Taking Solar to the Extreme

Clemens Betzel, G24 Innovations Ltd.

When polar explorer Robert Swan – the first person to walk to both the North and South Poles – returned from his most recent expedition to Antarctica in March 2008, he brought back proof that solar technology is entering a new era. Swan had successfully demonstrated that solar energy can provide a reliable, consistent source of power in some of the world’s most extreme and inhospitable environments.

With no electricity at base camp, the project team powers high-tech devices with solar.

At first glance, that may seem like an improbable claim. It’s common knowledge that the solar industry is dominated by silicon-based technologies that are fragile and vulnerable to damage from external factors. Indeed, given solar cells’ need for a constant supply of sunlight to generate energy, it has been widely held that they could never be a viable source of electricity in the harsh Antarctic environment.

Pioneering technology

However, Swan and his team took advantage of a groundbreaking new technology – commercial-grade dye-sensitized thin-film cells from G24 Innovations Ltd. of Cardiff, UK. Silicon-free, the cells use a process that differs radically from that of traditional alternatives.

Originally conceived by Michael Graetzel at the Swiss Federal Institute of Technology Lausanne (Ecole Polytechnique Fédérale de Lausanne [EPFL]) as far back as 1991, “Graetzel cells” were more than 18 years in development before being commercially manufactured. As with all breakthrough technologies, the concept is relatively simple. Graetzel found that the combination of titanium oxide, a common pigment in white paint, and a colored dye could be used to mimic photosynthesis. When struck by sunlight, the dye emits an electron, which is immediately captured by the specks of titanium oxide. By collecting the electrons at one side of his new solar cell and replacing them at the other end with an iodide electrolyte solution, Graetzel produced an electric current.

A range of advantages

At less than 1 mm thick, each cell is extremely lightweight and easy to maintain but, most importantly, still durable enough not to require a hard-backed fixture for protection. The result is cells that are far more flexible than silicon-based alternatives, that are easy to transport and that are suitable for a large number of applications and uses.

Polar explorer Robert Swan uses the sun to charge his cell phone.

Dye-sensitized thin-film cells also produce electricity in low-light and indoor conditions. This solves one of the most significant problems experienced by traditional solar technologies: their ability to generate power only when sunlight falls directly upon them, which greatly reduces their potential. With the dye-sensitized thin-film technology, Swan and his team were supplied energy throughout the trip, with enough to power satellite, digital and videoconferencing devices, despite extremely poor weather conditions.

Efficient and friendly

The cells’ advantages extend beyond the operational. In contrast to traditional solar cells, which are made when wafers of silicon are sliced off and manually wired together into individual modules, dye-sensitized thin-film cells are made by a proprietary roll-to-roll manufacturing process that transforms a roll of metal foil into a 100-lb half-mile of cells in less than three hours. Because the component parts are made from lower-cost materials (titanium oxide is used also in toothpaste and sun lotion), it is possible to produce large numbers of cells at a reduced cost. Because the process as a whole is far less energy-intensive than that of silicon solar technologies – the energy payback time to produce the cells is eight times less than for other products – it is not only more efficient but also environmentally friendly.

Now that Swan’s Antarctic trip has shown that dye-sensitized thin-film technology can supply clean, green and affordable power in remote environments, the technology is poised to play a key role in applications where portability and durability are tested to extremes and in those where energy demands are made every day.

Meet the author

Clemens Betzel is president of G24 Innovations in Cardiff, UK; e-mail: info@g24i.com.