[amor de cosmos]

Sunlight generates hydrogen in new porous silicon
By A'ndrea Elyse Messer
April 10, 2014

UNIVERSITY PARK, Pa. -- Porous silicon manufactured in a bottom up procedure using solar energy can be used to generate hydrogen from water, according to a team of Penn State mechanical engineers, who also see applications for batteries, biosensors and optical electronics as outlets for this new material.

The surface area of this porous silicon is high," said Donghai Wang, assistant professor of mechanical engineering. "It is widely used and has a lot of applications."

The standard method for manufacturing porous silicon is a subtraction method, similar to making a sculpture.

"Silicon is an important material because it is a semiconductor," said Wang. "Typically, porous silicon is produced by etching, a process in which lots of material is lost."

Wang's team uses a chemically based method that builds up the material rather than removing it. The researchers start with silicon tetrachloride, a very inexpensive source of silicon. They then treat the material with a sodium potassium alloy.

"The bonds between silicon and chlorine in silicon tetrachloride are very strong and require a highly reducing agent," said Wang. "Sodium potassium alloy is such an agent."

Once the bonds break, the chlorine binds with the sodium, potassium and silicon, potassium chloride and sodium chloride -- table salt -- become solid, forming a material composed of crystals of salt embedded in silicon. The material is then heat-treated and washed in water to dissolve the salt, leaving pores that range from 5 to 15 nanometers. The researchers report their results in today's (Apr. 10) issue of Nature Communications.

http://news.psu.edu/story/311330/201...porous-silicon
http://www.sciencedaily.com/releases...0410111216.htm

Solar power growth is like an escalator (charts)
Zachary Shahan
Technology / Solar Technology
April 10, 2014

Global solar power installations are breaking records quarter after quarter. Almost every quarter in the past three years broke the record for most solar power installed in a quarter. Quarter 1 of 2014 just broke the record again, but it will only hold onto it for a couple more months. Every quarter this year is projected to be considerably larger than the one before it.

What's the driving cause of this escalator growth? It's a few things, naturally, but probably nothing is more important than the tremendous drop in the cost of solar power that we've seen in recent years, which roughly looks like an escalator in the other direction. That helps to make solar competitive with other sources of power or, for consumers, with retail electricity.

http://www.treehugger.com/solar-tech...or-charts.html

Better solar cells, better LED light and vast optical possibilities
11 April 2014 The Norwegian University of Science and Technology (NTNU)

Changes at the atom level in nanowires offer vast possibilities for improvement of solar cells and LED light. NTNU-researchers have discovered that by tuning a small strain on single nanowires they can become more effective in LEDs and solar cells.

NTNU researchers Dheeraj Dasa and Helge Weman have, in cooperation with IBM, discovered that gallium arsenide can be tuned with a small strain to function efficiently as a single light-emitting diode or a photodetector. This is facilitated by the special hexagonal crystal structure, referred to as wurtzite, which the NTNU researchers have succeeded in growing in the MBE lab at NTNU. The results were published in Nature Communications this week.

The last few years have seen significant breakthroughs in nanowire and graphene research at NTNU. In 2010, Professors Helge Weman, Bjørn-Ove Fimland and Ton van Helvoort and their academic group went public with their first groundbreaking discoveries within the field.

The researchers, who specialise on growing nanowires, had succeeded in controlling a change in the crystal structure during nanowire growth. By altering the crystal structure in a substance, i.e. changing the positions of the atoms, the substance can gain entirely new properties. The NTNU researchers discovered how to alter the crystal structure in nanowires made of gallium arsenide and other semiconductors.

With that, the foundation was laid for more efficient solar cells and LEDs.



Highly effective solar cells

– Our goal is to create solar cells that are more effective than when they are made with thin film technology, Weman emphasises.

Thin film technology is a term from the solar cell technology. This technology develops super-thin solar cell panels, where the active layer converting sunlight to electricity has a thickness of no more than three micrometres, i.e. three thousands of a millimetre. The low weight allows easy transportation, installation and maintenance of the solar cells, and they can in practice be rolled out like roofing felt on most buildings.

Now, the combination of nanowires and graphene facilitates much broader and more flexible solar cells.

In thin films like gallium arsenide, the atoms are placed cubically in a fixed, predefined structure. When the researchers manipulate the atom structure inside the nanowire, they can grow both cubic and hexagonal crystal structures. The different structures have completely different properties, for example when it comes to optical properties.

http://www.alphagalileo.org/ViewItem...CultureCode=en

• Video Link

Distributed Energy’s Big Data Moment
Mackinnon Lawrence — April 9, 2014

As my colleague Noah Goldstein explained in a recent blog, the arrival of big data presents a multitude of challenges and opportunities across the cleantech landscape. Within the context of distributed energy resources (DER), among other things, big data is unlocking huge revenue opportunities around operations and maintenance (O&M) services.

