Green tech: New solar tech offer sunny days ahead

Solar tech will play a key role in the new green economy, but with older solar panels needing upgrades, the green tech industry is switching its gaze to other solar solutions

In Durham, UK, Power Roll is about to begin commercial production of a flexible film capable of being fixed to flat roofs, non-load bearing roofs and even vertical surfaces such as window blinds and canopies. The concept is the result of Power Roll’s John Topping’s realisation that it was possible to combine the application of conductive metals with the latest microscale embossing technologies, using existing manufacturing techniques to achieve a high speed, roll-to-roll process to keep production costs low while creating a flexible, lightweight solar film.  Using widely available materials, the system yields a manufacturing cost that is around ten times lower than silicon PV.

The weight difference is considerable – a 100kw panel system weighs over 5,000 kg, while equivalent solar film weighs just 272kg. A 12-kilowatt roll of solar film, enough for an average house, can be carried by hand. Installation is simple, as it just has to be rolled out and fixed in place using adhesive backing, making it ideal for warehouses, distribution centres and agricultural sheds.

Such versatility brings a potentially massive new energy producing resource into operation. The UK Warehousing Association estimates that the total UK warehouse roof space now totals around 420 million sq. ft., and forecasts suggest that it is set to grow by a further 30 million.  Power Roll estimates suggest that current warehouse space alone could accommodate almost 7 gigawatts of solar energy, the equivalent to deploying 1,400 5MW ground-mounted solar farms. Payback time is approximately half the cost of solar panels, and the film has a projected lifespan of up to 15 years.

Licensing agreements are already being signed with manufacturing partners worldwide including India and Africa.

In the US, attention is being focused on the energy potential provided by windows. The California Energy Commission has given a $3m grant to support Next Energy Technologies manufacture of a solar PV windows system creating a transparent PV coating turning existing windows into energy producers. The coatings deploy production methods that have been used for many years within the printed electrics and display industries.  By adding proprietary technology to window manufacturing systems, the film is printed directly onto the glass. There are even customizable colour options.  Once installed, the films act as solar generators for 30 years and are regarded as being an ideal way of producing energy for offices and buildings containing large expanses of glass.

It is not just the windows themselves that can be utilised. There are the gaps between windows and blinds fitted to windows. SolarGap blinds are made from a combination of aluminium, steel, electronics and solar cells laminated onto fibreglass. They can be fitted onto any building, and automatically track the sun’s movement thus maximising energy generation. Around 100w of electricity can be generated every hour using just one square metre of blind.  Operating temperatures range from -20°C to 60°C, and can be retracted into overhead casings during severe weather.

Paint is a universal method of adorning buildings – but until now has only been regarded a decorative and protective system.  New research is resulting in the ways of turning it into an energy producer. At the University of Toronto, researchers are exploring ways of utilising nanoscale semi-conductor ‘quantum dots’ (also known as colloidal quantum dot photovoltaics) to create paint that captures light and turns it into an electric current.

Material world

An equally innovative approach has been taken by researchers at the Royal Melbourne Institute of Technology, Australia where attention is being focused on developing paint, which can generate energy from water vapour. The researchers are utilising a special paint made from a mix of synthetic molybedenum-sulfide and titanium oxide. When applied to a surface, the paint absorbs water, which is then used to separate hydrogen and oxygen molecules using water vapour. The resultant hydrogen is then capture for use as an energy source.

While at the University of Sheffield, UK, researchers are exploring ways of creating solar cell devices based on perovoskite films.  Perovskite possesses an ability to produce efficient liquid solar cells that can be mixed with paint. Work is underway on developing ultra-sonic spray-coating technologies enabling a range of materials to be coated with solar cell devices at high speed and low cost.

And what about pavements?  Budapest based Platio, are installing special solar panels within pavements.  The panels are made from recycled plastic, and while hardened glass tiles protect the solar cells. The result is a product that is extremely strong and durable, and can even carry the weight of a vehicle.  The pavements have been set in city streets, squares across the country.  At Komarom in NW Hungary, panels form a pavement beside a swimming pool and provide energy for public lighting as well as an USB-charging station. A similar system installed in Kazakhstan powers the air conditioning of a shopping mall, using just 80 sq. metres of pavement space.  One of the big advantages of these pavements is that they can be installed in locations where conventional solar systems are impossible, such as variations in roof structures.

Even the sea is being considered as a heat source.  Cornish company, Global OTEC, has developed a system whereby solar heat energy stored in oceans can be extracted and used for energy. It is now in the process of installing the world’s first commercial floating OTEC platform, capable of powering a small island. The platform acts like an oil platform, using seawater rather than drilling for oil. It will be located in the ocean beside the Democratic Republic of São Tomé and Principe, an island located on the equatorial coast of Africa. By deliberately focusing on small-scale projects, Ocean Thermal Energy is able to provide small communities with clean, affordable energy to off-grid islands throughout the tropics. This first floating energy creation platform is being part funded by the United Nations Industrial Development Organisation, and it is hoped to scale up the concept for use among other Small Island Developing States (SIDS) elsewhere.