Tuesday, July 29, 2014


A friend of mine asked me:

Do You Need to Install Solar Panels in Direct Sunlight?

Photovoltaic (PV) solar panels are widely regarded as an ideal method of generating electricity. The materials in the panels, usually silicon, create an electric current when met with natural daylight and this current is then used as standard electricity within properties. The energy is renewable, therefore, considered green. However, many question how effective solar panels are in cloudy climates and wonder whether direct sunlight is, indeed, needed to get the full benefits of the panels.

Daylight not Sunlight

Solar panels use the energy from daylight, as opposed to sunlight, to produce electricity so panels do not need direct sunlight to work. It is photons in natural daylight which is converted by solar panels cells to produce electricity. Heat has no effect on the production of electricity.
This being said, it is true that direct sunlight does provide the best conditions for the panels. However, even in overcast conditions light will diffuse through the clouds and reach the solar panels. Modern solar panels include concentrators which use a system of lenses and mirrors to maximize any light that does reach the cells. As a result it is estimated that solar panels will be 40% as effective in heavy cloudy as they would in direct sunlight. The clearer the skies are the more electricity will be produced.
So if you live in an area that is not the sunniest climate in the world, such as the east coastline  of Lake Michigan, but there appears to be sufficient daylight to ensure that solar panels will work effectively, a solar system may still produce energy for you. It is worth noting that this is true for solar array systems that are feed back into the power supplier. If your array is tied to battery storage, having a long period of sunny weather will create electricity which can be used later on. 
Solar panels will not work at night and the property will still be dependent on electricity from the energy provider. Solar panels will work in winter, even in the Midwest, but of course less electricity will be created as the hours of daylight are considerably shorter than they are in the summer months.
Despite common beliefs, solar panels do not need direct sunlight to work and the weather conditions in the Midwest should not put off potential solar panel buyers. It is energy from daylight, as opposed to sunlight, which powers the panels which means even on overcast days electricity will be generated. There are many questions potential solar panels owners should concern themselves with but the question of the panels needing sustained sunlight to work can be dismissed.

Tuesday, July 8, 2014


NIST test house exceeds goal; ends year with energy to spare

The net-zero energy test house at the National Institute of Standards and Technology (NIST) in suburban Washington, D.C., not only absorbed winter's best shot, it came out on top, reaching its one-year anniversary on July 1 with enough surplus energy to power an electric car for about 1,440 miles.

Despite five months of below-average temperatures and twice the normal amount of snowfall, NIST's Net-Zero Energy Residential Test Facility (NZERTF) ended its one-year test run with 491 kilowatt hours of extra energy.
Instead of paying almost $4,400 for electricity-the estimated average annual bill for a comparable modern home in Maryland-the virtual family of four residing in the all-electric test house actually earned a credit by exporting the surplus energy to the local utility.
A net-zero energy house produces at least as much energy as it consumes over the course of a year. A number of states are taking steps toward encouraging or even requiring construction of net-zero energy homes in the future. For example, California will require that, as of 2020, all newly constructed homes must be net-zero energy ready.

Both a laboratory and a house, the two-story, four-bedroom, three-bath NZERTF would blend in nicely in a new suburban subdivision. But it was designed and built to be about 60 percent more energy efficient than houses built to meet the requirements of the 2012 version of the International Energy Conservation Code, which Maryland has adopted.
The 2,700 square-foot  test house is built to U.S. Green Building Council LEED Platinum standards-the highest standard for sustainable structures. Its features include energy-efficient construction and appliances, as well as energy-generating technologies, such as solar water heating and a solar photovoltaic system.

Despite 38 days when the test house's solar panels were covered with snow or ice, the NZERTF's sun-powered generation system produced 13,577 kilowatt hours of energy. That's 491 kilowatt hours more than used by the house and its occupants, a computer-simulated family of two working parents and two children, ages 8 and 14.

First year energy use totaled 13,086 kilowatt hours, which was about 3,000 kilowatt hours more than projected usage in a year with typical weather. In a normal year, a comparable home built to meet Maryland's residential energy standard would consume almost 27,000 kilowatt hours of energy.

