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Large-Scale Solar and Repurposed EV Batteries to Play Large Role in California's Renewable Energy Future

In October, California Governor Jerry Brown signed into law an ambitious bill that will require the state to generate half of its electricity from renewable sources by 2030 and double energy efficiency.

The law does not lay out specific plans for how to accomplish this, but experts in the field say utility-scale solar will likely make up a large portion—assuming issues with siting and transmission can be solved, and innovations in energy storage can be applied.

“Looking at present trends, we'll see a lot more solar photovoltaics at utility-scale size,” says Ethan Elkind, associate director of climate change at the University of California, Berkeley's Center for Law, Energy and the Environment. “Barring other policy developments and technology changes,” says Elkind, “that will be the main contributor.”

Elkind spoke on a panel hosted by the San Francisco Planning and Urban Research Association last month, along with representatives from the utility Pacific Gas and Electric, the American Planning Association, and San Francisco's Public Utility Commission. The panelists discussed strategies for how California would reach its 50-percent-renewables goal.

The state is already well on its way. In 2014, California generated over 44,000 gigawatt hours of renewable electricity, or about 20 percent of its total usage. California defines renewables as biomass, geothermal, small hydro (under 30 megawatts), solar, and wind. It’-s on track to surpass 33 percent renewables by 2020.

Reaching the state’s 2030 goal may sound exceedingly ambitious, but generating enough renewables to make them the main part of its energy mix may not be too big a problem. In California, the “cost for developing solar is now comparable to the cost for developing natural gas fired plants,” says Josh Hohn, who founded APA’s energy initiative.

However, one major issue will be how that energy is stored and whether utilities can nimbly switch from storing to delivering electricity. Batteries will play a big role, as will demand-response strategies.

One idea especially favored by PG&E is solar-powered electric vehicle charging stations. That would help use surplus solar energy during the daytime, while reducing evening electricity demand. In addition, the more cars that plug into the electric grid, the more revenues for PG&E. The utility recently presented a proposal to build over 25,000 charging stations for $654 million. The California Public Utilities Commission, rejected the plan, although the agency approved a smaller-scale pilot project for 2,510 stations.

That setback for PG&E notwithstanding, California is interested in pushing electric vehicles because transportation is currently the largest source of greenhouse gas emissions, at around 38 percent of the state’s total.

Some companies are also looking to repurposed batteries from electric vehicles to store solar or wind energy. For instance, says Hohn, as the battery in an electric car loses range, customers may want to upgrade to a newer one with more range. However, that older battery still stores energy. Those batteries can be repurposed and stacked to store energy from solar and wind. Nissan and General Motors have already announced their intentions to repurpose batteries from the Leaf and Volt vehicles, respectively. And Tesla is also developing stationary battery packs aimed at homes, businesses and utilities.

Repurposing old electric vehicle batteries, says Elkind, “is very promising... [and] will be a critical piece to balancing renewables."

Hohn says another storage option is using surplus solar or wind energy to compress air. Then, when the sun isn't shining or the wind isn't blowing, the air can be released to turn a turbine. A southern California utility is looking to build a 300-megawatt pilot facility.

Another storage option is pumped hydro. Similar to the compressed air scheme, surplus wind or solar energy is used to pump water uphill. When the energy is needed, the water is released, flows downhill, and turns a turbine.

PG&E already operates one such plant: the Helms Pumped Storage Facility, which can produce 1,212 megawatts of electricity and go from a dead stop to full generation in about 6.5 minutes.

Elkind says that pumped hydro poses some challenges, however. “Mainly, where will we put them?” he asks. “We don't have a lot of water and it's not easy to build new reservoirs.”

California's four-year drought has already had a major impact on its large hydroelectric facilities. In 2014, in-state hydroelectricity production fell 32 percent from 2013 levels, and was down 61 percent from 2011.

That may not be as bad as it seems at first blush. One consequence of the drought is that it may in fact open up land for utility scale solar projects, Hohn says. As territory that was once prime farmland in the state’s Central Valley begins to dry up, installing solar may be one way for farmers there to still get value out of their land, says Hohn.

