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Success of the energy turnaround will depend decisively on the extended use of renewable energy sources. However, their efficiency partly is much smaller than that of conventional energy sources. The efficiency of commercially available photovoltaic cells, for instance, is about 20%. Scientists of Karlsruhe Institute of Technology (KIT) have now published an unconventional approach to increasing the efficiency of the panels. Optical invisibility cloaks guide sunlight around objects that cast a shadow on the solar panel, such as contacts for current extraction.

Energy efficiency of solar panels has to be improved significantly not only for the energy turnaround, but also for enhancing economic efficiency. Modules that are presently mounted on roofs convert just one fifth of the light into electricity, which means that about 80% of the solar energy are lost. The reasons of these high losses are manifold. Up to one tenth of the surface area of solar cells, for instance, is covered by so-called contact fingers that extract the current generated. At the locations of these contact fingers, light cannot reach the active area of the solar cell and efficiency of the cell decreases.

“Our model experiments have shown that the cloak layer makes the contact fingers nearly completely invisible,” doctoral student Martin Schumann of the KIT Institute of Applied Physics says, who conducted the experiments and simulations. Physicists of KIT around project head Carsten Rockstuhl, together with partners from Aachen, Freiburg, Halle, Jena, and Jülich, modified the optical invisibility cloak designed at KIT for guiding the incident light around the contact fingers of the solar cell.

Normally, invisibility cloak research is aimed at making objects invisible. For this purpose, light is guided around the object to be hidden. This research project did not focus on hiding the contact fingers visually, but on the deflected light that reaches the active surface area of the solar cell thanks to the invisibility cloak and, hence, can be used.

To achieve the cloaking effect, the scientists pursued two approaches. Both are based on applying a polymer coating onto the solar cell. This coating has to possess exactly calculated optical properties, i.e. an index of refraction that depends on the location or a special surface shape. The second concept is particularly promising, as it can potentially be integrated into mass production of solar cells at low costs. The surface of the cloak layer is grooved along the contact fingers. In this way, incident light is refracted away from the contact fingers and finally reaches the active surface area of the solar cell (see Figure).

By means of a model experiment and detailed simulations, the researchers demonstrated that both concepts are suited for hiding the contact fingers. In the next step, it is planned to apply the cloaking layer onto a solar cell in order to determine the efficiency increase. The physicists are optimistic that efficiency will be improved by the cloak under real conditions: “When applying such a coating onto a real solar cell, optical losses via the contact fingers are supposed to be reduced and efficiency is assumed to be increased by up to 10%,” Martin Schumann says.

More information: Martin F. Schumann, Samuel Wiesendanger, Jan Christoph Goldschmidt, Benedikt Bläsi, Karsten Bittkau, Ulrich W. Paetzold, Alexander Sprafke, Ralf B. Wehrspohn, Carsten Rockstuhl, and Martin Wegener, “Cloaked contact grids on solar cells by coordinate transformations: designs and prototypes,” Optica 2, 850-853 (2015) DOI: 10.1364/OPTICA.2.000850

Provided by: Karlsruhe Institute of Technology

The sweltering heat of summer may have subsided on this side of the equator, but one Lebanese student is keeping cool all year round with his innovative eco-friendly beach mat design that charges phones and chills beverages.

Powered by a five-watt solar panel and a built-in thermal fridge, the Beachill waterproof mattress lets beachgoers keep their drinks cold and their portable devices charged while making a positive impact on the environment.

Its lightweight design makes it easy to carry to and from any location, and a small pocket provides storage space.

Antoine Sayah developed the product for a university project that prompted students to invent something that was both ecological and useful to their day-to-day lives.

RELATED: 7 Prefab Eco-Houses You Can Order Today

“I designed something that could solve the problems I face when I go to the beach: My phone runs out of battery, water warms up in bottles, I can’t relax because mattresses cause back pain,” the 23-year-old student told Reuters. Sayah holds a degree in product design from a school in Italy but is studying architecture at Lebanon’s University Saint-Esprit de Kaslik, where he introduced the design.

Two weeks after posting the product to Instagram, Sayah sold 60 prototypes for $150 per mat and drew attention from people all around the world.

“I got phone calls from Brazil, Toronto, all Europe, especially France, America, from all continents, Africa, and even from Congo,” said the young designer. “When I started developing the project, I thought only people in Lebanon will see it and that will be it.”

