A system proposed by researchers at MIT recycles materials from discarded car batteries into new, long-lasting solar panels that provide emissions-free power. Lead acid car batteries are a potential source of lead pollution, which makes the idea a classic win-win solution.
The solar cell idea for recycled lead is based on a recent development in solar cells that makes use of a compound called perovskite – specifically, organolead halide perovskite – a technology that has rapidly progressed from initial experiments to a point where its efficiency is nearly competitive with that of other types of solar cells.
Belcher, the W.M. Keck Professor of Energy at MIT said, “It went from initial demonstrations to good efficiency in less than two years.” Already, perovskite-based photovoltaic cells have achieved power-conversion efficiency of more than 19 percent, which is close to that of many commercial silicon-based solar cells.
Initial descriptions of the perovskite technology identified its use of lead, whose production from raw ores can produce toxic residues, as a drawback. But by using recycled lead from old car batteries, the manufacturing process can instead be used to divert toxic material from landfills and reuse it in photovoltaic panels that could go on producing power for decades.
Because the perovskite photovoltaic material takes the form of a thin film just half a micrometer thick, the team’s analysis shows that the lead from a single car battery could produce enough solar panels to provide power for an astonishing 30 households.
As an added advantage, the production of perovskite solar cells is a relatively simple and benign process. “It has the advantage of being a low-temperature process, and the number of steps is reduced” compared with the manufacture of conventional solar cells, Belcher said.
Those factors will help to make it “easy to get to large scale cheaply,” Chen added.
In a finished solar panel, the lead-containing layer would be fully encapsulated by other materials, as many solar panels are today, limiting the risk of lead contamination of the environment. When the panels are eventually retired, the lead can simply be recycled into new solar panels.
Chen noted, “The process to encapsulate them will be the same as for polymer cells today. That technology can be easily translated.”
Hammond noted, “It is important that we consider the life cycles of the materials in large-scale energy systems. And here we believe the sheer simplicity of the approach bodes well for its commercial implementation.”
Belcher pointed out one motivation for using the lead in old car batteries is that battery technology is undergoing rapid change, with new, more efficient types, such as lithium-ion batteries, swiftly taking over the market saying, “Once the battery technology evolves, over 200 million lead-acid batteries will potentially be retired in the United States, and that could cause a lot of environmental issues.”
Today, she said, 90 percent of the lead recovered from the recycling of old batteries is used to produce new batteries, but over time the market for new lead-acid batteries is likely to decline, potentially leaving a large stockpile of lead with no obvious application.
Belcher believes that the recycled perovskite solar cells will be embraced by other photovoltaics researchers, who can now fine-tune the technology for maximum efficiency. The team’s work clearly demonstrates that lead recovered from old batteries is just as good for the production of perovskite solar cells as freshly produced metal.
Some companies are already gearing up for commercial production of perovskite photovoltaic panels, which could otherwise require new sources of lead. Since this could expose miners and smelters to toxic fumes, the introduction of recycling instead could provide immediate benefits, the team said.
This is good news for the solar cell industry. While the mining and recycling of lead is a minor issue in the developed world it remains a problem where employee safety and environmental pollution isn’t taken as seriously. Refined lead out in the environment is a really bad thing that justifies everyone keep an eye out and get those old batteries back in for recycling.
A Rice University laboratory has provided proof that foam may be the right stuff to maximize enhanced oil recovery (EOR) increasing production. With over half of all the oil found so far still in the ground this may develop into very important news.
The Rice team demonstrated that foam may be a superior means to displace and extract tough-to-reach oil. In their tests the foam pumped into an experimental rig that mimicked the flow paths deep underground proved better at removing oil from formations with low permeability than common techniques involving water, gas, surfactants or combinations of the three.
Crude oil rarely sits in an underground pool waiting to be pumped out to the surface. Oil usually exits in formations of rock and sand and hides in small cracks and crevices that have proved devilishly difficult to tap. Oil producers pump various substances down the hole to loosen and either push or carry oil to the surface.
