A key smart grid cost is the maintenance and replacement of smart meter batteries. Dr. Maximilian-Eckart Wernicke of Frost & Sullivan, Germany, assesses one solution.
A key element of a smart grid is the smart meter, which records minutely the user’s consumption, thereby permitting accurate estimation and control of the smart grid’s behaviour.
Frost & Sullivan forecasts that 126 million smart meters (electricity, gas, water and heat meters) are to be rolled-out annually around the globe until 2024, mainly driven by supportive national regulations.
Many of these will rely on disposable batteries as their sole source of power supply, as only electricity meters have the luxury of always having a grid connection nearby.
Smart meters maintenance
In the past many concerns have been raised about smart meter’s susceptibility to failure, but the list of malfunctions across all types of applications remained surprisingly small.
Nevertheless, utilities face the burden of shorter product life spans and the shorter maintenance cycles of smart meters.
While conventional mechanical gas meters have a life span of 24 years on average, static smart gas meters will probably last one third as long.
In addition, a battery powered meter requires a regular routine check-up on the condition of the battery.
New extended life lithium units can last up-to 20 years, but so far long-term field tests were not possible, as the first generation of smart meters have only been operational for 7-8 years.
Energy harvesting and smart meters
A potential solution that has recently gained some attention is the use of energy harvesters as an integrated power source in smart meters.
The term energy harvesting describes the transformation of energy from various naturally occurring or prevalent sources into electrical energy.
This harnessed energy is stored for or directly used in numerous applications, most particularly electronics and electrical systems.
The permanent availability of (rechargeable) batteries has diminished the application of energy harvesters, but the advantage of utilising free and ambient energy sources still lives on today.
There are various ambient energy sources and commercially available technologies to scavenge them.
Energy harvesters that may be incorporated in future smart meters will most probably utilise temperature differentials between water, gas or heat connections and room air to generate power.
Alternatively, smart meters could harvest energy from flow induced vibration or through piezoelectric flags.
By using energy harvesting solutions in both residential and industrial meters, the operational costs of smart grids can be significantly reduced.
At present, building automation is one of the key growth markets for energy harvesting.
In order to increase the intelligence of buildings a considerable amount of sensors and actuators will be required.
Many of those are to be installed in locations that do not feature power outlets and are difficult to access. This development will eventually have a spill-over effect onto smart metering infrastructure in the longer-term.
Owing to time-consuming national specification processes and tendering procedures, technical advancement in the meter industry tends to be relatively slow. Thus, we may not see self-powered smart meters before the end of the 2020s.
About the author
Dr. Maximilian-Eckart Wernicke is a consultant at Frost & Sullivan's Frankfurt office.