In terms of energy consumed per unit of living space-a measure of energy-use intensity-the NIST test house is calculated to be almost 70 percent more efficient than the average house in Washington, D.C., and nearby states.
From July through October, the facility registered monthly surpluses. In November, when space-heating demands increased and the declining angle of the sun reduced the energy output of its 32 solar panels, the NZERTF began running monthly deficits. Through March 31, when the house's net energy deficit plummeted to 1,800 kilowatt hours-roughly equivalent to the combined amount of energy a refrigerator and clothes dryer would use in a year-temperatures consistently averaged below normal.
Starting in April, the energy tide began to turn as the house began to export electric power to the grid on most days.

In terms of cost, the NZERTF's virtual residents saved $4,373 in electricity payments, or $364 a month. However, front-end costs for solar panels, added insulation, triple-paned windows, and other technologies and upgrades aimed at achieving net-zero energy performance are sizable.

In all, estimates that incorporating all of the NZERTF's energy-related technologies and efficiency-enhancing construction improvements would add about $162,700 to the price of a similar house built to comply with Maryland's state building code.
Planned measurement-related research at the NZERTF will yield knowledge and tools to help trim this cost difference. Results also will be helpful in identifying affordable measures that will be most effective in reducing energy consumption. And research will further the development of tests and standards that are reliable benchmarks of energy efficiency and environmental performance overall, providing information useful to builders, home buyers, regulators and others.

Tuesday, June 3, 2014


In theory, the idea could work: replace all of the nation’s asphalt with solar panels, and we’d generate more than three times the electricity the US uses. Great idea and it would road and highway problems. Solar roads design would also filter storm water, replace above-ground power cables, prevent icy roads by melting snow, and light up to warn drivers if a deer wanders onto the road.
Unfortunately, the list of obstacles is long. The main problem is cost. There are roughly 29,000 square miles of road surface to cover. We need roughly 5.6 billion panels to cover that area. That’s a price tag of $56 trillion.
 The researchers have been unable to secure any large piece of the more than $2 billion a year spent on solar research and development around the world. Probably because there are too many more-practical, more-promising investments to be made to seriously consider this pipe dream.
This brings up a good point. Rooftop panels and solar arrays are already established as a viable power source, but adoption is still low. It’s hard to imagine a city ripping up asphalt and installing a largely unproven technology when it could achieve the same level of power generation by planting panels along the road.
Most of the technological challenges seem solvable. Those include things like how to keep the roads clean, how to increase the efficiency of the panels in the road, how to store the solar power, how to get electricity from more remote roads to the grid, and whether the glass is durable enough. Whether they’re solvable for a reasonable price tag is another question.
The first thing that one has to understand before beginning to look at numbers is this: an apples to apples comparison between asphalt or concrete roads and solar roads is not possible. 

An asphalt/concrete road is simply a hard surface to drive a vehicle on. A solar is a modern modular system with a multitude of uses and features.

 For an accurate cost comparison between current systems and the solar road system, you'd have to combine the costs of current roads (including snow removal, line repainting, pothole repair, etc.), power plants (and the coal or nuclear material to run them), and power and data delivery systems (power poles and relay stations) to be comparable with the solar road system, which provides all three.

This will be interesting to watch.

Thursday, May 15, 2014

Coal Production/Consumption

China consumes almost as much coal as the rest of world combined

China consumes almost as much coal per year as the rest of the world combined, data from the U.S. Energy Information Administration show Wednesday.

EIA said Chinese coal production and consumption increased for the 13th year in a row in 2013, the last full year for which data are available.
China, EIA said, consumes about 49 percent of the coal produced globally, besting the No. 2 consumer, the United States, which consumes about 11 percent of the world's total coal.

EIA said Wednesday coal is fueling the Chinese economy. Gross domestic product in 2013 grew 7.7 percent, though that growth rate followed a decade of 10 percent expansion that ended in 2011.

In terms of production, EIA said China is by far the world's largest producer accounting for 46 percent of the coal produced globally.
China produced nearly four times as much coal as the second largest producer, the United States, which had a 12 percent share of global production. China has accounted for 69 percent of the 3.2 billion ton increase in global coal production over the past 10 years.

In February, the World Wildlife Fund said China could still thrive economically while removing coal from its power mix.

