Flexible Australian solar panels for military use

They didn't take up my suggestions for lightweight solar panels for the F-35, or solar generating windows for the Bushmaster vehicle, but ANU's Centre for Sustainable Energy Systems has won a defence contract to develop solar panels for the military.

Elongate Solar Cells for Energy Generation (The Australian National University) – Flexible solar panels with high efficiency under both normal and subdued light and with high power-to-weight ratios. These solar cells would allow soldiers to generate power in the field and reduce the need for batteries. The technology may be suitable for incorporation into wearable textiles. The proposal builds on extensive solar research undertaken by The Australian National University. ...

From: Capability and Technology Demonstrator Program Collaboration, Defence Science and Technology Organisation (DSTO), 20 June, 2008

Building solar panels into wearable textiles is a very difficult task. Solar cells are fragile and shiny. This makes them difficult to combine with military camouflage clothing. It would be a lot easier if the cells were built into something less flexible other than most clothing. Here is an alternative suggestion:

Low observability conformal solar panel matrix

The Low observability conformal solar panel matrix (LOCSPM) consists of thin SLIVER solar cells embedded in a resin fiber matrix. The matrix allows light to reach the cells, while supporting the cells and blocking reflections and radiation from them. The matrix consists of a grid which forms a high strength lightweight support. The matrix is composed of material which absorbs stray visible, infrared and radar frequency radiation.

The standard matrix is rigid, but can be made in shapes to conform to military equipment, such as the cases for radios and other electronic equipment, the covering of a helmet, protective vest, boots, vehicle or shelter roof panels. The matrix can be made in standard camouflage colors and patterns. The matrix can contribute to the ballistic and structural properties of the equipment it is attached to, proving protection from blast fragments and additional strength.

Flexible panels are also possible. For large scale non-mobile applications the panels can be made to track the sun for increased efficiency.

Triple Glazed Solar Cell Window Panels?

Had a query asking when the Sliver solar cells would be available. Assuming the money for research and development is available it will be years before you can buy a Sliver solar panel.

The major cost with solar panels is the silicon used for the solar cells. The Sliver design minimizes this by using thin slices ("slivers") of silicon. But perhaps this could be reduced further. I suggested building the cells into glass window panels of Shanghai offices and apartment blocks.

One way to reduce the amount of silicon used is to use a reflector to concentrate more sunlight onto the cell. This can be done with a trough concentrator above a long strip of cells Normally the trough is about a metre wide and several metres long and is mechanically steered to keep it facing the sun.

But the sliver cells are made in long thin strips. So they could be individually mounted above miniature trough concentrators each a few mm wide. Making thousands of tiny reflectors for one solar panel would seem like hard work. But they could be made all at once from a sheet of aluminized mylar plastic pressed to the shape. This would look like a shiny silver chocolate box liner (with indentations molded in for each chocolate). Mylar is already used in some solar panels.

The mylar sheet would be sandwiched between two sheets of glass provide a multiple functions:

1. Hold the sliver cells in place: The Mylar would be molded to form mounting points to hold the individual slivers in place.
2. Trough concentrator: The mylar would be curved to form a miniature solar trough concentrators (about 10 mm wide) for each sliver. The concentrators would be shaped to reflect concentrated sunlight onto both sides of the cells (Bifacial concentrator) for most of the day without the need for the panel to be mechanically steered.
3. Insulation: The Mylar would provide an additional layer of glazing to insulate the building panel.
4. Filtering: The reflective coating of the Mylar would prevent excessive sunlight entering the building.
5. Transmissive: The Mylar would be semi-transparent, allowing the panel to be used as a window, with the solar cells forming a decorative pattern.

Sliver Solar Cells for Military And Domestic Use

Professor Andrew Blakers presented an inspirational talk today, on the Australian National University's sliver solar cell technology. But what is needed is more research funding to develop the technology into a usable product. Andrew sees the cells being cheap enough to be installed by individual householders and businesses, as well as for solar power stations.

At present solar cells are cost effective for remote locations off the grid, such as Illawong Lodge and Kings Canyon:

Illawong Ski Tourers manages Illawong Lodge, located at about 1600 metres altitude in Kosciuszko National Park, New South Wales, Australia. Illawong is several kilometres from the nearest roads, power, gas, water, sewer, telephones, ski lifts, and other services. ...

