Algal biofuel

Algae is the fastest growing plant life, and as an organism it converts sunlight into oil, scientists theorize that Algal biofuel can produce a whopping 30 times more energy per acre than any other biofuel option. The US Department of Energy has estimated that if Algal Biofuel replaced all conventional fuel in the country, it would require 15000 square miles of land to harvest the algae… which is roughly one seventh of the area that is used to harvest corn in the US every year. And a diverse group of byproducts, such as neutraceuticals and feedstocks for producing plastics, can be created in algal biofuel operations, making the production more cost effective. But before we start celebrating the great biofuel solution we’ve been looking for, there are a few problems… the biomass for producing a significant amount of algal biofuel just doesn’t exist yet. The algae has to be grown from scratch and harvesting it is very expensive at this point in time. The potential of Algal Biofuel is staggering… but the problem is that, as of now, it’s all just potential. It might be years before the technology catches up to make producing algal biofuel on a large scale possible… but when that time comes, we might be able to finally celebrate a more efficient, renewable, and environmentally friendly energy source. For more information on this exciting and developing technology, check out AlgalBioMass.Org. I’m Elizabeth Chambers. Check back here for more eco friendly news and tips

A cool new Solar design from V3 Solar

Check out thier web page for full details v3solar.com/

 

V3Solar

CoolSpin

V3Solar’s patented spin technology is a new paradigm that covers any spinning PV form factor. The second iteration of this revolution is the V3 CoolSpin, which competes directly with existing one sun mono PV solar panels with lower cost of components (34% lower) while providing far more effective and simpler energy production.

The CoolSpin product has been designed to be “plug compatible” with existing one sun solar cells. The CoolSpin can be made to fit existing bracketing and tracking products in the solar industry.

CoolSpin will be available for licensing from the second quarter 2013, with mass production planned the third quarter.

Main CoolSpin Benefits:

  • lower cost per watt (34.3% less than 1x sun solar panels)
  • only requires a single axis tracker with linear Fresnel (cost savings)
  • high tolerance to off axis tracking alignment
  • dramatic reduction in amount of PV required per watt
  • lower operating temperatures could lead to higher net efficiency

Through the patented CoolSpin technology energy is constantly provided from one sun mono PV that remains cool from the spin. The heat generated by the concentrated lens does not have enough time to transfer to the PV as it cycles out of the sunlight into the shade allowing the next piece of standard PV to go through exactly the same process, again, and again, and again. Constant cooling through dynamic spin creates higher power.

 

Solar Roadways

Introduction

SR

U.S. Senator Mike Crapo (R-ID) talks about Solar Roadways

Years ago, when the phrase “Global Warming” began gaining popularity, we started batting around the idea of replacing asphalt and concrete surfaces with solar panels that could be driven upon. We thought of the “black box” on airplanes: We didn’t know what material that black box was made of, but it seemed to be able to protect sensitive electronics from the worst of airline crashes.

Suppose we made a section of road out of this material and housed solar cells to collect energy, which could pay for the cost of the panel, thereby creating a road that would pay for itself over time. What if we added LEDs to “paint” the road lines from beneath, lighting up the road for safer night time driving? What if we added a heating element in the surface (like the defrosting wire in the rear window of our cars) to prevent snow/ice accumulation in northern climates? The ideas and possibilities just continued to roll in and the Solar Roadway project was born.

Our latest video – by Michele Ohayon

In 2009, we received a contract from the Federal Highway Administration to build the first ever Solar Road Panel prototype. During the course of its construction, we learned many lessons and discovered new and better ways to approach this project. These methods and discoveries are discussed throughout this website. Please enjoy and send us any questions that you may have.

This YERT video is featured in their full-length documentary, now being screened across the U.S. For a screening or presentation near you, click on the following “YERT plate”: YERT

After successful completion of the Phase I SBIR contract, we were awarded a follow-up 2-year Phase II $750,000 SBIR contract by the Federal Highway Administration beginning in 2011. With this award, a prototype parking lot will be built and then tested under all weather and sunlight conditions.

