Energywise iconEnergywise

The Catalyst That Finally Gets Fuel Cell Vehicles on the Road?

One problem that has been plaguing the development of hydrogen-fueled vehicles is that hydrogen gas needs to be stored and transported in expensive pressurized tanks. Liquid energy carriers such as hydrogen dissolved in a salt solution are viewed as possible alternatives, but they’re also fraught with problems including the accumulation of byproducts. The simplest hydrogen carrier is water. But splitting hydrogen from oxygen requires, besides catalysts, a lot of energy. 

But now a research group called Team FAST, comprising students at the Technical University Eindhoven (TUE), in the Netherlands, thinks it has the hydrogen storage problem licked. To supply the one-meter-long scale model fuel cell vehicle they’ve developed with as much hydrogen as it needs, they’ve turned to formic acid (HCOOH). The liquid compound that can be created by joining carbon dioxide molecules with hydrogen with the help of catalysts and stored under atmospheric pressure. What’s more, catalysts can do the job of splitting formic acid into hydrogen and CO2—without an external energy source. 

Though this idea is not new, the efficiency of catalysts had been too low to deliver a stream of hydrogen sufficient to run fuel cells that could power a car. That is, until research completed last year by Georgy Filonenko, a recently-departed graduate student there, led to the discovery of a catalyst that is 10 times as efficient.

"The catalyst is a ruthenium complex which dissolves in the formic acid, and it is so active that you need only, what I call 'homeopathic' quantities, to dissociate the formic acid,” says Emiel Hensen, a chemist who supervised Filonenko's PhD research. Besides being required in small quantities, the ruthenium complex is, unlike other catalysts, not fouled by air or water, facilitating its use in a automotive applications, says Hensen.

To test out the advance, the FAST team set out, a year and a half ago, to build a working an one-meter scale model of a hydrogen car. It contains an off-the-shelf fuel cell and a catalytic reactor the size of a coffee mug, explains Pieter Ottink, who is the spokesperson for the team. Having shown off this proof-of-concept version, they say the next step is to power a full-scale model, hopefully by the end of this year. The team also reports that they have struck a deal with a company that will supply them with a hydrogen bus.   

“We are not yet sure about how we will design the big system; scaling up a chemical reaction like this is dependent on a lot of variables,” says Ottink.  However, they plan to proceed carefully. “It does not seem to be efficient to make one big reactor, so we will [likely equip the bus with] multiple small ones,” he says. But who knows? “This technology is in a very early stage," Ottink adds.   

A fortuitous coincidence will certainly make things easier, however. “The catalytic reaction is efficient at around 80 degrees C, so you should warm it up. We have the advantage that the fuel cell also produces heat, and this heat can be used to warm up the reactor,” says Ottink.

Unfortunately, the CO2 liberated during the catalytic reaction is released into the air. But if the formic acid can be produced in a sustainable way—by, say, drawing CO2 from the flues of fossil-fueled power plants—the process would be carbon neutral.

Fluttering Flag Generates Power From Wind

Just by flapping in the wind, a new energy-generating flag produces enough electricity to power small electronic devices. The flag converts mechanical energy into electricity using the effect behind static electricity. Floating high above the ground using balloons, it could harvest high-altitude winds to power weather and environmental monitoring sensors, as well as navigation systems.

Winds at high altitudes are faster and more consistent than those near the ground, but ground-based turbines are unable to reach those heights. Many groups are testing technologies such as floating turbines, kites, sails, and winged craft to harness these high-altitude winds.

“How about a little piece of fabric for wind power?” asks Zhong Lin Wang, a materials science and engineering professor at Georgia Tech, in Atlanta. The flag’s low cost and easy scalability could make it competitive with other airborne wind power technologies, he says.The details of the Georgia Tech team’s research appear in the journal ACS Nano.

The flag operates on the triboelectric effect. When the surfaces of two different materials touch and separate, electrons transfer from one to the other, building up opposite charges on the two surfaces. This can lead to a voltage that drives electric current.