Though Sayah and his product team are working to supply the unexpected demand, only 10 Beachills can be produced a day. However, the young innovator is reaching out to investors so he can expand the production to fulfill orders for both local and global customers.

In the meantime, the Beachill has undergone a makeover. On Tuesday, Sayah’s team announced a bigger, customizable version that can be converted into a sofa or bed and features a seven-watt solar charger.

The world’s first luxury electric SUV is gorgeous. It’s futuristic. And once again, Tesla Motors is redefining the electric vehicle.

The Silicon Valley automaker has teased us for years with the Model X, and tonight it finally gave the world its first look at the production model, then handed six customers the keys.

Those people now own a $130,000 electric vehicle that will go 250 miles on a charge, carry seven people and haul more stuff than anyone but a hoarder might want with him. And although the X shares much of its DNA with the impressive Model S P90D sedan, in many ways it eclipses that phenomenal car. It’s not just the design, which is futuristic without being weird. It’s not just the performance, which is holy shit fast. And it’s not even the dramatic “falcon” doors that lift like the wings of a bird.

It’s how all of those features come together in a vehicle that somehow makes an SUV not just cool, but desirable.

But then, that’s what Tesla does.

“The mission of Tesla is to accelerate the advent of sustainable transport,” CEO Elon Musk said at the car’s reveal, held at the company’s factory in Fremont, California. “It’s important to know that any kind of car can go electric.”

Complications

Reaching this point has been a longer journey than Elon Musk hoped. This is the car that’s supposed to prove his company is more than a one hit wonder, and an interlude before the long-awaited Model III brings a $35,000 EV to the masses in 2017.

Musk unveiled a prototype X in 2012, saying production would begin the following year. He later pushed that to 2014, which came and went with a promise that we’d see the X this year. But then that’s Musk-he often makes big promises with short timelines, which might explain why he told us tonight that if he had it to do over again, he’d have made the X less complicated and therefore easier to engineer and build.

Be that as it may, the car is here, and first impressions suggest it was worth the wait. If you order one today, though, you’ll have to wait a while longer: Tesla estimates it’ll take 8 to 12 months to deliver cars ordered now.

Complexities

The X is, in a word, stunning. Its most amazing features are its mind-bending acceleration, gorgeous design, and amazing rear passenger doors. Tesla calls them “falcon” doors, because they lift like the wings of a bird. And because it sounds cool.

The big drawback of doors that open like wings-the Mercedes-Benz AMG SLS has them, as did the DeLorean-is they require a lot of room to open, so you’re always worried about hitting something. Tesla got around this by double-hinging the doors, and fitting each with an ultrasonic sensor and putting a third on the roof. They scan the area around the vehicle to determine how much space there is, then adjust the “span” and open accordingly.

It sounds complicated as hell, and it is, but it works beautifully. Tesla engineers say the doors can open with as little as 12 inches on each side of the vehicle-then proved it by having us park between two cars. The mirrors on the X were mere inches from those of the car on either side, yet the doors opened flawlessly. Capacitive sensors in the edges of each door sense obstacles within 2 to 4 inches, so you don’t have to worry about a descending door whacking your head or crushing your fingers.

All of this may sound like a frivolous extravagance, and in some ways it is-and you know part of the reason Musk wanted these doors was to prove he could make them-but it’s remarkably clever, even practical.

Unless you regularly haul enough cattle to supply all the leather in this thing, space is not a problem.

Yes, practical. The doors make it easy to get in and out of the vehicle. No gymnastic contortions to get into the (standard) third row seating. No more cantilevering yourself to get your kids into their child seats. No more playing Tetris trying to get your stuff in. Just throw open those doors-actually, push a button and let the doors lift automatically, in 6 to 7 seconds-throw in your groceries and bags and whatnot, and climb in after it.

Speaking of stuff, the X is cavernous. No one could tell us the internal volume-you’d think someone at Tesla would have had that figure-but one engineer said you could carry a sheet of plywood. Another said the X would easily swallow a surfboard. And yet another said you could carry a load of two-by-fours. Suffice it to say, this thing will swallow as much cargo as any normal person would carry. Tesla offers an accessory hitch that holds four bikes or six pairs of skis, and can be attached to the back of the car in just a few seconds.

Should you somehow manage to run out of room, the Model X has Class 3 towing capacity, which in lay terms means it’ll haul 5,000 pounds.