The first hut built here in 1925-26 was called Pounds Creek. ... The lodge consists of four small rooms with a roof and walls of iron, floor of wood, lined. It includes an innovative high-country solar power system for lighting.

From: Illawong Ski Tourers

Kings Canyon is a high-profile tourist resort in Central Australia's Watarrka National Park in the arid zone. The remote resort previously relied on a diesel-fuelled power station. ... Peak power demand in the Northern Territory closely matches solar availability, with the peak occurring early afternoon. The PV system provides peak load and is run in tandem with a smaller diesel engine. Battery storage is not required since the diesel engines supplement ...

From: Kings Canyon Solar Power Station, Australian Business Council - Sustainable Energy 2006

However, research funding is likely to come for more exotic applications first. The first uses for solar cells were military and remote uses in telecommucations.

Some which the sliver cells might be applied to are:

1. Solar Building Panels for China: The usual location for solar collectors on buildings is the roof. However, high rise buildings have only limited roof space. An alternative would be to use the same micro-louver technology as for military vehicles (below) and build the cells in to wall and window panels. Sun facing vertical panels would have cells arranged horizontally facing up towards the sun. For windows, sufficient space would be left between the cells to allow the occupants to have a view out the window. The cells could be made in aluminum frames as a direct replacement for domestic and commercial cladding, balcony balistrades and windows. Such panels could be used by the million for Shanghai offices and apartment blocks.
2. Lightweight solar panels for the F-35 Lightening II JSF: Sliver cell panels could be incorporated into the sun shields used to protect aircraft cockpits on the ground. This would have the dual function of cooling the cocpit and providing power to keep the aircraft batteries charged. The sliver cell shades would be light, flexible and compact enough to be stowed aboard the aircraft for deployment. Research for this could be funded under the Joint Strike Fighter (JSF) project.
   
3. Solar generating windows for military vehicles: Military vehicles, such as the Australian ADI Bushmaster Infantry Mobility Vehicle have difficulty keeping the occupants cool in desert regions and supplying sufficient electrical power for equipment. These vehicles have flat armored windows which could be fitted with sliver cell panels. The cells could be arranged as micro-louvers to shade the interior of the vehicle, while optimizing solar collection to power equipment. The silver cells have an anti-reflective coating which would enhance the situational awareness of the occupants of the vehicle, while reducing the visible and infrared signature. The ability to generate electricity would reduce the fuel consumption of the vehicle and its sound signature when stationary, as the diesel engine would not need to be run as much.

Australian solar cell technology, 27 October 2006

Back in March I mentioned an inspirational talk by Professor Andrew Blakers on Australian solar cell technology. He is giving another talk in Canberra next week.

Press reports, from as far as Turkey, indicate the technology will be developed offshore:

Origin Energy has confirmed commercial manufacture of ANU's solar sliver cell technology is poised to go offshore, possibly to Germany or the United States, to capitalise on government investment incentives for solar energy in those countries. ...

From Journal of Turkish Weekly, 3 Oct 2006

I don't see this as a bad thing, as long as Australia gets a reasonable payment for licensing the technology. Perhaps Professor McKibbin's "Architecture for International Cooperation on Climate Change" would make it cost effective to manufacture the cells in Australia. The cells could be used to charge our electric cars and run our houses.

INFOENG SEMINAR SERIES Colloquium series

Photovoltaics
Professor Andrew Blakers (Director, Centre for Sustainable Energy Systems & ARC Centre of Excellence for Solar Energy Systems, ANU.)

DATE: 2006-10-27
TIME: 11:00:00 - 12:00:00
LOCATION: RSISE Seminar Room, ground floor, building 115, cnr. North and Daley Roads, ANU

ABSTRACT:
The worldwide solar energy industry is doubling in size every 18 months, driven by concerns about global warming. Photovoltaic technology is likely to be a substantial component of future electricity supply. About 95% of solar cells are manufactured on crystalline silicon substrates. However, the current shortage of hyperpure silicon is constraining the industry. Possible solutions include thin crystalline silicon solar cells, non-silicon materials and solar concentrator systems. The talk will describe the technological and commercial problems and opportunities of the PV industry, and will include a survey of Australia's position.