Wang’s group has made several generators that scavenge energy from body movements and mechanical vibrations to produce electricity. In early 2015, the team reported a slinky-shaped generator and an energy-scavenging fabric that could power gadgets using human motion.

The flag is the researchers’ newest form of triboelectric generator. They made it by weaving together 1.5-centimeter-wide, 30-cm-long strips made from two kinds of fabric. The weft is a nickel-coated polyester textile belt and the warp is a polyimide plastic-coated copper film. All the nickel belts are connected using copper tape to form one electrode; all the copper belts are connected together as the other electrode. The flag, which weighs 15 grams, can be bent, folded and twisted. 

“The weave is loose and there is a few hairs’ distance between the two fabric strips,” Wang explains. So as the flag flutters in artificially generated wind, the two fabric units repeatedly touch and separate from each other, generating power.

At a wind speed of 22 meters per second, the flag produces a maximum of about 40 volts and 30 microamperes. Three flags connected in parallel could light up 16 commercial LEDs. As a demonstration, the researchers connected the flag’s output to a button cell battery that powered a humidity and temperature sensor node that transmits data wirelessly to a computer. This whole system was tethered to a meteorological balloon that hovered in an indoor laboratory where the researchers were able to vary temperature and humidity. 

Hydrogen Adds Longevity to Laptops, Phones, and Drones, But Is It Practical?

Back in August, when we wrote about Intelligent Energy’s prototype fuel cell iPhone, we weren’t totally convinced that it was an idea that would catch on. We’re still not totally convinced, but yesterday at the Consumer Electronics Show in Las Vegas, we stopped by Intelligent Energy’s suite to check out the prototype ourselves, along with a fuel cell-powered MacBook and a drone that can fly for up to two hours on a small canister of hydrogen gas.

Read More

Stable Perovskite Cell Boosts Solar Power

By adding cesium to a kind of crystal known as a perovskite, researchers say they can create tandem solar cells that may be much better at converting light to electricity than conventional solar cells while also being far more stable than previous comparable tandem cells.

Photovoltaic cells based on silicon currently make up about 90 percent of the global photovoltaic market. However, the rate at which the power conversion efficiency of silicon photovoltaics has improved has slowed dramatically, growing only from 25 percent to 25.6 percent in the past 15 years.

In order to create more efficient solar cells while making the most of the existing industrial capacity for silicon photovoltaics, researchers would like to create so-called tandem solar cells that combine silicon with other materials. One set of potential partners for silicon in these cells are perovskites, which are inexpensive and easily produced in labs.

Read More

A Renewable Supergrid in Russia

Russia and Central Asia could rely on an economically viable 100 percent renewable energy system—wind and solar—in 2030,  says a report commissioned by the Neo-Carbon Energy Research Project in Finland. (By economical they mean a price per kilowatt-hour slightly higher than € 0.045 but lower than the cost of energy produced by today’s solar plants.) It's highly doubtful that Russia will actually move to such an energy system, according to the report’s authors, but their simulation at least showed that it’s possible.

Read More

Ossia's Cota Wireless Power Tech Promises to Enable the Internet of Everything

Over the past year or so, we've seen enough companies promising to deliver truly wireless power that we're almost, almost starting to believe in it. But there's an awful lot of hype, compounded by the fact that there are a bunch of very different technologies all targeting the same goal: charging everything, everywhere, without plugs or cables or pads. Recently, we've taken a closer look at a few of these technologies, including uBeam's ultrasonic power transmitters and Energous' WattUp pocket-forming antenna arrays.

Yesterday at CES, we were introduced to Ossia, another company that wants to transform how we power our devices using wireless energy. Ossia's solution, called Cota, uses thousands of tiny antennas to deliver substantial amounts of power directly to embedded receiving antennas in devices located up to 10 meters away. Cota emphasizes safety, efficiency, and reliability, and their technology seems pretty incredible.

