Batteries that pair lithium with sulfur may now be a major step closer to propelling electric vehicles three times farther than the lithium-ion batteries used to do so today, researchers say.
For electric vehicles to have a 500-km range, their batteries would need to store nearly double the energy they do now. One possible solution are lithium-sulfur batteries, which store more electrons kilo for kilo than lithium-ion batteries. Moreover, sulfur is extremely abundant, relatively light, and cheap, making it potentially very attractive for use in novel batteries.
Researchers from the Karlsruhe Institute of Technology (KIT) in German have demonstrated a novel method of converting the outputs of biogas facilities into methane. The new type of methanation plant can fit inside a standard shipping container, and could be combined with renewable energy production as a means of storing the excess and intermittent supply that is inherent to wind and solar power.
“As conventional methanation processes reach their limits at this point, we have developed a new reactor concept,” said Siegfried Bajohr, the leader of the new project, in a press release. The concept takes the products of biomass gasification—hydrogen, carbon dioxide, and carbon monoxide—and uses a nickel catalyst to produce methane and water. The catalysis is done in a “honeycomb catalyst carrier,” already used as catalytic converters in cars, which are “characterized by a high thermal conductivity and mechanical robustness.”
A major fraction of the energy in all batteries lies untapped. Now, scientists have found a new way to pull some of it out—materials that change into pathways for electricity within the battery over time. The scientists report their results this week in the journal Science.
Perovskite solar cells are one of the hottest prospects in clean energy research, offering good power outputs from low-cost materials that are relatively simple to process into working devices. But their rapid progress has not been without some stumbling blocks.
Firstly, the cells’ power conversion efficiency often varies depending on how it is measured, suggesting an underlying instability in the cells’ light-gathering perovskite materials. That’s bad news for photovoltaic panels that need to work for a decade or more. Secondly, researchers were struggling to extend the range of the light wavelengths that the cells could harvest, a key strategy for improving their efficiency beyond the 20 percent or so achieved by typical silicon or thin-film solar cells. Some of the field’s leading lights have spent much of last year grappling with these issues.
Now a team researchers in South Korea has developed a perovskite blend that addresses both these challenges, and delivers what they say is the highest-efficiency perovskite cell to date.
If we want to stay positive, 2014 was the year when solar power started making the sort of noise in global energy markets that experts have long predicted. If we allow some cynicism to creep in, 2014 was a year when big ideas stalled out, when falling oil prices left renewable energy’s immediate future in limbo, and when international climate deals seem both hopeful and far too timid.
Another branch of marine-based renewable energy had a particularly disappointing year: wave power, long hyped as a great untapped source, seems to be taking steps backward all the time. Ocean Power Technologies, among the theoretical leaders in developing viable wave power tech, has scaled back or cancelled several plans this year, and the world still has no grid-connected wave power at all. In fact, we don’t even really know what wave energy should look like; designs abound, and research continues, but even a few megawatts of wave energy by decade’s end would be impressive.
Moving to the full part of the glass, solar power is really starting to explode. In the U.S., a big third quarter brought the country up to 16.1 gigawatts of installed photovoltaic capacity, with another 1.4 GW of concentrating solar power. According to the Solar Energy Industries Association, the growth through three quarters represented 36 percent of all new electricity capacity; in 2012, solar represented only 9.6 percent of new growth.
Around the world as well, solar made headlines this year. Germany produced half of its electricity from solar power on one particularly sunny day in June, and even the gloomy weather of the United Kingdom set records.
But wait, don’t get too excited: oil prices are dropping with remarkable speed. Though opinions differ about the consequence. Some—like Richard Branson—say this drop in dirty energy prices will have a severely limiting effect on solar power. Others argue that the markets are different, with oil prices affecting transportation fuels far more than the electricity generation markets where solar has been growing. Exactly how $50-per-barrel or lower oil will affect clean energy uptake will be a big story in 2015.
The other major driver of renewables moving forward is national and international climate policy. This year saw an historic deal between China and the United States, far and away the world’s two biggest emitters. It would cut U.S. emissions 26-28 percent below 2005 levels by 2025, and China commited to a peak emissions date of 2030. There are varying opinions on just how great this deal really is, but it undoubtedly changed the international, um, climate, surrounding emissions cuts. The Lima COP20 talks did produce something, though it is little more than a guideline for what might happen next year in Paris. A truly strong, binding, international climate deal, of the type we had all hoped for back in 2009 in Copenhagen and that some do hold out hope for in Paris in 2015, would have an immediate effect on renewable energy development.
Crawl forward, step back, leap forward, fall down flat. Renewable energy progress has never been particularly linear, and this year was no exception. Let’s check back in 12 months to see if these bumpy lines can all start pointing in the right direction.
In a report released this month, the U.S. National Transportation Safety Board (NTSB) found plenty of blame to go around when reviewing a lithium-ion battery fire inside a 787 Dreamliner passenger aircraft in January 2013.
The board's report in particular singles out the plane's manufacturer (Boeing), its contracted battery supplier (GS Yuasa), and the Federal Aviation Administration (FAA) as falling short in ensuring public safety. Last year during NTSB hearings, Boeing Vice President Mike Sinnett called their self-policing policy with FAA "in retrospect... [not] conservative enough."
The NTSB apparently agrees. Its report says FAA provided "insufficient guidance" for its own certification engineers to develop testing for rechargeable batteries used in a commercial jumbo jet. (Such conclusions are also consistent with other criticism of FAA, as noted in a 2013 investigation by the Wall Street Journal that the agency today "has neither the budget nor the expertise to do extensive testing on its own.")
