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A coal-fired power station in Helsinki

How Finland Could Ban Coal by 2030

UPDATE 28 November: On 24 November, the Finnish government approved its national energy and climate strategy. The strategy calls for completely phasing out coal for energy production in the 2020s—a move requiring either taxation or explicit legal prohibition. The government is submitting the strategy as a report to the Finnish parliament, where discussion will begin on 30 November. 

On 24 November, as people in the United States are preparing to sit down for Thanksgiving dinner, Finland’s government will unveil its newest energy and climate policy. What will observers have to be thankful for? Many are hoping Finland’s energy plan will include a complete ban on coal by 2030. Scientists, politicians, and industry experts believe that such a ban is actually feasible.

“I think this could work,” says Peter Lund, a renewable energy researcher at Aalto University in Finland.

Olli Rehn, the minister of economics affairs, announced this month that the government was mulling it over. He told Reuters that “giving up coal is the only way to reach international climate goals.”

The Finnish government does not have the power to enact a ban itself—Finland’s parliament would have the final say—but several other places around the world have already made similar anti-coal commitments. Among them are the U.S. state of Oregon and the province of Ontario, Canada.

In Europe, the Danish government wants Denmark to be fossil-free by 2050, and the British government plans to phase out the last of its coal-fired plants by 2025. But neither country has enacted a law explicitly prohibiting coal. If Finland follows through with an anti-coal statute, it would be the first country to have a ban on the books, Helsinki Times reports.

In 2015, only eight percent of Finland’s energy generation—heat and electricity—came from coal, according to Statistics Finland. The country imports it from nations to its southeast—primarily Russia.

Riku Huttunen, Director General of the Energy Department of Finland’s Ministry of Economics and Employment, told IEEE Spectrum that a ban would be possible because of the direction the country is already heading.

Huttunen says that coal plants that generate only electricity and not heat are either under consideration for decommission or already scheduled for it. He expects only one of them to be left by 2030.

Plants that generate combined heat and power can typically use different fuels, he says.

On its current trajectory, coal could wind down to about 1 percent of Finland’s energy mix by 2030. (He writes in an email that some coal would still be stored for “exceptional” situations such as a lack of fuel supply during peak demand hours or a crisis, but not for regular use.) This drop to an even smaller trickle would happen in a couple of ways.

First, energy needs would be lowered with energy efficiency improvements for buildings, with a focus on “smart grids, demand response, and overall flexibility,” Huttunen says.

Meanwhile, coal would be replaced by two primary sources: additional nuclear power and wood-based bioenergy fed by leftovers from the forestry industry. Expanded wind power is also an option, he says.

The switch away from coal to alternative sources is already happening in Finland’s cities. In the capital, Helsinki, there are currently two coal-fired power plants. One will be shut down in 2024 and swapped for smaller plants running on biomass and geothermal energy, says the deputy mayor, Pekka Sauri.

“There’s no chance you can ban coal by tomorrow,” says Sauri. But, “with some luck,” it might be possible to do, even in as short of a timeframe as 2030, he says.

Lund, who chairs the energy panel of an independent European Union science advisory council made up of national science academies, analyzed some ways to address Finland’s energy efficiency as part of research published in Energy in 2007.

He believes that energy efficiency improvements could be applied across industry, businesses, and residences. Residents could lower their thermostats by one or two degrees, homes could use heat pumps instead of electric heating, and buildings could be built with better insulation, ventilation, and lighting. In the industrial sector, pump flow systems for liquids could be optimized—by replacing traditional on/off control or flow throttling with different regulation.

“That all piles up to major improvements,” says Lund.

Although he agrees that wood-based biofuel could be a short-term replacement for coal, he points out that the biofuel is not a sustainable fuel source. About 80 percent of the country’s bioenergy now comes from Finland’s forests, which cover about 75 percent of the country's land area.

When the forest industry produces timber for construction, paper, and pulp, the processes leave behind by-products such as black liquor, wood residues, and wood chips—suitable for energy use.

Huttunen says there is a surplus of trees, so there would be enough to meet increased demand. He writes that the energy produced is “economically and environmentally sustainable,” but Lund warns that the existing production strategy could “actually cause an increase in CO2 emissions.”

Trees naturally absorb carbon during photosynthesis, thus acting as carbon sinks. Huttunen writes that the trees eyed for use as biomass grow faster than they’re used; by 2030, he says, the sink could be pulling about 15 million tons of CO2 per year out of the atmosphere. Still, Lund worries that a plan relying on leftovers from logging for energy may make it difficult to meet the emission requirements of the Paris Climate Agreement. He says it takes 60 to 70 years for the cut trees to grow back.

An alternative could be importing bioenergy sources from other countries, or simply planting more faster-growing trees, such as Salix willow and poplar, Lund says.

Another potential issue Lund points out is a switch to nuclear. He thinks that the four existing nuclear reactors in Finland should be at the end of their lives by 2030, with maybe a couple years of wiggle room, depending on the results of safety inspections. But they would remain commissioned until 2035 at the latest.