Friday, April 18, 2014


Let the Sun Shine In: Redirecting Sunlight to Urban Alleyways

In dense, urban centers around the world, many people live and work in dim and narrow streets surrounded by tall buildings that block sunlight. And as the global population continues to rise and buildings are jammed closer together, the darkness will only spread.

To alleviate the problem, researchers have developed a corrugated, translucent panel that redirects sunlight onto narrow streets and alleyways. The panel is mounted on rooftops and hung over the edge at an angle, where it spreads sunlight onto the street below.

Researchers expect the device to provide illumination to perform everyday tasks, and improve the quality of light and health conditions in dark areas. These dimly lit areas specifically include narrow streets, but the new panel could be used as a greener, cheaper, and more pleasant alternative to fluorescent and other artificial light.

While other commercially available window-like devices can redirect light, they are designed for shade and redirecting glare or for brightening a room-not a narrow street. So the researchers decided to create their own design. They wanted a simple way to redistribute natural light without the need for a tracking device that follows the rising and setting sun.

What they came up with is a panel made of polymethyl methacrylate (PMMA), the same acrylic plastic of which Plexiglas is made. The bottom of the panel is smooth while the top is covered in ridges that are based on a sine wave, the mathematical function that describes everything from light to pendulums.

The researchers used computer simulations to find the size and shape of the grooves that distribute the most amount of sunlight in a wide range of sun positions all year round, whether it's high or low in the sky. A sine-wave pattern is also easy to manufacture.

Using simulations of sunlight shining on an alleyway, the researchers found that their panels increased illumination by 200 percent and 400 percent in autumn and winter, respectively, when sunlight is most limited. They also tested a small prototype and found that it lit up the area as designed.
The next step will be to build a full-scale model 10 times bigger to validate their calculations and to test it in a real alleyway. The team then plans to market and commercialize the panel.

And that may be a small price to pay for the benefits of sunlight. The lack of sun in urban areas doesn't just make life gloomy; it can be harmful to your health. Research has shown that lack of natural lighting can cause severe physiological problems, such as serious mood changes, excessive sleeping, loss of energy and depression.

Tuesday, April 1, 2014


Kyocera Solar reduces cost and increases efficiency with new 1000-volt modules

Kyocera Solar Inc. is now offering new 1000-volt solar photovoltaic (PV) modules designed to significantly reduce labor and materials costs while simultaneously increasing overall system efficiency.
The US electrical code was only recently amended to allow 1000-volt solar modules, following a similar development in Europe that enables wider use of high-efficiency 1000-volt inverters.
By specifying a 1000V system instead of the previous 600V standard, installers can reduce total system costs by a substantial amount — up to 20%, according to Kyocera engineers, depending on the individual project.
The cost reduction is achieved in several ways:
  • Because 1000V PV systems incorporate more modules per string, materials and labor costs are minimized by reducing the total number of strings and combiners the system requires. 
  • String cable used for 1000V modules is thinner and uses less copper, making it less expensive to purchase and install. 
  • 1000V inverters are likewise smaller and less expensive to install than their 600V counterparts.

A more long-term advantage of the 1000V system is its ability to minimize resistive losses, also known as “voltage drop” — which is typically about 0.75% lower in a 1000V system than in a comparable system of 600V. This increase in efficiency results in significant energy retention over the 20+ year lifespan of a system.

Wednesday, March 5, 2014


Wind farms can tame hurricanes: scientists

Huge offshore wind farms can protect vulnerable coastal cities against devastating cyclones like Katrina and Sandy by tempering winds and ocean surges before they reach land. researchers said.

Had such installations existed at the time, Hurricane Katrina which ravaged New Orleans in 2005, and Sandy, which smashed the coastlines of New York and New Jersey in 2012, would have been reduced to strong but not devastating winds.

The study, published in the journal Nature Climate Change, is the first to demonstrate that wind farms, deployed on a grand scale, can buffer violent hurricanes, the researchers said.

The team simulated the impact from farms of tens of thousands of turbines, placed miles offshore and along the coast of cyclone-vulnerable cities.

They found that turbine blades extracting energy from the wind on a very large scale can have a marked effect on the internal dynamics of a cyclone.  When wind turbines are present, they slow down the outer rotation winds of a hurricane.

