Why we need a replacement for glass

Last week I took part in the Australian Technology Competition, an excellent program. After the investor “speed dating” session, John O’Brien asked us to nominate a technology in which we would love to invest.

My response: a replacement for glass.

Glass is a wonder material: transparent, structurally strong, water proof and resistant to weathering. People started making glass in Mesopotamia (now Iraq and northern Syria) over 4,000 years ago.  Today the industry is certainly mature and dominated by a small number of large players. China is a major player, shipping heavy, but extremely cheap

So why do we need a replacement?  Glass is now a significant part of the cost of solar panels.

For crystalline silicon panels, the top costs after the silicon cells include glass, EVA, and aluminium frames. The silver paste for cell interconnects is a big target for cost reduction, but after that it becomes increasingly hard to drive down module costs. At the same time it is getting hard to drive efficiencies further without increasing the cost per Watt.

For thin film PV, the active materials are only a few microns thick and cost in the order of cents per Watt. First Solar has shown there is a lot of efficiency upside (18 or 19%) so we can easily see the cost of the modules tending towards the cost of glass.

So why not use polymers to encapsulate the solar panels?  The main purpose of the glass is to keep out water which can corrode metal and degrade semiconductors.  You can make polymer films that have a Water Vapour Transport Ratio (WVTR) similar to glass by depositing laters of metal oxide over a polymer film that looks like Glad Wrap.  But it ends up being just as expensive as glass due to the cost of materials and use of vacuum deposition tools (even assuming massive scale).

Some may argue that the added flexibility of polymer is a benefit over glass, but most solar panels are mounted on an incline to the sun and the structural rigidity of glass is therefore a benefit.  In addition you still have to worry about UV weathering, scratching and soiling.

The folks who make highly efficient solid state lighting (LED and OLED) and flat scree TV would also love to see an encapsulant as good as glass, but much much cheaper.

So, it’s time to disrupt a 4,000 year old industry!