Rice scientist Sibani Lisa Biswal working with George Hirasaki have learned a great deal about how foam forms. With an eye toward EOR, she and her colleagues created microfluidic models of formations – they look something like children’s ant farms – to see how well foam stacks up against other materials in removing as much oil as possible.
The lab’s formations are not much bigger than a postage stamp and include wide channels, large cracks and small cracks. By pushing various fluids, including foam, into test formations, the Rice team can visualize the ways by which foam is able to remove oil from hard-to-reach places. They can also measure the fluid’s pressure gradient to see how it changes as it navigates the landscape.
The team determined the numbers are strongly in foam’s favor. Foam dislodged all but 25.1 percent of oil from low-permeability regions after four minutes of pushing it through a test rig. This compares to 53 percent for water and gas and 98.3 percent for water flooding; this demonstrated efficient use of injected fluid with foam to recover oil. This technology vastly improves upon water flooding by 73.2%!
The less-viscous fluids like water appear to displace oil in high-permeability regions while blowing right by the smaller cracks that retain their treasure. But foam offers mobility control, which means a higher resistance to flow near large pores.
Biswal, an associate professor of chemical and biomolecular engineering explains, “The foam’s lamellae (the borders between individual bubbles) add extra resistance to the flow. Water and gas don’t have that ability, so it’s easy for them to find paths of least resistance and move straight through. Because foam acts like a more viscous fluid, it’s better able to plug high-permeable regions and penetrate into less-permeable regions.”
Charles Conn, a Rice graduate student and lead author of the paper, said foam tends to dry out as it progresses through the model. “The bubbles don’t actually break. It’s more that the liquid drains away and leaves them behind,” he said.
Drying has two effects: It slows the progress of the foam even further and allows surfactant from the lamellae to drain into low-permeability zones, where it forces oil out. Foam may also cut the total amount of material that may have to be sent down the well hole.
One of the challenges will always be to get the foam to the underground formation intact. “It’s nice to know that foam can do these things, but if you can’t generate foam in the reservoir, then it’s not going to be useful,” Conn said. “If you lose the foam, it collapses into slugs of gas and liquid. You really want foam that can regenerate as it moves through the pores.”
Biswal said the lab plans to test foam on core samples that more closely mimic the environment underground.
Foam technology has been idea flirted with for a few years now. The Rice team has finally came up with an experimental system that produces real data. The data looks really interesting. Perhaps industrial researchers and academics will be able now to hasten the work and progress.
Brown University scientists have discovered that copper foam could provide a new way of converting excess carbon dioxide into useful industrial chemicals. The catalytic foam is foamy form of copper with vastly different electrochemical properties from catalysts made with smooth copper in reactions involving carbon dioxide.
Oxidizing fuels releases CO2 making its recycling an attractive means to save on fuels and to control and participate in the carbon cycle more responsibly. One approach is to capture CO2 and once sequestered, researchers are looking for ways to make use of it. The problem is that CO2 is an extremely stable molecule, and reducing it to a reactive and useful form isn’t easy.
Tayhas Palmore, professor of engineering and senior author of the new research explains, “Copper has been studied for a long time as an electrocatalyst for CO2 reduction, and it’s the only metal shown to be able to reduce CO2 to useful hydrocarbons. There was some indication that if you roughen the surface of planar copper, it would create more active sites for reactions with CO2.”
Copper foam, which has been developed only in the last few years, provided the surface roughness that Palmore and her colleagues were looking for. The foams are made by depositing copper on a surface in the presence of hydrogen and a strong electric current. Hydrogen bubbles cause the copper to be deposited in an arrangement of sponge-like pores and channels of varying sizes.
Experiments were performed by Sujat Sen and Dan Liu, graduate students in chemistry working in Palmore’s lab at Brown’s School of Engineering to see what happens after depositing copper foams on an electrode and to see what kinds of products would be produced in an electrochemical reaction with CO2 in water.
