We might not always notice it, but the air around us is constantly heating up and cooling down. Now scientists at MIT have decided to put these temperature changes to good use, with a device that turns them into electricity.
Their device, called “thermal resonator” improves on conventional thermoelectric generators, which work by converting a temperature differential into electrical power. This particular system doesn’t require two different temperature inputs – instead, it uses a special material that guarantees a slow radiation of heat, so the temperature of one side of the device always lags behind the other.
The researchers, who described their work in the journal Nature Communications, wanted to develop a material with strong “thermal effusivity”, namely the combination of how quickly heat can travel through a substance, and how effectively it can be stored. Typically, if one of these properties is high, the other one is low.
The thermal resonator avoids that outcome by combining a metal foam made from copper of nickel with a layer of graphene to enhance its conductivity. It’s then infused with a phase-change material called octadecane, which is capable of storing and releasing a huge amount of heat.
One side of the device captures heat, which is then slowly transported to the other side. The material is very good at holding on to the heat, but can also move it around effectively, facilitating the differential required to generate electricity.
The researchers ran initial tests using the 24-hour cycle of ambient air temperature. However they think that the device could also harvest electricity from other temperature variations, such as those produced by on-off cycling of everything from a domestic refrigerator to industrial machinery.
However exciting, the system still has significant limitations. Its modest power levels mean that it can only charge tools that don’t require lots of electricity, like remote sensors. We are unlikely to see such system powering our home appliances anytime soon, but this idea adds to an array of innovations that provide alternatives to more mainstreams sources of clean energy, such as wind or the sun. And to wean ourselves off fossil fuels every small step counts.
Europe is making impressive strides in the clean energy revolution. The continent as a whole was able to produce more electricity from renewable sources like solar, wind, and biomass than it did burning coal in 2017. A data analysis by the climate policy campaign group Sandbag showed that renewable energy just edged out coal-generated power with 679 terawatt-hours compared to coal’s 669 terawatt-hours.
But before we break out the champagne from biodegradable bottles, this achievement needs to be put into context. According to figures compiled by Eurostat, only about 19 percent of Europe’s energy was generated from solid fuels like coal. An additional 24 percent was generated from other sources like natural gas and crude oil — which means phasing out coal-generated power is just one step towards reducing carbon emissions.
Moreover it isn’t clear whether using biomass — organic matter like wood and organic plant material — to generate power provides any more environmental relief than burning coal or other fossil fuels. Researchers from a group of concerned universities published a study published in the journal Environmental Research Lettersin which they explained while burning wood may lower long-term carbon dioxide concentrations in the long run, in the short term it will actually raise those levels.
The data from Europe are still welcome news. In just five years, coal-generated power went from being double that of renewable source-generated power to less than solar, wind, and biomass energy. But the struggle against climate change is ever-present, and utilizing the most environmentally energy sources is critical towards limiting carbon emissions.
Google CEO Sundar Pichai, speaking at a taped television event hosted by MSNBC and The Verge’s sister site Recode, said artificial intelligence is one of the most profound things that humanity is working on right now and compared it to basic utilities in terms of its importance.
Speaking to Recode’s Kara Swisher and MSNBC’s Ari Melber, Pichai said AI is “one of the most important things that humanity is working on. It’s more profound than, I don’t know, electricity or fire,” adding that people learned to harness fire for the benefits of humanity, but also needed to overcome its downsides, too. Pichai also said that AI could be used to help solve climate change issues, or to cure cancer.
Denmark recently set a new record in wind power generation, harvesting 43.4 percent of its electricity from the resource in 2017 — beating its previous best from 2016. The country’s government is hoping to use the momentum to encourage other countries to get on board.
“The price of wind energy is moving in one direction only, and that’s a steep downward trajectory,” commented Denmark’s energy minister Lars Chr. Lilleholt, according to a report from Bloomberg.
While Denmark’s decision to pursue renewable resources is part of a larger global effort to phase out fossil fuels, the country does have something of a vested interest. The world’s biggest turbine maker, Vestas Wind Systems A/S, is Danish. Furthermore, its government holds a controlling stake in Orsted A/S, which remains the biggest operator of offshore wind farms internationally.
Denmark still subsidizes wind power projects, as it has done since the 1970s. However, Lilleholt is confident that this will not be necessary for much longer.
Just six years ago, more than 40% of Britain’s electricity was generated by burning coal. Today, that figure is just 7%. Yet if the story of 2016 was the dramatic demise of coal and its replacement by natural gas, then 2017 was most definitely about the growth of wind power.
Wind provided 15% of electricity in Britain last year (Northern Ireland shares an electricity system with the Republic and is calculated separately), up from 10% in 2016. This increase, a result of both more wind farms coming online and a windier year, helped further reduce coal use and also put a stop to the rise in natural gas generation.
In October 2017, the combination of wind, solar and hydro generated a quarter of Britain’s electricity over the entire month, a new record helped by ex-hurricane Ophelia and storm Brian.
Since that record month, large new offshore wind farms have started to come online. Dudgeon began generating off the Norfolk coast, as did Rampion, which can be seen from Brighton town centre.
In all, Britain’s wind output increased by 14 terawatt hours between 2016 and 2017 – enough to power 4.5m homes. To give a sense of scale, this increase alone is more than the expected annual output from one of the two new nuclear reactors being built at Hinkley Point C.
Not only is offshore wind growing fast, it is also getting much cheaper. When the latest round of government auctions for low-carbon electricity were awarded last year, two of the winning bids from offshore wind developers had a “strike price” of £57.50 per megawatt hour (MWh). This is considerably cheaper than the equivalent contract for Hinkley Point of £92.50/MWh (in 2012 prices).
