New Fabric uses Sun and Wind to Power Devices

A piece of fabric woven with special strands of material that harvest electricity from the sun and motion.

A piece of fabric woven with special strands of material that harvest electricity from the sun and motion.

Fabrics that can generate electricity from physical movement have been in the works for a few years. Now researchers at Georgia Institute of Technology have taken the next step, developing a fabric that can simultaneously harvest energy from both sunshine and motion.

Combining two types of electricity generation into one textile paves the way for developing garments that could provide their own source of energy to power devices such as smart phones or global positioning systems.

“This hybrid power textile presents a novel solution to charging devices in the field from something as simple as the wind blowing on a sunny day,” said Zhong Lin Wang, a Regents professor in the Georgia Tech School of Materials Science and Engineering. The research was reported in the Nature Energy.

To make the fabric, Wang’s team used a commercial textile machine to weave together solar cells constructed from lightweight polymer fibers with fiber-based triboelectric nanogenerators.

Triboelectric nanogenerators use a combination of the triboelectric effect and electrostatic induction to generate small amount of electrical power from mechanical motion such as rotation, sliding or vibration.

Wang envisions that the new fabric, which is 320 micrometers thick woven together with strands of wool, could be integrated into tents, curtains or wearable garments.

“The fabric is highly flexible, breathable, light weight and adaptable to a range of uses,” Wang said.

Fiber-based triboelectric nanogenerators capture the energy created when certain materials become electrically charged after they come into moving contact with a different material. For the sunlight-harvesting part of the fabric, Wang’s team used photoanodes made in a wire-shaped fashion that could be woven together with other fibers.

“The backbone of the textile is made of commonly-used polymer materials that are inexpensive to make and environmentally friendly,” Wang said. “The electrodes are also made through a low cost process, which makes it possible to use large-scale manufacturing.”

In one of their experiments, Wang’s team used a fabric only about the size of a sheet of office paper and attached it to rod like a small colorful flag. Rolling down the windows in a car and letting the flag blow in the wind, the researchers were able to generate significant power from a moving car on a cloudy day. The researchers also measured the output by a 4 by 5 centimeter piece, which charged up a 2 mF commercial capacitor to 2 volts in one minute under sunlight and movement.

“That indicates it has a decent capability of working even in a harsh environment,” Wang said.

While early tests indicate the fabric can withstand repeated and rigorous use, researches will be looking into its long-term durability. Next steps also include further optimizing the fabric for industrial uses, including developing proper encapsulation to protect the electrical components from rain and moisture.


From Dirt-Cheap Panels to Charging Your Car with the Sun: 3 Solar Trends

Experts show off the future of solar at North America’s largest solar trade show

By: Kim Brunhuber

Companies like Google are installing mobile solar charging stations like this for their employees' electric vehicles. (Kim Brunhuber/CBC)

Companies like Google are installing mobile solar charging stations like this for their employees’ electric vehicles. (Kim Brunhuber/CBC)

The exhibition floor seems virtually endless. With 600 vendors and almost 18,000 visitors, the size of the solar power trade show in Las Vegas gives you an idea of just how big the American solar industry is becoming.

In 2015 it was worth almost $23 billion US. And according to theSolar Energy Industries Association, it’s expected to double in 2016.

One of the trends driving that growth has been the falling cost of solar energy. The price of installing solar has dropped by more than 70 per cent over the last 10 years. And according to Hugh Bromley, who analyzes the industry for Bloomberg New Energy Finance, it’s expected to fall even further.

In the past decade, the cost of solar panels has plummeted 70 per cent. (Kim Brunhuber/CBC)

In the past decade, the cost of solar panels has plummeted 70 per cent. (Kim Brunhuber/CBC)

“The technology’s evolutionary, not revolutionary, but the costs are being pushed down year on year,” Bromley says. “And in fact, you see oversupply in the amount of solar equipment produced, which means you can source equipment quite cheaply.”

A Solution for High Cost of Installation

The cost that still remains relatively high is for installing solar panels on rooftops. But thanks to new technology — from placemat-thin solar panels to innovative engineering — installation is getting cheaper, too.

Neil Goldberg, CEO of Smash Solar, lifts a solar panel at his booth and reveals the rivets underneath. “We’ve developed a system where you just take a module, you put it on the roof … no structure to build, you just bolt it down.”

Neil Goldberg, co-founder of Smash Solar, shows off a design that he says can be installed for a third of the cost of earlier models. (Kim Brunhuber/CBC)

Neil Goldberg, co-founder of Smash Solar, shows off a design that he says can be installed for a third of the cost of earlier models. (Kim Brunhuber/CBC)

Goldberg’s system has done away with a costly metal framework. “This is attached with the same glue that hangs glass off the sides of skyscrapers, so it’s never coming off,” Goldberg says.

