Posts belonging to Category green power

Barcelona, The Sun And Wind City

Barcelona‘s beach is being lit up with new-look street lights. The six innovative lamp posts are each fitted with two solar panels, a wind turbine and a battery. As a result, the environmentally-friendly lights generate enough energy to run for ten hours overnight. The new product has been designed by the company Eolgreen with the collaboration of a research team from the Universitat Politecnica de Catalunya (UPC).


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Compared to a traditional street lighting system, these six street lights that we have set up emit two tonnes less CO2 per year than sodium vapour or mercury vapour bulbs we see in conventional systems,” says Pedro Montes leads research at developers Eolgreen. The company also says its lights are 20 percent cheaper to run than conventional lights because they use LED technology and are independent from the electricity grid. While solar-powered LED street lighting is used elsewhere, Eolgreen‘s system is unique because its graphene turbines turn with even a gentle breeze.

Ramon Bargallo, researcher at the UPC, who helped  design the independently-powered lights adds:  “It was a big challenge as generators often need high speed winds to turn, between 1500 rpm and 3000 rpm. But we needed a generator able to work with only four or five rpm. Also generators are normally more efficient the higher the wind speed and less efficient at low wind speeds, so we had to design it in the opposite way.” Barcelona’s planners aim to roll out the new lighting system across the whole city. It’s part of their drive to achieve energy self-sufficiency in the next 40 years. Eolgreen intends to ramp up production to 700 streetlights by the end of the year. While the sustainable energy developers continue to improve efficiency, they hope their system will soon be brightening streets all over Spain.


Black Silicon Solar Cells Efficiency Jump

Researchers from Aalto University (Finland) together with colleagues from Universitat Politècnica de Catalunya (Spain) have obtained the record-breaking efficiency of 22.1% on nanostructured silicon solar cells as certified by Fraunhofer ISE CalLab. An almost 4% absolute increase to their previous record is achieved by applying a thin passivating film on the nanostructures by Atomic Layer Deposition, and by integrating all metal contacts on the back side of the cell.black_silicon_solar_cell_hele_savin_aalto_university_en

The surface recombination has long been the bottleneck of black silicon solar cells and has so far limited the cell efficiencies to only modest values. The new record cells consists of a thick back-contacted structure that is known to be highly sensitive to the front surface recombination. The certified external quantum efficiency of 96% at 300nm wavelength demonstrates that the increased surface recombination problem no longer exists and for the first time the black silicon is not limiting the final energy conversion efficiency. The energy conversion efficiency is not the only parameter that we should look at, explains Professor Hele Savin from Aalto University, who coordinated the study. Due to the ability of black cells to capture solar radiation from low angles, they generate more electricity already over the duration of one day as compared to the traditional cells.

The results were published online 18.5.2015 in Nature Nanotechnology.

Solar Cell: How To Boost Perovskites Performance

One of the fastest-growing areas of solar energy research is with materials called perovskites. These promising light harvesters could revolutionize the solar and electronics industries because they show potential to convert sunlight into electricity more efficiently and less expensively than today’s silicon-based semiconductors. These superefficient crystal structures have taken the scientific community by storm in the past few years because they can be processed very inexpensively and can be used in applications ranging from solar cells to light-emitting diodes (LEDs) found in phones and computer monitors.
A new study published online in the journal Science by University of Washington (UW) and University of Oxford researchers demonstrates that perovskite materials, generally believed to be uniform in composition, actually contain flaws that can be engineered to improve solar devices even further.
peroskite solar cell
Perovskites are the fastest-growing class of photovoltaic material over the past four years,” said lead author Dane deQuilettes, a UW doctoral student working with David Ginger, professor of chemistry and associate director of the UW Clean Energy Institute.

In that short amount of time, the ability of these materials to convert sunlight directly into electricity is approaching that of today’s silicon-based solar cells, rivaling technology that took 50 years to develop,” deQuilettes said. “But we also suspect there is room for improvement.”

Perovskite solar cells have so far have achieved efficiencies of roughly 20 percent, compared to about 25 percent for silicon-based solar cells. The team found “dark” or poorly performing regions of the perovskite material at intersections of the crystals. In addition, they discovered that they could “turn on” some of the dark areas by using a simple chemical treatment.

Energy Storage for a Sustainable Home

The electric car maker Tesla has devised a new electric home battery, the PowerWall. Current generation home batteries are bulky, expensive to install and expensive to maintain. In contrast, Powerwall’s lithium ion battery inherits Tesla’s proven automotive battery technology to power your home safely and economically. Completely automated, it installs easily and requires no maintenance. The home battery charges using electricity generated from solar panels, or when utility rates are low, and powers your home in the evening. It also fortifies your home against power outages by providing a backup electricity supply. Automated, compact and simple to install, Powerwall offers independence from the utility grid and the security of an emergency backup.
Tesla PowerWall
Solar Powered Day and Night
The average home uses more electricity in the morning and evening than during the day when solar energy is plentiful. Without a home battery, excess solar energy is often sold to the power company and purchased back in the evening. This mismatch adds demand on power plants and increases carbon emissions. Powerwall bridges this gap between renewable energy supply and demand by making your home’s solar energy available to you when you need it.

