The ebb and flow of gas and electricity into your home contains surprisingly detailed information about your daily life. Energy usage data, measured moment by moment, allows the reconstruction of a household's activities: when people wake up, when they come home, when they go on vacation, and maybe even when they take a hot bath.

California's PG&E is currently in the process of installing "smart meters" that will collect this moment by moment data—750 to 3000 data points per month per household—for every energy customer in the state. These meters are aimed at helping consumers monitor and control their energy usage, but right now, the program lacks critical privacy protections.

That's why EFF and other privacy groups filed comments with the California Public Utilities Commission Tuesday, asking for the adoption of strong rules to protect the privacy and security of customers' energy-usage information. Without strong protections, this information can and will be repurposed by interested parties. It's not hard to imagine a divorce lawyer subpoenaing this information, an insurance company interpreting the data in a way that allows it to penalize customers, or criminals intercepting the information to plan a burglary. Marketing companies will also desperately want to access this data to get new intimate new insights into your family's day-to-day routine–not to mention the government, which wants to mine the data for law enforcement and other purposes.

This isn't just a California issue. Many threats to the privacy of the home—where our privacy rights should be strongest—were detailed in a 2009 report for the Colorado Public Utility Commission. The federal government has been promoting the smart grid as part of its economic stimulus package, and last year, EFF and other groups warned the National Institute of Standards and Technology about the privacy and security issues at stake. For example, security researchers worry that today’s smart meters and their communications networks are vulnerable to a variety of attacks. There are also questions of reliability, as PG&E faces criticism from California customers who have seen bills skyrocket after the installation of the new "smart meters." Unsurprisingly, California legislators are questioning the rapid rollout. Texas customers are also complaining.

There are far more questions than answers when it comes to this new technology. While it's potentially beneficial, it could also usher in new intrusions into our home and private life. The states and the federal government should ensure that energy customers get the protection they deserve.

Special thanks to Berkeley Law students Jonas Herrell, David Marty, and Shane Witnov, along with School of Information Masters Candidate, Longhao Wang for their work in drafting these comments to the California PUC.