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When polar explorer Robert Swan returned from his most recent expedition to Antarctica in April 2008, he brought with him confirmation that solar technology was entering a new era. Swan, the first person to walk to both the North and South Poles, had successfully demonstrated that solar energy could provide a reliable, consistent source of power in some of the world’s most extreme and inhospitable environments.
On first analysis the achievement may seem unlikely. The solar industry is dominated by silicon-based technologies that are fragile and vulnerable to damage from external factors. Indeed, given their need for a constant supply of sunlight in order to generate energy, it was widely held that solar cells would never be a viable source of electricity in the harsh Antarctic environment.
Pioneering technology
However, Swan and his team were able to make use of a groundbreaking new technology. Cardiff-based G24 Innovations has produced the world’s first commercial grade dye-sensitized thin-film cells, the most promising of a new family of advanced solar technology. Silicon-free, these utilise a radically different process to traditional alternatives.
Originally conceived by Dr. Michael Graetzel at the Swiss Institute of Technology (Ecole Polytechnique Fédérale de Lausanne (EPFL) as far back as 1991, ‘Graetzel cells’ spent over eighteen 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 nature’s own 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 with an iodide electrolyte solution, Graetzel produced an electric current.
A range of advantages
The benefits of this new breed of solar technology are considerable. At less than 1mm thick, each cell is extremely lightweight and easy to maintain but—most importantly-- is still durable enough not to require a hard-backed fixture to protect it. The result is that the cells are far more flexible than silicon- based alternatives, easy to transport, and suitable for a large number of applications and uses.
Dye-sensitized thin-film cells are also able to produce electricity in low- light and indoor conditions. This resolves one of the most significant problems experienced by traditional solar technologies, which are only able to generate power when sunlight falls directly on to them, greatly reducing their potential. As a direct result of this breakthrough, Swan and his team enjoyed energy throughout the trip and had enough electricity to power satellite, digital and video conferencing devices, despite experiencing extremely poor weather conditions.
Efficient and friendly
The advantages of the cells also extend beyond the operational. In contrast to traditional solar cells that are made when wafers of silicon are sliced off and manually wired together into individual modules, a proprietary roll-to-roll manufacturing process is able to transform a roll of metal foil into a 100-pound half-mile of cells in less than three hours. Because the component parts used are made from lower cost materials than conventional technologies (TiO2 is also used 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 other silicon solar technologies (the energy payback time to produce the cells is 8 times less than for other products), it is not only more efficient but also more environmentally friendly.
The success of Robert Swan’s trip to Antarctica is a huge endorsement for Dye Sensitized Thin Film technology. The mission has confirmed that it is able to offer clean, green, affordable power in remote environments were portability and durability are tested to extremes. It is these qualities that have led many to believe that it will play a key role in helping the world to meet its future energy requirements.
