The European Data Protection Supervisor (EDPS) has warned that energy suppliers could sell the data gathered from smart meters to third parties.
Although it has stated that the meters could bring significant benefits, it added that safeguards needed to be put in place to regulate how firms, including the big six energy companies, could use the data provided by the meters.
Both energy suppliers and the UK government, however, have moved to quell concerns, stating that consumers privacy would be protected once the 53 million energy smart meters are installed by 2019.
It isn't yet know though whether consumers will have the option of deciding whether they wish for their information to be shared with third parties.
Assistant European data protection supervisor at the EDPS, Giovanni Buttarelli, said: "For the roll-out of smart metering systems, to ensure adequate protection of personal data, the EDPS is calling for the European Commission to assess whether further legislative action is necessary.
Meanwhile, Anna Fielder, consumer rights advocate from Privacy International, told the BBC: "The proposed safeguards need to be toughened up: as things stand, if you don't want your daily data uploaded you have to opt out.
"Suppliers will go for daily data collection and our experience tells us many people won't bother to opt out. We think people should have the right to opt into frequent data collection at every stage," she added.
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