower plants to run at maximum capacity. The ICE estimates that the country will continue to see mostly renewable production in the second quarter, with power prices dropping further; a price reduction of up to 15 percent is expected for consumers.

On average, hydropower comprises about 75 percent of Costa Rica’s electricity generation, and geothermal, at about 12 percent, is the country’s second-leading source of power according to the International Energy Agency.  

Costa Rica has an ambitious goal of becoming the first carbon-neutral nation by 2021, although some have questioned how much political support there is for the goal within that timeframe.

The country, which has successfully reforested a large portion of its land, has been voted the “greenest and happiest” country on Earth by the New Economics Foundation. Reforestation has been a priority, but so have large-scale renewable energy projects.

There are plans to open the government-controlled electricity market, according to the UN. There are also incentives for renewable power plants over 7 megawatts. Additionally, government is offering incentives for biofuels.

In 2013, Costa Rican government announced three geothermal projects valued at nearly US $1 billion, with major funding coming form the Japanese International Cooperation Agency. Costa Rica has also been increasing its wind capacity, doubling it to about 150 megawatts at the end of 2013, from 74 megawatts in 2008. In 2014, an additional 49 megawatts of wind power came online.

Costa Rica is not alone in pushing the envelope and achieving impressive gains in clean energy. Last year, Germany met nearly three-quarters of its peak power needs with renewable energy—primarily wind and solar. Another country that already gets nearly all of its electricity from hydro, Norway, is also diversifying its renewables portfolio by investing in wind.

Other countries such as Australia and the United States are adding renewables at an impressive rate, but it still may not be enough to unseat fossil fuels as the primary source of electricity there in coming decades.

Perovskites for "Tandem" Solar Cells

By developing a way to coat silicon photovoltaics with crystals known as perovskites, researchers are creating tandem solar cells that may be substantially better at converting light to electricity than conventional solar cells while also being manufactured at low cost.

Although photovoltaics based on crystalline silicon currently account for 90 percent of the global photovoltaic market, the power conversion efficiency of silicon photovoltaics has been at a creep, advancing from 25 percent to 25.6 percent in the past 15 years. In order to produce solar cells with higher efficiencies while making the most of the existing manufacturing capacity for silicon photovoltaics, the industry has explored devices that combine silicon with other materials. But these so-called tandem solar cells, despite offering better efficiencies, have have yet to capture more than a fraction of a percent of the global photovoltaic market. Why? Because they are typically made using expensive processes.

Scientists at MIT and Stanford, hoping to achieve high efficiency without high costs, looked into creating tandem solar cells using perovskites, which have recently become the darlings of the photovoltaic world. The efficiencies of solar cells made from perovskites have shot up from under 4 percent to more than 20 percent in the last five years or so, quickly catching up to silicon. Moreover, perovskites are inexpensive and easily produced in labs. The MIT-Stanford group detailed its findings in today’s online edition of the journal Applied Physics Letters.

In the new tandem solar cells, a layer of methylammonium-lead(II)-iodide perovskite is stacked on top of crystalline silicon. The device also incorporates layers of other materials on top of and between the perovskite and silicon to assist with the flow of electric charge. The perovskite absorbs higher-energy visible photons, while the silicon absorbs lower-energy infrared photons. According to the researchers, dividing the spectrum of sunlight between specialized absorbing layers is more efficient than letting a single layer attempt to convert the entire spectrum by itself.

The team says it developed a 1-square-centimeter tandem solar cell with a 13.7 percent conversion efficiency. The scientists suggest that if they could improve each component of the tandem solar cell to match the highest-quality devices available today, they could achieve an efficiency of roughly 29 percent; ultimately, they predict, perovskite-silicon tandems could surpass 35 percent efficiency.

New Commercial Buildings in France Must Get Green Roofs or Solar Panels

For the most part, Europe has been steadily advancing towards a smarter, more efficient power grid, heavily based on renewable energy as opposed to coal or nuclear power plants. There’s enough reliance on solar power, in fact, that solar eclipses have the potential to cause gigawatt-scale power fluctuations. France, however, is still primarily dependent on nuclear power, which provided over 80 percent of its power in 2012. In an effort to rebalance its energy mix, the French parliament has approved a law mandating that all new commercial buildings feature roofs that are at least partially covered in either solar panels or plants.

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Better Battery Anodes Made From Packing Peanuts

Packing peanuts are excellent at protecting fragile objects but terrible for the environment. Recycling them is not cost-effective, so most end up in landfills, where they could sit around for a hundred years or more.

But the pesky little pieces of foam could be turned into anodes for lithium-ion batteries, Purdue University researchers say. The chemical engineers have found a simple, inexpensive way to convert packing peanuts into carbon nanoparticles and microsheets that perform better than the graphite anodes used in today’s batteries.

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