Powerwall comes in 10 kWh weekly cycle and 7 kWh daily cycle models. Both are guaranteed for ten years and are sufficient to power most homes during peak evening hours. Multiple batteries may be installed together for homes with greater energy need, up to 90 kWh total for the 10 kWh battery and 63 kWh total for the 7 kWh battery.
Common household electricity consumption: Flat Screen TV, 0.1 kWh /hr. Lights Per Room, 0.1 kWh /hr. Laptop, 0.05 kWh /hr. Refrigerator, 4.8 kWh /day. Clothes Washer: 2.3 kWh each use. Clothes Dryer: 3.3 kWh each use.

Run A Car With Water And Air

The German automaker Audi announced it has created the first batch of liquid “e-diesel” at a research facility in Dresden. The clear fuel is produced through a “power to liquid” process, masterminded by the German clean tech company and Audi partner Sunfire.

The process uses carbon dioxide, the most common greenhouse gas, which can be captured directly from air. Carbon dioxide is created largely by burning fossil fuels and contributes to global warming. Now Sunfire said it can recycle the gas to make a more efficient, carbon-neutral fuel.
Unlike conventional fossil fuels, the “e-diesel” doesn’t contain sulphur and other contaminants.
audi e-diesel
The engine runs quieter and fewer pollutants are being created,” Sunfire‘s Christian von Olshausen said.
The fuel is produced in three steps. First, the researchers heat up steam to very high temperatures to break it down into hydrogen and oxygen. This process requires temperatures of over 800 degrees Celsius (1,472 Fahrenheit) and is powered by green energy such as solar or wind power.
Second, they mix the hydrogen with carbon dioxide under pressure and at high temperature to create so-called blue crude. Lastly, the blue crude is refined into fuels in a similar way fossil crude oil is refined into gasoline.
Audi (AUDVF) said its lab tests have shown the “e-diesel” can be mixed with fossil fuels or used as a fuel on its own.
At this stage the e-diesel cost 40 % more than the regular gasoline per liter to produce.

Motorbike Runs On Its Own Generated Energy

Mexican students in Oaxaca City design a motorbike that runs on its own generated energy, without using any combustion. They say their prototype model is a breakthrough invention for eco-friendly motorbikes. What if you could harvest the energy of a moving vehicle to continue to power it? That is the question asked by students of this technical high school college in Oaxaca, Mexico, one year ago. It resulted in this prototype motorcycle called R-Walker created by 17-year-old Victor Garcia.
The project is a prototype that generates its own energy as it goes along: As it goes faster and covers longer distances, it generates more energy. In that way, you don’t have to charge the battery every 6-8 hours,” says Garcia. He calls the process “auto-sustainability.” It’s based on the principle of converting energy through speed and distance travelled; the engine becomes self-sustaining, generating more than 2,000 revolutions per minute. A battery is used to spark ignition, and afterwards without using any combustion the vehicle can carry up to 110 kilograms and travel at more than 60 kilometers per hour.

Co-designer Raul Grajales said R-Walker could bring huge savings for motorcycle users, as well as the environment. “With this, we have reduced the use of 200 batteries a day and seventy percent of pollution, because it does not contaminate and has zero emissions and we use one battery every 5-10 years“, assures Grajales. They built the eco-friendly motorbike from recycled materials, bringing its final price tag to around $200 – a comparatively small sum when considering its potential benefits.

Solar Power From Space

Collecting solar energy to convert to electricity is not a new concept. However, there are significant advantages to space solar power compared to ground solar power. Solar energy in space is seven times greater per unit area than on the ground. The collection of solar space energy is not disrupted by nightfall and inclement weather, thus avoiding the need for expensive energy storage.

Now  researchers from the University of Waterloo in Canada report a novel design for electromagnetic energy harvesting based on the “full absorption concept.” This involves the use of metamaterials that can be tailored to produce media that neither reflects nor transmits any power—enabling full absorption of incident waves at a specific range of frequencies and polarizations.


The growing demand for electrical energy around the globe is the main factor driving our research,” said Thamer Almoneef, a Ph.D. student. “More than 80 percent of our energy today comes from burning fossil fuels, which is both harmful to our environment and unsustainable as well. In our group, we’re trying to help solve the energy crisis by improving the efficiency of electromagnetic energy-harvesting systems.”

Since the inception of collecting and harvesting electromagnetic energy, classical dipole patch antennas have been used. “Now, our technology introduces ‘metasurfaces’ that are much better energy collectors than classical antennas,” explained Omar M. Ramahi, professor of electrical and computer engineering.