A second major trend builds on interest in finding ways to recharge electric cars without using fossil fuels.

In the trade show parking lot, Michael Kung of King Solarman demonstrates a solar panel on wheels that’s hooked up to a Tesla automobile.

Solar Charging in the Employee Lot

He crawls under the panel and points at a battery underneath. “Sun is pretty bright right now. We’re charging and storing the power in the battery. And from the battery, we have power from the inverter that charges the car.”

He says you can spot these solar stations charging cars in parking lots at companies like Google, Apple, Tesla and UPS.

One of the trends: portable solar car-charging stations. (Kim Brunhuber/CBC)

One of the trends: portable solar car-charging stations. (Kim Brunhuber/CBC)

“You come to the office, your electrical vehicle is maybe one-third or half empty,” Kung says. “So you just park in the parking lot, in afternoon or lunchtime, your car is fully charged.” He pauses, lifts his hands towards the sky. “Is free!”

The third major trend doesn’t directly involve solar panels.

“A lot of the exciting developments happening at the moment are around the software side,” Bromley says. “How do you integrate solar and storage systems into your environment? What app do you have that shows you how much solar energy you’re producing, how much is that saving you?”

Apps Track the Solar Advantage

Coming soon: Apps that tell you when you can make the most money selling power back to the grid.

Andrew Krulewitz has spent hours extolling the virtues of Geli software to interested passersby.

Andrew Krulewitz says solar customers will be able to use apps to find out when they can make the most money selling power to the grid. (Kim Brunhuber/CBC)

Andrew Krulewitz says solar customers will be able to use apps to find out when they can make the most money selling power to the grid. (Kim Brunhuber/CBC)

“It lets homeowners take greater control of their energy,” Krulewitz says in his polished pitch. “They can see what they’re using, where it’s coming from, whether it’s coming from the grid, solar, battery, and they can decide what to do with it.”

But it’s the software that his company is developing that shows where the industry is heading.

“What our software will allow for, is when the grid operator — the utility — says, ‘We could really use support from all these residential solar systems,’ the homeowner will get an alert on their phone saying, ‘Do you want to participate in this grid service, yes or no?'” Krulewitz says. “And if they say ‘yes,’ the utility is now starting to compensate homeowners for excess energy that they sell at a very specific point in time.”

This year marked the installation of the millionth solar system in the U.S. That took 40 years from the inception of a solar industry. Installing the next million is expected to take just two.


New Solar Markets With Next-Gen Flexible Solar Product

Is this finally the moment for building-integrated photovoltaics to take off?

By: Julia Pyper

Solar industry leaders talk about the need to install solar everywhere. Some companies are taking that literally by developing new products they claim can expand solar power infinitely.

This week, as Solar Power International kicked off in Las Vegas, Hanergy-owned MiaSolé announced the launch of its new “flexible, thin, ultra-light, high efficiency, shatterproof modules” that the company expects to open up new solar markets and enable manufacturers to integrate solar in unique ways.

This is the first major product announcement for MiaSolé since it was acquired by the Chinese renewable energy company Hanergy at a fire-sale price in 2013. (China’s Hanergy had its shares suspended for one year in 2015 due to an investigation over financial manipulation. It now says its thin-film division is profitable.)

According to the company, the flex series panels are up to 17 percent efficient, which is significantly higher than previous flexible solar technologies. The panels come in a bendable form factor that’s four times lighter than traditional rigid solar panels, and just 2.5 millimeters thick. The product can be configured in various sizes and adapted to any building-integrated photovoltaic (BIPV) application by attaching directly to surfaces with a peel-and-stick adhesive.

Anil Vijayendran, vice president of product sales and marketing at MiaSolé, said the product represents “a generational shift compared to previous limitations of rigid glass panels, and has reached a new level of efficiency and adaptability.”

MiaSolé makes thin-film copper indium gallium selenide (CIGS) solar cells and panels — a technology that has attracted (and burned) billions of dollars in venture capital and put multiple companies out of business.

When crystalline silicon PV began dominating the market, it became very difficult to differentiate CIGS products purely on cost, said Vijayendran. MiaSolé was making a double-sided glass panel and had sold roughly 90 megawatts of the product when Hanergy acquired the company in 2013. After raising around $500 million in venture capital, MiaSolé sold for just $30 million. With the acquisition, MiaSolé pivoted from making rigid glass CIGS panels to the flexible design and has effectively been operating in stealth mode — until now.

