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Hydrostor's Terra system for compressed-air energy storage in underground caverns

Hydrostor Is Building Underground Caverns for Affordable Compressed-Air Energy Storage

Hydrostor, the Canadian company that wants to store energy as compressed air in large balloon-like bags underwater, is now turning its attention to terra firma. Specifically, the company unveiled a system to store large-scale energy in underground compressed-air caverns.

The system comes in at “half the cost of competing battery technologies, and on part with new natural gas plants,” the company claims.

The case for storing large quantities of electrical energy is getting stronger and stronger, whether to expand the use of solar and wind power or to meet surges in demand on the grid. Batteries are making headway for energy storage, but compressed-air energy storage (CAES) is a strong contender. Such systems use off-peak electricity to run compressors and store the compressed air, which can later be expanded to drive a turbine.

CAES systems have the potential to cost less and last longer once they have been built. The problem with conventional CAES is that it is expensive and requires underground geological formations to store the air.

In 2014, Hydrostor introduced plans to pack compressed air into large bags submerged underwater, with the idea of storing energy from offshore wind farms. Their latest system, called Terra, stores compressed air in an underground cavern built to operate at low and constant pressure.

The cavern has to be connected to a local water body via a pipe so that water can enter and leave the cavern as air goes out and in. The water in the shaft and cavity helps keep the air under constant pressure. To improve efficiency, Hydrostor uses an adiabatic design, in which the heat generated during compression is removed via heat exchangers and stored in a volume of water, and then, in turn, used to heat the air when it is expanded to drive the turbine.

The company’s design offers two key advantages over traditional CAES systems. It does not require special geological formations and can be built at any site close to a body of water, including urban areas. As a plus, it does not require natural gas to generate the heat for air expansion.

According to Hydrostor’s president and CEO Curtis VanWalleghem, the company is now “engaged with several utilities around the world to deploy systems rated at hundreds of megawatts.”

Hydrostor might have competition from a few other CAES startups looking to enter the market. SustainX in New Hampshire has demonstrated a full-scale system to store compressed air in pipes, while LightSail Energy plans to store air in steel tanks.

New Tool Helps African Countries Find the Best Sites for Renewable Energy Projects

Africa has the lowest per capita electricity consumption in the world, due in part to scarce power generation and transmission infrastructure.

By some estimates, demand in the Eastern Africa Power Pool (EAPP) and Southern African Power Pool (SAPP), which include more than 50 percent of the continent’s population, may exceed 1,000 terra-watt hours (TWh) by 2030, nearly three times 2010 electricity consumption. Much work needs to be done to supply that expected demand.

Some of that supply will come from East Africa’s signature wind project, the $680-million, 310-megawatt Lake Turkana Wind Power site in Kenya. Last month, workers installed the last of 350 850-kilowatt Vestas turbines. Engineered by Siemens, the wind farm will add the equivalent of around 18 percent of Kenya’s total installed generating capacity and could serve up to 1 million households.

But there’s a catch. The Lake Turkana project is so remote that it needs a 438-kilometer-long transmission line to deliver its power to population centers. The powerline is years late and was only about 60 percent complete in January, according to the power journal ESI Africa. The project has suffered delays due to community opposition, legal issues, environmental problems, and the World Bank’s decision to withdraw support in 2012. The government recently had to take over payment and procurement from Madrid-based Isolux.

A new tool called Multicriteria Analysis for Planning Renewable Energy (MapRE) might keep such delays from happening by helping governments, utilities, and developers pick better sites for renewable energy projects. Developed by researchers at the University of California, Berkeley; Lawrence Berkeley National Laboratory; and International Renewable Energy Agency, MapRE lets users characterize solar and wind energy sites according to a fuller set of criteria than other analyses have.

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Photograph of President Trump shaking hand of hard-hat-wearing coal miner

Commentary: Photo Ops with Coal Miners Offer No Substitute for Fact-Based Climate Policy

President Donald Trump surrounded himself with coal miners at the EPA yesterday as he signed an executive order calling for a clean sweep of all federal policies hindering development of fossil fuel production in the United States. The order’s centerpiece is an instruction to federal agencies to cease defending the EPA’s Clean Power Plan and thus, according to Trump’s rhetoric, revive coal-fired power generation and the miners who fuel it.