The experiments showed that the copper foam converted CO2 into formic acid, a compound often used as a feedstock for microbes that produce biofuels, at a much greater efficiency than planar copper. The reaction also produced small amounts of propylene, a useful hydrocarbon that’s never been reported before in reactions involving copper.
Palmore said, “The product distribution was unique and very different from what had been reported with planar electrodes, which was a surprise. We’ve identified another parameter to consider in the electroreduction of CO2. It’s not just the kind of metal that’s responsible for the direction this chemistry goes, but also the architecture of the catalyst.”
Now that it’s clear that architecture matters, Palmore and her colleagues are working to see what happens when that architecture is tweaked. It’s likely, she says, that pores of different depths or diameters will produce different compounds from a CO2 feedstock. Ultimately, it might be possible to tune the copper foam toward a specific desired compound.
Palmore said she’s amazed by the fact that there’s still more to be learned about copper.
“People have studied electrocatalysis with copper for a couple decades now,” she said. “It’s remarkable that we can still make alterations to it that affect what’s produced.”
The work in the study is part of a larger effort by Brown’s Center for the Capture and Conversion of CO2. The Center, funded by the National Science Foundation, is exploring a variety of catalysts that can convert CO2 into usable forms of carbon.
“The goal is to find ways to produce some of the world’s largest-volume chemicals from a sustainable carbon source that the Earth not only has in excess but urgently needs to reduce,” said Palmore, who leads the center. “This is a way for us as scientists to begin thinking of how we produce industrial chemicals in more sustainable ways and control costs at the same time. The cost of commodity chemicals is going nowhere but up as long as production is dependent on fossil fuels.”
CO2 has value that so far, only the plants have been successfully exploiting as a food source. Recycling back some of that value would go far in keeping the fossil fuels in the market longer by recovering some of their cost as well as making second and repeated use of the carbon a part of modern human activity.
A sponge-like plastic that sops up the greenhouse gas carbon dioxide was presented at a meeting of the American Chemical Society by chemists from the University of Liverpool. The material, a relative of the plastics used in food containers could be integrated into power plant smokestacks in the future. The report on the material is one of nearly 12,000 presentations at the 248th National Meeting & Exposition of the American Chemical Society.
Andrew Cooper, Ph.D. said, “The key point is that this polymer is stable, it’s cheap, and it adsorbs CO2 extremely well. It’s geared toward function in a real-world environment. In a future landscape where fuel-cell technology is used, this adsorbent could work toward zero-emission technology.”
Today CO2 adsorbents are most commonly used to remove the greenhouse gas pollutant from smokestacks at power plants where fossil fuels like coal or gas are burned. However, Cooper and his team intend the adsorbent, a microporous organic polymer, for a different application, one that could lead to reduced pollution.
The new material would be a part of an emerging technology called an integrated gasification combined cycle (IGCC), which can convert fossil fuels into hydrogen gas. Hydrogen holds great promise for use in fuel-cell cars and electricity generation because it produces almost no pollution. IGCC is a bridging technology that is intended to jump-start the hydrogen economy, or the transition to hydrogen fuel, while still using the existing fossil-fuel infrastructure. But the IGCC process yields a mixture of hydrogen and CO2 gas, which must be separated.
Cooper explained that the sponge works best under the high pressures intrinsic to the IGCC process. Just like a kitchen sponge swells when it takes on water, the adsorbent swells slightly when it soaks up CO2 in the tiny spaces between its molecules. When the pressure drops the adsorbent deflates and releases the CO2, which they can then collect for storage or convert into useful carbon compounds.
The material, which is a brown, sand-like powder, is made by linking together many small carbon-based molecules into a network. Cooper explained that the idea to use this structure was inspired by polystyrene, a plastic used in styrofoam and other packaging materials. Polystyrene can adsorb small amounts of CO2 by the same swelling action.
One advantage of using polymers is that they tend to be very stable. The material can even withstand being boiled in acid, proving it should tolerate the harsh conditions in power plants where CO2 adsorbents are needed. Other CO2 scrubbers, whether made from plastics or metals or in liquid form, do not always hold up so well, he says.