David Zuckerbrod, CEO of Baltimore-based Electrochemical Solutions, praises NTSB's thorough report. Zuckerbrod says he was shocked that the metal battery containers’ design had not taken into account the rare but often devastating thermal runaway fires well known in the cellphone, laptop, and portable electronics industry.
"Even the battery box design was poor," he says. "No one had engineered for cascading failure— one cell going boom and taking out the next cell and the next cell and the next cell. Battery folks know that [can] happen. Have you ever googled 'laptop battery fire'? These folks never watched that movie."
Press coverage at the time suggested that the 7 January 2013 Japan Airlines battery fire, which fortunately only ignited after all passengers and crew had disembarked at the gate at Boston's Logan Airport, might have been caused by overcharging, external heating, or environmental conditions surrounding the battery pack.
However, NTSB has concluded the battery caught fire because of an internal short circuit, possibly arising from either a manufacturing defect in the cell or from temperature spikes allowed by a poorly designed battery management system.
Zuckerbrod says NTSB's report found lax battery manufacturing protocols that are not up to the best industry standards.
For instance, he says, battery manufacturer GS Yuasa wasn't sufficiently careful in keep welding debris and other metal filings out of the battery cells. Moreover, cell assembly involved winding battery materials around a cylindrical mandrel and then flattening the cells by hand into a squashed oval shape that was then compacted into the battery container.
"I was surprised that GS Yuasa wasn't doing a better quality job on those cells, because they were going to be used in aircraft. When you have [military] spec stuff, they drive the vendors crazy with their specifications. It becomes a gigantic portion of the work to deal with the quality control. But the way they were assembling the cells was a little bit high-risk."
One number in the NTSB report in particular really took Zuckerbrod by surprise, he says. According to the report, GS Yuasa "stated that less than 1 percent of manufactured [battery] cells were rejected."
If this number is close to 1 percent and accurately reflects the battery's potential failure rate, he says, then it should give considerable pause. By contrast, he says, the industry standard 18650 lithium-ion battery cell has a typical failure rate of about one-in-ten-million (0.000001 percent).
"It seems like they took [a battery design] off the shelf that in retrospect wasn't aircraft grade," he says.
And while it's not known yet how much of the NTSB's Dreamliner recommendations have been adopted, Zuckerbrod says he thinks the agency's and media's scrutiny has made it likely they'll be taken seriously.
"There's a lot of good stuff in the report, with a big list of things they could do better," he says. "Some of which are easily adopted. We got lucky this time."
When you drink alcohol, enzymes in your liver break it down into a series of byproducts, including carbon dioxide. A group of scientists in Austria are trying to run the process in reverse, using the same sort of enzymes to convert CO2 to alcohol and other products that can be used as fuel or as raw materials for the biochemical industry.
The ever-useful buckminsterfullerene, or buckyball, has a new potential application: carbon capture. Researchers at Rice University in Texas used buckyballs (carbon-60 molecules, technically) as a “cross-linker” with polyethyleneimine (PEI), and produced a compound that binds carbon dioxide very well, avoids binding methane, and can be used at lower temperatures than other materials.
“We had two goals,” said Andrew R. Barron, of Rice, senior author of the paper describing the advance, in a press release. “One was to make the compound 100 percent selective between carbon dioxide and methane at any pressure and temperature. The other was to reduce the high temperature needed by other amine solutions to get the carbon dioxide back out again. We've been successful on both counts.”
The researchers published their findings in Nature’s Scientific Reports. They discovered that the PEI-C60 compound bound about one-fifth of its weight in carbon dioxide, and essentially zero methane—a big deal for carbon capture materials. The buckyballs are hydrophobic, and push the hydrophilic amines of the PEI to the outer surface of the compound; carbon dioxide floats past, and binds to exposed nitrogen atoms.
The PEI-C60 captured carbon better than materials known as metal organic frameworks (MOFs), which are nanoporous materials considered among the most promising for trapping CO2. The idea of using buckyballs was a natural progression for Barron’s lab; in previous work, the team found that single sheets of graphene did well at absorbing carbon dioxide. Multiwalled carbon nanotubes did better, and nanotubes with thinner single walls did even better still. The spherical buckyball takes the level of curvature to its extreme, which Barron said clearly plays a role in how well the molecules bind.
Another advantage comes up when the CO2 needs to let go of its new home—the final step on its road to toward the “sequestration” part of CCS. Other materials require temperatures to reach 120 and 130 degrees Celsius for the “amine scrubbing process” where the carbon dioxide is released. PEI-C60, meanwhile, has a lower “temperature of regeneration,” below 90 degrees Celsius.
The downside? Cost. “Compared to the cost of current amine used, C60 is pricy,” says Barron. “But the energy costs would be lower because you’d need less to remove the carbon dioxide.”
Progress toward deployment of a practical CCS regime remains slow, so any advances are obviously welcome. One of the first utility-scale CCS plants did recently openin Canada—a billion-dollar add-on to a half-century old coal plant. But without some major advances, or political shifts involving huge infusions of cash to the idea, projects like that are going to remain exceptions rather than the rule.
Bangalore-based IBM Research India has a bright idea for keeping discarded lithium laptop batteries out of landfills: repurposing their cells as energy supplies for the powerless. The idea, presented at this weekend's fifth annual Symposium on Computing for Development (DEV 2014) in San Jose, has passed a small proof-of-principle test run with Bangalore's working poor.
Making ceramic fuel cells with a 3-D printer would be a quick and easy way to manufacture the devices and could lead to new fuel cell designs that do a better job of converting a gas into electricity, according to researchers at Northwestern University.