Posts Tagged ‘phys.org’

31 May

The Dutch Has Shown Us How To Produce Solar Energy & Art Via Bike Paths

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Dear Friends, Visitors/Viewers/Readers,

Solar Bikepath of Netherland, first in the world, being installed in Nov. of 2014 (credit:  notrickszone.com.)

Solar Bike Path of Netherlands, first in the world, being installed in Nov. of 2014 (credit: notrickszone.com.)

(Please click on red links & note magenta)

My associations with people from Netherlands have always been extremely positive, enthusiastic, optimistically ambitious. So, it was not surprising that during Nov. of 2014 the Dutch (people from Netherlands) developed the first Solar Bike Path (with embedded solar cells) in the world, outside Amsterdam connecting the suburbs of Krommenie and Wormerveer! This Dutch project integrated solar panels into a bike commuter path to generate power to be funneled into the national energy grid.  The crystalline silicone solar cells are encased in two layers of tempered safety glass, mounted in a concrete housing.

Solar Bikepath of Netherland, first in the world, being installed in Nov. of 2014 (credit: npr.org)

Solar Bikepath of Netherland, first in the world, being installed in Nov. of 2014 (credit: npr.org)

According to SolaRoad, it’s been a challenge to produce energy-producing slabs that are both durable and rideable by thousands of cyclists per day. “It has to be translucent for sunlight and repel dirt as much as possible,” the company says. “At the same time, the top layer must be skid resistant and strong enough in order to realize a safe road surface.” This $3.7 million project is a collaboration between the research group TNO and the government of North Holland. Its technical aspects may be found in Phys Org site.

Solar Bikepath of Netherland, first in the world, being installed in Nov. of 2014 (credit: pri.org)

Active Solar Bike Path of Netherland, first in the world, installed in Nov. of 2014 (credit: pri.org)

This 70-meter or 230 feet (over two-third of the length of an NFL football field) section solar bike path is flat instead of angled to optimally take advantage of the sun, therefore the path’s panel will produce about 70% of what similar panel might produce on a rooftop.  With approximately 87,000 miles of roadways, Netherlands’s total road surface area is much larger than that of rooftops.

This project is the first step that the local government hopes will extend to 100 meter (or 328 feet) by 2016. Now that it’s been half year into the installation of the solar bike path, it’s become clear that the solar panels are outperforming expectations, having already generated 3,000 kilowatt-hours (kWh) of electricity. This is fantastic! In a space that previously generated no clean electricity, now it is functioning well and ready for further development and expansion. I have no doubt that the cost and overall efficiency of any solar roadway will continue to improve as more and more visionaries collaborate to enable such Clean Solar Renewable Dream of Solar Roadway to become a reality. Our hats off to the visionaries in Netherlands!

Another solar bike path later unveiled in the same month, but in the city of Eindhoven, Netherland, of the passive solar form, is inspired by Van Gogh’s “Starry Night”, below:

 

Passive Solar Bike Path (at night) of Eindhoven, Netherland, also being installed in Nov. of 2014, inspired by Van Gogh's "Starry Night" (credit: thisistange.com.)

Passive Solar Bike Path (at night) of Eindhoven, Netherland, also being installed in Nov. of 2014, inspired by Van Gogh’s “Starry Night” (credit: thisistange.com.)

(Be sure to view the whole  video below, “Visions of Public Art: by Daan Roosegaarde”….you won’t regret it….)


Of course, it is the Dutch who would embrace a challenge by innovating first, by being efficient, in being artistic while pragmatic and remaining connected to both the past and the future……look at the Solar Bike Path at night, an inspiration by Van Gogh’s “Starry Night”.

Solar Bikepath of Netherland, first in the world, being installed in Nov. of 2014 (credit:  dogonews.com)

Passive Solar Bike Path in Eindhoven, Netherland, installed in Nov. of 2014, inspired by Van Gogh’s “Starry Night” (credit: dogonews.com)

Our future would be simply breath-takingly beautiful, if we don’t destroy our planet first…there lies the beauty of Solar Energy…for it is the answer to Energy-Pollution-Economic Prosperity-Climate Change-International Conflicts. SO, LET’S USE IT !

As long as we’re on the subject of solar roadway, let me remind you of the Indiegogo campaign here at sunisthefuture.net for Scott & Julie Brusaw of Idaho, asking for $1 million but ended up raising more than $2.2 million for their Solar Roadway R & D project. Yes, it is exciting to live in a world where dreamers and visionaries are in many places!

