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Grid-connected Electric Buses Could Displace Diesels

Anyone who has taken a school bus is familiar with the crunching sound of an idling diesel engine—and the nasty exhaust they give off. Researchers at the University of Delaware argue that cleaner electric school buses can make financial sense for school districts if they provide services to grid operators.

In an economic analysis published in Applied Energy and announced yesterday, researchers found that switching over to a fleet of electric buses, each of which costs more than twice a diesel bus, could save a school $38 million over at typical 14-year lifespan. “It would be cheaper to operate these buses,” said Jeremy Firestone, director of the Center for Carbon-free Power Integration at the University of Delaware. “And kids don’t need to be exposed to diesel fumes.” 

The University of Delaware has an ongoing experiment that's at the leading edge of vehicle-to-grid technology. It has 15 electric Mini Cooper sedans that earn money by providing quick bursts of power—as short as a few seconds or as long as several minutes--to balance the local electric grid. The cars’ batteries effectively act as a mini power plant, providing frequency regulation services that are normally provided by fossil fuel plants or very large stationary batteries.

Electric school buses could provide the same services and, in some ways, are better suited for the task than consumer-owned plug-in cars. Because electric buses are only used for short periods of time, their batteries are typically available for many hours of the day, which makes them more valuable to the local grid operator that would purchase frequency regulation services. Also, fleet owners are more likely to invest in the inverter and control hardware to create two-way connection to the grid.

The shorter range of an electric bus compared to a diesel bus is not going to be a problem for most urban and suburban school districts, said Firestone. Regenerative braking from frequent stops can aid battery range as well.

The analysis included the medical and climate benefits of using an electric bus. Even when they were not included, a vehicle-to-grid-capable electric bus could save a school district more than $5,700 per seat over its life, according to lead author Lance Noel.

Diesel exhaust, which contains benzene and soot, is classified as a probable human carcinogen by many government agencies, including the International Agency for Research on Cancer and the US Environmental Protection Agency. And children are particularly susceptible to the adverse respiratory effects from fine particular matter, according to the nonprofit Environment and Human Health. It's estimated that 0.3 percent of in-cabin air comes from the bus's exhaust, the University of Delaware paper notes.

Practically speaking, many school districts will be unwilling or unable to pay more for electric buses. In its test, the University of Delaware ran its analysis with a bus that costs $260,000, compared to $110,000 for an equivalent diesel.

Firestone speculated that parents could be motivated by the health benefits of an electric bus to press school districts to pay the higher upfront costs. Also, a third-party fleet operator could own the buses and earn money from the frequency regulation grid services. Third-party ownership of rooftop solar panels has helped fuel rapid growth of distributed solar in the U.S. States and the federal government could also provide financing for first-of-a-kind vehicle-to-grid projects, Firestone said.

Another variable in vehicle-to-grid technology is the local grid operator. The University of Delaware is earning money with its fleet of electric Mini Coopers with PJM, which is a large and progressive grid operator. PJM makes relatively large frequency regulation payments and pays more for fast-acting energy resources, such as batteries, which has helped enable a number of innovative applications. For example, the Philadelphia subway authority has been able to finance an energy storage system that captures energy from braking trains and provides balancing services to the local grid.

Firestone is hopeful that school districts will consider electric buses when they need to upgrade. "Once you have the first couple installed and people understand both the economic and health benefits, it's an idea that could catch on rather quickly," he said.

EPA Set to Unveil Climate Proposal for Existing Power Plants

Next week, the U.S. Environmental Protection Agency (EPA) will unveil its climate rule for existing power plants. The details of the plan have not been released, but they will require reductions in carbon emissions although states will have flexibility in how they make those cuts, according to news reports.

The proposal will likely create regional carbon-trading programs, according to The Washington Post. No matter what the details, there will likely be a challenge from utilities, especially those that rely heavily on coal-fired power plants for generation. Utilities are responsible for about one-third of greenhouse gas emissions in the United States.

Rather than each power plant having to meet the requirement, EPA would require states to meet the overall target. In that case, utilities could meet the requirements by cutting emissions at an individual plant, or could finance energy efficiency on the demand side.

