Energy Storage Application 3: Load Following

Given the predicted diurnal variation in electric demand, many utilities must operate generation equipment below its optimal output level until demand increases. In Figure 1 (below) demand is below the optimal power output of 4kW for the base load generator from 22:00 to 9:00; at these times the generation equipment must operate inefficiently above demand in anticipation of the need to follow the load up when demand increases. From 9:00 to 11:00 the generator continues to follow the load up towards its less efficient maximum output. After 11:00 until 21:00 the generator operates at the less efficient maximum capacity while load following and then peak generators make up the difference between demand and output. After 21:00, this same base load generator must follow the load down, again operating below its optimal output. Energy storage can be used to follow the load up by discharging and down by charging, allowing base load generation to operate at its optimal output providing maximum efficiency (Droste-Franke, et al., 2012). It is important to reiterate that generation equipment (especially large base load generators) consumes less fuel per unit of output and require less maintenance when they operate at their optimal efficiency point. Significant environmental benefits can be realized by allowing generation equipment to operate at its optimal level (Sandia Corporation, 2012).

Works Cited

Droste-Franke, B., Paal, B. P., Rehantz, C., Sauer, D. U., Schneider, J. P., Schreurs, M., et al. (2012). Balancing Renewable Electricity; Energy Storage, Demand Side Management, and Network Extension from an Interdisciplinary Perspective. Verlag Berlin Heidelberg: Springer.

Sandia Corporation. (2012). Energy Storage Systems - Technology; Power Electronics. Retrieved January 5, 2012, from Sandia National Laboratories: http://www.sandia.gov/ess/tech_power.html