"Eurotunnel experienced new power supply problems this morning which meant that both tunnels were again closed for two hours," a message on Eurostar's website read.
A crowd of some hundreds of people at the train station in London was offered to take the ferry across the channel or wait for services to resume.
"This closure was a separate incident, unrelated to the problems experienced yesterday," Eurostar's service update continued.
On Saturday, all high-speed Eurostar train services through the Channel Tunnel were halted due to smoke caused by a fire on a lorry in the north tunnel. Last November, over 1,000 Eurostar passengers were left stranded inside two high-speed trains due to a power outage on the rail link.