Although utility-scale solar projects have a lot of potential for helping California reach the 50-percent-renewable benchmark, there are also significant land-use challenges with such projects.

A recent study found that only 15 percent of existing and proposed large-scale solar projects were on ideal sites. “Energy developers put projects where they can easily get land and where they're likely to get a power purchase agreement,” says Elkind. “They're not always thinking about the biological value of the land.”

Elkind added that, “As a state, we haven't figured out what kinds of lands we want to see solar developed on [and how to] steer incentives toward those lands.”

One potential solution is to install more solar in urban environments. Hohn says that is an idea he favors, and he does think that there will be more “solar gardens” in communities. However, he acknowledged that these smaller scale projects are less appealing financially to developers.

Another challenge, says Elkind, will be meeting the goal without increasing fossil fuel usage. Advances in the various storage technologies will be needed to handle the intermittency of renewables without relying on natural gas for stability. In addition, the state will need to integrate its renewable grid with other western states, figure out how to link grid operators, and set up the markets to trade surplus renewable electricity, he said.

“We've learned a lot of lessons getting to 20 percent renewable energy,” Elkind says. And “we're learning as we push toward 50 percent.”


Solar Towers Don't Seem to Be the Bird Destroyers Once Thought

Solar power towers have had a reputation as alleged avian vaporizers since preliminary reports emerged in 2014 of birds being burned in mid-air as they flew through the intense photonic flux at California's Ivanpah solar thermal plant. Their reputation was muddied even more during tests early this year at SolarReserve’s Crescent Dunes power tower in Nevada; the solar thermal plant just recently began producing power. California public radio station KCET reported that as many as 150 birds were killed during one six-hour test in January.

It is obviously upsetting to imagine birds ignited in the name of renewable energy. (KCET reporter Chris Clarke, who has tracked the issue since BrightSource Energy began building Ivanpah in the Mojave Desert, described burning birds as “beyond the pale” in a recent article suggesting that power towers may be finished in California.) 

But, upsetting as any killing of birds is, avian mortality is a downside common to many modern human creations—including buildings, highways, and powerlines. The best data on bird mortality at Ivanpah, macabre as it might be, shows the death rate to be small and likely of little ecological significance.

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Leap in Lithium-Air Battery Tech Could Supercharge Electric Cars

Lithium-air batteries can in principle hold five to 10 times as much energy as a lithium-ion battery of the same weight and double the amount for the same volume. They could theoretically give electric cars the same range as gasoline ones. Now scientists in England claim to have overcome many of the current barriers preventing their use.

In a lithium-air battery, the anode is generally made of lithium metal, the cathode is typically a porous carbon material that brings in oxygen from the surrounding air, and the electrolyte is a liquid connecting the anode and the cathode, helping ions shuffle between them. As the lithium oxidizes, it discharges electricity. Recharging the device reverses the process.

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Chile's Hybrid PV-Solar Thermal Power Stations

SolarReserve, the technology developer behind the world’s biggest solar thermal power tower project optimized for energy storage, says its Crescent Dunes plant in Nevada recently delivered power to the grid for the first time and should reach its full 110-megawatt rating by the end of 2015. While SolarReserve has a similar plant starting construction in South Africa, much of its development activity—like that of a key rival, Spanish engineering firm Abengoa—is focused on a novel solar technology twist destined for Chile’s power hungry energy market. 

SolarReserve’s and Abengoa's Chilean projects both seek to unite solar power’s hitherto competing technology wings: solid-state photovoltaics and steam-raising thermal solar. The aim is to deliver cheap round-the-clock power for Chile's big mines. Their PV component will keep the power on during the day. Solar thermal installations akin to Crescent Dunes—with mirrors or 'heliostats' that concentrate sunlight to directly heat molten salt— will take care of the rest, efficiently storing heat to provide competitive generation overnight.