As illustrated by large multinational equipment manufacturers like GE and Caterpillar, big data represents not only a potential key revenue source, but also an important brand differentiator within an increasingly crowded manufacturing marketplace. Experience shows, however, that capitalizing on this opportunity requires much more than integrating sensors into otherwise dumb machinery on the factory floor.

The recent tragedy of Malaysia Airlines Flight 370 brought international focus to the concept of satellite pings whereby aircraft send maintenance alerts known as ACARS messages. These types of alerts highlight the degree to which O&M communication systems are already in place in modern machinery. But Malaysia Airlines reportedly did not subscribe to the level of service that would enable the transmission of key data to Boeing and Rolls Royce in this instance. Although data may be produced via a complex network of onboard sensors, it is not always collected in the first place.

The collection and utilization of big data is not necessarily as simple as subscribing to a service, however. Today, the sheer volume of data produced by industrial machinery is among the main challenges facing manufacturers of DER equipment.

http://www.navigantresearch.com/blog...ig-data-moment

Panasonic breaks conversion efficiency record
11. April 2014 | Products | By: Peter Carvill

Panasonic's HIT module has broken the conversion efficiency record and is the first module to surpass the 25% barrier.

Panasonic has announced a conversion efficiency of 25.6% in its HIT solar cells, a feat which the company calls a “major increase” over the previous record of 24.7%. A statement from the company said that the conversion efficiency for practical size cells broke for the first time the 25% barrier.

Panasonic said the new record was made possible by its proprietary heterojunction technology and its adoption of a back-contact solar cell structure which allows more efficient utilisation of sunlight. Other factors for the increase in efficiency were given by Panasonic to be reductions in recombination and optical losses and a minimisation of resistance loss.

Going forward, Panasonic said it will continue to pursue technology development of its HIT solar cells aimed at realizing higher efficiency, a more efficient use of resources, and mass production.

http://www.pv-magazine.com/news/deta...ord_100014811/

Solar’s dramatic cost fall may herald energy price deflation
By Giles Parkinson on 11 April 2014

We’ve seen and published many dramatic graphs about the fall in solar, such as this one tracing the fall over the past 30 years and this from Citigroup, but the following graph from investment bank Sanford Bernstein is quite stunning – not just for its simplicity but because it draws attention to the potential impact of solar to the $5 trillion global energy market.

As you can see, the cost of solar PV has come from – quite literally – off the charts less than a decade ago to a point where Bernstein says solar PV is now cheaper than oil and Asian LNG (liquefied natural gas). It does its calculations on an MMBTU basis. MMBTU is the standard unit of measure for liquid fuels, often referred to as one million British thermal units.



“For these (developing Asian economies) solar is just cheap, clean, convenient, reliable energy. And since it is a technology, it will get even cheaper over time,” Bernstein writes in a newly released report.

“Fossil fuel extraction costs will keep rising. There is a massive global market for cheap energy and that market is oblivious to policy changes” in China, Japan, the EU or the US, it writes.

This has potentially massive impacts for the oil, gas and LNG markets, and therefor the massive investments in the LNG plants in Queensland, Australia, where tens of billions of dollars have been invested by Australian and international energy majors on the assumption that the demand, and the price, of LNG will rise ever upwards.

As Bernstein notes in its report, the share of solar PV in the global energy market is currently so small (see graph to the right) that “the idea that oil and gas is the “loser” in this formulation is laughable … in 2014.”



But that’s not the case a decade hence. Solar is already eating away at the margins of oil and gas demand. Bernstein says the adoption of solar in off-grid areas in developing markets means less kerosene and diesel demand. The adoption of solar in the Middle East means less oil demand. The adoption of solar in China and developed Asia means less LNG demand. And distributed solar in the US, Europe and Australia means less natural gas demand.

And then Bernstein drops this bombshell – while solar has a fractional share of the market now, within one decade, solar PV (plus battery storage) may have such a share of the market that it becomes a trigger for energy price deflation, with huge consequences for the massive fossil fuel industry that relies on continued growth.

*snip*

“If the downward sloping forward curve is ever accepted as permanent, rational behavior from energy producers will guarantee it is so. Sitting on oil and gas reserves for the benefit of generations yet to come ceases to be a rational strategy if that reserve represents a depreciating rather than an appreciating asset.”

This, Bernstein says, is the hidden flaw with the idea that solar is “too small to matter”. Ultimately, it says, what may kill the energy market for equity investors is not the fact that renewable technology and battery storage will turn into behemoths, but the realisation of that future as inevitable.

http://reneweconomy.com.au/2014/sola...eflation-76250