The electric power sector, however, responded with polite dismissal. 

What separates President Trump and some of his top officials from power engineers and utilities? The latter operate in a world governed by science and other measurable forces. Unlike President Trump, scientists, engineers, and executives suffer reputational and financial losses when they invent new forms of logic that are unsupported by evidence. And a world of fallacies underlies the President and his administration’s rejection of climate action.

The biggest Trump administration fallacy at work yesterday is its claim that climate change may not be primarily human-caused—the standard line on climate espoused by top GOP leaders in Congress and Trump administration officials such as EPA administrator Scott Pruitt and Secretary of State Rex Tillerson

This oft-repeated claim is scientifically indefensible, given multiple lines of evidence that indict rising levels of greenhouse gases such as CO2 and methane caused by fossil fuel combustion, cement production, deforestation, and other economic activities. This includes robust satellite observations showing that natural factors have had negligible impact since 1980. As NASA scientist Thorsten Markus reminded us recently, anthropogenic climate change is simply, “what the data show.”

Fallacy of the day goes, however, to the only research cited in defense of Trump’s order: a NERA Economic Consulting report from November 2015 suggesting that “40 states could have average retail electricity price increases of 10 percent or more” thanks to the Clean Power Plan.

EPA designed the Clean Power Plan to cut power sector carbon emissions by nearly one-third by 2030 by emphasizing renewable energy, natural gas, and energy efficiency and dialing back coal-fired power. President Trump sees “an out-of-control anti-energy agenda that has destroyed millions of jobs.” Most modeling, however, projects net economic gains from reduced use of coal, including health benefits and long-term savings for consumers.

World Resources Institute economist Noah Kaufman examined four power price projections in January, including the NERA report cited by Trump officials. Three of the studies project that electrical bills will be down in 2030, from 3 to 17 percent. Here’s Kaufman’s explanation for how NERA’s research, which was commissioned by a coal advocacy group, reached the opposite conclusion:

In every case, the study funded by the coal advocacy group used assumptions at or above the top of the range of expert forecasts or empirical estimates of the costs of clean energy available in late 2015 when the studies were conducted. In other words, the study assumed that the rapid advances in clean technologies like solar and wind energy prior to 2015 would not continue into the future, a hypothesis that has already been proven wrong.

Yesterday the electric power sector responded to Trump’s order by rejecting NERA’s negative view of renewable energy, as well as Trump’s fallacy-based fantasy that he can put coal miners back to work. “The sector plans to keep moving steadily toward a cleaner, more distributed energy future—no matter what happens with the Clean Power Plan,” reported UtilityDIVE, a mainstream business publication.

UtilityDIVE issued its annual survey of electric utility executives yesterday, concluding that rescinding the Clean Power Plan was unlikely to reverse coal’s fortunes “mostly due to the economics of natural gas and renewables.” Over two-thirds of executives surveyed expected their power mix over the coming decade would include modestly or significantly more wind power and 82 percent expected solar growth.

Only one in four executives expressed a desire for the federal government to abandon a decarbonization policy, while a majority—58 percent—called for additional measures beyond the Clean Power Plan. A national price on carbon, such as that which Canada is adopting, was the leading policy option.

UtilityDIVE’s big picture view was endorsed by dozens of state-level reports from such utilities as American Electric Power, which slashed its reliance on coal from 71 percent to 47 percent over the last two years. Based in Columbus, Ohio, AEP said it would continue to “balance out our portfolio with more natural gas and renewable generation,” according to local journal Columbus Business First. The journal added context by reminding readers of 10 natural gas plants under development in the state.

Duluth-based Minnesota Power told Michigan Public Radio that it would press on with plans to slash coal-fired generation in favor of wind and natural gas. That report provided context by noting local climate shifts meant “fewer pond hockey days, longer ragweed seasons, and heavier rainstorms that wreak havoc on farm fields, highways, and homes.”

The radio station also quoted the Republican chairman of the state’s House energy committee, Pat Garofalo, who dismissed Trump’s vow to put coal miners back to work. “The combination of wind and natural gas on price, pollution, and productivity are just trouncing every other energy source. And this executive order won’t change that.”