"I cannot see a credible resolution to our climate change challenges without an enormous contribution from the demand side of the equation. The efficiency side is going to have to drive our strong response," U.S. Department of Energy Secretary Moniz, said recently at the 2014 Energy Efficiency Global Forum, according to Greentech Media. The new rules are part of Obama's climate action plan, which was first announced last summer. 

The proposal could look like renewable portfolio standards (RPS), according to The Washington Post, which require a certain percentage of electricity to come from non-fossil generation. So the 30-plus states that already have an RPS might find it easier to meet existing goals.

Various energy producers are already lining up for a fight. Wind producers and nuclear companies, such as Exelon, are in support of stricter carbon standards. “We think the reality is in the absence of carbon policy, it’s going to be difficult to keep the existing [base] of clean energy in service,” Joe Dominguez, Exelon’s senior vice president of governmental, regulatory affairs, and public policy, told The Washington Post.

On the other side, coal-heavy states such as Kansas, rural electric cooperatives, and some power producers are ready to fight the measures, as they have with EPA’s regulations for carbon emissions for new coal and gas-fired power plants

Depending on the details released next week, there could be many technologies that win. If there is wide-ranging flexibility for states to meet the reductions, energy efficiency measures could be one of the biggest winners.

A Natural Resources Defense Council (NRDC) proposal on how to cut carbon pollution is seen as one of the models for the standards EPA will adopt. NRDC’s proposal [pdf] calls for energy efficiency to be the primary means for reducing carbon. State-regulated energy efficiency programs could earn credits for avoided pollution and generators could purchase and use those credits towards meeting compliance. One issue with a focus on efficiency will be having standardized measurement and verification schemes to ensure the savings are being realized.

One technology that won’t necessarily win out if EPA is successful in regulating carbon emissions from existing power plants is carbon capture and storage (CCS) for coal-fired power plants. In Europe, which has decarbonization policies, there has yet to be commercial-scale, affordable CCS. Vattenfall, one of Europe’s largest energy producers, recently announced it was discontinuing its CCS research.

In the United States, coal is already on the decline, new EPA regulations on climate notwithstanding. Earlier this year, the U.S. Energy Information Administration increased its prediction for coal retirements from 40 to 60 gigawatts by 2016, mostly driven by the EPA’s Mercury and Air Toxics Standards and low natural gas prices. So far, the loss of capacity has been replaced by upgraded transmission, energy efficiency, and some renewables.

The EPA rule for existing power plants is expected to be finalized in June 2015.

New Battery Tech Could Turn Waste Heat to Electricity

Every year, Lawrence Livermore National Laboratory in California publishes an amazing chart cataloguing all the energy used in the United States. The striking thing about it is the "rejected energy" portion of the chart: in 2013, more than 60 percent of our 97.4 quads (around 293 billion kilowatt-hours) of energy were rejected, or wasted. Most of that dissipates as heat: from smokestacks and manufacturing processes, and from your tailpipe. Capturing some of that heat has long been a dream that would improve our efficiency and reduce energy use and emissions, and new research takes a novel approach to achieve it.

Most waste heat ideas involve the thermoelectric effect, where a voltage is created based on a temperature difference. This approach has been limited by materials and the need for very high temperatures and gradients, but the new idea, using the thermogalvanic effect can operate at much lower temperature differences. The researchers responsible for this idea, from Stanford and MIT, describe thermogalvanics as "the dependence of electrode potential on temperature."

Basically, it works like this: an uncharged battery is heated by waste heat (from, say, some manufacturing process in a factory), and then it is charged. The battery is then allowed to cool, and discharges only at a cooler temperature. The charging voltage is lower at higher temperatures, meaning the charging voltage is lower than the discharging voltage; that means more energy can be extracted via discharge than was inputed via charging. The extra energy comes from the heat differential.

They aim to use this type of system at temperatures below 100°C; in tests, at 60°C they achieved a conversion efficiency of 5.7 percent. The battery used in the tests consisted of a copper hexacyanoferrate cathode and a Cu/Cu2+ anode.