This feeds back to decrease wave height, which reduces movement of air toward the centre of the hurricane, increasing the central pressure -- which in turn slows the winds of the entire hurricane and dissipates it faster.

In the case of Hurricane Katrina, sustained peak wind speed would have been reduced by as much as 98 miles per hour. Katrina's storm surge -- waves whipped up by the exceptional winds -- would have abated by up to 79 percent, said the study.

In the case of Tropical Storm Sandy, the model projected a drop of up to 87 mph in sustained peak wind speed and a 34-percent decrease in storm surge. When Sandy, at an earlier stage, was rated as a powerful Category 3 hurricane, it packed gusts of up to 115 mph.

According to the study, the turbines should not be damaged and would continue to produce power during these events. By taming the leading edge of the storm, they would also dissipate the buildup of the winds that followed.

As a result, the wind speed would not exceed the turbines' designed cutout speed -- a threshold that prompts the device to go into lockdown and feather its blades to prevent damage.

But, according to the study, these mega-farms would pay for themselves by generating electricity in addition to providing storm protection.
A 20-mile installation off the New York coast would cost about $210 billion  to build.

By way of comparison, Tropical Storm Sandy inflicted about $80 billion  in damage when it hit three states in 2012. The disaster spawned plans to build higher sea walls to shield New York from rising storm surges expected from climate change -- a project that carries estimated costs of between $10-29 billion but produces no revenue.

Friday, February 7, 2014


 A Very Wobbly Planet Found by Kepler

Kepler was designed to detect ecoplanets by noticing the dips in brightness caused when these worlds transit, or cross in front of, their parent stars. Normally these transits occur in a regular pattern, but Kepler-413b behaved strangely.

Imagine living on a planet with seasons so erratic you would hardly know whether to wear Bermuda shorts or a heavy overcoat. That is the situation on a weird, wobbly world found by Kepler space telescope.

The planet, designated Kepler-413b, precesses, or wobbles, wildly on its spin axis, much like a child's top. The tilt of the planet's spin axis can vary by as much as 30 degrees over 11 years, leading to rapid and erratic changes in seasons. In contrast, Earth's rotational precession is 23.5 degrees over 26,000 years. Researchers are amazed that this far-off planet is precessing on a human timescale.

Kepler 413-b is located 2,300 light-years away in the constellation Cygnus. It circles a close pair of orange and red dwarf stars every 66 days. The planet's orbit around the binary stars appears to wobble, too, because the plane of its orbit is tilted 2.5 degrees with respect to the plane of the star pair's orbit. As seen from Earth, the wobbling orbit moves up and down continuously.

Kepler finds planets by noticing the dimming of a star or stars when a planet transits, or travels in front of them. Normally, planets transit like clockwork. Astronomers using Kepler discovered the wobbling when they found an unusual pattern of transiting for Kepler-413b.

Looking at the Kepler data over the course of 1,500 days, scientists saw three transits in the first 180 days -- one transit every 66 days -- then  had 800 days with no transits at all. After that, they saw five more transits in a row. The next transit visible from Earth's point of view is not predicted to occur until 2020. This is because the orbit moves up and down, a result of the wobbling, in such a great degree that it sometimes does not transit the stars as viewed from Earth.
Astronomers are still trying to explain why this planet is out of alignment with its stars. There could be other planetary bodies in the system that tilted the orbit. Or, it could be that a third star nearby that is a visual companion may actually be gravitationally bound to the system and exerting an influence.

Even with its changing seasons, Kepler-413b is too warm for life as we know it. Because it orbits so close to the stars, its temperatures are too high for liquid water to exist, making it inhabitable. It also is a super Neptune -- a giant gas planet with a mass about 65 times that of Earth -- so there is no surface on which to stand.

Friday, January 10, 2014


Electronic valet parks the car, no tip required

There is no one inside the Range Rover in a Las Vegas parking lot. But it still guides its way to a parking space, after what looks like some hesitation.

The self-parking is directed by an app which controls the vehicle, detects an available space and maneuvers into it.

The "automated parking valet" created by the French equipment maker Valeo is among the technology innovations for the sector on display at this week's Consumer Electronics Show.

While the idea of a fully autonomous car is a dream for some, this is a step which promises to alleviate at least some of the tedium facing motorists.

