Solar glass breakthrough promises to turn skyscrapers into power stations
Spun out from Oxford University in late 2010, Oxford Photovoltaics (PV) has combined a dye-based thin film solar cell with glass substrates to produce tinted glass that simultaneously acts as a solar generation system.
“We screen print metal oxides, dyes, plastics and polymers directly on to glass,” explained Kevin Arthur, chief executive of the company. “Light reacts with the dye to create a current that we collect through two terminals, just like a standard battery.”
He added that the glass could be tinted to any colour or made opaque, providing a flexible renewable energy option for architects and builders.
The technology has been successfully developed in the lab and Arthur is in San Francisco this week as part of the UK’s Clean and Cool Mission with a view to raising £3.5m in venture capital funding to support the development of a pilot production line.
“We have small prototype cells that are 10cm by 10cm, but we want to move to a full scale pilot production line that can make panels that are two metres by three metres,” he said, adding that the company aims to complete its funding round later this year and have its first batch of solar glass panels commercially available by the third quarter of 2013.
“We are under a lot of pressure from architects we have presented the technology to. They love this idea and are asking us to go faster.”
Arthur predicted that solar glass technology has the potential to undercut conventional silicon-based solar panels on price.
“There are a lot of cost advantages to thin film solar technologies,” he argued. “Because you are basically screen printing, production costs are much lower than for conventional solar cells and the cost of the materials is also falling. But most importantly once a company has decided to have a glass façade on their building they have already decided to install our substrate.”
Arthur was reluctant to predict the precise cost of the technology when it is produced at commercial scale, but he revealed that modelling done by the company suggested the system could produce solar power at a cost of just 35 cents per watt.
“We envisage a time relatively soon when this technology will be able to operate without subsidy,” he said.
One of the criticisms levelled at thin film solar cells is that they have much lower rates of conversion efficiency that silicon-based cells. Arthur admitted that currently the technology is delivering efficiencies of over six per cent, but he argued that the company has a development roadmap that would allow the system to ultimately offer efficiencies of around 20 per cent.
More importantly, he said early modelling had shown that the large surface areas available to solar glass means that even with relatively low conversion efficiencies the technology can deliver significant amounts of power.
“Figures from architects show that 60 per cent of many modern commercial buildings’ surface area is glass,” Arthur explained. “We have modelled the effect of the solar glass on a 700 foot skyscraper in Texas and it revealed that we could generate up to 5.3MWh a day.
“That’s enough to power 52,000 iPads. If you combined the solar glass with the installation of LED lighting in the building you could power all your lights, as well as DC powered devices such as laptops.”