Chile, which is the world’s top producer of fine copper and second leading gold producer, is also the source of half of the world’s lithium, according to a 2014 report on Chile’s mining sector by consulting firm KPMG. As a result, Chile's mining sector is the country’s largest power user, consuming about 85 percent of capacity on the northern grid (the Sistema Interconectado del Norte Grande). Demand is growing: power use by copper mines is projected to double by 2025.

Imported natural gas is pricey, so Chile has met new demand with a mix of coal-fired generation, wind power, and PV farms. Utility-scale PV, much of which exploits the intense sun that bathes northern Chile's Atacama Desert, is surging this year. Chile will have installed 1 gigawatt of solar PV this year alone, according to PV-TECH, up from 493 megawatts in 2014. 

While PV is a good deal—it costs as little as $70 per megawatt-hour (before subsidies), which is well below the heavily-discounted bulk rate of $100 per MWh that Chilean mining firms pay for grid power—it is a glass-half-empty electricity source. As the flat line across the power chart on the Sistema Interconectado del Norte Grande homepage shows, Chile's mines don't stop gobbling power when the sun sets and PV shuts down. 

In fact, as a result of the surging PV development, Chilean power prices are now higher at night than during the day, according to Kevin Smith, SolarReserve’s CEO.

Hybrid PV-thermal solar plants promise a nearly complete 24-hour-a-day power solution. The first, which Abengoa began building last year in the Atamaca Desert city of Calama, combines a 100-MW PV farm with a 110-MW molten salt power tower designed to run 18 hours without sunlight. The PV plant is to be completed this year, while the salt tower (Abengoa’s first) is to begin operation in 2017. 

Abengoa entered the Calama plant’s solar thermal component into a government-mandated auction for renewable power supplies in 2014 and was approved to earn $115/MWh. SolarReserve, in contrast, is offering power from its Chilean hybrid PV-thermal solar projects as a bundle, which CEO Kevin Smith promises will sell for “well under” $100/MWh. 

Smith says SolarReserve’s first proposed Chilean hybrid plant, near Copiapó at the southern end of the Atacama, would combine a pair of 130-MW salt towers—each 18 percent more powerful than the tower at Crescent Dunes—with 150 MW of PV output. 

In August, environmental regulators approved the project (a critical hurdle, particularly since documentation of high avian mortality at the triple-tower Ivanpah installation in California’s Mohave Desert appeared). Smith says SolarReserve is seeking industrial buyers for its hybrid power, but may also bid it into a grid power auction in April 2016. 

Both solar thermal developers have big plans for additional hybrid plants in Chile. SolarReserve’s Smith says they have over 1,000 MW of solar projects in “advanced development” in Chile. Abengoa has filed for environmental permits for two follow-on projects, including a twin of its hybrid 110-MW plant approved by environmental regulators for the northern Atacama and a triple-tower, 315-MW project near Copiapó

Abengoa’s challenge will be raising the capital required. The company is struggling with a heavy debt load, and its financial valuation slid last week after an audit by KPMG, driven by Abengoa creditors, detected a larger than expected cashflow deficit

Analysis this weekend by notes similar stock slides at other renewable energy firms. Among them is the one suffered by PV giant SunEdison, whose stock is down by about 70 percent from its valuation in July 2015.  The report suggests this is due both to the financial structure some renewable firms have adopted, and to fallout from sliding oil prices that has hurt the competitiveness of their renewable energy. 

Solar panels

This Is How Good Solar-to-Fuel Conversion Can Be

In the artificial photosynthesis world, the recent buzz has been about new records set on water splitting by solar energy to make hydrogen.

However, a slightly newer, but similar, field of research is looking at another form of artificial photosynthesis—using solar energy to turn carbon dioxide into fuel. Such a technology would have the added benefit of removing a potent greenhouse gas from the atmosphere or preventing it from getting there in the first place.

Researchers with the Joint Center for Artificial Photosynthesis at Lawrence Berkeley National Laboratory report today in the Proceedings of the National Academy of Sciences that they have evaluated the potential efficiencies of this process for several different photoelectric cell configurations, catalysts, and fuel end products.