~have a bright and sunny day~

Gathered, written, and posted by sunisthefuture-Susan Sun Nunamaker

Any comments and suggestions are welcomed at sunisthefuture@gmail.com

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26 April

Multijunction Solar Cells May Exceed 50% Efficiency In The Near Future

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Dear Friends, Visitors/Viewers/Readers,

(Please click on red links below)

Just quickly sharing some of the things I’ve learned from a solar-cells course I’ve been taking recently at Stanford and from www.phys.org.

In the past decade, the best lab examples of traditional silicon solar cells have efficiencies around 25%, while current world record of multi-junction/3-junction solar cells is 43.5% (based on former Professor/Dr. Jim Harris & his group  at Stanford and then Solar Junction ) . Commercial examples of tandem cells are widely available at 30% under one-sun illumination, and improve to around 40% under concentrated sunlight. However, this efficiency is gained at the cost of increased complexity and manufacturing price. To date, their higher price and lower price-to-performance ratio have limited their use to special roles,   such as in aerospace (where their high power-to-weight ratio is desirable).

Sun Seen From Space Station (Credit:STS-129 crew, NASA), available @ Sun Is The Future of http://www.cafepress.com/sunisthefuture

In earthly applications, these multijunction (MJ)  solar cells are used in concentrated photovoltaics (CPV) with operating plants all over the world.

Tandem techniques can also be used to improve the performance of existing cell designs, although there are strict limits in the choice of materials. In particular, the technique can be applied to thin-film solar cells using amorphous silicon to produce a cell with about 10% efficiency that is lightweight and flexible.

At this point, please allow me to share a graph developed by NREL (now available at www.cafepress.com/sunisthefuture), the Best Research-Cell Efficiencies, summarizing the results of various solar cell efficiencies from 1975-2013, below:

Best Research-Cell Efficiencies (by NREL, available at www.cafepress.com/sunisthefuture)

Now, based on the collaboration of researchers from the California Institute of Technology in Pasadena; the National Institute of Standards and Technology in Gaithersburg, Maryland; the University of Maryland in College Park; and ,Boeing-Spectrolab Inc., in Sylmar, California. The team published a paper on their work in a recent issue of Applied Physics Letters.  These scientists have designed a new multijunction solar cell that can achieve an efficiency of 51.8%. This high performance exceeds the current goal of 50% efficiency in multijunction solar cell research as well as the current world record of 43.5% for a 3-junction solar cell. In multijunction solar cells each junction or subcell absorbs and converts sunlight from a specific region of the spectrum. The subcell can be stacked one on top of  another so that sunlight first strikes the highest bandgap subcell (tuned to light with shortest wavelengths or highest frequencies). The longer wavelengths pass through the first subcell and strike the lower band gap subcells. In order to approach its theoretical limit, multijunction solar cells not only need multiple subcells but also optimal semiconductor materials for the subcells to provide a combination of band gaps that cover as much of the solar spectrum as possible. To improve upon the current best 43.5% efficiency level of MJ solar cells, researchers focused on improving the current match between the different subcells, along with using a lattice-matched design. These two factors have previously limited MJ solar cell efficiency. Below is a video clip on new multijunction solar cell during a lecture given by Dr. Vijit Sabnis of Stanford University:

 

The lattice match corresponds to the matching between the crystal unit cells from the different subcells,” lead author Marina Leite, an energy researcher at the National Institute of Standards and Technology, told Phys.org. “By using subcells that are lattice-matched, we can minimize dislocations and other crystal defects that can significantly affect the performance of the device. A current match is required for two-terminal tandem configurations because in this case a single current passes through all the subcells and the voltages are added; therefore, if one subcell has less photocurrent it will limit the current generated by the entire device. The current match is desired so that each individual subcell works at its own maximum power point of operation.”

Solar energy world is definitely dynamic, with constant progress made beating the previous record ! We will look forward to the day when  a new Multijunction Solar Cell will be able to exceed 50% efficiency goal.

~have a bright and sunny day~

Gathered, written, and posted by sunisthefuture-Susan Sun Nunamaker

Any of your comments & suggestions are welcomed at sunisthefuture@gmail.com

Homepage: http://www.sunisthefuture.net

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