Tawanai

For decades researchers have investigated a theoretical means to double the power output of solar cells–by making use of so-called “hot electrons.” Now researchers at Boston College have provided new experimental evidence that the theory will work. They built solar cells that get a power boost from high-energy photons. This boost, the researchers say, is the result of extracting hot electrons.

The results are a step toward solar cells that break conventional efficiency limits. Because of the way ordinary solar cells work, they can, in theory, convert at most about 35 percent of the energy in sunlight into electricity, wasting the rest as heat. Making use of hot electrons could result in efficiencies as high as 67 percent, says Matthew Beard, a senior scientist at the National Renewable Energy Laboratory in Golden, CO, who was not involved in the current work. Doubling the efficiency of solar cells could cut the cost of solar power in half.

Via: Technology Review

Clean Technology, Electronics, Solar

Everybody’s rooting for wind and solar power. How could you not? But wind and solar are use-it-or-lose-it resources. To make any kind of difference, they need better storage.

Source: AEP

Battery packs located close to customers can store electricity from renewable wind or solar sources and supply power when the sun isn’t shining or the wind isn’t blowing. Energy is collected in the storage units and can be sent as needed directly to homes or businesses or out to the grid.

Scientists are attacking the problem from a host of angles—all of which are still problematic. One, for instance, uses power produced when the wind is blowing to compress air in underground chambers; the air is fed into gas-fired turbines to make them run more efficiently. One of the obstacles: finding big, usable, underground caverns.

Similarly, giant batteries can absorb wind energy for later use, but some existing technologies are expensive, and others aren’t very efficient. While researchers are looking at new materials to improve performance, giant technical leaps aren’t likely.

Lithium-ion technology may hold the greatest promise for grid storage, where it doesn’t have as many limitations as for autos. As performance improves and prices come down, utilities could distribute small, powerful lithium-ion batteries around the edge of the grid, closer to customers. There, they could store excess power from renewables and help smooth small fluctuations in power, making the grid more efficient and reducing the need for backup fossil-fuel plants. And utilities can piggy-back on research efforts for vehicle batteries.

Via WSJ

Electricity, Energy, Solar, Wind battery packs, Lithium ion

Cross Post from TelecomPk.net

Telecom companies in Pakistan are one of the major power consumers and in addition to the increasing cost of electricity, they also face the challenge of lack of access to the electricity grid in rural areas to supply power to base stations. A few pilot deployments of  solar powered base stations were luanched earlier.Now Telenor Pakistan and Nokia Siemens Networks (NSN) have signed an agreement that will provide NSN’s off-grid site solutions that use solar energy to power Telenor base station sites in rural and remote areas. This is expected to result in substantial cost savings for Telenor Pakistan along with the social benefits that come with using renewable and clean energy.

Nokia Siemens Networks will design the sites, taking into account local solar mapping, site landscape and other factors to maximize the use of an abundant, clean, and natural energy source. Nokia Siemens Networks’ Green Energy Control will help deliver a sustainable solution while optimizing operating costs.

The solar-powered sites will be implemented using Universal Services Fund (USF) that was awarded to Telenor Pakistan in 2009. USF-based contracts aim to provide access to mobile services for underserved and unserved areas of Pakistan. Telenor Pakistan, till now, has been awarded three USF contracts for Mirpurkhas, Malakand and Bahawalpur region.

“It’s important that we connect the world in such a way that not only maximizes benefits for consumers and businesses, but also ensures the welfare of our planet,” said Saad Waraich, the Pakistan country director for Nokia Siemens Networks. “Providing communications to rural areas will become increasingly important and we believe renewable energy will be the first choice for such installations. In fact, the majority of base station sites installed by us by 2011 will use this form of energy. We are especially proud to partner with Telenor – a definite trend setter for the use of environmental technologies in network expansion.”

The GSMA has estimated that more than 75,000 new off-grid sites will be built each year through 2012 in developing countries. About 80% of the energy in a typical mobile telecommunication network is consumed by base stations. Renewable energy sources such as wind and solar power offer a reliable alternative to sites with limited or non-existent electrical grid access. Nokia Siemens Networks has already deployed more than 360 sites that exploit renewable energy and has over 25 years of experience in implementing solar-powered sites.

Source: Nokia Siemens Press Release

Clean Technology, Consumers, Electricity, Energy, Pakistan, power, Solar base stations, nokia siemens network, off-grid, telenor

For more than three decades, visionaries have imagined tapping solar power where the sun always shines—in space. If we could place giant solar panels in orbit around the Earth, and beam even a fraction of the available energy back to Earth, they could deliver nonstop electricity to any place on the planet.

