This post is part of the continuing Paths to Transactive Energy series. You can find them all listed by clicking on the matching metatag at the bottom of each post.
Grid operators cannot know the purpose of each system attached to the grid. On a college campus, very similar sets of components: fans, ducts, temperature sensors, could provide environmental conditioning for a classroom whose windows can be opened, for office space, or for document archive which requires constant temperature and humidity. The most important attribute of animal quarters might be constant high-volume ventilation, while for a biohazard lab it might be maintaining a negative air pressure in the room. Humidity and temperature changes might make a basketball court slippery, and environmental management is focused on making sure that the All-American is not injured before the NCAA tournament.
Direct control for demand response requires that all parties know these issues and agree on their import. A central operator cannot know this.
If we look at pure DER, we will see more hybrid systems in the future. Solar will be paired with power storage. Power storage will be hybrid systems blending fast response and slow draw technologies. The best chemical battery systems are starting to come with internal intelligence to extend battery life. Power flows are optimized over time to manage dendrite growth, or to recondition one cell among many. Unless the grid operator understands the intelligence imbued within the storage system, then they can damage expensive assets by interrupting these processes in mid cycle.
Some of the earliest DR was based on refrigeration management. The purpose of such a system may be for food safety during shipping and storage. Such a system may be able to time shift chilling, or even skip a cycle without harm. After repeated shifts within a short period, the next cooling cycle becomes more critical to maintain biological safety of food, or the integrity if a chemical or pharmaceutical manufacturing process. As we look to more complex systems in the future, this tension between local purpose and remote direct control strengthens.
As we scale down, we might get to the refrigerator in the home. The ice-maker is a pre-consumption agent, which could time-shift ice production to the cheapest prices on the power market internal to the facility. On the other hand, as we get closer to the planned weekend party, the goal of a full ice bin may become more important…
Many early adopters of behind-the-meter power storage are concerned first about reliability. Their facilities may be able to perform a mix of pre-consumption, DR cycle skipping, internal generation, and battery storage management. By intelligent internal management, such a facility may be able to act as a DERA—but be completely unwilling to turn over direct monitoring and control.
Power use in a facility should always be driven by the local or personal needs