According to Huttunen, two units might be shut down by 2030, but the others would probably continue to run afterward. A fifth unit would come online by the end of 2018, and the government might decide to build a sixth in 2018.

But even if proven possible, there’s still a leap from there to probable. Part of that gulf is financial concerns.

Sauri says replacing existing plants would require “considerable investment.” A spokesperson for Finnish Energy told Helsinki Times that there would need to be “substantial compensation” to energy producers. Huttunen writes that production would be cheaper with alternative sources, but also that CO2 taxation is a “clear incentive.”

“Now we know that the outlook for coal production is not really good,” says Esa Hyvärinen, a spokesperson for Fortum Corporation, an international energy firm with interests in Europe and Russia. While zero coal might work, he doesn’t think a ban would have a significant effect on Europe’s CO2 emissions.

The EU has a trading system where companies cover their yearly emissions with allowances. Hyvärinen explains that another member state could just increase emissions while paying less.

Hyvärinen believes there’s a better way to decrease CO2 emissions: Instead of limiting the technology toolbox, lower the existing emissions cap and let industry decide what technologies let it meet that goal.

Lithium-ion ain't the only power backup game in town

Building a Better Grid Backup

With all the news Tesla Motors makes, you might be excused for thinking that lithium-ion batteries are the answer to all the world’s energy storage needs—even storing wind and solar energy on the electricity grid.

But, as noted before, companies with new grid-scale battery chemistries are emerging to fill what had been a growing void. The U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) has supported grid battery R&D to the tune of $85 million in research grants since 2009. And even as companies pitching the latest in large-scale energy storage appear in the marketplace today, ARPA-E continues to press ahead with research into even cheaper, safer, more powerful, and longer lasting grid storage.

Last month, for example, ARPA-E announced US $37 million in funding for research into a new class of solids in which some ions are mobile and thus can store and conduct energy.

The announcement follows up on the 2011 discovery of ion-conducting solids. In fact, the Japanese team that discovered the material noted in the paper documenting the discovery that it could act as a solid, non-volatile, and non-explosive battery electrolyte.

According to Paul Albertus, head of ARPA-E’s new Integration and Optimization of Novel Ion Conducting Solids, (IONICS) initiative, ion-conducting solids have at least two possible applications in the field of grid-scale batteries. The first, he says, is a more powerful and less volatile traditional rechargeable battery, like a next-generation Tesla Powerwall.

Albertus says research that IONICS underwrites will “help lead to batteries that, while having high energy density, nevertheless have improved intrinsic safety compared with today’s lithium ion batteries, because they will include a solid separator rather than one filled with a liquid electrolyte. The presence of the liquid electrolyte is a key reason for the fires that periodically occur in lithium ion batteries.”

The largest of IONICS’s solid-electrolyte grants, for $5.25 million, went to the Berkeley, Califorina-based company PolyPlus. A 2014 patent awarded to PolyPlus describes in detail the company’s approach to making lithium-based batteries with glass or ceramic as the electrolyte. The company’s website says its battery’s stability and light weight suggest initial applications providing portable power for remote sensors and for soldiers in the field.

A second application for the new materials, Albertus says, involves solving a longstanding problem in flow batteries, probably the gold-standard grid battery technology today. Flow batteries, like the current-generation of vanadium and iron-based batteries ARPA-E has helped develop, use a liquid electrolyte on the cathode side and a liquid electrolyte on the anode side. Both solutions can be scaled up by simply adding more tanks of electrolyte. This cheap and easy expandability is one of the main selling points for energy storage banks that need enough flexibility to power an entire neighborhood or office park during nights or cloudy or windless days.

One of the essential ingredients for any flow battery, says Albertus, is the membrane that separates the electrolyte on the cathode side from that on the anode side. It should selectively let ions pass, but shouldn’t facilitate any reactions that might degrade the battery materials, change electrolyte’s pH, or reduce the battery’s performance. For most materials, though, this is too tall an order.

“The chemistries of today's flow batteries are limited by the selectivity of the membrane,” Albertus says. “When the active materials pass through the membrane, they can react in a reversible or irreversible manner. Current membranes are not very selective, limiting the active materials to chemistries with the same element on both sides of the membrane such as the all-vanadium flow battery. Even a tiny amount of crossover—say, 0.01 percent per cycle—over the course of 5000 cycles leads to unacceptably high degradation. If the membrane had higher selectivity, a new paradigm allowing the use of a far wider range of active materials would be enabled, especially those that are less expensive, such as iron and chromium.”

With that in mind, ARPA-E, through IONICS, awarded $2.7 million to East Hartford, Conn.–based United Technologies Research Center for a flow battery with solid ion membranes that the company says could make flow batteries cheaper and more durable. ARPA-E also awarded $1.5 million to the Colorado School of Mines to develop a “hybrid polymer” membrane that the research team says could “offer a highly selective, robust solution for the production of flow batteries at a price point that allows their affordable integration into the power grid.”