Image Source: New Scientist

Sunlight is reflected off giant orbiting mirrors to an array of photovoltaic cells; the light is converted to electricity and then changed into microwaves, which are beamed to earth. Ground-based antennas capture the microwave energy and convert it back to electricity, which is sent to the grid.

The technology may sound like science fiction, but it’s simple: Solar panels in orbit about 22,000 miles up beam energy in the form of microwaves to earth, where it’s turned into electricity and plugged into the grid. (The low-powered beams are considered safe.) A ground receiving station a mile in diameter could deliver about 1,000 megawatts—enough to power on average about 1 million U.S. homes.

The cost of sending solar collectors into space is the biggest obstacle, so it’s necessary to design a system lightweight enough to require only a few launches. A handful of countries and companies aim to deliver space-based power as early as a decade from now.

Via WSJ

Energy, Solar

Fool’s gold, also called pyrite or iron sulfide, can be unearthed just about anywhere, from the hills of California to the villages of Yunnan Province in China. But instead of digging pyrite up, researcher Cyrus Wadia is making pure nano particles of the compound from iron and sulfur salts in his lab at the University of California, Berkeley. His ultimate goal is to turn fool’s gold into real treasure: an inexpensive solar cell.

Today, most solar cells are made of silicon, but they are expensive: though silicon is abundant, turning it into photovoltaics requires extensive, energy-intensive processing. Materials such as cadmium telluride and copper indium gallium diselenide are simpler to process, yielding thin-film cells that cost less to produce. But the elements needed to make these compounds, such as tellurium and gallium, are too rare to meet global energy demands.

So Wadia did a study of possible solar-cell materials, examining not only their chemistry and physics but also their availability. One of the standouts was fool’s gold: it is abundant and cheap, and it has optical properties that allow it to efficiently convert sunlight into electricity. “The theoretical efficiency of iron sulfide is 31 percent. That’s as good as silicon,” says Wadia. What’s more, 20 nanometers of pyrite can absorb as much light as 300 micro meters of silicon. Because it absorbs so much more light, it can be made into thinner cells, which require less raw material.

Via Technology Review

Clean Technology, Energy, Environment, Innovation, Solar

I met this company Soleitec a year ago and they had an interesting product. What do you think?

Consumers, Electronics, Energy, Solar

This is the big event for consumer oriented solar gadgets – two major companies launch solar phones.

Samsung Electronics Co. and LG Electronics Co. separately started selling solar-powered phones this week, a big step in a budding trend of cellphone makers seeking to tap growing consumer interest in eco-friendly products.

Samsung rolled out a touch-screen model, dubbed Blue Earth, with a shell made from recycled plastic water bottles and a solar panel on the back. LG’s model, called the GD510 Pop, also has a touch screen but its solar panel is an optional add-on.

Consumer demand for solar-based phones is hard to gauge, but makers are planning to market them as good for the environment as well as a way to hedge against running out of battery power.

Both the Samsung and LG phones have features that promote walking, such as software that measures distance traveled, and allow customers to calculate how much they can reduce carbon dioxide emissions with physical activities that replace driving.

“It is premature to say whether they will be successful, but overall it’s the right direction because people are increasingly interested in saving energy,” says Park Sung-min, a telecom industry analyst at Kyobo Securities in Seoul.

Samsung is aiming the Blue Earth model at premium customers, with pricing around $300. The phone, which can also be charged with a traditional plug-in cord, is initially available in Sweden; Samsung said it will quickly roll it out elsewhere in Europe and Asia.

G said the Pop phone will also initially be sold in Europe and be priced around $300 with the optional solar panel about $50. The companies said decisions are pending about U.S. sales.

Samsung said the Blue Earth phone can accept enough charge under an hour of normal sunlight to allow for 10 minutes of talk. LG said the Pop model permits about 13 minutes of talk after being charged for an hour under normal sunlight. The companies said the phones will also charge under artificial light, but more slowly.

Nokia Corp., the world’s largest cellphone maker by units and revenue, introduced a solar-based cellphone in 1997 but it didn’t continue in the company’s regular lineup. The company earlier this year demonstrated a concept phone that runs entirely on solar power.

Samsung, the second-largest maker, in June introduced its first solar-based phone, a bar-shaped model with a normal keypad and solar cells on the back. That phone, called Solar Guru in some markets and Crest Solar in others, was aimed chiefly at developing countries and sells for as little as $60. But Samsung also offers it in some wealthy European countries like France.

Source: WSJ

Consumers, Energy, Solar cell phones

Suntech Power Holdings Co., Ltd. (NYSE: STP), the world’s largest crystalline silicon
photovoltaic (PV) module manufacturer, announced today that it has entered
into a memorandum of understanding (MOU) with Pakistan’s Alternative Energy
Development Board (AEDB) to work towards the widespread use of solar energy
technologies to meet the energy shortage in Pakistan.

