Load Flexibility Can Enhance Grid Reliability

With much of the US experiencing extreme temperatures throughout the summer, the issue of grid stability is making headlines again. California issued energy conservation alerts for several days in early September to avoid rolling blackouts as power demand reached an all-time high. Rolling blackouts were avoided, in part, due to customers taking actions to reduce their energy consumption between 4 p.m. and 9 p.m. Emergency alerts like those issued by the California Independent System Operator in September are some of the key tools for maintaining grid reliability in extreme situations like heat waves when there is more electric demand on the grid. However, more advanced grid reliability tools will be required as heat waves become more extreme, frequent, and prolonged across all regions of the world.

Load Flexibility Offers an Alternative to Emergency Conservation

Load flexibility effectively decouples power demand from end use meaning grid operators can transition from a strictly follow-the-load model to one where certain load timing is controlled to match supply conditions. This approach is critical with the role of dispatchable fossil fuel plants being reduced and eventually eliminated as countries look to transition entirely to variable renewable sources such as solar and wind. Emergency conservation notices and traditional demand response are reactive measures that require end users to alter their energy consumption in response to alerts. Load flexibility differs from those techniques because it is a process whereby grid operators can continuously control demand profiles to maintain grid stability without affecting end user comfort levels. This can be done primarily through load shifting whereby demand for certain end uses is met earlier in the day when solar output is abundant or overnight when wind generation is plentiful. Load flexibility not only helps maintain grid reliability during peak conditions but also can be used to reduce renewable curtailment. This increases the economic benefits of resources and prevents oversizing future projects, which can minimize increases in electric rates to subsidize new projects.

Opportunities for Load Flexibility Are Increasing

The cornerstone of load flexibility is the electrification of loads that are not time sensitive. Electrification is gaining traction in all business segments as customers look to transition end uses historically powered by fossil fuels to electricity to decarbonize their operations. Using heat pumps for HVAC, shifting to electric storage water heaters, and adopting EVs will increase the demand for electricity, but because they each have an aspect that enables a form of energy storage, they can be used in load flexibility applications. EVs use a physical battery to store electricity for later use while HVAC heat pumps and electric storage water heaters use the thermal mass of building envelopes and water in the tank, respectively, as virtual energy storage devices.

The growing digitalization of the energy sector is also facilitating more automated control over supply and demand for grid operators through energy management solutions. For end users, shifting loads to off peak hours in the past may have required manual adjustments to consumption patterns. However, with advancements in grid edge customer solutions, thermostat, water heater, and EV charging technology, those changes can be automated so no action is required by the end user and their comfort level is not affected. Climate change will continue to bring unprecedented weather events and as a result, power grids will be stressed more frequently. Customers and grid operators can enhance grid reliability by taking advantage of increased electrified loads, excess renewable energy capacity, and load flexibility to seamlessly relieve grid strain, resulting in improved quality of service for customers.