The US Patent and Trademark Office issued a patent to Sequentric Energy Systems for its variable-capacity, grid-interactive water heating technology.
Designed specifically for electric utility energy storage and grid management programs, Sequentric’s variable-capacity technology allows grid operators to manage second-by-second timing of the electricity required for water heating. Sequentric’s technology provides the ability to pre-heat the incoming cold water in a way that is essentially decoupled from the customer’s hour-by-hour hot water usage. This makes a number of energy products possible for the utility, including traditional demand response and energy storage. In addition, it guarantees a constant supply of safe hot water for the utility’s customers at all times.
The technology can be incorporated into any brand of storage tank electric water heater. Sequentric has begun licensing discussions with water heater manufacturers.
Sequentric’s variable-capacity water heaters are linked in real-time with utility operated servers for direct dispatching. This allows them to be used in legacy demand ￼response programs as well as load management initiatives including: energy storage, and neutralizing variability to assist in ever increasing renewable energy contributions. When, for whatever reason, the communication link to the utility server becomes unavailable, the variable-capacity water heater simply reverts back to function as a conventional, fixed capacity water heater that runs autonomously.
Sequentric estimates there are 50 million electric water heaters in North America, and there is an 8 percent annual turnover rate of the water heater population, which creates the opportunity to add many Gigawatts of storage capacity to the power grid over the next few years. According to Sequentric, fleets of water heaters employing its variable capacity technology are far less expensive for utilities than other storage technologies and can be deployed at grid scale.
As for how the arrangement would work between utilities and their customers, a spokeswoman for Sequentric said: “There are a number of ways utilities would do this. The subsidy arrangement is one commonly used method. It also appears that water heater rental programs are set to return to the US in a big way. In Canada, about 12 percent of the homes rent their water heaters. There are also third party companies that will be offering the water heaters because the sale of ancillary services is so valuable.”