Scientists Combine Solar Cell and Battery into a Single Highly Efficient Package

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A team of researchers at the Ohio State University (OSU) successfully produced a dye-sensitized solar cell, which can store power by using air to decompose and re-form lithium peroxide. This device combines a solar cell and battery into one, and it is the first device of its kind. The adoption of this technology could also considerably lower the costs of solar cells.

The design they came up with utilizes only three electrodes, whereas the standard practice until now has been to use four. At the bottom of the electrodes there is a lithium plate, followed by a layer of electrolyte, a thin sheet of porous carbon and finally another layer of electrolyte. At the tip of the electrode, there is a permeable titanium gauze mesh, which contains a dye-sensitive titanium dioxide photoelectrode. The latter generates trioxide ions when illuminated and these then travel to the oxygen electrode surface via an iodide “shuttle.” Once there they oxidize into lithium peroxide.

The electrons in the battery then chemically decompose the lithium peroxide into lithium ions and oxygen, with the latter being released into the air. The lithium ions, on the other hand, are stored as lithium metal. During the discharging process, the battery draws oxygen from the surrounding environment and uses it to re-form lithium peroxide.

The titanium gauze mesh is coated with a red dye (a ruthenium compound), which assists in tuning the wavelength of the captured light. This dye is also capable of absorbing light and releases electrons, which creates an electric current in the process of new electrons being drawn from the iodide solution to replace them. However, this dye that they are using is depleted after only eight hours of charging and discharging, which is much too quickly for serious consideration in designing and building a cost-effective, rechargeable solar cell.

The scientists are currently testing hematite (rust) as a replacement for the dye-sensitized titanium oxide, which they hope will prove to have a much longer lifespan. If they succeed in making this device as efficient as currently used solar cells, it could prove a remarkable breakthrough in the renewable energy field. The research is being funded by the US Department of Energy.

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MIT Researchers Develop A More Efficient Battery

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The more widespread adoption of renewable sources of energy is at least in part hampered by our poor ability to store energy. But a team of MIT researchers has recently a made a breakthrough in developing a new battery system. This all-liquid battery system is more efficient at storing energy, and costs less to produce, than currently available solutions. The further development of this system and use could make solar and wind energy more attractive and therefore facilitate its wide scale adoption.

The batteries in this all-liquid system are composed of several layers of molten material, each of which has a different density. This enables the layers to separate naturally, similarly to the way oil and water do. Magnesium is used for one electrode, and antimony for another, while molten salt serves as the electrolyte. In order to operate, the entire system needs to be heated to 700° C (1292° F). However, the MIT researchers have discovered that substituting some of these materials, namely using one electrode made from lithium and another from a combination of lead and antimony, reduces the necessary operating temperature to 450-500° C (842-932° F).

The most surprising breakthrough was the discovery of the benefits that come from antimony and lead being mixed together to create the electrode. Contrary to their assumptions prior to conducting the experiment, the melting point of the combined materials lay in between that of the individual materials, while the hybrid metal retained the higher voltage of the antimony, meaning that there was no decline in voltage of the end product.

Due to the lower operating temperature of the battery, it will have a longer life span and it will also be easier to design and manufacture, while costing less. According to the team’s findings, this battery should maintain around 85 percent of its initial efficiency even after 10 years of daily charging and discharging.

Going forward, the research team will continue to explore the effects of other metals on their new battery system with the hope of further reducing the operating temperature and cost, while improving performance.

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Could Tofu be the Answer to Greener Solar Cells?

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University of Liverpool News

Dr. Jon Major, a researcher at Liverpool University has recently made the discovery that the chemical used to make tofu, and bath salts, could also be used to replace one of the most toxic substances, namely cadmium chloride, that are used to manufacture solar cells. Using salts to replace cadmium chloride in solar cell production would also make them much cheaper. His study was published in the journal Nature.

Cadmium chloride is a soluble compound that is expensive to produce and very toxic, which means special care must be made during the production of solar panels, as well as during their disposal after they are no longer useful. Dr. Major has now discovered that this compound could be replaced by magnesium chloride. The latter can be extracted from seawater and is already in use for making tofu, bath salts and de-icing roads.