The group concluded that solar energy could break down CO2 into synthesis gas—a blend of hydrogen and carbon monoxide that used to make other hydrocarbons—at an efficiency of 18.3 percent or could make liquid hythane—a mix of hydrogen and methane—at 20.3 percent efficiency.

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First New U.S. Nuclear Reactor in Two Decades to Begin Fueling in Tennessee

Yesterday, U.S. federal regulators approved an operating license for Unit 2 of Tennessee Valley Authority's Watts Bar nuclear power plant; it's only taken 19 years and almost 4.5 billion dollars. The Gen II plant should be producing power by the end of the year, and it shouldn’t bother you in the least that we mostly stopped building Gen II reactors sometime in the mid ‘90s. 

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Startup Time for Fukushima's Frozen Wall. Here’s Why it Should Work

Japan's TEPCO is about to flip the switch on the infamous ‘ice wall’ intended to divert flowing groundwater around its crippled reactors at Fukushima and thus help stem the contamination of fresh groundwater at the site. The widely mischaracterized and maligned installation—which is a barrier of frozen soil rather than a wall of ice—has every chance of delivering the hoped for results, say radiation cleanup experts at U.S. national laboratories and feedback from initial system tests.

"The frozen barrier is going to work,” predicts Brian Looney, senior advisory engineer at the U.S. Department of Energy's Savannah River National Laboratory in South Carolina and co-author of an independent assessment of TEPCO’s frozen barrier. The report, produced in collaboration with researchers at Looney's lab and at Pacific Northwest National Laboratory, was completed in February but only released late last month; it found the system’s design to be sound and within the bounds of prior practice. 

Since the 2011 meltdowns at Fukushima, TEPCO has been fighting a losing battle with groundwater that flows downhill towards the sea, permeates Fukushima’s fractured reactor buildings, and contacts their melted-down nuclear fuel. Until recently, TEPCO was sucking 300-400 tons of contaminated water out of the buildings every day, adding continuously to the site’s ballooning fields of radioactive water storage tanks. The frozen barrier is one of a suite of measures intended to stem that tide. 

In September, TEPCO started operating a system of ‘subdrains’ to capture groundwater around the reactors before it enters the buildings. After months of negotiations, fishermen’s groups agreed to allow TEPCO to treat the lightly contaminated water and then discharge it to the sea. The subdrain could cut groundwater inundation of the reactor buildings in half, leaving “only” about 150 tons per day according to World Nuclear News.

The frozen barrier is a more definitive solution, intended to completely isolate the reactor buildings from groundwater by encircling them with a 1.5-kilometer-long, 30-meter-deep wall of frozen soil. It was designed by Japanese engineering and construction firm Kajima Corp., which began piecing together its infrastructure in June 2014. Since then, Kajima has perforated the ground surrounding Fukushima’s four reactors with 1571 bore holes, lined them with chiller pipes, and hooked up those pipes to refrigeration plants that pump out brine at an icy -30 degrees Celsius.

This groundwater isolation technology has been applied hundreds of times since the 1950s at mines and at deep excavations for tall buildings. But at Fukushima, it has been a magnet for scorn. The negativity stems from an understandable dearth of confidence in TEPCO and misreporting by media outlets. 

Many news outlets accidentally conflated Kajima's frozen barrier with a distinct and ill-fated TEPCO effort to freeze 5,000 to 6,000 tons of contaminated seawater in a utility trench adjacent to one of the reactors. CleanTechnica’s August 2014 report, "TEPCO Concedes Failure of Fukushima Ice Wall”, was one of many to describe the failed trench freeze as a section of the frozen barrier. 

And this confusion persists. Al Jazeera opined in March that the frozen barrier had “turned out to be another of the cleanup’s dramatically costly and utterly ineffective schemes.” It is also one of many new outlets to erroneously assert that Kajima's design was beyond the scale or applications of prior frozen walls.

The U.S. national labs’ analysis is as complimentary of Kajima’s design as the media’s opinions have been skeptical. According to Looney, their report found that Kajima’s design is “within the envelope of experience for successful barriers.” The team identified installations larger than Kajima’s design, such as a 3.66-km-long freeze wall at an open pit gold mine in Ontario that was four times deeper than Fukushima's, as well as urban projects that had more buried structures to work around (or through) than is the case at Fukushima. 

