A smart meter is a digital metering device used to measure public utility electric power consumption. They typically report their information via a wireless link every fifteen minutes or so. This allows the utility company to collect metering information without using human meter readers to manually observe the meter and to gain a more accurate understanding of power consumption. It also allows the consumer to gain the same improved understanding and to connect a home network to the smart meter for advanced uses.
A smart meter serves basically the same function as our older electric power meters with the spinning wheel and number dials, but does it electronically and reports the data wirelessly. As electric power utility companies have begun replacing older meters with the new smart meters, controversy has sprung up about them.
Description of Smart Meter Configurations
A typical smart meter installation involves several components:
- HAN – there may or may not be a Home Area Network (HAN) inside the house. This is a consumer purchased and installed option that allows you to use the data from your meter and also connect to other appliances if you wish. Most homes don’t yet have HANs installed.
- RF Mesh Network – this wireless network connects the smart meter to either other smart meters or to a collection station located somewhere nearby, often on a utility pole.
- Data Relay Network – this network relays the data from the meters to the utility company and may use some form of wireless, or cellular phone or even a wired network.
Smart meters can use a variety of wireless techniques including:
- Zigbee – 802.15.4 is a low power mesh protocol that can operate at either 2.4 Ghz or the 900 Mhz band. This is often used to provide a link from the smartmeter to the HAN inside the house.
- Infrared – IR port on some meters is used for administrative purposes such as programming or updating firmware
- Cell phone
- WiFi or WiMAX
- non-wireless techniques include conventional network cables or signal over power lines.
There are two main areas of recent controversy about smart meters:
Health Impact
There are those who worry about the health impact and maintain that the Radio Frequency (RF) energy emitted by the wireless component may have negative health implications. There may or may not be some basis for concern about RF emissions in general, but the power of the wireless transmitter in smart meters is extremely low compared to other RF sources that we are exposed to every day and they transmit more infrequently than other forms of wireless because of the relatively low data volume.
Security and Privacy
There are many unsubstantiated security and privacy concerns about smart meters. They mostly involve theories that the utility company or government will be able to either monitor which device inside the house is using power or even control devices inside the house via the smart meter. While it’s true that measuring in fifteen minute increments may allow utility companies to make some intelligent inferences about how power is being used at different times of the day, there is no new significance to the data being transmitted that was not present before the meter type was changed. There is no ability whatsoever inherent in a smart meter to control devices inside the home. Once HANs become commonplace, some of these worries may become more substantial but at the present time HANs are not even available to most consumers.
A more substantial worry is whether or not the addition of wireless networks to public power companies will weaken their defenses against attackers who wish to bring down the power grid. This is no different than adding wireless networking to any information system and should be handled by standard security conventions and controls. Physical access to meters located outside in public is not easy to control and will need special attention.
NOTE – similar advanced metering devices for utilities other than electric power should be available soon: water, gas. And the embedding of wireless sensors will continue across our environment, including inside the home. Smart appliances of all types as well as smart carpet, smart furniture, smart walls etc.