  PyPSA-Eur-Sec-30 is an open-source, hourly-resolved, networked model of the
European energy system which includes one node per country as well as
electricity, heating, and transport sectors. The capacity and dispatch of
generation and storage technologies in every country can be cost-optimised
under different CO2 emissions constraints. This paper presents an overview of
the most relevant results previously obtained with the model, highlighting the
influence of solar photovoltaic (PV) generation on them. For 95% CO2 emissions
reduction, relative to 1990 level, PV generation supplies in average 33% of the
electricity demand. Southern European countries install large PV capacities
together with electric batteries, while northern countries install onshore and
offshore wind capacities and use hydrogen storage and reinforced
interconnections to deal with wind fluctuations. The strong daily generation
profile of solar PV heavily impacts the dispatch time series of backup
generation and storage technologies. The optimal PV and wind capacities are
investigated for variable CO2 emissions, transmission interconnection among
neighbouring countries, and cost assumptions.
