Large seasonal variations in solar radiation and other adverse climatic factors have made the implementation of PV technologies challenging in Canada, especially in the North

PV modules and components operating in high latitudes require special consideration to ensure continued operation under extremes of cold, snow and ice. The PV for the North programme, initiated in 1993 by the CANMET Energy Diversification Research Laboratory, and the Research Institutes of Aurora and Nunavut, is Canada's response to the need for PV systems better adapted to harsh Arctic conditions.

Studies undertaken early in the programme clearly showed that the largest market in Canada's Northwest Territories (17 MWp) is to displace running costs of community diesel grids. Diesel engines currently account for 60% of electricity generation. Tapping this market remains an objective for the future, as estimates suggest that installed costs need to drop to below 4,25 CAD/Wp (about 2,75 USD/Wp) before PV is cost-competitive with current supply options.

However, near term markets for radio- or telecommunications sites, remote parks and fire towers totalling some 690 kWp are already within reach. For instance, a techno-economic study for NorthwestTel demonstrated that the conversion of small VHF telecommunication sites, from disposable potash batteries to photovoltaic power, had a payback of little over one year and would lead to savings over 500 000 CAD over 20 years. This quickly encouraged the company to convert 9 out of 11 VHF telecom-sites to PV systems in 1995-1996.

Modelling studies and field testing, undertaken as part of the programme, have demonstrated that the absorption of solar radiation reflected on the back of the module and the insulating air space at the back of the panel are central for helping keep modules free from snow and ice. This has helped in the development of kits to modify commercial PV modules for use in the North. Similarly, maintaining moderate battery temperatures thought the year makes the storage sizing of remote PV systems simple. Battery capacity decreases substantially when operating temperatures drop below 0 degrees Celsius, so efforts were made to improve insulated battery enclosures. This has led to an advanced housing incorporating phase change material; under field test In Canada, this has been shown to prevent the battery temperature falling below minus 5 degrees Celsius despite the outside temperature reaching minus 37 degrees Celsius, and also ensured that battery temperatures did not exceed 22 degrees in the summer. PV for the North, with international collaboration from the IEA  PVPS member countries, is responsible for a comprehensive new book: Photovoltaics in Cold Climates.

Information

• Raye Thomas
  Newsun Technologies, Canada
  Fax: +1 613 723 5980.

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