Rooftop PV has reached grid parity in main EU markets

If all the rooftops across the European Union able to host solar arrays did so, 680 TWh could be generated, providing 24.4% of the political bloc’s current electricity consumption.

That is the chief finding of a paper entitled A high-resolution geospatial assessment of the rooftop solar photovoltaic potential in the European Union, published on the ScienceDirect website.

The authors of the study combined geospatial and statistical data to assess the technical potential of rooftops for solar energy deployment on every building in the EU. The model, which also used machine learning, was used to quantify the total available rooftop surface for PV systems.

Making the datasets match up

To collect the data, the scientists used a spatial statistical tool to determine correspondence between the European Settlement Map – a dataset mapping human settlement in Europe based on images supplied by the SPOT5 and SPOT6 satellites – and building ownership data.

That comparison showed overestimation by a factor of 2-5 so the researchers also used data from the Corine Land Cover, a computerized inventory of land cover in the 27 European Commission member states and other European countries; and the European Urban Atlas, which provides comparable land use and land cover data for large urban zones. As a result, the researchers were able to adjust their estimations and have more harmonized data.

“The methodology applied over the harmonized, pan-European coverage resulted in the EU-building density map in 100m resolution”, stated the study. Most importantly, the total available roofspace was reduced to surfaces suitable for PV, and solar system losses and module degradation figures were taken into account.

European rooftop PV energy price

The methodology helped the researchers identify EU markets where rooftop PV could generate electricity at a very competitive levelized cost of energy.

“Specific countries such as Germany, France, Italy, Spain stand out in the maps as they host the highest economic potential that translates to more options for advantageous investments,” stated the paper, adding, electricity retail prices of €0.30-0.169/kWh meant rooftop solar could offer electricity savings of 49% in Germany, 44% in Spain, 42% in Italy and 23% in France.

Eastern EU member states such as Bulgaria, Hungary, Romania and Estonia, however, were cited as markets with very low retail electricity prices, of €0.095-0.12/kWh.

The rooftop PV analysis identified nine markets where grid-parity is some way off as a result of cheap grid power and all of them are in Eastern Europe: Romania, Poland, Hungary, Czechia, Slovakia, Croatia, Lithuania, Latvia and Estonia.

By contrast, Portugal was highlighted as a market with very favorable conditions, including high solar radiation, good financing availability and high retail electricity prices of around €0.22/kWh.