Further evidence of power sector resolve to reduce greenhouse gas emissions came from Carnegie Mellon University and equipment supplier Mitsubishi Hitachi Power Systems, which unveiled a novel index of power sector carbon intensity and plans for high-profile quarterly reporting. “We wanted to make sure that everyone understands how we’re doing,” explains Costa Samaras, an assistant professor of civil and environmental engineering at Carnegie Mellon.

How will all of this industry action on climate balance out against a hostile U.S. administration? Let’s take that up by correcting one more fallacy at work yesterday—one not from the Trump camp but built into yesterday’s coverage in the New York Times.

The Times ably reported on the near impossibility that the executive order would revive coal in the United States. It overreached, however, in this damning prediction for U.S. climate action: “Mr. Trump’s order signals that the United States will not meet its pledges under the Paris deal to cut its emissions about 26 percent from 2005 levels by 2025.” 

Experts contacted by IEEE Spectrum yesterday question the Times’ prognostication. “I wouldn’t be that definitive,” says David Waskow, director of WRI’s international climate program. Waskow says Trump’s attack will make it “much harder and more costly” for the U.S. to deliver its share of climate progress. But he said the price of renewable energy continues to drop, and states and businesses may compensate for federal inaction. 

“It’s like you’ve got a runner on a track and now there’s somebody on the side of the track throwing obstacles in the way. It makes it harder but the runner is continuing in the right direction,” says Waskow.

Samaras agrees. “Most of the action climate-wise is going to be at the states and at companies. That was the case yesterday and that’s going to be the case tomorrow,” says Samaras. He expects to see “a little” slowing of U.S. grid decarbonization, but says there is a “good chance” that the U.S. will meet its Paris pledge, barring an unforeseen steep rise in the cost of natural gas.

A return to the pricey natural gas of decades past appears unlikely. Why? Thanks to President Trump and GOP efforts to ease federal restrictions on gas production

Coal miners should read the fine print on the President’s executive order. While Trump’s coal-boosting boasts grabbed yesterday’s headlines, his order calls for “particular attention to oil, natural gas, coal, and nuclear energy resources.”

America’s dirtiest energy source is third in line, right behind natural gas.

turbine rotor in a gas turbine

Impact of Renewable Generation on Operational Reserves Requirement: When More Could Be Less

graphic link to the landing page for The Full Cost of Electricity

The Full Cost of Electricity project seeks to understand the factors involved in the cost causation of electricity. Among other things, the project seeks to understand costs associated with renewable generation integration.

The variability of renewable generation poses several challenges to reliable operation of power systems. Operational reserves—additional available online generation capacity—is used to compensate for variability in both load and generation. It is natural to think that, as the installed power of renewable generation increases, more reserves will be required. To test this intuition we explored trends in data from the Electric Reliability Council of Texas (ERCOT).  The historical procured regulating reserve data from ERCOT show that, although installed wind power has significantly increased over time, reserve requirements have decreased.

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Latex gloved hands holding a foot-wide black square

Efficiency of Silicon Solar Cells Climbs

In research published this week in Nature Energy, researchers at Kaneka Corp., a resin and plastics manufacturer based in Osaka, describe the first silicon solar cell to achieve a record-breaking 26.3 percent efficiency—a 0.7 percent increase over the previous record. That may not seem like a lot, but it’s really a big step when you consider that silicon solar cells’ theoretical maximum efficiency is just 29 percent.

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A space station flying over the earth with red, gold, and green beams fanning out of it. The beams connect with the earth, the sun, and the moon, respectively.

Trump Dumps Climate Science and Innovation in 2018 Budget Blueprint

Al Gore didn’t really claim to invent the Internet in 1999, but he did champion a NASA mission that installed a deep-space webcam pointed at Earth in 2015. And yesterday President Trump put a bull’s-eye on that mission. Or rather, on part of it. Trump’s 2018 budget blueprint asks Congress to defund the Earth-facing instruments on the Deep Space Climate Observatory (DSCOVR). Its sensors tracking magnetic storms emanating from the sun would keep doing their jobs.

Selectively deep-sixing well-functioning instruments on a satellite 1.5 million kilometers from Earth is one of the stranger entries in President Trump’s first pass at a budget request. But it fits a pattern: Throughout the document, programs aimed at comprehending or addressing climate change take deep cuts, even where there is no obvious fiscal justification. 