The heart of the Solar Roadway™ is the

Solar Road Panel™

The Solar Roadway is a series of structurally-engineered solar panels that are driven upon. The idea is to replace all current petroleum-based asphalt roads, parking lots, and driveways with Solar Road Panels that collect energy to be used by our homes and businesses. Our ultimate goal is to be able to store excess energy in or alongside the Solar Roadways. This renewable energy replaces the need for the current fossil fuels used for the generation of electricity. This, in turn, cuts greenhouse gases literally in half.

Solar Road Panel

Solar Road Panel

Each individual panel consists of three basic layers:

Road Surface Layer – translucent and high-strength, it is rough enough to provide great traction, yet still passes sunlight through to the solar collector cells embedded within, along with LEDs and a heating element. It is capable of handling today’s heaviest loads under the worst of conditions. Weatherproof, it protects the electronics layer beneath it.

Electronics Layer Contains a microprocessor board with support circuitry for sensing loads on the surface and controlling a heating element. No more snow/ice removal and no more school/business closings due to inclement weather. The on-board microprocessor controls lighting, communications, monitoring, etc. With a communications device every 12 feet, the Solar Roadway is an intelligent highway system.

Base Plate LayerLayer – While the electronics layer collects energy from the sun, it is the base plate layer that distributes power (collected from the electronics layer) and data signals (phone, TV, internet, etc.) “downline” to all homes and businesses connected to the Solar Roadway. Weatherproof, it protects the electronics layer above it.

TEDx logo TEDx

Scott presented the Solar Roadways at a TEDx Talk in Sacramento on April 16th, 2010. He was given 18 minutes for “The talk of his life” and it went great!

 

Overview

When multiple Solar Road Panels are interconnected, the intelligent Solar Roadway is formed. These panels replace current driveways, parking lots, and all road systems, be they interstate highways, state routes, downtown streets, residential streets, or even plain dirt or gravel country roads. Panels can also be used in amusement parks, raceways, bike paths, parking garage rooftops, remote military locations, etc. Any home or business connected to the Solar Roadway (via a Solar Road Panel driveway or parking lot) receives the power and data signals that the Solar Roadway provides. The Solar Roadway becomes an intelligent, self-healing, decentralized (secure) power grid.

The images below illustrate how the west can power the east in the evening and the east can power the west in the morning hours.North America North America

Africa/Europe Africa and Europe

Imagine a world-wide system where the “lit” half of the world is always powering the “dark” half of the world!

Everyone has power. No more power shortages, no more roaming power outages, no more need to burn coal (50% of greenhouse gases). Less need for fossil fuels and less dependency upon foreign oil. Much less pollution. How about this for a long term advantage: an electric road allows all-electric vehicles to recharge anywhere: rest stops, parking lots, etc. They would then have the same range as a gasoline-powered vehicle. Internal combustion engines would become obsolete. Our dependency on oil would come to an abrupt end.

It’s time to upgrade our infrastructure – roads and power grid – to the 21st century.

Advantages of Solar Power

Solar power systems have many benefits. They are quiet. They don’t produce any pollution. They are reliable, there are no moving parts to worry about, so they require minimal maintenance. Another great advantage of a solar power system is that it’s modular. The cells (or building blocks) are available in a wide variety of wattage, ranging from a mere fraction of a watt to more than 300 watts. Large solar power plants have higher megawatts, but most individual systems are much smaller. You can choose the solar power modules required to deliver the power you desire for your system.

One downside of solar energy is that much of the sun’s energy is lost during the process of transferring sunlight to electricity. To solve this challenge, larger and more efficient panels continue to be manufactured all the time. And while they are still less efficient than they ultimately might be, they are still the renewable energy system of choice because they require so little maintenance and are quite durable.

