“We’ve collected 38 years of global solar radiation, weather and temperature data with a spatial resolution of 40km x 40km for the entire globe, and compared this with historical data for photovoltaic installations in Europe,” said Aarhus University department of engineering researcher Marta Victoria, who has lead the project. “Based on this, we’ve made a very accurate model that, at global, regional and local levels, can tell you about the performance of PV installations in a given geography, depending on the type of facility being used. This means we can look at not only a single installation, but energy production in entire countries or continents from PV installations.”

Total solar energy production for all European countries 2013-2017. Each spot represents a week’s energy production, where brighter means more energy

For every country, four different PV configurations have been investigated statistically – rooftop, optimum tilt, tracking, and delta – the latter, Victoria told Electronics Weekly, has two rows of panels back-to-back some facing east and the others west. “The former maximise production in the morning and the latter in the evening,” she said. “Taking into account the low cost of PV panels this can be beneficial to modify the time of the day in which they generate electricity.”

Which of the four that are selected is “shown to have a strong influence on the hourly difference between electricity demand and PV generation”, according to the abstract of ‘Using validated reanalysis data to investigate the impact of the PV system configurations at high penetration levels in European countries’, the paper which describes the work in the journal Progress in Photovoltaics.

The abstract goes on to say that a key strength of the methodology used in the research is that it does not rely on historical solar power output, so it can be applied in places with no existing knowledge of photovoltaic performance.

Country-by-country analysis is included.

“Generating cheap green energy is no longer a challenge. The price of PV installations has tumbled over the last 10-20 years, so we’re now seeing huge investments in this particular energy source,” said Victoria. “The challenge is to link energy production from myriads of small installations across the landscape with a country’s total energy demand and energy production from other sources, some of which is also linked across national borders.”

All data in the model has been made readily available through an open licence.

The project is part of the RE-Invest project, which is being funded by Innovation Fund Denmark, and which brings Danish and other universities, and companies.

Diagram credit: Marta Victoria

Photo: Marta Victoria taken by Lars Kruse.