In other words, unless you regularly haul enough cattle to supply all the leather in this thing, space is not a problem.

Cavernous

Another clever trick is the “monopost” design of the second-row seats, which is fancy way of saying that each seat (two if you get the six-passenger model, three if you get the seven), sits on its own chrome-plated post. That makes each seat almost infinitely adjustable fore and aft and provides ample room for everyone’s feet. The designers drew inspiration from high-end office chairs and admit they were, like the doors, a bitch to engineer.

Along with the doors and the seats, Musk is especially proud of the “panoramic” windshield, which extends back over the front seat seats to provide an exceptional view. Tesla claims it is the largest windshield ever installed in a production vehicle-yet, oddly, no one had actually measured the damn thing and so couldn’t say exactly how big it is.

Inside, the X is futuristic without being funky, with acres of white leather, plenty of cubbies and cupholders, and that enormous 17-inch touchscreen in the middle of the dash.

Whatever the number, we can tell you that if you look at the X head-on, it appears to have a glass roof, and riding up front almost like being in a convertible.

Equally impressive is the sound system which is, in a word, glorious. But then, with 560 watts and 17 speakers, how could it not be? Tesla designed the system in-house specifically for the X because it wanted to ensure the system delivered the best sound with the smallest power requirements-essential in an electric vehicle. (General Motors took a similar tack with the Chevrolet Volt, tapping Bose to design a system specifically for the car.) The sound is crisp, clear, and loud-even when standing 15 feet away from the car.

The styling is perhaps best described as a Model S on steroids. It’s a taller, obviously, and, at 5,441 pounds, about 740 pounds heavier than the S. That said, it also looks more than a little like the BMW X6 from the rear three-quarter view-but when it glides by you silently on the freeway, you’ll know it’s a Tesla.

Inside, the X is futuristic without being funky, with acres of white leather, plenty of cubbies and cupholders, and that enormous 17-inch touchscreen in the middle of the dash.

Competition

Although the X is the first electric luxury SUV, it won’t be alone for long. Bentley promises a plug-in hybrid version of its new, ultra-luxe Bentayga SUV in about a year. Rolls-Royce and Lamborghini have hinted at similar plans. Last month, Audi showed off an all-electric crossover concept that’s probably a preview of the 2019 Q6. Aston Martin wants to have one ready in two years.

If you decide to stomp on the accelerator, make damn sure you’ve got plenty of open road ahead of you.

No one at Tesla would say just what performance, handling, and comfort benchmarks they aimed at with the X, but they’re well aware of everyone’s plans and not terribly worried. And the fact they had a Porsche Cayenne and a BMW X5 in the parking lot for comparison suggests they’re quite confident of the Model X’s sporting capabilities.

They have every reason to be.

Let’s start with the acceleration. It’s crazy. Every Model X comes with a 90 kilowatt-hour battery and dual motors, a model known as 90D. Drop another 10 grand and you get the P90D, which is the performance model with its “ludicrous mode.” Yes, Tesla actually calls it that, and it’s fitting. If you decide to stomp on the accelerator, make damn sure you’ve got plenty of open road ahead of you, because things happen very quickly. Sixty mph comes in 3.2 seconds, which is on par with the some of the best sports cars from anyone in Italy, Germany, or Britain. We tried it. That number’s legit.

We didn’t have the room to do a quarter-mile run, but Tesla says the Model X P90D will do it in 11.7 seconds. That put its alongside cars like the BMW M5, Corvette Z06, and Porsche Panamera Turbo. Top speed is limited to 155 mph.

If you find ludicrous mode just a bit too, well, ludicrous, or you don’t want to spend that extra dough, the base model adds about half a second to the acceleration and quarter-mile times. Which is to say, it’s still bloody fast. The Model X 90D starts for $132,000 and goes 257 miles on a charge, the more acceleration-friendly P90D will cost you $142,000 and cover 250 miles.

Under the skin, the Model X is identical to the Model S. Same 90 kilowatt-hour lithium ion battery. Same drive motors (259 horsepower at the front, 503 at the rear). Same software controlling it all. And the vehicles share the same (semi) autonomous capabilities.

