The beauty of photovoltaics

The beauty of photovoltaics (PV) is that it has the capacity to displace our dependence on coal for the generation of electricity, yet PV modules are attractive simple devices with no moving parts and proven field reliability.

The challenge is to bring the cost down.

The history of PV is intimately tied up with silicon – the material that underpins our microelectronic information society.  

The same properties that have allowed silicon to maintain its dominance in microelectronics are key to its dominant position in PV, accounting for over 90% market share.

 

Silicon is abundant (silicon and oxygen, the major components of sand, are the most abundant elements in the earth’s crust). Silicon is non-toxic. As it is a very well understood material, technologists can focus on inventing devices and processes without having to create new science. 

As a result of all these factors, inventions innovations continue to aggregate, furthering the leading position of silicon, both in microelectronics and in PV. 

 

Over the last 30 years, through a series of innovations that build on each other, the performance of silicon PV has increased and the cost has dropped at a steady pace.

Having come a long way, the field is now in striking distance of coal parity. 

1366 Technologies intends to close this gap with key innovations in all areas of silicon photovoltaics.

 

The lens that we hold up to PV is that of manufacturing. We bring to bear the knowledge, skills and passion required to create new manufacturing technologies and the machines that implement them.

New twists on the design of the solar cells themselves go hand-in-hand with these new processes in order to manufacture PV with higher performance (conversion efficiency) at dramatically lower costs.

 

The science is understood. The material is abundant. The products work. All that is left is to build the largest manufacturing industry in the history of mankind. That is what we intend to do.

 

The annual global energy consumption of humankind is 5 x 10²⁰ Joules; roughly equivalent to the amount of sunshine that reaches our planet in one hour. The amount of energy in one year of sunshine is larger than the Earth’s entire remaining supply of fossil fuels and uranium.

 

Covering 1% of Continental U.S. with 20% efficient PV systems would provide all energy needs of the US.  Covering 0.2% of the surface would generate all the electricity that the US consumes. To put this number in perspective: roads cover 1.5% of the U.S.

 

At 1366 Technologies we were so impressed with size of the available solar resources that we named the company after Earth’s Solar Constant of 1366 W/m².

The Solar Constant is the average amount of solar radiation in Watts per square meter just above the atmosphere, as measured over the last 30 years by the Active Cavity Radiometer Irradiance Monitors (ACRIM) on a number of NASA satellites.

1366 Technologies is Bringing Solar Power Closer to $1/Watt

1366 Technologies, a company named after the solar constant (there are 1366 watts of solar radiation hitting each square meter of the Earth on average) is working on improving multi-crystalline silicon solar panels. They claim to have found ways to make them about as efficient as single-crystal silicon solar cells, which are more efficient but also more expensive, without losing the cost benefits.

Three different innovations (described below) allowed them to make their prototype 27% more efficient than conventional multi-crystalline silicon solar cells, bringing its total efficiency to 19.5%, about the same as single-crystal silicon solar cells.

Here’s the first innovation:

[...] adding texture to the surface of the cells that allows the silicon to absorb more light, a trick that’s been used before with single-crystalline devices but has been difficult to implement with multicrystalline silicon.

The goal is to bend the light slightly so that it doesn’t bounce out of the cell but rather is reflected and bounces back in, giving it a higher chance of being absorbed and converted into electricity.

The second innovation:

[...] silver wires harvest electrical current generated by the silicon. Sachs has developed a method for making these wires as small as one-fifth the width of the wires that are typically used, while improving their conductivity.

Less silver equals lower costs, Thinner wires means less light blocked.

(see also the first image in this post)

The third innovation (and the most interesting, in our opinion):

a set of wide, flat wires used to collect current from the thin silver wires. These bars typically block light entering the cell, reducing efficiency. But Sachs has etched their surfaces so that they act as faceted mirrors.

 

1366 Technologies plans to make its own cell – they just raised $12.4 million and are planning to build a 25 megawatt plant if all goes well – but they are also open to licensing their technology to other solar panel makers. The company expects solar cells produced on a large scale to compete directly with coal at about $1/watt generated by 2012.