A solar panel system should last around fifty years, as long as it was properly installed. A pretty wise investment, all things considered! If you choose to install your own solar power system, you will appreciate its quiet, low-maintenance, pollution-free, safe and reliable operation, as well as the degree of independence it provides.

Visit this site for more Alternative Energy Info. Dave’s Alternative Energy Site

Renewable Energy Off the Grid

Renewable Energy Off the Grid

This page contains information on why and how to generate renewable energy while living off the grid, also you will find useful tips on how to satisfy most of your power needs without having to rely on the city for electricity. Generating your own power off the grid is very essential if you want to declare your independence and be fully or mostly self suffecient. Spending around $700 on wind generators and solar panels can reduce your power costs more than $1300 a year (especially if you build them and install them yourself), plus you will feel good about using green and renewable energy.

Benefits of Generating Renewable Energy

You can cut your electricity costs by 80%, or even make your power company pay you, and of course, you will feel good to know that you’re doing your part to save the planet from pollution. These are uncertain times, energy costs continue to soar, natural resources are being depleted at an alarming rate, and pollution and global warming continue to worsen. While it can all seem distant and overwhelming, the solution to each of these issues actually lies within each of us. Our actions today can create change. Our daily decisions do have an impact on the world at large.

Harnessing the power of wind and sun is not only possible by most people, but it’s increasingly affordable and easy to set up. But before discussing ways to harness wind and solar energy, it’s very important to note that, the first step to start, is by changing our behaviour. Right now, even though renewable energy is not exactly cheap and often not very accessible in its current state, there are still plenty of ways you can cut down on energy costs. Here are just a few:

•  Turn off your appliances when you’re not using them. Computers and televisions continue to use energy even when they’re in standby mode.

•  Instead of always using your dryer or dishwasher, consider air-drying your clothes and dishes at least some of the time, and only run your dishwasher, dryer, or washing machine with full loads.

•  Use energy-efficient fluorescent lightbulbs in your household lamps.

•  Set your thermostat at a comfortable but moderate temperature – not too warm in the winter, not too cool in the summer.

•  Take shorter showers and avoid baths.

•  Maintain your vehicle – regular tune-ups insure that you get maximum fuel efficiency. When you drive, be aware that excessive speeds and rapidly accelerating and braking uses more gas.

•  Seal your windows and doors. Preventing warm or cool air from escaping will make a significant difference in your utility costs.

If you are seriously considering using renewable energy sources like wind or solar power to heat and cool your home, then you MUST implement the suggestions above. There’s simply no value in using a wind or solar generator if you continue to leave lights and appliances on when not in use, use more water than is necessary, etc.

Other Useful Links

Alternative energy deal links

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Cargo Container Homes

Cargo Container Student Residences

Shipping containers can be readily modified with a range of creature comforts and can be connected and stacked to create modular, efficient spaces for a fraction of the cost, labor, and resources of more conventional materials. With the green theme growing in popularity across every stretch of the world, more and more people are turning to cargo container homes for green alternatives for office, and even new home, construction. There are countless numbers of empty, unused shipping containers around the world just sitting on the shipping docks and taking up space. The reason for this is that it’s too expensive for a country to ship empty containers back to the their origin in most cases, it’s just cheaper to buy new containers from Asia. The result is an extremely high surplus of empty shipping containers that are just waiting to become someone’s home or office. Container home Video

Other Cargo Container home links

http://dornob.com/diy-used-cargo-homes-shipping-container-house-plans/

http://weburbanist.com/2008/05/26/cargo-container-homes-and-offices

 

 

Advantages of Solar Power

Solar power systems have many benefits. They are quiet. They don’t produce any pollution. They are reliable, there are no moving parts to worry about, so they require minimal maintenance. Another great advantage of a solar power system is that it’s modular. The cells (or building blocks) are available in a wide variety of wattage, ranging from a mere fraction of a watt to more than 300 watts. Large solar power plants have higher megawatts, but most individual systems are much smaller. You can choose the solar power modules required to deliver the power you desire for your system.

