Greece is being referred to the European Court of Justice for failings over energy efficiency.
The country failed to enact the Energy Efficiency Directive, under which EU Member States must meet certain energy-saving targets from 2014 to 2020.
They must implement policies and schemes to improve energy efficiency in homes, businesses, industry and transport.
Other requirements include energy audits for big companies every four years, increased rights for consumers regarding metering and billing for their energy use and renovating at least 3% of central government buildings every year.
The European Commission said: “To date, no legislation transposing the Directive into national law has been adopted and/or notified to the Commission.”
It has proposed a daily penalty of more than €29,000 (£20,683) until the law is put in place.
The Energy Efficiency Directive plays a key role in helping the EU achieve its target of cutting Europe’s annual primary energy usage by 20% by the end of the decade.