According to reports, India has taken a blind jump into the solar-power sector, with developers putting up projects without knowing how much of sun will shine on the panels. Perhaps okay for starters, but this should change, for there are established techniques available to measure and estimate irradiance.
A discussion at the Solarcon India 2011 conference, an international conference of the solar industry, threw up this insight. Importantly, a reliable estimate of irradiance and consequently a projection of electricity generation will help bring down cost of financing, experts said here.
Dr Pascal Storck, whose company 3Tier specialises in irradiance measurement, underscored the importance of measurement of direct normal irradiance in his speech.
Today, most developers in India take plentifully available satellite-generated data as the basis for locating a solar farm, but satellite data is error-prone. Measured against the actual data, satellite data has been found to be wayward by as much as 10 per cent, Mr Storck said.
Companies like 3Tier take actual measurements over a period of time and take the satellite data for the corresponding period and arrive at an estimate of the extent of adjustment that would be needed. Then they take the satellite data for several back years and adjust the errors. This is a far more scientific way of working out irradiance.
In India, 3Tier is working with an Indian company Emergent Ventures India Pvt Ltd, which is currently collecting measurements in Rajasthan.
Dr Storck recommends putting up measuring instruments at all potential sites. The data will influence the design, which in turn will have a bearing on electricity generation, cost and bankability.