The European Data Protection Supervisor has warned that smart meters are a significant privacy threat and wants limits on the retention and use of customer data before it's too late.

The EDPS is an independent authority figure tasked with identifying where EU policies might represent a risk to privacy. He reckons next-generation meters, which precisely monitor electricity use within homes, are a very likely candidate unless his concerns are addressed ahead of time.

Peter Hustinx, who fills the role with the assistance of Giovanni Buttarelli, admits there are advantages of smart metering, but warns that the technology will "also enable massive collection of personal data which can track what members of a household do within the privacy of their own homes". He pulls up examples of baby monitors and medical devices, which have identifiable patterns of energy consumption and could therefore be used to monitor what people are doing.

That might sound fanciful, but researchers have already demonstrated that the pattern of energy consumed by a decent flat-screen TV can be used to work out what programme is being watched, and Hustinx is probably right that this isn't information most of us would wish to share with our electricity providers.

Smart meters need to collect all that data in order to reduce our reliance on power - it's now an article of faith that once we know how much energy we're using we'll magically reduce that consumption, so the EU is committed to mandating smart meters by 2020. Therefore the EDPS thinks we need legislation now, before it's too late, stating what the data can be used for and how long it can be retained.

The real way to reduce power consumption is by using smart appliances - such as a washing machine that can be configured to run during the night - at the behest of electricity suppliers and with a suitably discounted rate. But this scenario is still a long way off from reality for the majority of us, so energy targets remain pinned to the idea we'll voluntarily wash less.

The UK's Department of Energy and Climate Change has taken some steps in this direction, promising that collected data won't be shared with third parties, and requiring decent security to prevent it being stolen, but even that stops short of the limitations suggested by the EDPS.

The European Commission is preparing a document on the impact of all this new data, but as planned it's limited to vague objectives rather than specific requirements, which is what the EDPS thinks will be necessary. ®