2 January 2019

Sunny year leads to record yield

2018 a dream year for solar panel owners: up to 25% greater yield

2018 was a record year for solar panel owners. The yield was 10-25% higher than expected, according to calculations by researchers from Utrecht University. It is striking that owners in the east of the Netherlands benefit most.

"We were already saying this in October, when many owners had generated the same amount of energy with their solar panels as they would usually have done in an entire year. With the sunny weeks in the last quarter, especially in October, we now see a record yield," says Wilfried van Sark, professor of solar energy at Utrecht University.

Compared to the long-term averages from 1981 to 2010, in 2018 solar panels had about a 10-25% greater yield, depending on the location in Netherlands. The national average surplus yield in 2018 compared with 1981-2010 was 18.9%.

Afbeelding met meeropbrengst zonnepanelen

Researchers Nick NortierGeert Litjens and Wilfried van Sark from Utrecht University used KNMI (Royal Netherlands Meteorological Institute) data from all measurement stations in the Netherlands. For the calculation of energy yield they took an optimally oriented solar panel system.

Solar panel yield is often expressed in kWh / kWp - a unit of measurement independent of the number of panels on a roof. The capacity of an average system of about four panels is now slightly higher than 1 kilowatt peak (kWp). In De Bilt, the yield in 2018 was calculated to be 1090 kWh / kWp, in Den Helder 1109 kWh / kWp, in Twente 1115 kWh / kWp, and in Maastricht 1177 kWh / kWp. The national average was 1111 kWh / kWp. This means that in 2018, an average Dutch household with 10 panels could have generated its entire electricity requirement itself.

Higher revenue for solar panel owners

In the Netherlands, one can usually count on 875 kWh / kWp as standard specific energy yield for solar panels. The number is also used by CBS (Statistics Netherlands) to determine the share of solar energy in the Dutch electricity supply. The map below shows that in an optimal system there was much higher energy yield in 2018, with clear regional differences. More energy also generates a higher revenue for the owner; in 2018 this was about 100 euros for a system containing 10 panels.

Opbrengst zonnepanelen

"Solar energy currently contributes about 3% to the electricity supply in the Netherlands," says Van Sark. "This growth is continuing steadily. In 2030 about a third of our electricity will come from the sun."