“At the time in the industry, glass was a very saturated market, so it was difficult to compete, and we had a very good differentiator here,” Vijayendran said. “The technologies became available in terms of encapsulation — water-barrier protection — that allowed us to pivot to something that would be reliable for 25 years. That’s why we made the move, and then, over the last few years, developed the technology, developed the product, seeded the market, and then built a factory in China.”

With Hanergy’s support, MiaSolé built a 100-megawatt plant in Heyuan, China that recently started running at full volume production. The China factory is where most of MiaSolé’s manufacturing will be done. The company has another pilot factory in Silicon Valley where the company designs and tests new product configurations.

According to Vijayendran, new opportunities for flexible solar technology are limited only by people’s imaginations.

Efficiency no longer a barrier

On a recent tour of MiaSolé’s manufacturing plant in Santa Clara, a flash test showed a sample panel measuring 16.3 percent efficiency. Vijayendran said this was one of the earlier panel generations and that the latest models have tested as high as 17.5 percent efficiency. MiaSolé expects to be making 18-percent-efficient panels by the end of next year.

A benefit of CIGS technology is that Read more »

Green-Powered Boat Prepares for Round-the-World Voyage

Vessel aiming to be the ‘Solar Impulse of the seas’ will be powered solely by renewable energies and hydrogen during its six-year voyage

Work on the hull of the Energy Observer in Saint Malo, western France. Photograph: Loic Venance/AFP/Getty Images

Work on the hull of the Energy Observer in Saint Malo, western France. Photograph: Loic Venance/AFP/Getty Images

Dubbed the “Solar Impulse of the seas”, the first boat to be powered solely by renewable energies and hydrogen hopes to make its own historic trip around the world.

A water-borne answer to the Solar Impulse – the plane that completed its round-the-globe trip using only solar energy in July – the Energy Observer will be powered by the sun, the wind and self-generated hydrogen when it sets sail in February as scheduled.

The multi-hulled catamaran is in a shipyard at Saint Malo on France’s west coast, awaiting the installation of solar panels, wind turbines and electrolysis equipment, which breaks down water to produce its component elements, hydrogen and oxygen.

“We are going to be the first boat with an autonomous means of producing hydrogen,” says Frenchman Victorien Erussard, who is behind the project – confidential until now – with compatriot Jacques Delafosse, a documentary filmmaker and professional scuba diver.

The plan is for the boat’s batteries, which will feed the electric motors, to be powered in good weather by solar and wind energy, explained the 37-year-old merchant navy officer.

“If there’s no sun or wind, or if it’s night, stored hydrogen – generated by electrolysis powered by the solar panels and two wind turbines – will take over,” he said.

As a result, the vessel’s trip will not use any carbon-emitting fossil fuels, as is the case for 96% of boats today.

An artist’s impression of the Energy Observer. Photograph: PR Company Handout

An artist’s impression of the Energy Observer. Photograph: PR Company Handout

The vessel itself has a storied past.

The catamaran won the Jules Verne trophy for a team sailing non-stop round the world, in 1994. It was bought for €500,000 ($562,000) and extended by a whopping six metres, to 30.5 metres (100 feet), for the project.

One of the backers of the endeavour is well-known French environmentalist Nicolas Hulot.

“I support it because it’s the first project of this kind to actually be undertaken, it’s ambitious and looking toward the future,” Hulot, a former special envoy on environmental protection to President François Hollande, told AFP.

“It’s very promising for marine transport,” Hulot added. “The Energy Observer is going to demonstrate that you can have great autonomy (at sea) and you can store and find energy when there isn’t any more wind or sun.”

The Energy Observer was designed in partnership with a team of naval architects and the CEA-Liten research institute in the French city of Grenoble, which is dedicated to renewable energy technologies.

At a total cost of €4.2m ($4.72m), the green energy boat will be fitted with sensors to act as veritable moving laboratory for CEA-Liten, whose director Florence Lambert describes the project as a “great challenge”.

“Energy Observer is emblematic of what will be the energy networks of tomorrow, with solutions that could even be used within five years,” said Lambert.

“For example, the houses of tomorrow could incorporate a system of hydrogen storage, which is produced during the summer months and then used in the winter.”


The head of the project at CEA-Liten, Didier Bouix, adds that hydrogen can store “20 times more energy” than conventional batteries.

Energy Observer’s world tour is expected to take six years. After a careful crossing of the Mediterranean, the catamaran will venture out into the Atlantic and then Pacific oceans.

In all, 101 stopovers are planned from Cuba to New Caledonia to Goa on India’s west coast.

There are still hurdles to overcome, not least in funding: the Energy Observer’s trip is expected to cost a minimum of €4m a year, notably to develop a traveling exhibition.

But the team said it is confident of getting the funds.