In other words, says Albertus, ARPA-E’s latest research effort into grid-scale batteries could solve one of the crucial outstanding problems in flow batteries: making the perfect separator for a cheaper, more stable, and longer-lasting system.

“The goal for the IONICS program is a per-cycle selectivity of 99.995 percent, dramatically higher than existing membranes,” he says. “Which in turn have better selectivity than simple porous membranes. A specific goal of the IONICS program is to make sure that, even as researchers develop membranes that have higher selectivity, they pay careful attention to ensure their membranes are also stable, highly conductive, and low cost at the production volumes flow batteries may achieve in the next 10 to 15 years.”

Coal plants in Kosovo

The Numbers Don’t Add Up for Kosovo’s Coal Plant

Two aging coal plants puff away on the outskirts of Pristina, the capital of the regionally-disputed Eastern European territory of Kosovo. The question facing the world is what to do when they can no longer continue to generate electricity.

“The government is moving in completely the wrong direction,” says Visar Azemi, the coordinator of KOSID, a consortium for sustainable development in Pristina. Right now, the government plans to build a new coal power plant, but  Azemi and his colleagues argue in a 13 October analysis in Environmental Research Letters that a mix of renewables is both cheaper and better for health and the environment.

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.11 m^2 leaf-shaped, colorful photovoltaic modules with solar concentrators

Flashy Recyclable Photovoltaic System Breaks Record for Solar Energy

If you want your home to stand out, a flashy new photovoltaic module might be just what you’re looking for. The leaf-shaped prototype uses color and shape to redirect light to two silicon solar cells.

Researchers announced last month at the annual Photovoltaic Science and Engineering conference in Singapore that their 0.11-square-meter photovoltaic modules had achieved a record high for efficiency in converting the sun’s rays to electricity: 5.8 percent.

“[This technology could] become more attractive to architects and people involved in the building sector,” says Angèle Reinders, an industrial design engineer at University of Twente in the Netherlands.

With traditional silicon solar cells on roofs, costs can add up quickly. With that in mind, many researchers, with an eye toward commercial viability, have tried using materials that can concentrate light into one or two solar cells.

Typically, engineers place solar cells on the edges of panels and guide the light using novel materials such as quantum dots and organic dyes. For example, in research published in 2008, one group achieved 7.1 percent efficiency with four expensive gallium arsenide solar cells on the edges of a tiny luminescent solar concentrator with colored dyes. Earlier this year, a Journal of Renewable and Sustainable Energy article described research using silicon solar cells on the back of PMMA (acrylic glass) panels; those modules achieved only 3.8 percent efficiency.

Reinders favors the use of plastic because chemical processes exist to remove the PMMA and recover the electronics, so the photovoltaic modules are recyclable. In glass sheet photovoltaics, the solar cells and wires in between them end up as waste. But in order to improve the performance of medium-size solar concentrators using plastic, Reinders and her colleagues came up with new designs aided by computer simulations of different shape combinations, colors, numbers of silicon solar cells, and solar cell positioning.

Here’s how the designs work. When sunlight strikes a flat PMMA film mixed with a particular colored dye, the light reflects inside the film. Depending on the dye’s color, it adjusts the wavelength of the light so that it’s closer to the infrared range. This is advantageous because the two silicon solar cells at the bottom of the panel absorb more light in the infrared range. 

The researchers tried to strike a balance between the photovoltaic module’s size and accessibility of light.

The team built a prototype—which has continued to convert photons to electrons with 5.8 percent efficiency for the past 1.5 years—by cutting each of the two solar cells into three pieces and attaching them to the bottom of films featuring a red dye. In simulations, the geometry of a rhombic shape appeared to harvest more light rays than a rectangular shape.

Sue Carter, a physicist at the University of California Santa Cruz who was not involved in the study but has designed solar concentrators for greenhouses, points out several potential issues with the design.

First, she says the company she consults for, Soliculture, ships solar concentrator systems for greenhouses that can achieve up to 7 percent efficiency with reflective backgrounds. The work, says Carter, is unpublished because she is focusing on commercialization. Referring to the Dutch research, she said it’s misleading to list efficiency in the whole system, because efficiency can always be improved by adding additional silicon photovoltaic cells.

“People can make their own conclusions by going to the website,” Carter says.

She added that although photovoltaic cells function better on acrylic, it can become more expensive than glass and be more difficult to certify. Also, it is challenging to prove 20-plus-year lifetimes on the organic plastic luminescent materials; it took her team “a lot of work” to find a combination of techniques that made it possible, she writes in an email.

Carter says the size of a photovoltaic system wouldn’t have a noticeable effect on its overall efficiency, but Reinders says the main difference between her lab’s work and Carter’s work is that, because the new prototype uses smaller modules, it’s easier for photons to become concentrated because they aren’t as widely distributed across the surface. Also, there are differences in dye concentrations and in where the cells are positioned on the back of the PMMA film.