Although these wind farms won’t be built for another five years, this puts competitive pressure on other forms of low-carbon electricity. If there is to be a nuclear renaissance, or if fossil fuels with carbon capture and storage are to become a reality, these industries will have to adjust to the new economic reality of renewable energy.
Britain is using less electricity
Overall demand for electricity also continued its 12-year downward trend. More of the electricity “embedded” in the products and services used in the UK is now imported rather than produced at home, and energy efficiency measures mean the country can do more with less. This meant Britain in 2017 used about as much electricity as it did way back in 1987 – despite the considerable population growth.
At some point this trend will reverse though, as electric vehicles and heat pumps become more common and electricity partly replaces liquid fuels for transport and natural gas for heating respectively. One major challenge this brings is how to accommodate greater seasonal and daily variation in the electricity system, without resorting to the benefits of fossil fuels, which can be pretty cheaply stored until required.
Electricity generated in Britain is now the cleanest it’s ever been. Coal and natural gas together produced less than half of the total generated. Britain’s electricity was completely “coal free” for 613 hours last year, up from 200 hours in 2016. This position would be wholly unthinkable in many countries including Germany, India, China and the US, which still rely heavily on coal generation throughout the year.
However, the low level of coal generation over 2017 masks its continued importance in providing capacity during hours of peak demand. During the top 10% hours of highest electrical demand, coal provided a sixth of Britain’s electricity. When it matters most, coal is relied on more than nuclear, and more than the combined output from wind + solar + hydro. Additional energy storage could help wind and solar meet more of this peak demand with greater certainty.
Looking forward to 2018, we would be surprised if wind generation dropped much from its current levels. Last year wasn’t even particularly windy compared to the longer-term average, and more capacity will be coming online. Equally, it would be surprising if solar and hydro combined produced significantly less than they did last year.
It is therefore inevitable that another significant milestone will be reached this year. At some point, for several hours, wind, solar and hydro will together, for the first time, provide more than half of Britain’s electricity generation. This goes to show just how much a major power system can be reworked within a decade.
The data used in this article is based on the Energy Charts and Electric Insights websites, which allow readers to visualise and explore data on generation and consumption from Elexon and National Grid. Data from other analyses (such as BEIS or DUKES) will differ due to their methodology, particularly by including combined heat and power, and other on-site generation which is not monitored by National Grid and Elexon. Our estimated carbon emissions are based on Iain Staffell’s research published in Energy Policy, and account for foreign emissions due to electricity imports and biomass fuel processing.
CES, the world’s biggest tech event, is treating attendees to a decidedly retro experience this year: there’s no electricity. The power went out around noon local time and there’s no telling when it’s coming back on. What is it? It’s either a fascinating piece of performance art depicting humankind’s over-dependence on technology, or there’s an issue with the grid in Las Vegas somewhere. Either way, our on-the-scene correspondant Bryan Clark reports the venue may be evacuated over safety concerns at this point. Yikes. #CES2018 blackout is the first time a lot of tech journos have seen the sun in months.…
In science, there exists a law known as the Wiedemann-Franz Law that states, simply, that most metals that are good conductors of electricity are also good conductors of heat. This law essentially explains why things like motors and smartphones become hot when they’re used for an extended period of time.
However, one metal has been discovered to break this rule. Known as metallic vanadium dioxide (VO2), it’s seemingly capable of conducting electricity without the accompanying heat. VO2 is already a unique metal — it can switch between being an insulator and a conductor when heated to 67 degrees Celsius (152 degrees Fahrenheit) — but its diversion from the Wiedemann-Franz Law means that it could be ideal for a wider range of applications which other metals are not suited for.
“This was a totally unexpected finding,” said lead researcher and physicist Junqiao Wu, from Berkeley Lab’s Materials Sciences Division. “It shows a drastic breakdown of a textbook law that has been known to be robust for conventional conductors. This discovery is of fundamental importance for understanding the basic electronic behavior of novel conductors.”
Wu and his team reached out to Oak Ridge National Laboratory Associate and Duke University professor Olivier Delaire to learn more about VO2. Using simulations and X-ray scattering experiments, their combined efforts enabled them to observe the material’s crystal lattice — known as phonons — and how its electrons move. Vanadium dioxide then revealed to the team that the thermal conductivity attributed to the electrons is ten times smaller than what the Wiedemann-Franz Law led them to expect. Furthermore, the electrons were moving in a manner similar to a fluid.
“The electrons were moving in unison with each other, much like a fluid, instead of as individual particles like in normal metals,” explained Wu. “For electrons, heat is a random motion. Normal metals transport heat efficiently because there are so many different possible microscopic configurations that the individual electrons can jump between.”
Wu added, “In contrast, the coordinated, marching-band-like motion of electrons in vanadium dioxide is detrimental to heat transfer as there are fewer configurations available for the electrons to hop randomly between.”
The surprises didn’t stop there. The team then discovered that the amount of electricity and heat VO2 can conduct can be adjusted when other materials are introduced. Adding metal tungsten, for example, simultaneously decreased the temperature at which VO2 would become metallic, and made it a better heat conductor.
“This material could be used to help stabilize temperature,” said Fan Yang, a postdoctoral researcher at Berkeley Lab’s Molecular Foundry and co-lead author on the study. Yang went on to explain that more work and research would be required before vanadium dioxide could be commercialized and used in publicly available products.
That said, the team notes that VO2 has the potential to be used to remove, or at least reduce, the heat in engines, or to create a window coating that “improves the efficient use of energy in buildings.” Imagine being able to cool down a room without using any air conditioning or standing fans, or keeping the heat inside of a building during the Winter.
Of course, only time will tell if vanadium dioxide is up to the task. Regardless of the outcome, it’s interesting to learn how such characteristics exist in unsuspecting materials.