The Power Of Solar Radiation

SunTechnics, a provider of renewable energy systems, hosted from 23rd to 25th October top-class experts of the International Energy Agency (IEA). For the 4th international expert workshop of the IEA workgroup "Solar Resource Knowledge Management", 30 renowned scientists and engineers from USA, Canada, France, Spain, Switzerland, Austria, Italy, Brazil and Germany came together at the invitation of Dr. Richard Meyer, responsible at SunTechnics for the Technical Analysis of Solar Energy and member of the IEA Task, as well as under the direction of Dr. Dave Renne from the US National Renewable Energy Laboratory.

The group of participants also included members of NASA, DLR (German Aerospace Center), the Joint Research Centre of the European Commission, universities as well as important research institutes.

"I am happy that this three-day IEA workshop could take place on our premises this time. As a provider of all energy technologies powered by the sun we are very keen to take an active part in this workgroup", reported Christoph Koeppen, Managing Director of SunTechnics GmbH. "Thanks to our colleague, Dr. Richard Meyer, who as part of the IEA expert group is improving data quality in the field of solar radiation, we are contributing to the development of worldwide standards. The entire solar industry and also our customers profit from this.

We have very high quality requirements for our planning. By collaborating directly we can optimise the dimensioning and financing of large-scale solar plants. Especially when developing and planning solar thermal power plants – a field which we have developed in the past two years with a team of experts – reliable data input is essential due to the high investment volume", added Koeppen.

A vast majority of all worldwide solar projects is implemented based on solar resource products by participants of the IEA Task

The general goal of this top-class international symposium is the standardisation and improvement of data records on worldwide solar irradiance. Using data derived from satellites, readings, weather and climate modelling, in the future the spatial and temporal distribution of solar irradiance on the earth surface is supposed to be determined and forecasted more accurately. New information systems are meant to permit engineers to work anywhere with harmonised and proven tools. Altogether, these measures simplify the planning for developers, architects and engineers, maximise energy yields and reduce the cost of realising solar projects. The utilisation statistics of the data providers belonging to this IEA Task indicate that the vast majority of all solar projects worldwide draw on the data of this IEA group in the planning phase.

Since this work group came together in 2005, three global data sets have been produced and improved. In comparison to products previously available, the quality of the data has been distinctly optimised, so that today solar energy projects have greater planning reliability. The precondition for this was the improvement of satellite algorithms and also the marked expansion of the volume of data. Before the IEA task started, solar radiation climatology data covered only a few years. Today it accounts for 20 or more years. This development means that the long-term average radiation of a site can now be given almost twice as accurately as before.

"If one only had readings to qualify sites, this would considerably delay the further expansion of solar energy. However, the combination with data derived from satellites allows the project development to be accelerated and means that more solar power will go into the grid earlier and cheaper", Dr. Richard Meyer explains the progress. "In the course of the IEA Task, the data quality was already improved considerably. However, investors could be convinced more easily in the future, if there were internationally recognised standards for determining and validating the radiation resources. We need to intensify our work on this", Meyer explains, who also represents the IEA Task at SolarPACES, a panel of the IEA, which is primarily concerned with solar thermal power plants.

Optimising the utilisation of solar power in the power grid

At the end of 2006, according to the Federal Association of the Solar Industry (Bundesverband Solarwirtschaft) in Germany, nearly 300.000 solar power plants with a total output of 2,5 gigawatt were installed. These significantly contribute to the power supply on such days when the output of conventional power plants is restricted due to lack of cooling water. To achieve an optimal use of solar power in the grid, Dr. Elke Lorenz of the University of Oldenburg coordinates via the IEA Task groups of researchers, who develop forecasting procedures for solar radiation. "Radiation data is indispensable in order to cope with the fluctuating performances of solar systems. On long term, the distributed generation of solar energy will contribute to the stabilisation of the power grids", according to Dr. Elke Lorenz.