The objective of the MOU is to facilitate cooperation between Suntech and
the public sector and private companies in Pakistan to help implement solar
programs including the AEDB’s Rural Electrification Program; the development
of Solar Power Pumping Systems with the AEDB and the World Bank; and Solar
Power Telecom Projects in collaboration with Pakistani telecom companies.
“We are proud to collaborate with the Alternative Energy Development Board
to bring the latest in crystalline silicon solar technology to Pakistan,” said
Dr. Zhengrong Shi, Suntech’s Chairman and CEO. “This is a clear example of the
promise of solar energy in meeting growing demands for electricity in the
developing world in an environmentally friendly way. With rapid improvements
in solar energy technology and operational efficiency, solar energy is
establishing itself as a crucial, cost-competitive part of the global energy
mix.”

“We are very pleased to be working with Suntech towards developing clean
renewable energy in our country,” said Mr. Masood Khan, Pakistan’s Ambassador
to China. “Pakistan is committed to using solar power as a way to solve
Pakistan’s energy shortage, and we are confident in Suntech’s reputation as a
global industry leader to bring reliable environmentally sustainable solutions
to Pakistan’s growing energy needs.”
The MOU sets forth the agreement in principle of the parties concerning
the project and related activities. Final agreement between the parties is
subject to the negotiation and execution of definitive agreements among the
parties.

Read more…

Clean Technology, Pakistan, power, Renewable Energy, Solar

Via WSJ article.

Energy from renewable sources come and go at nature’s whim. Wind tends to blow hardest at night — a problem, since people use electricity mostly during the day. Sunshine can lose its intensity in seconds if eclipsed by a cloud — inconvenient for people who like their air conditioners to run steadily on summer days.

Many states and countries are pledging to produce 20% or more of their electricity from renewable sources within about a decade. That will be a major stretch. The recession has severely crimped renewable-energy investment. Proposals to turn over large swaths of desert and coastline to renewable-energy generation are encountering angry opposition. And the drop in fossil-fuel prices has removed much of the public appetite for a big renewable-energy bid. Yet those very pressures are pushing renewable-energy proponents to pursue their goal as efficiently as possible. And so the search for ways to accommodate the vicissitudes of wind and sun continues to shape up as one of today’s great technological quests.

A convenient solution would be to overcome wind and sun’s intermittence by storing the energy and then dispensing it later, on windless or overcast days. But storage technology is still embryonic.

So the power industry is having to change the way it operates. To adapt its fossil-fuel-dependent infrastructure to renewable energy’s ebbs and flows, it is trying to forecast them better. Knowing how nature is likely to behave will help the industry better balance different sources of renewable energy, scientists and utility executives say. The goal: maximizing wind, sun and other natural sources when each is at its peak.

Currently, every wind farm and solar installation has to be backed up by a nearly equivalent amount of conventional fuel to keep the power grid running. That raises costs.

“We’re putting renewables into a system that wasn’t designed for renewables,” says Paul Denholm, an analyst for the federal government’s National Renewable Energy Laboratory, in Golden, Colo.

Wind power is the fastest-growing renewable source of electricity. Buoyed by government mandates and subsidies, wind farms accounted for more than half of all net electricity-generating capacity added in the U.S. in 2008, according to the Department of Energy.

But capacity to produce is not actual production. Largely due to wind’s unpredictability, the thousands of wind turbines installed across the country collectively produced only 1.3% of actual U.S. electricity in 2008, the department’s figures show.

The Bonneville Power Administration, a government-owned utility based in Portland, Ore., taps one of the biggest collections of wind farms in the country. Between January and August, average wind-power production accounted for 12% of average electricity consumption in Bonneville’s service area.

From hour to hour, though, wind power swings wildly depending on how things blow at the Columbia River Gorge, where most of the wind turbines in Bonneville’s service area are located.

This Tuesday was typically erratic. At 1 a.m., wind farms in the Bonneville service area were cranking out about 1,550 megawatts of power. By 7 a.m., that fell to about 800 megawatts, just as people were waking up and turning on their lights and toasters. That night, once most people were asleep, the wind picked up again. By 11:45 p.m., wind power topped 2,000 megawatts.

Most of the electricity in Bonneville’s service area comes from hydroelectric power. To compensate for the volatility of wind, Bonneville tweaks the amount of water it lets through the dams. But that doesn’t work for the most extreme shifts in wind. Sometimes, when the wind is blowing hard, Bonneville releases extra water over the tops of dams without using it to generate electricity. Otherwise, electrical wires might get overloaded. And when the wind is so strong that Bonneville can’t ditch enough water, the utility orders wind turbines shut off.

Read more…

Clean Technology, Energy, Solar, Wind

Clean Technology, Energy, Innovation, Solar, Wind