The European Union could miss a binding goal for 20% of its energy to come from renewables by 2020, despite rapid growth in renewable electricity generation in recent years, the European Court of Auditors said.

Although about a third of the EU’s electricity now comes from renewables, the 20% target for 2020 also covers energy used in transportation and in heating and cooling of buildings, where less progress has been made, according to the report, issued June 6.

In 2017, the share of renewables in transportation fuels was 7.6% and while heating and cooling came in at...