The system allows drivers to leave their car at the entrance of a parking lot and let it find a space to park itself. Drivers activate the feature from their smartphone, and can also use it to summon the car to pick them up.

The system does not require garages or parking lots to have special equipment. It relies on the kinds of sensors some cars already use, with some extra electronics.

The system may require a camera to recognize and avoid spaces designated for the handicapped or unusual features in a garage. 

The system was designed to be as simple as possible, so that it would not be only for luxury vehicles.

Parking maneuvers, experts say, are the most difficult for motorists.

Valeo said three million cars already have its semi-automatic system, which can perform parallel parking but require the driver to remain at the wheel.

Tuesday, December 10, 2013


US solar sector small but growing

Solar power, only a minuscule part of the energy mix in the United States, is getting a boost from cheaper panels, growing acceptance by large companies and chances for homeowners to rent solar systems.

Analysts expect a phenomenal growth for renewable solar power over the next two decades, after huge gains in the past two years: 60 percent growth in 2012 and 30 percent on top of that this year.

Heavily reliant on oil, natural gas, coal and nuclear, the United States only gets 12 percent of its power from renewables, of which solar is the smallest part, less than one percent.

But the solar sector is expanding faster than any.

The US Energy Information Administration predicts that photovoltaics -- the semiconductor technology that converts sunlight into electricity -- will grow 11.6 percent a year through 2040.

By comparison, wind power is expected to grow at two percent a year and geothermal power at four percent a year.

They attribute solar power's fast growth to a decrease in the price of photovoltaic panels in a generously oversupplied market, making the energy source more competitive with other types of renewable energy.

Additionally, the possibility for homeowners to simply rent panels rather than purchasing them has helped their popularity.

Around 55 percent of US demand for solar panels currently comes from power generating companies.

Another 30 percent comes from businesses that have large buildings and massive rooftops where installing solar systems for their own power makes sense.

This includes companies like retail giant Walmart, and Google, which puts the panels on top of its huge data centers. The rest of demand comes from the residential sector. Experts estimate that solar's growth could drive renewables to 20 percent of the entire energy market by 2030-2035.

Wednesday, November 20, 2013


Whither the teakettle whistle

With the winter weather comes the  flu and cold season, which means this device will be getting alot more attention.

Did you know...

Despite decades of brewing tea in a whistling kettle, the source and mechanism of this siren sound of comfort has never been fully described scientifically. Acknowledging the vibrations made by the build-up of steam escaping through two metal spout plates is about as far as the explanation went -- and was good enough for most people.

But not for a team of engineering investigators, who have at last illuminated the mystery. Through a series of experiments, the team has produced a breakthrough in breakfast musings with the world's first accurate model of the whistling mechanism inside the classic stovetop kettle.

They have located the physical source of the teakettle whistle at the spout as steam flows up it, and identified a two-mechanism process of whistle production. Their results show that as the kettle starts to boil, the whistle behaves like a Helmholtz resonator -- the same mechanism that causes an empty bottle to hum when you blow over the neck.

However, above a particular flow speed, the sound is instead produced by small vortices -- regions of swirling flow -- which, at certain frequencies, can produce noise.

The findings are potentially able to explain familiar problems of other wayward whistles, such as the annoying plumbing noises caused by air trapped in pipes or damaged car exhausts.

To interrogate kettle whistles, the team tested a series of simplified kettle whistles in an apparatus by forcing air through them at various speeds.
They then recorded the resulting sounds produced by rushing air, plotted the frequency and amplitude data of the sound, then analyzed it to identify trends in the data. They also used a two-microphone technique to determine frequency inside the spout.

Vortex production starts as steam comes up the kettle's spout and meets a hole at the start of the whistle, which is much narrower than the spout itself. This contracts the flow of steam as it enters the whistle and creates a jet of steam passing through it.

The steam jet is naturally unstable, like the jet of water from a garden hose that starts to break into droplets after it has traveled a certain distance. As a result, by the time it reaches the end of the whistle, the jet of steam is no longer a pure column, but slightly disturbed.

These instabilities cannot escape perfectly from the whistle. As they hit the second whistle wall, they form a small pressure pulse. This pulse causes the steam to form vortices as it exits the whistle, and it is these vortices that produce the siren sound that has conditioned millions of people to anticipate the coming of the tea.