Reinders agrees that plastics are not as durable as glass—she says pieces of glass from Roman times are still found at archaeological sites—but she’s confident that they will stand the test of time. She says it’s not reasonable to expect that a plastic sheet would last 25 years. But it’s possible to make plastic headlights that can resist degradation for a period of 15 years, so a five to 10 year lifetime would certainly be reasonable as research progresses.

Reinders says she’s found that the plastics are about half the cost of glass—mainly because they are thinner. But the cost will ultimately depend on how the materials are processed, which requires further investigation. Usually plastics manufacturing is a lot faster than the glass production process.

As far as certification goes, Reinders points out that requirements in the United States could be different than those in the Netherlands. And as such, it might be difficult to meet all certification requirements with plastic. She doesn’t see any problems with electrical performance, but it is easier to scratch plastic than it is to scratch glass. This, however, could possibly be remedied by using some sort of coating.

Sayantani Ghosh, a physicist at the University of California, Merced, who was also not involved in the research, writes in an email that “once certain issues are addressed, this could potentially prove a novel way of capturing solar power in houses, with significantly lower costs” than covering a roof with silicon photovoltaic cells.

According to Ghosh, the questions that still have to be answered include whether the materials would be stable under weather conditions such as snow and rain, and how their thinness could affect their robustness. There’s also the issue of putting the cells underneath the solar concentrator tile instead of on its edge, which allows a “significant portion” of the reemitted light to escape because there isn’t a solar cell to capture it. Also at issue is whether other light harvesting materials could have a broader light absorption spectrum. Finally, she isn’t sure whether a proposed idea of mixing dyes would work in practice because the emission range of one would overlap with the absorption of another.

Reinders writes in an email that she has not tested the prototype in harsh weather conditions yet, but it “may be more suitable for climates with a diffuse irradiance than the glass sheet-based photovoltaic modules.” She writes that diffuse irradiance usually “goes hand in hand” with climates with lots of clouds and rain.

Reinders also admitted more work needs to be done on ensuring that it can handle the heat on rooftops. “We still can do a lot of research in this field,” she says. 

A small boat goes past the Lillgrund offshore wind farm

Offshore Wind Farms Don’t Harm Marine Life

When commuters take the train across the bridge from Malmö, Sweden, to Copenhagen, Denmark, they pass by Sweden’s largest offshore wind farm: Lillgrund. Similar power-generating farms are gaining traction in the United States—just take the Block Island Wind Farm recently built in Rhode Island.

More renewables is all good, right? Not quite. Normally, wind farms get a bad rap for deaths of birds and batsAnd they have been the suspected cause of increased sightings of other species such as shore crabs (which could lead to unknown consequences). But now, biologists report (on 25 October in PLoS One) that the Lillgrund farm doesn’t seem to harm local marine life.

“Engineers, they don’t think so much about the environment,” says Olivia Langhamer, a marine biologist at Chalmers University of Technology in Gothenburg, Sweden. She worked on the study of Lillgrund’s effect on the environment with the Norwegian University of Science and Technology in Trondheim. “It’s really important to discuss with them, what impact you can have so you can modify and you can improve.”

Langhamer points out that there is a delicate biodiversity balance in the marine ecosystem. The relevant food web goes like this: Fish such as cod eat crabs, seals eat the fish, and so forth. But has Lillgrund affected the food chain? After it became operational in 2008, the Swedish Agency for Marine and Water Management noticed that both fish and crabs gather around the turbines’ foundations. The agency’s 2013 report documenting this phenomenon explained why. Stones around the turbines’ foundations—meant to combat erosion from ocean currents—attract crabs. The foundations are like artificial reefs that marine animals can use as protection from predators. But this got Langhammer thinking: Would these artificial reefs upset the crabs’ ecosystem—leading to unexpected consequences? Invasive species, for example, can become dominant species and break the balance in food chains. A 2009 research paper published in PLoS One cited an extreme case where an invasive species probably led to mass extinctions millions of years ago, during during a period known as the Late Devonian extinction.

To find out whether Lillgrund was a hospitable home or a harmful habitat, Langhamer and her colleagues visited Lillgrund and two other sites (Sjollen, which is 13 kilometers north of the wind farm; and Bredgrund, 8 km south) during the summers of 2011 and 2012. Each of the bodies of water covered about 6,000 meters and had limestone, stone, and sand seabeds at depths between 4 and 9 meters. They also had similarly strong gradients of salinity.

The researchers collected Carcinus maenas shore crabs, which are easy to measure and rank among the world’s worst invasive species. The team caught 3,962 in 2011 and 1,995 in 2012. Crunching numbers, they found that while the crab populations had increased across all three sites, with a slight edge at Lillgrund, there was no statistically significant difference in the total crab numbers, body conditions, sizes, or male-to-female ratios.

Langhamer says one reason for stability in the crab numbers might be because cods are also attracted to the artificial reefs formed by the turbines’ foundations. She suspects that they might be keeping the crab population from exploding.

“Finding no effect could be due to so many reasons,” Magnus Wahlberg, a marine scientist at the University of Southern Denmark in Odense who was not involved in the research, writes in an email. “A large variation between years and sites for reasons we may not know may easily overrule” effects on the crabs.