One investigator, Yi Cui of Stanford University, said in a press release that the potential for this idea is enormous. "Virtually all power plants and manufacturing processes, like steelmaking and refining, release tremendous amounts of low-grade heat to ambient temperatures. Our new battery technology is designed to take advantage of this temperature gradient at the industrial scale."

To be sure, though, they are far from actually sending these batteries to a steel mill to capture a bunch of lost energy. It has a much lower power density than thermoelectric devices, meaning huge versions of this battery might be required to deliver enough power. And charging and discharging probably needs to be sped up substantially before the technology becomes viable as well. But with wasted energy pouring out of every smokestack in the world, this idea isn't likely to dissipate any time soon.

Iron-Chromium Flow Battery Aims to Replace Gas Plants

Photo: EnerVault

The four round structures pictured above may look like grain silos but they're actually giant flow batteries. They're part of a demonstration plant going online this week, and proponents say it could represent the future of long-duration energy storage on the electric grid.

Startup EnerVault will unveil tomorrow what it says is the largest iron-chromium flow battery ever made. Installed in Turlock, Calif., the four-hour, 250-kilowatt battery will be charged by a solar array and power an irrigation system. The project was funded by about US $5 million from Department of Energy through the stimulus program and the California Energy Commission.

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Airbus’s E-Fan Electric Plane Takes Flight

The Airbus E-Fan took its first public test flight last month, making it the latest in a group of all-electric aircraft to take to the sky.

The flight was not just a media stunt. Airbus Group hopes to eventually develop a hybrid-electric regional plane that could seat 70 to 90 people, according to a report in Reuters. Developing such an aircraft, however, could take up to 20 years.

In the more near, term, Airbus sees a future for its E-Fan test plane. The composite, two-seater training aircraft is equipped with two lithium-ion polymer batteries (250 volts total) from KOKAM, a leading advanced battery maker, that are housed in the wings. The batteries provide 60 kilowatts of power to the plane's electric motors. The motors drive a variable pitch fan. The plane can fly for up to about 45 minutes, but Airbus says it can eventually get that flying time closer to an hour and 15 minutes.  

There are various electric aircraft prototypes across the world, but the difference is that Airbus is one of the world’s leaders in commercial aircraft manufacturing. (Check out 10 Electric Planes to Watch). While the A380 isn't going to go electric anytime soon, any breakthroughs that Airbus develops in electric-powered planes could reverberate through its business. 

Unlike some other electric aircraft, Airbus says that the E-Fan was built from the ground up to be electric rather than being based on existing fuel-powered airframes. For example, the landing gear is integrated into the fuselage for low drag, and the energy management and safety features were designed to be driven by electrical propulsion. There is a backup battery for emergency landing.

At the same time, the E-Fan needs to have flight parameters that are similar to existing training aircraft if it’s going to be used as a test plane. Ultimately, Airbus wants to construct a fleet of E-Fans and manufacture them close to the Bordeaux Airport in France. Production could start as early as 2017, according to Reuters.

Because the aircraft runs on electric motors, it emits no carbon dioxide during the flight and vibrates far less than a comparable fossil-fuel-powered plane. It is also quieter during take off and landing, which should be a benefit to communities surrounding test flight areas.

The investment in electric flight is spurred in part by the European Commission’s “Flightpath 2050” [PDF] which calls for a 75-percent reduction in aircraft CO2 emissions, a 90-percent drop in nitrous oxide emissions, and a 65-percent cut in noise levels compared with the respective numbers from the year 2000.

“It will not only lead to a further reduction in aircraft emissions and noise to support our environmental goals but will also lead to more economic and efficient aircraft technology in the long run,” Jean Botti, chief technical officer for Airbus Group, said in a statement.

The E-Fan will also make an appearance at the ILA Berlin and Farnborough airshows this year. Airbus has not released a projected cost for the electric plane.

UPower's Truck-Size Nuclear Power Plant

There are a number of efforts to build small modular nuclear reactors aimed at lowering the cost of nuclear power. But one company is designing a reactor that’s so small it would fit in a shipping container.