The two vehicles both “quick charge” at one of Tesla’s stations in 30 minutes. They are designed to be updated in tandem, so any software updates or performance upgrades will apply to both the S and the X. And they will roll down the same assembly line at Tesla’s sprawling factory in Fremont. The company plans to ramp up production, immediately, but wouldn’t say how many might be built by the end of the year.

Of all the things that, at first glance, make the X so remarkable, the most impressive thing about it is the overall impression it imparts. It’s a practical car-Musk has five young children, and clearly considers the demands of hauling them all when designing vehicles-but it’s not a minivan or station wagon that embarrasses parents and kids alike.

Tesla has made the family car cool.

Consider the plastic foam cup. Every year, Americans throw away 2.5 billion of them. And yet, that waste is just a fraction of the 33 million tons of plastic Americans discard every year. Less than 10 percent of that total gets recycled, and the remainder presents challenges ranging from water contamination to animal poisoning.

Enter the mighty mealworm. The tiny worm, which is the larvae form of the darkling beetle, can subsist on a diet of Styrofoam and other forms of polystyrene, according to two companion studies co-authored by Wei-Min Wu, a senior research engineer in the Department of Civil and Environmental Engineering at Stanford. Microorganisms in the worms’ guts biodegrade the plastic in the process – a surprising and hopeful finding.

“Our findings have opened a new door to solve the global plastic pollution problem,” Wu said.

The papers, published in Environmental Science and Technology, are the first to provide detailed evidence of bacterial degradation of plastic in an animal’s gut. Understanding how bacteria within mealworms carry out this feat could potentially enable new options for safe management of plastic waste.

“There’s a possibility of really important research coming out of bizarre places,” said Craig Criddle, a professor of civil and environmental engineering who supervises plastics research by Wu and others at Stanford. “Sometimes, science surprises us. This is a shock.”

Plastic for dinner

In the lab, 100 mealworms ate between 34 and 39 milligrams of Styrofoam – about the weight of a small pill – per day. The worms converted about half of the Styrofoam into carbon dioxide, as they would with any food source.

Within 24 hours, they excreted the bulk of the remaining plastic as biodegraded fragments that look similar to tiny rabbit droppings. Mealworms fed a steady diet of Styrofoam were as healthy as those eating a normal diet, Wu said, and their waste appeared to be safe to use as soil for crops.

Researchers, including Wu, have shown in earlier research that waxworms, the larvae of Indian mealmoths, have microorganisms in their guts that can biodegrade polyethylene, a plastic used in filmy products such as trash bags. The new research on mealworms is significant, however, because Styrofoam was thought to have been non-biodegradable and more problematic for the environment.

Researchers led by Criddle, a senior fellow at the Stanford Woods Institute for the Environment, are collaborating on ongoing studies with the project leader and papers’ lead author, Jun Yang of Beihang University in China, and other Chinese researchers. Together, they plan to study whether microorganisms within mealworms and other insects can biodegrade plastics such as polypropylene (used in products ranging from textiles to automotive components), microbeads (tiny bits used as exfoliants) and bioplastics (derived from renewable biomass sources such as corn or biogas methane).

As part of a “cradle-to-cradle” approach, the researchers will explore the fate of these materials when consumed by small animals, which are, in turn, consumed by other animals.

Marine diners sought

Another area of research could involve searching for a marine equivalent of the mealworm to digest plastics, Criddle said. Plastic waste is a particular concern in the ocean, where it fouls habitat and kills countless seabirds, fish, turtles and other marine life.

More research is needed, however, to understand conditions favorable to plastic degradation and the enzymes that break down polymers. This, in turn, could help scientists engineer more powerful enzymes for plastic degradation, and guide manufacturers in the design of polymers that do not accumulate in the environment or in food chains.

Criddle’s plastics research was originally inspired by a 2004 project to evaluate the feasibility of biodegradable building materials. That investigation was funded by the Stanford Woods Institute’s Environmental Venture Projects seed grant program. It led to the launch of a company that is developing economically competitive, nontoxic bioplastics.

More information: “Biodegradation and Mineralization of Polystyrene by Plastic-Eating Mealworms. 1. Chemical and Physical Characterization and Isotopic Tests.” Environ. Sci. Technol., Just Accepted Manuscript DOI: 10.1021/acs.est.5b02661

“Biodegradation and Mineralization of Polystyrene by Plastic-Eating Mealworms. 2. Role of Gut Microorganisms.” Environ. Sci. Technol., Just Accepted Manuscript DOI: 10.1021/acs.est.5b02663

Provided by: Stanford University

Teenager becomes regional finalist in Google’s 2014 Science Fair with shoe insole that generates electricity

By John Vibes,

True Activist.