Thursday, November 14, 2013


Sensor Suitcase - Brings Energy Efficiency to Small Commercial Buildings

Most buildings in the U.S. don't perform as energy-efficiently as they could simply because energy-using equipment in the building has never been set up to maximize energy performance. Thermostat set points are too low or too high, so rooftop units (RTUs) cool buildings down below recommended temperatures, or keep them too warm (or both).

Or, there is no difference in the set point during hours when the building is unoccupied versus occupied-turning the heat and space conditioning down during unoccupied hours helps lower energy bills substantially. Lights may be left on at night when no one is in the building, or there may be daytime opportunities in spaces that are not continuously occupied.

These are only a few of the problems that energy performance professionals see in the field, problems they can correct through retro-commissioning,the process of assessing the energy performance of an existing building, and then tuning its systems, and implementing no or low-cost energy efficiency improvements. When this is done to a new building, it is called commissioning.

Research published in 2009 by scientists demonstrated that in a large sample of existing buildings, retro-commissioning could save as much as 15 percent of a building's annual energy use, and pay for itself in less than a year, through the resulting utility cost savings.

In large commercial buildings, where the cost-effectiveness of this process is highest, retro-commissioning is beginning to become more common, thanks to growing awareness of its economic benefits to building owners and operators, as well as a thriving industry of building energy performance professionals.
In smaller commercial buildings efficiency efforts, including retro-commissioning have been hampered by several factors.

Small commercial buildings do not typically have budget or business economics that allow investing in enhancements such as comfort and energy improvements. They also don't have in-house staff with the expertise in building systems who can perform retro-commissioning or identify improvement opportunities.

The Sensor Suitcase, is a turn-key hardware and software solution that non-experts can use to generate low or no-cost recommendations automatically on how to improve a building's operating costs, comfort and energy performance.
This project is accomplished by 'embedding' the knowledge and skills of a highly experienced building commissioning practitioner into a scalable hardware and software package that can be easily deployed by a variety of building services personnel to make it easier for building owners and operators reap the benefits and cost savings for building commissioning.


Tuesday, October 29, 2013


Weatherizing Homes to Uniform Standard Can Achieve $33 Billion in Annual Energy Savings

With winter around the corner some homeowners may be thinking about plugging all the leaks in their home to make them less drafty. Imagine if every homeowner in the country did that-how much energy could be saved? 
Using physics-based modeling of the U.S. housing stock, researchers found in a new study that upgrading airtightness to a uniform level could achieve as much as $33 billion in annual energy savings.

Currently people who weatherize can get their homes about 20 to 30 percent tighter. But they're not sealing all the cracks. There's still quite a bit left on the table, and those extra leaks and cracks could potentially save a lot of energy. Energy impacts of envelope tightening and mechanical ventilation for the U.S. residential sector. while researchers need to figure out how much energy is wasted from leaky homes and determine the optimal standard of airtightness-one that would maximize energy savings while minimizing the cost of achieving those savings.

This is an important question because the residential sector-113 million homes-uses about 23 percent of total U.S. source energy annually. (Source energy includes site energy, the energy consumed by buildings for heating and electricity, as well as the raw energy required to transmit, deliver and produce it.) Heating and cooling accounts for about half of the site energy used in residences.

The largest potential savings are in the hottest and coldest climates. As new air enters homes through leaks and cracks, it has to be cooled or heated. Although the trend has been towards building tighter houses, the science is still not settled on the best ways to minimize leaks. More research is needed to figure out what are the most effective ways to weatherize.

The researchers considered five levels of tightening:
  • "average" tightening, 
  • "advanced" tightening, 
  • the International Energy Conservation Code (IECC) standard, 
  • the R2000 standard (common in Canada, tighter than IECC) 
  • and the "passive house" standard, the tightest and most difficult to achieve.

They found that upgrading all homes to be as airtight as the top 10 percent of similar homes (advanced tightening) would decrease energy demand by 2.6 quads annually-out of the total 22 quads of source energy used by the residential housing sector-leading to roughly $22 billion in savings in energy bills. Reaching the IECC standard would yield savings of 3.83 quads in annual source energy, yielding $33 billion in savings.