Site-specific analysis by Looney et al, meanwhile, projects that the freezing energy to be deployed by Kajima’s system will be equal to the task of managing Fukushima’s hydrological conditions. That finding is affirmed by initial testing of about 60 meters of the barrier in May 2015; the ground chilled as predicted.

The national labs study did identify small areas that could potentially resist freezing. But it also identified 10 to 12 available fixes, and also concluded that small leaks would be of little consequence given the suite of other groundwater control systems TEPCO has in place. “The goal of the barrier is to minimize flow to the reactors. You don’t actually need 100 percent effectiveness to reach that goal,” says Looney. 

While skepticism over the barrier’s water-stopping capability reigns in the popular media, Japanese regulators have been fretting over whether it might prove overly effective. Japan’s Nuclear Regulation Authority (NRA) has been holding back TEPCO from beginning the freeze while it assesses the risk of groundwater levels plummeting within the perimeter as the freeze kicks in, drawing highly radioactive water out of the reactors and contaminating the soil below.

Looney argues that this scenario is unlikely. It will take 1-2 months of refrigeration to establish each section of the barrier and at least six months of refrigeration before it has a measurable impact on groundwater levels within the frozen wall's perimeter, according to Looney. He adds that extensive monitoring should give TEPCO several months' notice of potential groundwater imbalances. 

But to minimize the risk of a groundwater crash, the NRA has requested that TEPCO first freeze the barrier’s side and downhill segments, saving the uphill segment (which Kajima finished first) for last. According to Looney and recent media reports, the final piping should be complete and the system should be ready to switch on within weeks.

If the barrier kicks in next year, concluding what will have been a five-year battle against groundwater, TEPCO will then be in a position to attack a still-tougher foe: its shattered reactors’ melted fuel. Naohiro Masuda, president of TEPCO’s cleanup subsidiary, Fukushima Daiichi Decommissioning Company, told Japanese state broadcaster NHK in March that TEPCO has “no idea” what the physical state of the fuel is (though it's got robots on the hunt) and no idea how to get it out. As Masuda put it: “We have to remove it remotely from 30 meters above. But we don’t have that kind of technology yet. It simply doesn’t exist.”

Photovoltaic panels near some palm trees

Only 15% of California's Big Solar Projects Are on the Right Kind of Land

The real estate agent’s mantra is well known: location, location, location. But location is important, too, when considering where to site utility-scale solar projects, and most of California's projects or planned projects are in less-than-ideal spots, according to a new study. As a result, these projects may have negative impacts on the environment and will not be as cost-effective or as carbon neutral as they could be.

Researchers from Stanford University and the University of California’s Riverside and Berkeley campuses identified 161 planned or proposed large-scale utility solar and applied an algorithm to determine how compatible they are with their location.

The results, which were published today in the Proceedings of the National Academy of Sciences, found that only 15 percent of sites were on compatible land.

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Batteries Running on Shrooms

Mushrooms have energized many a marinara sauce, not to mention a few vivid hallucinations, but soon the fungi may be powering your Prius or getting your Galaxy phone to run longer. Engineers at the University of California have shown that mushrooms can create long-lasting, environmentally friendly anodes for lithium-ion batteries.

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Nuclear Cybersecurity Woefully Inadequate

The risk of a major cyberattack on the nuclear industry is rising, potentially leading to blackouts or even meltdowns, researchers say.

The 2010 Stuxnet worm's infiltration of Iran's nuclear program was the most dramatic cyberattack the nuclear sector has ever seen. But it was not the only one. In one case in 2003, the Slammer worm infected the Davis-Besse nuclear power plant in Ohio, leaving reactor core safety data unavailable for nearly five hours. In another example from 2014, hackers stole blueprints of at least two nuclear reactors and other sensitive data from Korea Hydro and Nuclear Power Co., then demanded money from the company in exchange for not releasing potentially important files.

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