Langhamer cautions that the work shows only that the wind farms don’t have a net negative effect, and doesn’t indicate whether there is something positive or negative going on behind the scenes.

Others are more optimistic. “We don’t have to worry about the crabs,” says analyst Linus Hammar, who studies the environmental effects of fishing and wind farms at the Swedish Agency for Water and Management. He was also not involved in the new research.

Because fish and seals have also been shown to be attracted to the foundations of wind farms, and the exclusion of animals that are not attracted is “insignificant,” Hammar says the marine ecosystem has stayed essentially in balance. “I think it will even out,” he says.

Langhamer says she hopes to continue studying the effect of renewables on the environment, with a focus on acceptability and the artificial reef effect. She wants to have more collaborations with engineers and the renewable energy industry.

“I think it’s really important to see and study what is happening when you place something in nature,” she says. “What are the risks, what are the mitigations, and what can you improve the design?”

Quebec's wind farms can produce bursts of power to stabilize AC grid frequency

Can Synthetic Inertia from Wind Power Stabilize Grids?

As renewable power displaces more and more coal, gas, and nuclear generation, electricity grids are losing the conventional power plants whose rotating masses have traditionally helped smooth over glitches in grid voltage and frequency. One solution is to keep old generators spinning in sync with the grid, even as the steam and gas turbines that once drove them are mothballed. Another emerging option will get a hearing next week at the 15th International Workshop on Large-Scale Integration of Wind Power in Vienna: synthetic inertia.

Synthetic inertia is achieved by reprogramming power inverters attached to wind turbines so that they emulate the behavior of synchronized spinning masses.

Montréal-based Hydro-Québec TransÉnergie, which was the first grid operator to mandate this capability from wind farms, will be sharing some of its first data on how Québec's grid is responding to disruptive events such as powerline and power plant outages. “We have had a couple of events quite recently and have been able to see how much the inertia from the wind power plants was working,” says Noël Aubut, professional engineer for transmission system planning at Hydro-Québec. 

The short answer is good, but not good enough to support massive wind power growth. Québec has about 3,300-MW of wind power today, but Canada's wind industry is calling for 8,000-megawatts more by 2025. Turbine manufacturers are upping their synthetic inertia technology to pave the way.

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Energy Storage Systems' iron-based flow battery

Arpa-E’s Grid Battery Moonshot

Grid-scale energy storage is the lesser-publicized half of the clean energy story. As solar and wind farms scale up, so does the grid’s need to put electricity on layaway for those nights and cloudy and windless days when solar and wind farms lie fallow. Storing electric power via flywheels, compressed airsuperconductorspumped water reservoirsthermal storage, hydrogen gas, and even rocks on railcars are methods being researched—and in some cases, commercially prototyped today. 

But ARPA-E, the U.S. Department of Energy’s technology incubator, retains a strong focus on the familiar electrochemical battery as a likely backbone of an increasingly solar and wind-powered electric grid of the future.

report published by ARPA-E earlier this year outlines the $85 million in R&D funding it’s invested in battery-based grid storage since 2009. The report details the agency’s grid-scale battery plans, including projected system costs, which they say should eventually drop by at least an order of magnitude compared with 2010. That, say ARPA-E researchers, would allow them to become viable commercial players in the years ahead.

According to Eric Rohlfing, ARPA-E’s Deputy Director for Technology, some technologies they’ve invested in are headed that way. But he notes that the agency backs portfolios of projects, and is not in the business of picking single winners in any category. “One of the things that we like to say we do at ARPA-E is we provide technological options,” Rohlfing says. “As much as we love many of these projects, for me to look into a crystal ball and say, ‘This particular chemistry, this particular flow battery will be the answer,’ I think is premature.”

That said, though, Rohlfing called the aforementioned report a sampler of some of the 73 ARPA-E–supported grid storage projects that appear poised for commercial opportunities in the months and years ahead. (IEEE Spectrum discussed some of these projects in a previous story.)

One of these grid-scale battery companies, Portland, Ore.-based Energy Storage Systems (ESS), now has its batteries installed in an Army Corps of Engineers deployment and at a winery in Napa, Calif. Its technology is an example of a new approach to a promising grid storage idea: the flow battery.

A flow battery is like a melding of a fuel cell and a conventional battery. A liquid electrolyte flows in both the cathode and anode sides of the cell; they’re separated by a membrane. The battery’s capacity can be easily expanded by adding more reservoirs of electrolyte. If the chemistry and engineering is done right, the battery should have enough capacity to handle grid-scale power needs while still remaining neither expensive, nor toxic, nor volatile.

Of course, that’s easier said than done.

“We’re seeing a lot of potential in these flow battery systems,” Rohlfing says. “You have two large tanks that you can store a lot of energy in. And you can ramp up that energy scaling quite easily. And your active medium is a small part of that, that the reactive parts are flowing through. When we first started, the state of the art was based on all vanadium flow batteries—which were and still are very expensive, because of the vanadium. All of our projects have looked at ways of lowering that cost. Energy Storage Systems originally started with vanadium and has shifted to an all–iron-chloride approach. And iron is dirt cheap… or rather, rust cheap.”