The study found that the IECC standard offered most of the benefit that the tighter standards would yield. Moreover this standard is likely more achievable than the tighter standards. According to their analysis, raising the U.S. housing stock to the IECC standard would reduce airflow in homes by a median value of 50 percent.

The analysis in the study factored in the energy costs of increasing ventilation where necessary to maintain good indoor air quality. A separate analysis looked at the energy cost of only bringing the housing stock into compliance with ASHRAE 62.2, a national ventilation standard for homes that ensures sufficient ventilation for human health.

Leave us a comment on what you are doing to achieve a tighter, more energy efficient home this winter.

Thursday, October 24, 2013


Low-priced plastic photovoltaics

Solar cells and panels, which tap the power of the sun and convert it to electricity, offer a green - and potentially unlimited - alternative to fossil fuel use. So why haven't solar technologies been more widely adopted?

Quite simply, they're too expensive, Researchers have come up with a technology that might help bring the prices down.

To collect a lot of sunlight you need to cover a large area in solar panels, which is very expensive for traditional inorganic - usually silicon - photovoltaics. The high costs arise because traditional panels must be made from high purity crystals that require high temperatures and vacuum conditions to manufacture energy potential.

A cheaper solution is to construct the photovoltaic devices out of organic compounds - building what are essentially plastic solar cells. Organic semiconducting materials, and especially polymers, can be dissolved to make an ink and then simply "printed" in a very thin layer, some 100 billionths of a meter thick, over a large area.

Covering a large area in plastic is much cheaper than covering it in silicon, and as a result the cost per Watt of electricity-generating capacity has the potential to be much lower.

One major difficulty with doing this, however, is controlling the arrangement of polymer molecules within the thin layer. Scientists have developed an advanced structural probe technique to determine the molecular packing of two different polymers when they are mixed together. By manipulating how the molecules of the two different polymers pack together, they have created ordered pathways - or "nanowires" - along which electrical charges can more easily travel. This enables the solar cell to produce more electrical current.

This work highlights the importance of the precise arrangement of polymer molecules in a polymer solar cell for it to work efficiently. Researchers and scientists expect polymer solar cells to reach the commercial market within 5 to 10 years.

Wednesday, October 2, 2013


IKEA rolls out consumer solar panel systems in British stores

I'll take the Billy bookcase, the Karlstad sofa, and a pack of solar panels in black.

Don't laugh it may be true some day.

IKEA stores in Britain this week began selling rooftop solar panel systems, giving the industry a boost after rounds of feed-in tariff cuts and freezes.

The Swedish retail giant confirmed Monday it would roll out the systems to 17 of its stores in Britain in coming months in partnership with Chinese panel-maker Hanergy Solar U.K. after conducting trial run this summer at an outlet in Southampton, England.

Believed to be the first time photovoltaic energy systems have been made available through a mass-market retailer, IKEA's move comes a year after feed-in tariffs paid to British panel owners were slashed from 69 cents per kilowatt to their current 23 cents.

IKEA announced the consumer roll-out after using solar panels extensively to help power its own facilities. Under its corporate sustainability program, the retailer has installed more than 250,000 panels across its stores worldwide and is aiming to produce as much energy as it consumes by 2020.

The price of a standard 3.36-kilowatt PV system for a semi-detached home would run about $10,800, including value-added tax, with 15-percent discounts available under IKEA's Family loyalty program.

Steve Howard, IKEA's sustainability chief, told The Wall Street Journal despite likely low profit margins, the retailer wants to build PV systems into "a real business."

They're becoming easier to sell thanks to the volatility of energy prices, he said, adding, "You don't have to care about the environment and climate change, you can just care about the finances."

After a surge of PV panel-buying when Britain first introduced its feed-in tariff scheme, the number of homes installing rooftop systems has dropped as the FIT has gone down. The British Solar Trade Association says the solar market is currently installing about 100,000 solar systems per year -- far below the projected 300,000.

It will be interesting to see which model prevails. Either way, IKEA's move represents a big bet on solar panels' potential to shake their reputation as boondoggles and become the latest sleek status symbols for the modern home. The company has already begun the work of recasting their aesthetic image, suggesting that its solar panels resemble "flat-screen televisions."