The Fourth Amendment and Smart Grids
Wednesday, January 6, 2010 at 10:49AM
Toby Considine in Energy, Microgrids and Distributed Systems, Musings, Privacy, Re-thinking things, Smart Grid

If we are not careful, smart grids are in direct collision with the bill of rights. Some smart grid activities define or enable business practices for balancing energy supply and demand. There is a direct link between commonly accepted business practices and some definitions of our constitutional rights. With the best of intentions, we may be casually removing significant barriers to some of our most cherished freedoms.

The Fourth Amendment to the United States Constitution is the part of the Bill of Rights which guards against unreasonable searches and seizures. During the American Revolution, British forces made extensive use of writs of assistance, a sort of general search warrant that could be extended and used without ongoing review. In response, the Fourth Amendment created a standard whereby government searches must be issues only on a discovery of probable cause, and specifically limited in location and as to the matters being searched for, based on specific information supplied to a court.

The Fourth Amendment is the most explicit source of any support for privacy that I can find in the Constitution.

Dr Orin Kerr is one of the most respected legal voices on Fourth Amendment issues. Dr Kerr blogged this week on the relationship between technology, common practices, and developing standards for reasonable search (see reference below). Specifically, Dr Kerr was exploring the ten year old Supreme Court ruling in Kyllo vs. United States that defines the limits of police use of high technology in warrantless searches.

In cartoon form (IANAL), police scanned houses with some sort of IR scanning system and noted a hot spot in the attic. From the hot spot, they deduced that the defendant was growing marijuana under grow lights in his attic. Kyllo asserted that this was a prohibited search under the 4th amendment. The question was, in effect, is a non-intrusive search using high tech an unreasonable search. Clearly, if Kyllo had been growing the marijuana in his front yard, there would have been no dispute when police noticed this when on routine patrol. Previous rulings had stated that police fly-overs are legal searches because non-police could fly over the property and spot the plants; the property owner has no reasonable expectation of privacy applied to aerial views of his property.

In this case, the search was ruled unconstitutional; Kyllo won. The Supreme Court adopted a test designed to let the result change with social practice: “when . . . the Government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a “search” and is presumptively unreasonable without a warrant.” Because infrared temperature sensing was not in “general public use,” the thermal imaging was a “search” that required a warrant.

Dr. Kerr was blogging on whether under this standard, the search in Kyllo was still prohibited. Remote infrared temperature-sensing has become quite common in a wide range of applications. I heard an ad on the radio yesterday for a remote home thermometer enabling mom to take a sleeping child’s temperature from the door without waking the child. Thermal images of houses to reveal gaps in insulation have become common; many utilities will pay for them as part of energy efficiency efforts. The question was, then, is this high tech device now considered to be in in “general public use,” and if so, can the police use it without a warrant without violating the Fourth amendment.

And so, at last, I loop back to smart grids.

Some business practices we are defining, particularly in what we are calling Managed Energy, can routinely monitor the activity of every device in a home. If we establish these practices as general practice, have we eliminated any Fourth Amendment shield against the use of the same techniques by police?

Analysis of electrical power consumption reveals more than you might guess. Research a decade ago explored what engineers could learn from these signals. One anomaly occurred almost every day in a home somewhere between a half hour and two hours after the owners left each day. Further research determined that the family dog waited each day until it was sure that its owners were really gone for the day—and then climbed onto the warm waterbed. They were detecting the change in the pattern of water heater use. Further research demonstrated an ability to distinguish how much activity was on that waterbed…

When we define business practices for the smart grid, we are doing more than solving a a difficult engineering problem. We may be creating practices that re-define our precious constitutional rights. Privacy is more than a best business practice for smart grids.

Article originally appeared on New Daedalus (
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