One downside of solar energy is that much of the sun’s energy is lost during the process of transferring sunlight to electricity. To solve this challenge, larger and more efficient panels continue to be manufactured all the time. And while they are still less efficient than they ultimately might be, they are still the renewable energy system of choice because they require so little maintenance and are quite durable.

A solar panel system should last around fifty years, as long as it was properly installed. A pretty wise investment, all things considered! If you choose to install your own solar power system, you will appreciate its quiet, low-maintenance, pollution-free, safe and reliable operation, as well as the degree of independence it provides.

Visit this site for more Alternative Energy Info. Dave’s Alternative Energy Site

Stanford Scientists Develop Peel-and-Stick Solar Cells

Stanford Scientists Develop Peel-and-Stick Solar Cells

SOLAR TECHNOLOGY NEWS | JANUARY 11, 2013 BY  | 0 COMMENTS

Stanford University scientists have developed a flexible, decal-like thin-film solar cell that can be attached to almost any kind of surface.

These solar cells can be produced using conventional, industry-standard materials and methods.

According to the team of scientists, the peel-and-stick method provides a simple way of integrating thin film solar cells into buildings, clothes and many other unconventional substrates.

Step-by-Step Guide to Saving on Solar

Thin-film solar cells at different stages of the peel-and-stick process. Credit: Stanford

The cells are made by depositing a 0.3-micron layer of nickel on a standard silicon wafer, which then has a standard, hydrogenated amorphous silicon thin-film solar cell deposited on top of that. A protective polymer covers the wafer, and then a thermal release tape is attached to the top of the solar cell that can be peeled off and stuck to almost any surface.

According to lab testing, the peel-and-stick process leaves the thin film cell completely intact and retains its performance through thousands of bending cycles.

“The silicon wafer is typically undamaged and clean after removal of the solar cells can be reused,” said Xiaolin Zheng, lead researcher of the Stanford team.

“Now you can put them on helmets, cell phones, convex windows, portable electronic devices, curved roofs, clothing—virtually anything,” he added.

According to the researchers, this new process has enabled the further reduction of the cost and weight for thin film production and has enhanced flexibility and attachability for broader application areas.

Other cool stories

 

5 Reasons a Radical Shift to Solar Power Makes Perfect Sense

5 Reasons a Radical Shift to Solar Power Makes Perfect Sense

August 1, 2012 By  Leave a Comment

solar panels

The vast potential of solar power is extraordinary.

For many years the idea of switching from reliance on power plants for electricity torenewable energy sources such as solar power was considered by most in the U.S. to be a far-fetched and unreasonably costly proposition.  Whether mostly due to the cost of solar panels or political pressures related to keeping the need for fossil-fuel a national priority, the switch to renewable energy moved at a snail’s pace for decades.  In the meantime, more and more homeowners have recognized that switching to solar power makes good sense, especially since the related costs are significantly less, it now seems more far-fetched to continue relying on fossil-fuel run power plants for electricity.

Individuals across the U.S.A. are making the decision to go solar and to take on other initiatives which contribute to genuine energy independence and a cleaner world.  True energy independence with solar power:

1. Is self-generated.  When an electrical power grid goes down, blackouts occur, which can be catastrophic.  Think of notorious New York City blackouts; the entire metropolis comes to a grinding halt.  There are many potential dangers linked to a blackout, not to mention the incredible inconvenience of the situation.  On the other hand, any homeowners or companies who rely on solar thermal energy for their hot water needs are almost immune to short-term electrical blackouts.  In addition, the more solar PV systems there are, the smaller the chance that a power plant will shut down due to overwhelming demand.