Boston-based UPower Technologies, founded by three nuclear engineers from MIT, is betting that its very small nuclear “battery” can be cost-competitive with power from diesel generators used in remote locations. It’s one of a handful of companies creating new reactor designs with the hopes of improving nuclear power’s safety and cost.

By building a very small reactor, the company thinks it can test full-scale prototypes cheaply and meet a market need for energy in remote places, such as mining operations, island nations, or military microgrids. It expects that its reactor would generate between one and two megawatts of electric power. By contrast, a full-size nuclear power plant typically produces about 1000 megawatts.  

In addition to being small, its reactor technology breaks with the dominant light water design. In today’s power plants, fuel rods held in metal assemblies are submerged in water. The heat from the core is converted into steam to turn a turbine and generate electricity. To avoid overheating in the core, water needs to be constantly circulated through it.

With UPower’s design, the nuclear reactor would be placed in a tall cylinder buried underground. Rather than remove heat from the core with water, company engineers have developed a system that’s similar in concept to steam radiators.

The reactor is equipped with a number of vertical stainless steel pipes filled with a mixture of liquid and gas. Those pipes are slotted into channels, or holes, in a metal block at the base of the reactor, explains CEO Jacob DeWitte. 

As the core produces heat, it causes the liquids at the bottom of the pipes to evaporate and rise to the top. That heat would then be converted into electricity using conventional generators. Removing the heat from these steel loops causes the gas to condense and drop to the bottom to begin the evaporation cycle again. "You don’t need pumps and it’s able to move the heat,” DeWitte says. “It’s a completely passive, self-contained phase change.”

In a light water reactor, water acts to both moderate the nuclear reaction and to transport heat from the core. With the UPower design, the steel pipes are enclosed and would only carry away heat. The nuclear fuel would also fit into channels in the metal block at the base of the reactor, DeWitte adds. He envisions using the same low-enriched uranium in conventional reactors but it could use other nuclear fuels.

The company went with this scaled-down approach for business reasons. The cost of testing a prototype of a new type of nuclear reactor costs millions of dollars, whereas DeWitte expects UPower could test its thermal management system at full size for thousands of dollars.

The reactor also seeks to improve on the safety of current plants. In the Fukushima disaster three years ago in Japan, a loss of back-up power to run water pumps caused the cores to overheat and melt down. With the UPower design, the heat would dissipate through a separate set of horizontal cooling loops that would transfer heat to the ground through natural convection, DeWitte says.

A number of countries, including China, Russia, and South Korea, are building new nuclear power plants. But in the United States, nuclear power is more expensive than building a new natural gas plant. UPower’s strategy is to target locations that pay high costs for energy because they need to import diesel fuel. Its reactors could supply both heat and electricity at lower costs, DeWitte says.

The company is one of a handful of nuclear startups that are hoping to bring advanced reactors to market. Among them are Bill Gates-backed TerraPower, Transatomic Power, and a few companies pursuing nuclear fusion, including General Fusion, Helion Energy, and TriAlpha Energy. There are also a number of efforts to build small modular reactors, which are light water reactors designed to be simpler to build and install than full-size plants.

By working through a startup, rather than a national lab, entrepreneurs hope to move quickly and commercialize new nuclear technology But the process of obtaining a license to operate advanced reactors will likely take many years, says Jessica Lovering, a nuclear policy analyst at think tank the Breakthrough Institute. “All the regulations and applications are very focused on the light water designs,” she says. “The whole fuel cycle is optimized for it.”

DeWitte is hopeful that the company can test its basic design by the end of next year and start the licensing process. There’s a demand for alternatives to diesel generators in remote locations and strong commercial interest could help speed up the approval process, he says. 

Vattenfall Ditches Carbon Capture and Storage Research

Vattenfall, one of Europe’s largest energy producers, announced this week that it will discontinue its research and development activities in carbon capture and storage (CCS) for coal-fired power plants.