Photovoltaic research and commercialisation in the Australian National University will be described. Recent work shows that Sliver solar cell technology is capable of cost reductions of three quarters compared with current photovoltaic technology. Standard materials and techniques are used in novel ways to create 20% efficient thin single crystalline solar cells with superior performance and sharply reduced cost. Sliver technology is a disruptive technology within a well-established conventional industry. PV and hybrid PV/thermal solar concentrator systems are also under development at ANU. This is a multidisciplinary endeavour, and brings together solar cell physics & technology with materials, mechanical, electrical and control engineering. Solar concentrators have good economic prospects in Australia and elsewhere once the cost of carbon emissions is internalised into fossil fuel costs.

BIO:
Professor Andrew Blakers is the Foundation Director of the Centre for Sustainable Energy Systems at the Australian National University and Director of the ARC Centre of Excellence for Solar Energy Systems. His research interests are photovoltaics, solar energy systems and energy policy. Particular interests are Sliver solar cell technology (which he co-invented with Klaus Weber) and solar concentrators. He is a Fellow of the Academy of Technological Sciences & Engineering, the Institute of Energy and the Institute of Physics, and has published approximately 200 papers and 10 patents.

Australian Solar Cells to Power Indian IT Boom?

This morning I attended an inspirational talk by Professor Andrew Blakers on Australian solar cell technology:

"... Sliver solar cell technology is capable of cost reductions of three quarters compared with current photovoltaic technology. Sliver technology was invented at the Australian National University (http://solar.anu.edu.au).

Standard materials and techniques are used in novel ways to create thin single crystalline solar cells with superior performance and sharply reduced cost. Sliver technology is a disruptive technology within a well-established conventional industry, and has an excellent chance of dominating the burgeoning worldwide photovoltaic industry.

First generation Sliver technology is being commercialised in Adelaide by Origin Energy (http://sliver.com.au). ANU is developing a second generation Sliver technology which offers large technical and manufacturing improvements over first generation technology. ..."

From: "The Extraordinary Prospects for Sliver Solar Cell Technology", Prof Andrew Blakers, CSES SEMINAR SERIES, 2006-03-10 <http://cecs.anu.edu.au/seminars/showone.pl?SID=147>.

The clever bit about the technology is that it is uses existing silicon material and processes in a more efficient way. Instead of using a whole silicon wafer as a solar cell, they slice it into thousands of thin strips (slivers) and so get more electricity out of the same amount of material. As well as helping the environment, this could earn billions of dollars for Australia.

One use for the cells is in window panes. As the cells are thin slivers, they can be used as window shades, letting some light through and turning the rest into electricity.

One use which occurred to me might be in India, where there is a shortage of electricity. Offices and cyber cafes have large banks of batteries to supply electricity during blackouts. Cheap solar cells could be added to charge the batteries and supply surplus to the grid. The cells could also be used to charge the batteries of the electric cars being made in Bangalore.

One issue I raised at question time was regulatory impediments to energy conservation. My smart apartment is in a building with a computer controlled solar boosted gas hot water system. The cost of gas used is therefore very low. But the gas company, with the blessing of the the ACT government regulator, charges each apartment in the complex the same amount as if we each had a gas connection. As a result I am penalized for using solar power.

Professor Andrew Blakers is an inspiring speaker with a grasp of the economics as well as the materials science involved. He was asked if the Australian government had expressed interest. Unfortunately, while the Greens and the ALP politicians have been along to talk to him (as well as the Governor General), none of the relevant government ministers have bothered to visit.

ps: If the Ministers do visit, I recommend lunch at the Purple Pickle cafe on the ANU campus. Today is a stunning autumn day. Pedalling alongside Sullivans Creek to the seminar, there was a vista of cloudless blue sky, water, ducks and students ambling to lectures. Oxford and Cambridge Universities may have their dreaming spires, but it is a lot more pleasant most of the time and just as beautiful here in Canberra.