Magnesium chloride is also safe to produce, and costs only $0.001 per gram as compared to $0.3, which is the cost of producing cadmium chloride. According to Dr. Major, the only way for renewable energy to compete with fossil fuels is by lowering the cost of harvesting it. This was also the key aim of his research.

Right now, the least expensive solar cells are based on a thin film of insoluble cadmium telluride. Without the addition of cadmium chloride, these cells convert only 2 percent of sunlight into energy. But by adding cadmium chloride to them, their efficiency is raised to over 15 percent.

The same result can be achieved if cadmium chloride is replaced by magnesium chloride. Also, the solar cells created using magnesium chloride were made by simply applying it with a spray gun, while applying cadmium chloride has to be done in a fume cupboard in the lab.

While solar sunlight is considered a great source of renewable energy, the solar cells used to collect it are still far from sustainable. Breakthroughs are being made all the time in producing a greener solar cell, and hopefully the day when new, more eco-friendly solar cells become available.

Via University of Liverpool News

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Rooftop Mounted Wind Turbines That Make Homes Self-Sufficient

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When it comes to renewable energy, wind turbines are certainly one of the greener and more sustainable options. Their biggest drawbacks is that they have to be large to produce enough energy, and that they make a lot of noise, which is why they haven’t yet been widely adopted by homeowners. However, The Archimedes, a Holland-based renewable energy start-up is currently working on a solution to this problem. They are designing a wind turbine small enough to be mounted on the roof of a typical home, but which is still highly efficient at converting wind to energy and does so nearly soundlessly.

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According to the company, this so-called Liam F1 turbine would be able to generate 1,500 kWh of energy per year at wind speeds of 5m/s, which is enough to satisfy about half of an average household’s energy use. If combined with a rooftop mounted solar PV array, the system would generate enough energy to take a home off-the-grid.

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The blades of the Liam F1 turbine are shaped like a Nautilus shell, which enables the turbine to be pointed into the wind and therefore capture the maximum amount of energy, yet remain silent. This type of turbine design was invented by Marinus Mieremet, who is certain that the power output of the Liam F1 turbine is 80 percent of the theoretical maximum energy that could be harnessed from the wind.

According to Mieremet, the design of the Liam F1 is such that it will start to spin even when the wind is blowing at an angle of 60 degrees into the rotor. The turbine also does not need expensive software to run since its conical shape allows it to automatically open itself into the optimal wind direction, much like a wind wane would. The silent operation is guaranteed since there is so little resistance encountered by the turbine.

Each Liam F1 wind turbine weighs 75 kg, and is made from fiberglass and RVS. The company is currently working on an even smaller wind turbine which could be used to power LED lampposts or on boats.

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Innovative Ways of Using Solar Panels

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Photo: Mineirão stadium in Belo Horizonte

The photovoltaic technology is frequently used to obtain energy these days. Since it was discovered in the 19th century that it is possible to get energy from sunlight, the ways of harnessing solar energy went through many different stages. The first prototype of solar cells was, for example, used to provide the satellite Vanguard I with energy in 1958 and the technology has been used in this area ever since.

The oil crisis demonstrated our dependence on fossil fuels and led to the much needed rethinking of where the energy comes from with a view towards finding dependable sources of renewable energy. Coupled with the nuclear power plant catastrophes and a stronger environmental consciousness also stimulated this wish to use nonpolluting and sustainable sources of energy. Therefore many enterprises and households opted for solar energy, since solar panels can be easily installed on rooftops, where they can harness energy from the sun, which is a limitless source of renewable power. Due to the greater interest and demand it is also important to consider the Solar IRR, solar economic return projects, among others.

Lately, this technology has developed much further than the known uses of solar panels on rooftops and on the ground. One such example is the building of integrated photovoltaics. During World Cup 2014, the company Martifer presented their completed project of a 1.4 MW installation of solar panels on the rooftop of the Mineirão stadium in Belo Horizonte, Brazil. The match on June 14 was the first one ever played in a stadium that obtains its energy from solar panels.

Mineirão stadium was fitted with 6,000 solar panels, and it is the first ever World Cup stadium to be powered entirely by solar energy. This solar power array is capable of producing 1,600 megawatts-hours of electricity per year, which is enough to power 1,200 households. About 10 percent of this electricity will be used in powering the Mineirão stadium, and the rest will pass back into the grid and be used by consumers.

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