Bill Sproull, VP of Business Development and Sales at ESS, says the price of the company’s iron-based electrolyte is an order of magnitude cheaper than the vanadium-based electrolytes he’s studied. “The cost of our electrolyte today is somewhere on the order of $15 per kilowatt-hour. And my understanding of the cost of the vanadium electrolyte is somewhere in the $150 per kilowatt-hour range,” he says. “Given that, you’ve got to still build the rest of the battery out of low-enough-cost materials that you’re not going to reverse that situation.”

Julia Song, the company’s co-founder and CTO, says that at least one other company and two universities are also working on their own iron-based flow battery chemistry. And no doubt all competitors are facing up to one of the key challenges for an iron-based electrolyte, she says. Namely, the battery’s positive and negative electrolytes perfer t opareat at different pH levles for optimal performance. So there need to be some clever chemistry and chemical engineering efforts to keep electroyltes’ pH separate and stable during operation.

Sproull and Song both say that this is a tricky, but not impossible problem of optimization. And it ultimately needs to be solved only once. This is why they say ARPA-E’s support has been so important for the company and for the technology.

In 2012, ARPA-E awarded ESS $2.1 a million grant for what it called “transformational energy storage projects.”

“That really changed everything for us,” Song says. “We were able to get the people, get the space, do the research, and build early prototypes that we’re good at for two-and-a-half years—and really focus on technology development without worrying about raising money. That made a huge difference.”

Since then, ESS, armed with its more mature technology, has been able to raise venture capital, says Sproull. And now the company projects that it’ll be volume manufacturing its flow battery system within a year.

Scottsdale, Ariz.-based Fluidic Energy has, with ARPA-E support, developed a zinc-air battery that serves a different need than ESS’s iron flow batteries. Says the company’s CTO Ramkumar Krishnan, its zinc-air batteries have been developed to supplant lead-acid batteries and diesel generators—especially in countries with developing electricity grids (e.g. rural electrification) or for long-duration critical backup applications (e.g. cellphone towers), where power reliability needs can be met whenever sporadic power sources drop out.

Zinc-air batteries have been around for decades, powering hearing aids primarily. But it was with ARPA-E support that Fluidic tweaked the materials and the design to make its zinc-airs rechargeable.

The ARPA-E report described the multiple challenges Fluidic faced along the path to developing the technology. Fluidic, ARPA-E said, “focused on developing a battery design using an electrolyte based on ionic liquids. Ionic liquids are salts that are liquid at the battery operating temperature, delivering ionic conductance while maintaining substantial electrical insulation. The team developed chemistries that have negligible evaporation, are stable in the presence of oxygen, and do not absorb water over the cell operating voltages, and include additives that interact favorably with the zinc and air electrodes.”

ARPA-E is telling its grantees that, in order to be cost competitive in the commercial marketplace, they need to target battery benchmarks of $100 per kilowatt hour, with at least 5000 cycles (i.e. 10 years daily operation) and 80-percent or greater efficiency in cycling from charging to discharge.

Fluidic’s Krishnan says that Fluidic is competitive in all three of those categories. For instance, he says, “Today we’re four to five times over the life of lead-acid batteries. We’re providing a five-year warranty in telecom applications, where typically their [lead acid] batteries are replaced every 18 months.”

Krishnan says that, as with ESS, ARPA-E provided crucial support at an important time in the Fluidic technology’s development. “ARPA-E plays that really fine balance between pure R&D funding that is provided by national endowments and national labs, versus ventures that are funding something that has quick payback and low risk for technology to market entrance,” he says.

“Just like how in [President] Kennedy’s time, going to the moon was a dream. It was made a reality by setting out some bold visions and providing a means to achieve that. Similar to that, ARPA-E is breaking some new ground by allowing some bold technologies to be able to push the forefront, [letting companies] make that viable in a short timeframe, and take it to the next level where it becomes attractive for investors or the public to fund that further.”

This post was corrected on 7 November 2016 to better characterize the technologies of ESS and Fluidic Energy.

A home pictured with Tesla's solar roof, a car, and new Powerwall battery as the sun falls

The Challenges for Tesla's Solar Roofs

Last week, Tesla—best known for its electric vehicles—announced its latest product: roof tiles with built-in solar cells. To succeed where other companies have failed, engineers say they must strike a delicate balance among cost, aesthetics, safety, and performance.

Widespread adoption would yield clear environmental benefits, of course. Solar power could be a way to lower carbon dioxide emissions and combat global warming, Tesla CEO Elon Musk said in a presentation. Musk sees solar roofs as part of his plan for running the world on clean, sustainable energy.

Yet Ronnen Levinson, a mechanical engineer at Lawrence Berkeley National Lab who studies ways to keep roofs cool, points out that “Tesla isn’t offering a new idea.”