2. Is renewable.  There is a limit to the amount of gas, oil, and coal that is practically, economically and safely accessible within the earth.  Some researchers have projected that at the current level of demand, the earth will run out of these resources by the next century.  On the other hand, sun, wind, and geothermal energy are limitless resources. Did you know that more solar energy strikes the earth in one hour than the world’s population uses collectively in a year?

solar power results

Create a cleaner future for generations to come.

3. Doesn’t compromise the health of industry workers.  Anytime someone chooses to work in a coal mine, they know that they may be making a choice that sacrifices their health in exchange for a job.  Employees in the renewable energy industry, however, don’t have to make such a sacrifice.  Of course, there are places in the U.S.A. where coal mines are the backbone of the economy and are important to the citizens, in spite of the inherent dangers.  But the radical shift to renewable energy doesn’t have to mean widespread job loss.  Workers can be trained in other fields, including clean energy, and hold on to their health at the same time. In less than a century much of the industrialized world has gone from horses to cars. We can and must make a similar transition with energy.

4. Can eliminate dependence on foreign sources. Due to speculation, political manipulation and worldwide economic influences; even if the current hindrances to drilling in the U.S.A. were removed, our country would still need to import foreign oil, to keep up with demand.  The components for solar PV systems can be produced domestically thus generating jobs; and, of course, renewable energy sources are supplied by nature in real time.

5. Minimally affects the environment.  All components of solar panels are made with materials which can be recycled.  Little to no damage to air, land, or water is caused by using renewable energy sources. Furthermore, as even more refined manufacturing processes evolve any trace residues and polluting byproducts related to the PV manufacturing process are progressively being reduced or eliminated.

Imagine what a better world future generations will be able to enjoy when this radical shift to using renewable energy supplies such as solar panels becomes the norm.   For a happier and healthier future, for generations to come, visit the North American Solar Store near you.

 

Climate-Friendly Agriculture and Renewable Energy: Working Hand-in-Hand toward Climate Mitigation

By Laura Reynolds and Sophie Wenzlau, Worldwatch Institute
December 21, 2012 | 

Worldwide, agriculture contributes between 14 and 30 percent of human-caused greenhouse gas (GHG) emissions because of its heavy land, water, and energy use—that’s more than every car, train, and plane in the global transportation sector. Livestock production alone contributes around 18 percent of global emissions, including 9 percent of carbon dioxide, 35 percent of methane, and 65 percent of nitrous oxide.

Activities like running fuel-powered farm equipment, pumping water for irrigation, raising dense populations of livestock in indoor facilities, and applying nitrogen-rich fertilizers all contribute to agriculture’s high GHG footprint.

The good news? The UN Food and Agriculture Organization (FAO) estimates that the sector has “significant” potential to reduce its emissions, including removing 80 to 88 percent of the carbon dioxide that it currently produces.

Some of this reduction can be achieved by substituting renewable energy for the fossil fuels typically used to power day-to-day farm activities. Do-it-yourself solar heat collectors can warm livestock buildings, greenhouses, and homes; small or cooperatively owned wind and water turbines can pump water and power equipment; photovoltaic panels can power critical farm operations like electric fencing and drip irrigation systems; and designing or renovating buildings and barns to maximize natural daylight can dramatically reduce the electricity required to light and warm farm buildings.

These innovations can be scaled up for implementation on large farms, but their beauty is in their simplicity, accessibility, and application to the smallest of operations.

And greening a farm does not stop at replacing fossil fuels with renewable energy. To make a farm truly climate-smart, it must take into account all aspects of its environmental footprint: soil fertility, water use, chemical inputs, and biodiversity. Farmers can implement low-tech, low-cost practices to curb their emissions while building resilience to weather shocks and severe resource scarcity, two projected stumbling blocks for farmers in coming decades.

Any measure that reduces on-farm water use, for instance, will help to relieve the heavy pressures on the planet’s dwindling resources while reducing agriculture’s energy footprint. Agriculture accounts for a whopping 70 percent of global water use; in the United States, the figure rises to 80 percent. Rivers, lakes, and underwater aquifers are drying up across the globe, causing serious concerns over basic human rights like sanitation, food production, and safe drinking water.