15-year-old Angelo Casimiro, from the Philippines, has recently made international news with a new invention that generates electricity in a very new and interesting way. The invention is a shoe insole that harnesses electricity every time that the person wearing the shoe takes a step. Angelo constructed his device using piezoelectric materials, which actually generate an alternating current voltage every time they are squeezed.

According to a blog post made by the teenager, “Piezoelectricity was present ever since mid-18th century. Piezoelectricity is the electric charge that accumulates in certain solid materials (such as crystals, certain ceramics in response to applied mechanical stress.”

Young Angelo has been working hard developing this idea for the past 4 years, since he was 11 years old. Now that he believes he has perfected his invention, he is prepared to share it with the world. He started by entering the project into this year’s Google’s Science Fair, where he has become a regional finalist.

The device can be used to charge cell phones and other electronic devices, which may not sound like a big deal, but it is actually a huge innovation. Imagine never worrying about charging your cell phone ever again when you are out on vacation, at a festival or on a hike. Additionally, Angelo has made the plans for the device open sourced, so others can apply their own ideas to this concept, and possibly be able to improve this idea for wider uses.

Angelo says that while this device is fully operational, it is not yet ready for mass distribution.

At an event outside its Fremont, California factory later today, Tesla will at long last deliver its first batch of production Model X crossovers to early pre-order customers. This has been a hell of a journey: the vehicle has been kicking around in concept form for practically as long as the Model S sedan has been on the road, and was originally supposed to launch in 2013 – but challenges with design and manufacturing have pushed it way, way out. (Considering that the order waitlist is into next year, that doesn’t seem to have had much effect on demand.)

As with the Model S before it, very early buyers of the Model X are getting a Signature Edition, which is pre-specced with almost every option. (It’s not unusual for automakers to do a run of similar or identical cars when a new model comes out, which lets dealers stock a standard show car and gives the factory some runway to iron out production kinks.) Needless to say, the Signature Editions are sold out, and buyers are paying a premium for the privilege: more than $130,000, which puts this car in the upper echelon of Model S pricing. Full pricing information won’t be revealed until tonight, but considering the more complex mechanisms in the car, it’s almost certain that you’ll be able to spend more on this than you can on a fully loaded S.

So as you get ready for Tesla to unveil a new car – something that only happens once every few years – here are some interesting facts to consider.

A car this big shouldn’t be able to move this quickly

It is, in many ways, just a bigger Model S. The similarities between the S and X go well beyond the strong familial resemblance. Remember the launch of the dual-motor Model S last year, Tesla’s first all-wheel-drive vehicle? That powertrain was already being developed for the Model X, which made it easy for engineers to bolt it onto the sedan, too. The result is one of the quickest sedans in the world – and a car that is far more appropriate for winter climates than the original rear-wheel-drive version.

It will have three proper rows of seating. For families, this is likely to be a big deal. The Model S can be optioned with a sort of vestigial rear-facing seat in the trunk area, but it’s definitely not the sort of thing you’d want to have to use on a regular basis. If you’ve got five or more people in your posse, the X is going to be a more comfortable option than the S could ever be.

It’s still ridiculously (ludicrously?) quick. The X uses a version of the dual-motor powertrain from the Model S, which means it’s able to bend light almost as effectively – it’s only a little slower because it’s a bigger, heavier car. With the Ludicrous Mode option, the Model X will sprint from 0 to 60 mph in an estimated 3.2 seconds. That’s the same as a $151,000 Porsche 911 Turbo. It is liable to terrify your dog, your children, their friends, and whatever else you’re hauling to the Little League game.

It has less range than the Model S, but not way less. According to preliminary EPA numbers, the Performance version only gives up 3 miles of range against its Model S equivalent; the non-Performance version gives up 13 miles. Regardless of configuration, you’re getting at least 250 claimed miles of range with a 90kWh battery pack. Combine that with Superchargers, home charging, and the occasional Level 2 charge around town, and that should be just as livable as the Model S.