Another advantage of the new adsorbent is its ability to adsorb CO2 without also taking on water vapor, which can clog up other materials and make them less effective. Its low cost also makes the sponge polymer attractive.
“Compared to many other adsorbents, they’re cheap,” Cooper said, mostly because the carbon molecules used to make them are inexpensive. “And in principle, they’re highly reusable and have long lifetimes because they’re very robust.”
Cooper described ways to adapt his microporous polymer for use in smokestacks and other exhaust streams. He explained that for instance, it is relatively simple to embed the spongy polymers in the kinds of membranes already being evaluated to remove CO2 from power plant exhaust. Combining two types of scrubbers could make much better adsorbents by harnessing the strengths of each.
Any news means to capture CO2 is welcome and Cooper may be on to something, so breaking out a new field. CO2 is very useful, critical to life on this planet, and offers a steady reliable source for a wide range of materials with fuel a leading cause to recycle.
The announcement is the first step and hopefully others will take up the research for even better CO2 scrubbing materials.
Helion Energy plans to build modular power fusion reactors using somewhat larger than shipping container sized, 50 Megawatt modules for distributed base load power generation. Helion uses Magneto-Inertial Fusion that combines the stability of steady magnetic fusion and the heating of pulsed inertial fusion. They claim they have a commercially practical system that is smaller and lower cost than existing programs. (H/T Next Big Future.)
In simple lay terms the Helion reactor uses two funnels mated at the small ends. At the mating point is where the two fuel loads meet. A fuel is loaded at each outer end. The large ends of the funnels are surrounded with a series of electromagnets that reduce in size as the fuel works its way down to the smaller end of the funnel. The compression of the fuel in the smaller and smaller electromagnet confinements added to the very high speed is the energy input to the fuel that incites fusion events during a collision at the smallest central point.
The fuel is compressed and heated by magnetic fields operated with modern solid state electronics. At each electromagnet ring the fuel increases speed from the magnet pulses. Helion says the fuel heated from the compression to a plasma enters the fusion reaction chamber at over 1 million miles per hour.
The result is a fusion event that releases heat at over 100 million degrees. Helion proposes to convert the heated and rapidly expanding plasma directly into electricity.
The starting fuel is deuterium that can be reclaimed from seawater. One reaction waste material is tritium, a material in short supply that also can be stored and decays to Helium3 that can also be used as a fuel. Another waste is simply Helium3 that can recycled back as fuel immediately.
This system offers some very attractive aspects. There is nothing to “melt down”, although at 1 million degrees is it seems possible that things could be melted. There is no hazardous waste in the conventional sense. Nor are there masses of radioactive materials or used equipment. The Helion concept is about as clean as energy generation is going to get.
Of course there are unresolved issues. Helion hopes to recover up to 90% of the energy used to power the electromagnets back into capacitors. This is a substantial engineering challenge. The recovery leads to matters about repeating the process and engineering to build in reliability for years of use.
The reliability matter asks question on the lifetime of the interior walls. They are subjected to high magnetism that pulsates each second, while holding high temperature plasma that reacts in fusion to even higher temperatures.
Then the matter becomes operating the process in the aiming of the two incoming plasma fuel charges that would affect the productivity of a unit and other issues that constant operation are going to reveal.
One point that needs considered is the Helion unit, once it achieves operations at commercial generating status is there is kick start power input needed to start up. As conceived so far the reactor will need a power source to start.
Helion looks like a leader and is gaining technical proficiency fast. There doesn’t seem to be any physics theory matters casting doubt. Nor are the financials looking desperate. The Department of Energy has awarded $5 million, a paltry sum, while the firm is raising $35 million independently.
Helion’s reactor and the theory behind it look sound. The issues to be worked out are engineering and materials science. The effort may well see some commercial success. There is a long way to go, but Helion is optimistic that a 2019 commercial offering date in the plan can be met.
More likely is that Helion will face things as others do in finding and or building components that meet the newly established specifications.
Helion first saw fusion in 2010. That may turn out to be the easy part.