Proactive energy storage operation strategy and optimization of a solar polystorage and polygeneration system based on day-ahead load forecasting

To improve the battery utilization ratio in winter and promote the system's techno-economic performance, the present study proposes a novel proactive energy storage operation strategy based on day-ahead load forecasting for a solar polystorage and polygeneration system coupled with thermal energy storage and vanadium redox flow battery. The differences in operation procedure and techno-economic performance of the polygeneration system under the proactive energy storage strategy and the traditional strategy are comparatively investigated. Furthermore, the energy outputs and operation states of main equipment in cooling and heating modes under these two strategies are examined. Finally, a multi-objective optimization based on the proactive energy storage strategy for the polygeneration system is conducted to tradeoff the exergy efficiency and unit energy cost. The results illustrate that: the battery utilization ratio under the proactive energy storage strategy is up to 14.65 % points higher than that under the traditional strategy, with a maximum saving of about 17.48 % of the annual grid electricity cost. The maximum system exergy efficiency under the proactive energy storage strategy achieves 30.41 %, which is 5.39 % greater than that of the traditional strategy. Under the same capital expenditure, the proactive energy storage strategy for the polygeneration system presents excellent economic advantages, and the net present value, simple payback period, internal return ratio, and levelized cost of energy are all superior to those of the traditional strategy by 3.07 %, 0.12 years, 1.79 %, and 2.29 %, respectively.