In the past, solar power has had mixed results in the United States. Years ago, the Obama Administration supported the solar power company Solyndra, which went bankrupt in August 2011. Dow Chemical recently tried a solar shingles project that it shut down in July.

Tesla declined to comment for this story. Former Solyndra CEO Brain Harrison and Greg Bergtold, a business advocacy director at Dow Chemical, also declined to comment.

The discernible difference with Tesla’s photovoltaic roofing material, Levinson says, is that the company will offer integrated tiles. Instead of buying a roof, paying for workers to install it, then buying new solar panels and paying for extra labor, you can consolidate the cost--which could be cheaper. Musk said there are about 4 to 5 million new roofs in the United States every year, with more worldwide, so there is a market.

“Over time, every house would become a solar house,” Musk said.

During the presentation, Musk unveiled solar-cell glass tiles that could integrate with Tesla’s new Powerwall 2 battery as well as electric cars. TechCrunch reported that Musk claims the new roofs would last two to three times as long as typical 20-year-cycle roofs and be more impact resistant.


The marketplace challenges this product faces, Levinson says, are a mix of different factors: where you are, how much local electricity costs, whether you are buying a new home and new roof or need to replace a worn-down roof, and what the solar availability is. If you’re away from home during the week and only use electricity on the weekends, then storing electricity might not be practical. Also, not all states and utility companies have measures in place that allow homeowners and businesses to sell their excess solar energy, negating what would otherwise be an additional financial benefit.  

Angèle Reinders, an industrial design engineer at the University of Twente in Enschede, Netherlands, works on integrating photovoltaics into infrastructure. She says consumer acceptance might also be difficult to get.

“If it’s affecting their building or their daily behavior, people are usually quite reluctant to adapt to that new technology,” she says.

In terms of performance, she wondered why Tesla doesn’t specify what technology the solar cells use or their tested efficiency—Musk has claimed that they achieve 98 percent of the efficiency of traditional solar panels. “I would like to talk with Elon Musk and ask him personally,” says Reinders. “You can’t put something on the market and not say what sort of technology’s in it,” she says.

Rodrigo Ferrão de Paiva Martins, a materials scientist at the Instituto de Desenvolvimento de Novas Tecnologias in Caparica, Portugal, is working on thin-film solar cells. He says it’s possible to get a high enough energy efficiency for market practicality.

He begs to differ with Musk, saying that solar shingles are inherently less efficient than traditional solar panels. He notes that they can deliver about 3 to 4 percent conversion efficiency. They become cost effective at about the 10-percent-efficiency mark, and there’s a way to get there by tweaking the manufacturing process.

When solar cells are made, they are typically put in a mold and heated, leaving tiny holes in the material. By heating the materials at higher temperatures than normal, these holes could be smoothed out, improving efficiency.

Levinson, however, pointed out that efficiency can be a misleading way to think of the cost effectiveness problem—because it is a product of several variables such as location and the local price of electricity.

There could also be various technical and safety challenges.

Reinders says that glass would not be the most insulating material for cold climates and stressed that there would be a tradeoff between performance and the need to adhere to building code requirements. In the Netherlands, for example, there are rules that spell out what roofing material must be in terms of fire resistance as well as being non-toxic, durable, and resistant to erosion.

Bjørn Petter Jelle of the Norwegian University of Science and Technology and SINTEF Building and Infrastructure in Trondheim--who is investigating resilient solar cells--says it’s important that the new roofs are resistant to harsh weather conditions such as snow, ice, wind, rain, and ultraviolet radiation.

Also, there is a tradeoff between aesthetics and performance. Jelle knows of a man in a city outside of Trondheim who bought curved Chinese solar panels to match the homes of his neighbors, even though they were less efficient than flat panels.

Levinson says it remains to be seen whether the Tesla product will succeed, but Reinders says “the timing is really well done” with respect to market readiness.

There’s at least one buyer. Don Weidner, a Tesla Model S owner and founder of Formidable Ventures, says “I’m blown away by how good they look.”

He says he just moved into a new house in 2015, but assuming Tesla lives up to Musk’s promise regarding the cost for new roofs, “the very next time I move or build or need a roof, I would absolutely” buy one.

A train on tracks is part of the Advanced Rail Energy Storage project, which stores energy for the electricity grid as the potential energy of a train on a hill.

Arpa-E's $85 Million Plan to Build a Battery the Size of the Grid

As the electric grid is increasingly powered by renewables, it will need energy storage for when the wind isn’t blowing and the sun isn’t shining. But the three top grid-scale energy storage technologies today—pumped hydropower, lithium-ion batteries and “flow” batteries—arguably, aren’t up to the challenge.

The U.S. Department of Energy’s technology incubator ARPA-E (Advanced Research Projects Agency-Energy) wants to change that. It’s going long on a number of high-risk, high-reward R&D projects that might change the entire grid storage equation. U.S. Energy Secretary Ernest Moniz has said he thinks grid-scale battery storage will be the key innovation that enables the grid to completely decarbonize by midcentury. 