It will have the craziest doors of any family car ever put into production (and it’s not even close). One of the Model X’s defining features is its “falcon wing doors,” which allow enormous openings into the second row of seats – convenient if you have to throw a big Ikea box back there, or a child seat. They’re also hinged so they can be opened inside a garage without hitting the walls. They are nuts, and they made it to the production version of the car, which is doubly nuts. This is the kind of feature that typically falls by the wayside as engineers make the transition from concept to reality.

This is the last extremely expensive car Tesla will be launching for a while. Next on Elon Musk’s agenda is the Model 3, a vehicle more important than the S and X combined. Why? It’s easy to forget that both of Tesla’s current models are very, very expensive cars – the overwhelming majority of car owners can only dream of owning something this pricey. The 3 is expected to be a mass-market vehicle that will deliver long, practical range for around $35,000. If Musk can deliver on the promise and make enough of them, they’ll sell far better than the S and X can ever hope to.

The event kicks off at 8PM PT / 11PM ET this evening – including a livestream – and we’ll have all the news for you.

Jackson Hole, Wyoming, may not be a place many people pick out on a map to travel to, let alone even know exists.

The town experiences long, cold, bitter winters, resulting in its produce taking a huge hit because quite simply, residents can’t grow much of anything due to the harsh weather.

In the past, Jackson Hole had to rely on neighboring states and even other countries to import fresh fruits and vegetables, but a new project called Vertical Harvest is hoping it can help feed the town’s residents in a more efficient manner.

Vertical Harvest is a multi-story greenhouse built on the side of a parking garage, a rare vertical farm capable of growing tomatoes, herbs, and microgreens.

How It Works:

Vertical Harvest’s 30 foot by 150 foot plot of land features carousels that keep plants moving the length of the greenhouse, giving them equal time in natural light, and also allowing workers to pick and transfer the crops.

Hydroponics enables the initiative to produce over 37,000 pounds of greens, 4,400 pounds of herbs, and 44,000 pounds of tomatoes!

Best of all, Vertical Harvest uses 90 percent less water and 100 percent fewer pesticides than traditional farming.

“The worldwide transition from fossil fuels to renewable sources of energy is under way …” according to the Earth Policy Institute’s new book, The Great Transition.

Between 2006 and 2012, global solar photovoltaic’s (PV) annual capacity grew 190 percent, while wind energy’s annual capacity grew 40 percent, reported the International Renewable Energy Agency. The agency projects that by 2030, solar PV capacity will be nine times what it was in 2013; wind power could increase five-fold.

Electric vehicle (EV) sales have risen 128 percent since 2012, though they made up less than 1 percent of total U.S. vehicle sales in 2014. Although today’s most affordable EVs still travel less than 100 miles on a full battery charge (the Tesla Model S 70D, priced starting at $75,000, has a 240-mile range), the plug-in market is projected to grow between 14.7 and 18.6 percent annually through 2024.

The upward trend for renewables is being driven by concerns about climate change and energy security, decreasing solar PV and wind prices, rising retail electricity prices, favorable governmental incentives for renewable energy, the desire for energy self-sufficiency and the declining cost of batteries. Growing EV sales, also benefitting from incentives, are affecting economies of scale in battery manufacturing, helping to drive down prices.

Sun and wind energy are free, but because they are not constant sources of power, renewable energy is considered “variable”-it is affected by location, weather and time of day. Utilities need to deliver reliable and steady energy by balancing supply and demand. While today they can usually handle the fluctuations that solar and wind power present to the grid by adjusting their operations, as the amount of energy supplied by renewables grows, better battery storage is crucial.

Batteries convert electricity into chemical potential energy for storage and back into electrical energy as needed. They can perform different functions at various points along the electric grid. At the site of solar PV or wind turbines, batteries can smooth out the variability of flow and store excess energy when demand is low to release it when demand is high. Currently, fluctuations are handled by drawing power from natural gas, nuclear or coal-fired power plants; but whereas fossil-fuel plants can take many hours to ramp up, batteries respond quickly and when used to replace fossil-fuel power plants, they cut CO2 emissions. Batteries can store output from renewables when it exceeds a local substation’s capacity and release the power when the flow is less or store energy when prices are low so it can be sold back to the grid when prices rise. For households, batteries can store energy for use anytime and provide back-up power in case of blackouts.

Batteries have not been fully integrated into the mainstream power system because of performance and safety issues, regulatory barriers, the resistance of utilities and cost. But researchers around the world are working on developing better and cheaper batteries.