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Lithium-ion energy storage units stand in front of an array of solar photovoltaic panels in Hawaii.

Tesla Teams With Tiny Hawaiian Utility to Store Solar

A 33,000-member electric power cooperative on the island of Kauai in the Hawaiian archipelago is emerging as a leader as it moves from fossil-based power generation to renewables, and deploys what ranks as one of the world’s largest arrays of lithium-ion battery packs.

The battery storage became operational in March and is expected to make solar power produced during the daytime available to customers well into peak demand periods after sunset.

Tesla Motors Inc., in association with Kauai Island Utility Cooperative (KIUC), deployed the battery storage using a design derived from the Tesla Model S vehicle. The 272 Powerpack energy storage units are sited at a solar farm whose 55,000 photovoltaic panels have a generating capacity of 13 megawatts (MW).

Under terms of the deal with Tesla, KIUC will buy power for 20 years at the rate of 13.9 cents per kilowatt-hour (KWh). The 52 MWh battery system is design to feed up to 13 MW of electricity onto the grid. Doing so is expected to shave the amount of conventional power generation needed to meet the evening peak, which lasts from 5 p.m. to 10 p.m.

KIUC President and CEO, David Bissellsays the cost is lower than that incurred to buy power from diesel-fueled power plants and is below the charge paid by electricity customers elsewhere in the state.

The solar-plus-battery facility means that KIUC has achieved roughly 44% renewable generation, says Bissell. “This is truly remarkable when you consider that as recently as 2011 we were 92% dependent on fossil fuel generation,” primarily diesel and naphtha.

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Kelp farm

Robotic Kelp Farms Promise an Ocean Full of Carbon-Neutral, Low-Cost Energy

Renewable, carbon neutral energy is critical to a future where we’re not all living on rafts in the middle of a suddenly much larger ocean. Happily, we’ve got lots of ways of generating renewable energy, like solar farms, wind farms, and hydropower. Despite this diversity, renewables are horrendously inefficient compared with the dense solid or liquid combustibles that come straight out of the ground, both in terms of the energy density that they represent, as well as the amount of physical space that it takes to harvest them.

This is an often overlooked problem with renewable energy: Scaling up solar, wind, and hydro to make a dent in overall energy consumption takes up a significant amount of land area. Plus at some point, it starts to become impractical: There’s a finite amount of land area that is appropriate for and can be devoted to large-scale renewables. Not to mention that usually, these installations aren’t things that people want next door. As the global population increases, and energy consumption increases even more, we’re simply going to run out of space.

At the ARPA-E Energy Innovation Summit, a company called Marine BioEnergy was showing a potential new way of producing an enormous amount of low-cost energy in a way that doesn’t compete for land area. Their idea is to use drone submarines to farm kelp out in the open ocean, and then process it into carbon-neutral liquid biofuel. Turns out there are a lot of reasons why this might be a very good idea.

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ARPA-E Energy Innovation Summit: Self-Fluffing Fabrics and the World's Coolest Paint

Every year, ARPA-E (the government's Advanced Research Projects Agency-Energy) holds a big conference/party in Washington, D.C., that includes an expo hall full of all of the latest, most exciting government-funded technology innovations in the energy sector. No, we're not being sarcastic. Last year, we focused on ARPA-E's push towards personal thermal regulation. The big idea: that heating an entire building is incredibly wasteful, when you could potentially save massive amounts of energy by heating each human inside of that building (or a small area around them) instead. We're happy to report that both RoCo and SRI's foot coolers have been significantly improved over the last year, although neither are quite ready for you to buy just yet.

This year, we're going to branch out a bit, and take a look two new technologies that ARPA-E has funded to try and improve our lives by saving energy.

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A flying satellite with several green beam projecting down to a cliff of ice

Is This Twilight for the Golden Age of Earth Observation?

When leaders of the Congressional committees that approve NASA’s missions and budgets put forth their priorities in February, only space science and deep space exploration made the cut. Conspicuously absent was Earth science—a US $2 billion function within NASA that tracks our rapidly changing “home planet.”

Add in White House skepticism of climate science, and what experts call today’s “golden age” of monitoring Earth via satellite faces some serious challenges.