Installing drip irrigation, which applies precise amounts of water to the plant roots instead of spraying water over plants, is a simple way to invest in climate-stress mitigation. Watering crops using “greywater,” or water used in domestic activities like dishwashing, laundry, and bathing — not to be confused with blackwater, or sewage — can also reduce water use on farms, particularly small-scale operations. And switching from “thirsty” crops like rice, wheat, and sugarcane (which account for nearly 60 percent of the world’s irrigated cropland) to less-demanding plants like sorghum, millet, lettuce, broccoli, carrots, beans, and squash can reduce on-farm water use and help farmers cope with drought and other threats (while broadening access to fresh and nutritious foods).

Water conservation is just one approach to making a farm more climate-friendly. Practices such as using animal manure rather than artificial fertilizer, planting trees on farms to reduce soil erosion and sequester carbon, and growing food in cities all hold huge potential for reducing agriculture’s environmental footprint.

Interestingly, biofuels can combine the need for renewable energy with climate-friendly agricultural practices.

Perennial bioenergy crops stand as a shining example of agricultural innovation. While corn has long reigned the biofuels industry, its relative energy-conversion inefficiency and its sensitivity to high temperatures make it an unsustainable long-term energy option. But trees and shrubs like willow, sycamore, sweetgum, and cottonwood offer promising alternatives. These perennials grow quickly for many years, can often thrive on marginal land, and are often much hardier than annual plants like corn or soybeans. Their long roots can also reduce erosion, filter groundwater, harbor beneficial microorganisms, and help soil retain key nutrients like phosphorus and nitrogen.

Because we may need to double our global food production by 2050 to feed the projected world population, it is important that farmers do not divert their food-bearing land to grow energy crops. Although corn- and soy-based biofuels must be produced on fertile agricultural land, perennial crops can often thrive on marginal land (i.e. steep slopes and eroded soil) that would otherwise fallow. In the United States, 27 million acres are currently enrolled in the U.S. Department of Agriculture’s Conservation Reserve Program, which pays agricultural landowners to grow long-term, resource-conserving cover crops on their marginal or unused farmland. A portion of this program’s enrolled land could be planted with perennial crops and harvested regularly for fuel production.

And because perennial crops require considerably less fertilizer, pesticides, and herbicides — not to mention time and labor — than annual crops, they are a natural choice for the millions of farmers around the world who cannot access or afford expensive chemical inputs.

By tapping into the multitude of climate-friendly farming practices that already exist, agriculture can continue to supply food for the world’s population, and also help to reduce our dependence on fossil fuels. But if we want agriculture to contribute to climate change mitigation, climate-friendly food production will need to receive increased attention — in the form of both research and investment — in the coming years.

A step in the right direction: in early December, a presidential advisory council on science and technology warned that U.S. agricultural research has not prepared the country for the predicted impacts of climate change, population growth, emerging pests and diseases, and severe resource depletion and scarcity. The United States and other countries must promote innovative agricultural research to brace for these serious challenges, and to protect the livelihoods of the 1.3 billion people whose livelihoods rely on agriculture.

Laura Reynolds and Sophie Wenzlau are Staff Researchers for the Food and Agriculture Program at the Worldwatch Institute. Laura co-authored Innovations in Sustainable Agriculture: Supporting Climate-Friendly Food Production, which was released earlier this month.
Bioenergy, Solar Energy, Wind Power

The information and views expressed in this article are those of the author and not necessarily those of RenewableEnergyWorld.com or the companies that advertise on its Web site and other publications.