Read More

Climate Change Could Challenge the Water Needs of Power Plants

Most power plants need water. As water resources are challenged in coming decades due to climate change, the bulk of the world’s power plants could see reduced capacity, because of water limitations or temperature changes according to a new study published today in Nature Climate Change.

The output of more than than 80 percent of thermoelectric plants could be affected after 2040, according to the research. However, the technologies to mitigate any capacity reductions due to change in water availability already exist.

Read More

Nitrogen Can Triple Energy Capacity of Supercapacitors

Nitrogen can triple the energy storage capacity of carbon-based supercapacitors, researchers in China and the United States say, potentially helping make them competitive against some advanced batteries.

Supercapacitors can capture and release energy much more quickly than batteries, but they usually can store less energy. Most supercapacitors in use today use carbon-based electrodes, because their high-surface area stores more charge. "We are able to make carbon a much better supercapacitor," says Fuqiang Huang, a material chemist at the Shanghai Institute of Ceramics.

The scientists began with a framework of porous silica and lined the pores with carbon. They next etched away the silica, leaving porous tubes 4 to 6 nanometers wide, each made of five or less layers of graphene-like carbon.

They then doped the carbon with nitrogen atoms. The nitrogen altered the otherwise inert carbon, helping chemical reactions occur within the supercapacitor without affecting its electric conductivity.

These changes enhanced the capacitor's ability to store energy by roughly threefold without reducing its ability to quickly charge and discharge. "It is as if we have broken the sound barrier," Huang says.

The scientist say that their devices could store 41 watt-hours per kilogram, comparable to lead-acid batteries.

"A bus can run on an 8 watt-hours per kilogram supercapacitor for 5 kilometers, then recharge for 30 seconds at the depot to run on the trip again,” says I-Wei Chen, a materials physicist at the University of Pennsylvania who also worked on the breakthrough. “This works in a small city or an airport, but there is obviously a lot to be desired," he says. "Our battery has five times the energy, so it can run 25 kilometers and still charge at the same speed. We are then talking about serious applications in a serious way in transportation."

The new supercapacitor does not store as much energy as lithium-ion batteries, which achieve 70 to 250 watt-hours per kilogram. However, the researchers say their supercapacitor beats them on power. The nitrogen supercapacitor can crank out 26 kilowatts per kilogram, while lithium-ion batteries are only capable of 0.2 to 1 kilowatts per kilogram.

The scientists are now investigating ways to create these supercapacitors in a scalable, robust, and inexpensive manner, Huang says. They are also experimenting with a variety of electrolytes to further improve the energy and power of these devices.

They detailed their findings this week in in the journal Science.

Metal Powder: the New Zero-Carbon Fuel?

The two solid fuel boosters that burned for two minutes helping the U.S.’s old space shuttle fleet to reach its orbit each contained 80 tons of aluminum powder, which corresponds to 16 percent of the total weight of the solid fuel.  "This idea of burning metals as a fuel sounds pretty far out there, but this is something that has been done in rockets forever," says Jeffrey Bergthorson, an aeronautics engineer at McGill University in Montreal, Canada.  He and colleagues at McGill and at the European Space Agency  published this week in Applied Energy a study outlining how metal powder could serve as a zero-carbon fuel to power transportation and the grid.

Read More

How the Paris Climate Deal Happened and Why It Matters

One month after the terror attacks that traumatized Paris, the city has produced a climate agreement that is being hailed as a massive expression of hope. On Monday the U.K. Guardian dubbed the Paris Agreement, “the world’s greatest diplomatic success.” Distant observers may be tempted to discount such effusive language as hyperbole, yet there are reasons to be optimistic that last weekend’s climate deal finally sets the world on course towards decisive mutual action against global climate change. 

Read More
Advertisement

Newsletter Sign Up

Sign up for the EnergyWise newsletter and get biweekly news on the power & energy industry, green technology, and conservation delivered directly to your inbox.

Load More