The move comes as Vattenfall looks to shore up costs as profits fall considerably for European power producers. Vattenfall said in a statement that research will continue in smart grid, wind, hydro, coal, and nuclear.

"Tough market conditions are expected to continue for another few years, and we are restructuring our research and development operations as it is becoming increasingly important to have the right knowledge at the right time to meet the ever-changing needs of business," Karl Bergman, head of R&D Nordic for Vattenfall, said in a statement.

Europe’s power producers are already losing money on many coal and natural gas power plants due to depressed wholesale electricity prices from the recession, coupled with increased renewable capacity due to decarbonization policies. A study earlier this year from Oxford University [PDF] found that coal prices have fallen by about one-third in Europe since 2011.

Despite years of research, CCS continues to be an expensive option to cut greenhouse gas emissions from coal-fired power plants. Even in the European Union, which has decarbonization policies, it has yet to become a commercial-scale, affordable option to keep older coal plants operating while producing fewer emissions.

Vattenfall does not have money to bet on technologies that might not pay off in the near term. The Oxford study found that the Swedish power giant wrote down €3.46 billion (US $4.78 billion) in 2013 related to losses from coal and natural gas plants in the Netherlands and Germany.

The Vattenfall announcement is another blow to CCS, but there are some other bright spots on the globe for the technology. A 110-megawatt coal-fired power plant refitted with carbon capture in Saskatchewan is expected to come online within weeks, according to MIT Technology Review. The utility that owns the plant, SaskPower, is using some CCS research from Vattenfall. Vattenfall said it would continue knowledge exchange with other entities even though it will not conduct further research.

Another project, in Mississippi, will install carbon capture on a coal plant and is expected to start up later in 2014. Like the Canadian project, it can reduce costs because it uses cheap lignite coal and it is can sell the carbon dioxide to nearby oilfield operators. In January, the U.S. Energy Department pledged $US 1 billion towards a carbon capture and storage project in Illinois.

But in most regions, the outlook for CCS is unsure at best. The Norwegian government announced last fall that it would not escalate a large CCS pilot project to commercial-scale operation.

CCS is not the only research area to get axed by Vattenfall. The company said it will also close down “a number of” projects in offshore wind and gas power. For wind and hydro, the focus going forward will be on lessening environmental impacts of new projects. Vattenfall’s nuclear research will continue into how to safely dispose of spent nuclear fuel and it will also continue to look at ways to use coal assets as a regulator for intermittent renewables.

"We now need to prioritize our R&D investments and choose whatever is most needed,” said Bergman. “We are opting for efficient research projects that can contribute further to our business operations, now and in the future."

Monitoring Nuclear Fuel With Sound

Nuclear reactors are packed with a host of sensing and control systems. But at their innermost core, where nuclear fuel burns inside metal rods, conditions are so extreme that placing any kind of sensor has been a huge challenge. As a result, reactor operators haven't been able to get a complete picture of how their nuclear cores are performing.

Now researchers have developed sensors that convert the heat differences inside the reactors into whistle-like sounds that reveal the condition of the fuel. These thermoacoustic sensors could provide operators with valuable data like temperature, gas composition, and pressure inside the fuel rods, as well as fuel burn-up rate and swelling of the rods.

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DOE Spends $141 Million to Speed Offshore Wind Project Development

Though the actual waters off of the United States' windy shores remains free of turbines (with one minor exception), the theoretical waters are getting crowded with turbines. Along with frontrunners Cape Wind and Deepwater Wind near Massachusetts and Rhode Island, a few other projects are starting to get the sort of backing that will help them join the party. Yesterday, the Department of Energy announced funding of up to $47 million each for three projects off of New Jersey, Virginia, and Oregon.

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U.S. Climate Report Predicts Growing Problems for Energy Sector

More frequent and intense weather events—from hurricanes to wildfires to sweltering summers—can be attributed to climate change and are affecting energy production and power delivery in the United States, according to a new government report.

The latest National Climate Assessment, prepared by the U.S. National Climate Assessment and Development Advisory Committee (NCADAC) and released yesterday, says that climate-related effects are not only already being felt but will likely get worse.

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