Ancillary services for the electrical grid by waste heat

This paper proposes a method to provide ancillary services to the electrical grid with waste heat recovery. The thermal flexibility needed to provide variable electrical output is provided by connecting the thermal source to a thermal grid and a thermal storage unit. Large capacity low heat grade thermal storages are cheaper and more readily available than large capacity electrical storage solutions, and hence thermal storage is preferable. s paper, the dimensions of a low temperature thermal storage buffer to balance the variability of a wind- or solar plant is determined. It is calculated that a spherical storage tank of 25 m diameter and 90–130 °C would be sufficient to balance the unpredictability of a 100 MW plant of either solar- or wind energy.