And once again it finds inspiration from its airplane mentor Solar Impulse – which flew around the world on renewable energy and accomplished “what everyone said was impossible,” said Delafosse.


Storing Energy in the Sea

William Steel

Engineers in Germany are gearing up for pilot-scale testing of a promising new design for marine energy storage.

The Stored Energy in the Sea (StEnSEA) project represents a novel pumped storage concept aiming to facilitate large-scale storage of electrical energy that’s cost-competitive with existing solutions.

Since early 2013, the three-year, consortium-backed project led by the Germany-based Fraunhofer Institute for Wind Energy and Energy System Technology (F-IWES) and supported by Germany-based Hochtief Solutions, has delivered promising results: from concept design and analysis, through to developing a road map for market implementation.

The technology leverages water pressure to drive electromechanical pump components housed within a central tube of submerged spherical storage units. These spheres, constructed of concrete, operate in a manner akin to pumped-hydro storage, as Jochen Bard, Head of Energy Process Engineering at F-IWES, told Renewable Energy World: It’s a straightforward principal — physically speaking, it’s the same as a conventional pumped-hydro scheme featuring upper and lower reservoirs. Naturally, technical realization of these principals is different, however.

Detailing the concept, Bard said: “What we have is a pressure tank that maintains a lower pressure than ambient pressure of the water head above the device, the water column. Assuming the tank is empty, it has a very low pressure.”

He added that, “when you release water into the tank, the pressure of the water column is driving water through a turbine. This process generates energy, and represents the discharge part of the cycle — similar to water flowing through turbines, down into a lower reservoir, in a pumped-hydro system.”

Conversely, Bard said, pumping water out of the system requires energy as the pump is working against the pressure head of the water column.

“This is analogous to pumping water from a lower reservoir up to a higher one,” he said.

For this system, water depth is crucial.

“It’s clear that the deeper you install the system, the higher the pressure, so the more energy you can store within the tank,” Bard said. “But there’s a limit to that — at extreme depths, the system is infeasible. So the highest head we’re using is around 800m. In the end, to remain competitive with existing storage solutions, we’re targeting installment within the 600 to 800m range.”

At commercial scale, StEnSEA envisions arrays featuring 30m-diameter spheres, each with a storage capacity of around 20 MWh at 700m depths. This size, Bard said, “was found to be a reasonable compromise between all design, economic, and manufacturing parameters we needed to take into account.”

StEnSea’s geographical site requirements may appear at first to reduce applicability of the technology to several regions; but the consortium has undertaken comprehensive analysis that serves to relieve such concerns.

“As part of the project we undertook a detailed analysis of eligible sites for the technology, using geographic information systems featuring a list of criteria — distance to shore, distance to ports, sea depth, slope of seabed, exclusions zones etc. — we see there’s great potential for the application of the technology,” Bard said.

Of relevance for European stakeholders, one site in particular is highlighted: the Norwegian Trench off the southern coast of Norway holds technical potential of 8 TWh. Ideal site conditions were also identified in the Mediterranean Sea, the Pacific and Atlantic coast of the U.S., and Japan.

A Cost-effective Solution

Early project work focused on design, cost-efficiency and feasibility of the concept and produced several important outcomes, not least confidence in the physical and financial viability of the system even under conservative assumptions.

We’ve looked at economic variations of the system ranging in scale, from arrays of five to 10 spheres, to up to more than 100. At that latter scale, we’re looking at several hundred MWs, so about comparable with typical pumped-hydro systems,” Bard said.

He added that, “the economics have turned out nicely — all things considered, CAPEX would be very similar to pumped storage; 1,500 euros to 2,000 euros (US $1,675-$2,231) per kW (location dependent). It’s very encouraging for a storage system. Projected efficiency is also very comparable to pumped storage, somewhere in the region of 75 percent cycle efficiency is what we’re expecting.”

Commenting on estimated lifetime costs of storage, he said, “[at] 1000 cycles/year (3 cycles/day), 20 MWh storage per sphere, 5 MW pump turbine, four-hour charge/discharge cycle – [we expect] a levelized cost of storage of about 2 euro cent per KWh. That’s a very competitive price.”

Pilot Testing

The project is currently preparing for its second phase: a small-scale test at Lake Constance, on the Swiss-German border, featuring a fully functional 1:10 scale model of the storage unit installed at water depth of around 100m.

Looking forward to the test — scheduled to begin in the second half of October — Bard says there were several motivations for the pilot, not least the opportunity to gain experience relating to construction and installment of the system. Additionally, he said, “[the test will also] generate field test data to prove our concept and validate our assumptions.” This test is being held prior to a full-scale, open sea pilot of 30-m diameter sphere, a date for which is yet to be confirmed.