Metasurfaces are formed by etching the surface of a material with an elegant pattern of periodic shapes. The particular dimensions of these patterns and their proximity to each other can be tuned to provide “near-unity” energy absorption. This energy is then channeled to a load through a conducting path that connects the metasurface to a ground plane. The key significance of the researchers’ work is that it demonstrates for the first time that it’s possible to collect essentially all of the electromagnetic energy that falls onto a surface. Conventional antennas can channel electromagnetic energy to a load—but at much lower energy absorption efficiency levels,” said Ramahi. “We can also channel the absorbed energy into a load, rather than having the energy dissipate in the material as was done in previous works.

As you can imagine, this work has a broad range of applications. Among the most important is space solar power, an emerging critical technology that can significantly help to address energy shortages. It converts solar rays into microwaves—using conventional photovoltaic solar panels—and then beams the microwave’s energy to microwave collector farms at designated locations on Earth. Japan is way out in front of rest of the world in this realm, with plans to begin harvesting solar power from space by 2030.


How To Clean Oil Spills For $1Per Square Foot

The unassuming piece of stainless steel mesh in a lab at The Ohio State University doesn’t look like a very big deal, but it could make a big difference for future environmental cleanups. Water passes through the mesh but oil doesn’t, thanks to a nearly invisible oil-repelling coating on its surface. In tests, researchers mixed water with oil and poured the mixture onto the mesh. The water filtered through the mesh to land in a beaker below. The oil collected on top of the mesh, and rolled off easily into a separate beaker when the mesh was tilted.
The mesh coating is among a suite of nature-inspired nanotechnologies under development at Ohio State and described in two papers in the journal Nature Scientific Reports. Potential applications range from cleaning oil spills to tracking oil deposits underground.

mesh captures oil
If you scale this up, you could potentially catch an oil spill with a net,” said Bharat Bhushan, Ohio Eminent Scholar and Howard D. Winbigler Professor of mechanical engineering at Ohio State.

The work was partly inspired by lotus leaves, whose bumpy surfaces naturally repel water but not oil. To create a coating that did the opposite, Bhushan and postdoctoral researcher Philip Brown chose to cover a bumpy surface with a polymer embedded with molecules of surfactant — the stuff that gives cleaning power to soap and detergent. They sprayed a fine dusting of silica nanoparticles onto the stainless steel mesh to create a randomly bumpy surface and layered the polymer and surfactant on top.
The silica, surfactant, polymer, and stainless steel are all non-toxic and relatively inexpensive, said Brown. He estimated that a larger mesh net could be created for less than a dollar per square foot.


How To convert Your Waste Heat Into Electricity

A mathematical model of heat flow through miniature wires could help develop thermoelectric devices that efficiently convert heat — even their own waste heat — into electricity.

Developed at A*STAR (Singapore), the model describes the movement of vibrations called phonons, which are responsible for carrying heat in insulating materials. Phonons typically move in straight lines in nanowires — threads barely a few atoms wide. Previous calculations suggested that if parts of a nanowire contained random arrangements of two different types of atoms, phonons would be stopped in their tracks. In actual alloy nanowires, though, atoms of the same element might cluster together to form short sections composed of the same elements.

phononsPhonons (vibrations) are typically responsible for carrying heat along a nanowire. A*STAR researchers have used a numerical model to calculate the effects of short-range ordering on phonon behaviour.

Now, Zhun-Yong Ong and Gang Zhang of the A*STAR Institute of High Performance Computing in Singapore have calculated the effects of such short-range order on the behavior of phonons1. Their results suggest that heat conduction in a nanowire does not just depend on the relative concentrations of the alloy atoms and the difference in their masses; it also depends on how the atoms are distributed.


3D Printed Homes Are The Future Of Construction

This Amsterdam building site is a little different. The Europe’s first 3D-printed house is being constructed here. It’s being made from a bio-plastic mix, containing 75 percent plant oil reinforced with microfibres. DUS Architects co-founder Hans Vermeulen says the house won’t be perfect, but an important staging post to a sustainable, eco-friendly, future for construction.
3D printed anal-house-by-DUS-Architects

The building industry is a little bit more conservative at the moment but digitalisation can totally transform that industry into a more agile industry as well where you can actually share online and upgrade your neighbourhood online, and share world-wide good ideas and then send it to the machine“, he added.  Vermeulen calls traditional construction polluting and inefficient. 3D-printing homes will reduce waste and transportation costs, creating homes that can be taken down and reconstructed if the owners wants to leave town. He says the technology offers endless design possibilities. “Digital fabrication allows us and allows customers to tweak designs into their own personal needs,” he concluded. Last year Chinese firm WinSun displayed a five-storey apartment building it said it 3D-printed using recycled materials. But the technology remains in its infancy. Vermeulen’s 13-room complex should be ready by 2017.