“There’s a lot of discussion about what the grid of the future will look like,” says Eric Rohlfing, ARPA-E Deputy Director for Technology. “Of course what we want to do is enable much higher penetration of renewables. So storage is an obvious way to do that… The two key points of grid storage are: it has to be cheap, and it has to be durable—to go through a lot of cycles.”

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Exhaust comes out of the tailpipe of a vehicle

If Germany Bans Internal Combustion Engines, It'll Change the Game

A recently proposed ban on internal combustion engines could improve air quality and lower noise pollution and CO2 emissions in Germany.

“We do not expect it will become a law within the next 12 months,” writes Volker Quaschning, an energy researcher at the Hochschule für Technik und Wirtschaft (HTW) Berlin, in Germany, in an email. “However, the discussion is interesting…because it increases the pressure on the car industry.”

Echoing similar proposals in Norway and other countries, the heads of 13 out of 16 of Germany’s states voted two weeks ago to allow sales of only zero-emission cars starting in 2030. That would be no small matter, considering that Germany—home of BMW, Mercedes-Benz, and Volkswagen—had 44 million registered cars in 2013

The states alone are not able to put the ban into effect; only the German federal government can. But they have started a conversation, and researchers say there would be clear benefits.

First, Quaschning calculated that switching to zero-emission vehicles powered by today’s energy mix—about 30 percent generated from renewable sources and 70 percent from nonrenewable sources such as coal and natural gas—would cause a noticeable decrease in CO2 emissions.

In the June 2013 issue of IEEE Spectrum, Ozzie Zehner argued that this sort of emission analysis of electric vehicles often leaves out an important factor: The emissions released during the manufacturing process can overshadow the benefits. However, 2015 research by the science advocacy group Union of Concerned Scientists found that over its life cycle, an electric car still creates about half of the CO2 emissions of a traditional gasoline-fueled car. And once the car has been driven enough, the emission savings add up.

Without taking into account the emissions released during the manufacturing process, Quaschning’s estimates suggest a 30 percent decrease in transportation emissions. The emissions from the transportation sector account for about 20 percent of Germany’s total emissions.

There’s another advantage of the proposed ban. “Reduction in CO2 is only secondary to the air pollution health benefit,” Mark Jacobson, a civil and environmental engineer at Stanford University in California, writes in an email.

Diesel engines are still widely used in Europe—and the black carbon particles they produce can lead to even greater global warming and health effects than does carbon dioxide, Jacobson writes. Early California Environmental Protection Agency research yielded some of the many bits of empirical evidence showing that diesel fumes directly affect health and can increase the risk of cancer. But as of 2013, about 1.4 out of 2.9 million new German passenger cars were diesels.

An additional rationale for the proposed ban: A switch to electric cars could reduce noise pollution. “Today, there is little knowledge about how a whole city or region feels and sounds, in which only electric and nonmotorized vehicles drive,” Christian Scherf, a spokesman for the Innovation Centre for Mobility and Societal Change in Berlin, writes in an email. “However, we assume that the quality of life is noticeably increased.”

Werner Zittel, a physicist and energy consultant at Ludwig-Bölkow-Systemtechnik, in Munich, says a ban “is feasible.” He believes politicians should set rules and let the car industry react by creating engines that meet the new requirements.

Not all agree. Last week, Forbes reported that Germany’s minister of transportation dismissed the idea out of hand. He told the German wire service DPA that an internal combustion engine ban by 2030 would be “utter nonsense.”

A spokesman for Oliver Krischer, the vice chairman of Germany’s Green Party, says the Green Party supports the ban, but notes that the federal government would not likely pass a law without the transport ministry’s support. To his knowledge, the German parliament hasn’t passed legislation without a ministry’s support in at least the past 10 years.

“It’s kind of a big discussion right now going on in Germany,” he says. But the states made a “clear statement.” 

The Green Party is calling for an all-renewable energy grid by 2030—an idea that Zittel calls “impossible.”

Don Anair, an electrical engineer with the Union of Concerned Scientists in the United States who studies transportation, says, “I think the important thing for Germany is where the electricity grid is heading.”

“You can’t just look at today’s grid mix and say, here’s what the benefits of electric vehicles are years from now,” he says.

Neither the German Ministry of Economics and Energy nor the Ministry of Transportation were available for further comment.

Germany’s next election is in September 2017, which both Quaschning and Krischer say could change the game—both for the extent of Germany’s use of renewables and whether consideration of an internal combustion engine ban will remain in gear.

Thirteen years from now, Anair says, “obviously that would be a dramatic shift in the auto industry.” He does, however, point out that in the United States there are over 25 models of plug-in or fuel cell vehicles—up from “essentially zero” before 2010.

Sales of these vehicles with much less reliance on the combustion of fossil fuel are increasing, but the question remains: How fast can the industry ramp up, and where is the tipping point at which electric vehicles become a normal purchase, he asks.

“This is a technology that’s here to stay,” he says.

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