Watch Legendary Bruce Oreck’s Plenary Presentation from WREF 2012

Long but good

Bruce Oreck, the U.S. Ambassador to Finland, began on one of the days at WREF with a talk on how to use language effectively to promote renewable energy. Oreck’s presentation focused on using a different style of language than currently used to promote renewables. For example, instead of using the phrase that renewable energy “saves money,” focus on using “making money” by going solar instead. You can view Oreck’s presentation from WREF here:

Watch Legendary Bruce Oreck’s Plenary Presentation from WREF 2012

Solar Windows

If you picture the glittering glass skyscrapers that dot America’s cities, it becomes clear why the idea of using that vast window space to generate solar power is gaining traction. In 2009 alone, 437 million square feet of windows were installed in non-residential buildings in the United States. That many square feet of standard solar panels would generate around 4 gigawatts of power, roughly the total installed solar capacity in the U.S. today.

Such potential is leading engineers and entrepreneurs to more intensively explore the idea of turning windows into solar-power producers. Solar windows, a subset of the growing field known as building-integrated photovoltaics, are based on the concept that a window doesn’t need to be 100 percent transparent, and a solar panel doesn’t need to be 100 percent opaque. Several ways currently exist to turn a window into a power-generating device, from thin-film silicon, to dye-sensitized solar cells, to tiny organic cells.

New Energy SolarWindow

Some experts think the field is poised to take off, and although the world may not see an all-solar skyscraper for a while, a number of companies are promising commercial-scale production of various solar windows in the next two years. Still, the cost and technical hurdles facing this fledgling technology could get in the way of a future filled with towering, emission-free power plants. Like other cutting edge alternative energy sources, energy-generating windows could become a mainstay of a greener future in the coming decades, or they could prove to be impractical and produce only a fraction of solar-powered electricity.

“The challenge is whether you can get the cost down and the electricity generation up,” says Sarah Kurtz, a scientist with the U.S. government’s National Renewable Energy Laboratory (NREL) in Colorado. “There are lots of different schemes and strategies, and creativity will be the name of the game. If you can get the cost to the place where those windows don’t really cost any more than conventional windows, it obviously makes sense to go ahead and have your windows generate electricity.”

Building-integrated photovoltaics, or BIPV, is moving slowly, with solar panels now doubling as walls, shingles, and other parts of buildings. MJ Shiao, a senior analyst at GTM Research, a market analysis group in Cambridge, Massachusetts, says the market still represents only around 1 percent (a few hundred megawatts last year) of solar powerbeing installed around the world, and that’s mostly rooftops or semi-opaque skylights. Windows pose a greater challenge than rooftops or walls because of the need to actually see through them. So far, very few examples of skyscrapers with solar windows exist; the highest profile site is the Willis Tower (formerly Sears Tower) in Chicago, where Pythagoras Solar installed a small prototype in 2011.

Several technologies have emerged for solar windows, though none have yet taken off in a meaningful way. But one company that says it is close to commercial deployment is New Energy Technologies, based in Columbia, Maryland. It has developed a method for spraying tiny organic solar cells onto windows in a see-through coating that lets in 40 to 80 percent of sunlight, absorbing the rest. With 10 patent filings pending and no commercial prototypes yet in the field, the company is divulging few details. But the spray-on method could reduce production costs dramatically. Recently, the company announced the development of a large solar cell — 170 square centimeters — made in collaboration with NREL, which could make adding the cells to windows even cheaper.
Despite the company’s progress, its technologies highlight one of the major obstacles to solar windows: efficiency. The rate at which a solar panel turns the sun’s energy into electricity is a concern for all types of solar power, but especially for windows. “The challenge is that the light you see, if you absorb that and use it to make electricity, that means you don’t have a window anymore,” says Kurtz.

To date, the record efficiency for an organic solar cell is 10 percent, and production line efficiencies never get up to the record levels. While traditional solar panels are now producing power with 15 to 20 percent efficiency, efficiency levels for solar windows of roughly 5 percent are unlikely to be economical.