That age began in 2009, when President Barack Obama responded to a U.S. National Research Council warning that budget cuts had left the United States’ Earth observing system “at risk of collapse.” NASA, the lead federal agency for satellite development, saw its Earth science budget rise 56 percent between 2008 and 2016, and it placed eight new Earth-observing satellites in orbit during that period packing state-of-the-art sensors.

The data they deliver inform a widening range of activities—crop planning and management, wildfire risk assessment, extreme air pollution warnings, and more. NASA delivered 1.42 billion data products in 2015—174 times as many as it delivered in 2000—according to a November 2016 review by the agency’s Inspector General.

More missions are in the pipeline, such as NASA’s second Ice, Cloud, and land Elevation Satellite (ICESat-2), whose primary objectives are tracking melting polar ice sheets and glaciers and quantifying the carbon locked up in the globe’s forests.

ICESat-2, however, exemplifies both the present strength of the U.S. Earth observation program and a less visible weakness. To understand why, you need a sense of the ambitious nature of ICESat-2’s mission.

Rather than rerunning the first ICESat mission, which ended in 2009, NASA redesigned the laser altimeter to boost its impact. One laser beam firing sporadically became six beams firing 365 days a year; higher-precision digital photon counting replaced analog detection of beams bouncing back from Earth.

ICESat-2 should enable measurement of annual elevation changes in ice sheets at ± 4-millimeter accuracy (and better for other targets), and at 17 times the spatial resolution of its predecessor, according to Thorsten Markus, chief of cryospheric sciences at NASA’s Goddard Space Flight Center, in Maryland. Such data, he says, will elucidate some basic physical processes that elude climate models, and thus improve their predictions.

But pushing for the best has not come cheap. Instead of $300 million for an ICESat rerun, NASA’s estimate for ICESat-2’s development started at $559 million and has grown to $764 million. Including operations for up to seven years, the mission could cost nearly $1.1 billion, according to that November Inspector General report. Launch dates, meanwhile, have slipped from 2015 to 2018.

Delays and cost creep in ICESat-2 and other missions, as well as several failed launches, put a significant tarnish on Earth observation’s golden age. Extending existing missions to avoid gaps in observational data creates risk, according to NASA’s Inspector General: “More than half the Agency’s 16 operating missions have surpassed their designed lifespan and are increasingly prone to failures that could result in critical data loss….”

Similar risks confront the National Oceanic and Atmospheric Administration, a key partner in climate and weather observation, according to a February report by Congress’s watchdog agency the Government Accountability Office NOAA’s polar readings currently come from a dying NASA demonstration mission. If it fails before the agencies’ long-awaited Joint Polar Satellite System launches, it would degrade weather forecasts, “exposing the nation to a 15 percent chance of missing an extreme weather event forecast,” writes the GAO.

If the golden age of Earth observation harbored weak spots before the 2016 election, experts say the new administration introduces new risks. One is the $54 billion in belt-tightening proposed for federal agencies by President Donald Trump. In early March the Washington Post reported that the President will ask for 17 percent less funding for NOAA.

Another is potential interference with climate science. In February, Lamar Smith, chairman of the House Committee on Science, Space, and Technology, called for “rebalancing” of NASA’s portfolio. A former chairman, Robert Walker, now a lobbyist for space-related industries, built a similar plank into the space platform that he drafted for Trump’s campaign. Both men question human-induced climate change—a view held by many Republicans in Congress and Trump appointees.

Walker says expanded Earth observation under Obama came at the expense of other science programs, particularly deep space robotic missions. He also alleges that NASA science was “tainted" by a political agenda against fossil fuels, focusing on impacts from burning coal, oil, and natural gas and neglecting natural climate influences such as volcanic eruptions. “There’s an extremely complex system that involves a lot more than CO2,” he says.

The Intergovernmental Panel on Climate Change’s 2014 assessment, however, expressed “very high confidence” that volcanic eruptions caused only “a small fraction” of the warming observed since the Industrial Revolution. And it cites “robust evidence” from satellite data showing that natural factors have had “near-zero” effect since 1980.

The notion that human activities alter climate is not a political invention, but a scientific judgement based on gigabytes of data downloaded daily from a gilded era’s orbiting sensors. “It’s not a belief,” says NASA’s Markus. “That’s what the data show.”


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