“Look at it from a physicist’s point of view,” Kurtz says. “A solar panel that’s put out in the desert in a nice location with lots of sunshine may have something on the order of a one-year payback. If that [panel] sits out there for another 20 years, you get that much return on your investment for society.” If a solar window can only achieve one-third the efficiency of a solar panel, then it will take three times as long to pay back the investment.

But some experts think it’s just a matter of time before efficiencies rise high enough — and costs drop low enough — to make solar windows a sound investment. Andreas Athienitis, a professor of mechanical engineering at Concordia University in Montreal who is working on technologies for solar windows, says more mature technologies like thin-film silicon might represent a short- and mid-term solution for BIPV, until organic cells can catch up and meet long-term goals. “I think eventually it will be a big market,” he says, but the adoption is slow because “it’s a disruptive technology.”

organic-valley-solar-windows

Another company using organic solar cells, Heliatek, based in Germany, has panels that can achieve 8 percent efficiency. The company’s organic cells use molecules called oligomers rather than traditionally used polymers — basically, short rather than long collections of atoms — which means cheaper, more precise application of the cells. Heliatek says it expects that within five years it can manufacture solar cell windows in the 50 cents-per-watt range, making them competitive with other solar technology.

Spain-based Onyx Solar offers a number of solar glass technologies. However, its windows only allow up to 30 percent of sunlight through, so a lot of light inside the building is lost. In varying formations, though, Onyx says its amorphous-silicon solar glass — a type of thin-film silicon cell — can get up to 9-percent efficiency.

But such efficiencies don’t take into account some of the practical limitations of actually covering a skyscraper with solar windows.

“The optimal installation for solar is you want it to be facing south, you want a slight tilt to it, and you want good solar access, so you don’t want anything to shade those panels,” says Shiao, of GTM Research. “The problem with skyscrapers is suddenly you’re putting them in vertical orientation, there’s only one south side to the building, and chances are that skyscraper is next to another skyscraper, which is going to shade that side of the building.”

Such challenges have left Shiao and other experts skeptical that solar windows will have a bright future. “There are a lot of technical and design challenges, which quite honestly aren’t going to be fixed,” Shiao says. “It doesn’t make sense almost at any cost, unless you’re getting the panels for free or something, to really install that system on those big structures.”

These obstacles haven’t deterred numerous fledgling companies. Oxford Photovoltaics, spun out of research done at Oxford University, says that computer modeling of a 700-foot skyscraper in Texas suggests thatcovering it in solar windows would generate up to 5.3 megawatt-hours per day of electricity. That’s enough to power 165 homes, and it could provide a skyscraper with sufficient power for all its lighting.

Oxford’s technology involves a type of cell for solar windows called a dye-sensitized solar cell. Dye-sensitized cells use a photo-electrochemical process to generate power and can be made relatively cheaply. Oxford’s transparent panels are so far getting around 6 percent efficiency, and the company hopes to bring them to market late next year.

Nazir Kherani, a professor of engineering at the University of Toronto, believes that the economics of solar windows may be most compelling for new construction with a focus on net-zero energy buildings — not for retrofitting existing skyscrapers. “With sufficient attention to design and seamless engineering, it is conceivable that we may see such buildings gradually evolving into net-zero communities, villages, and towns,” Kherani says.

Several companies involved in solar window production say they are within a year or two of scaling up or bringing a product to market, and they maintain that cell efficiencies will continue to rise and prices continue to fall, as is the case with solar panels.

What continues to drive the inventors and entrepreneurs involved in developing solar windows is the enormous potential for energy savings. Buildings accounted for 41 percent of all electricity consumption in the U.S. in 2010, more than transportation or industry. Taking a bite out of that with power-generating windows is an alluring target.

“I wouldn’t write off the possibility,” Kurtz says. “How soon will it happen? I find it’s really dangerous to predict the future.”

source :http://www.earthtechling.com/2012/05/will-solar-windows-transform-buildings-to-energy-producers/