Upgrade of the thermal power plant flexibility by the steam accumulator

Abstract

Thermal power plants are forced to operate under frequent load changes in energy systems with increased share of solar and wind power plants. These load changes increase thermal power plant aging and reduce their efficiency. Therefore, solutions for energy storage are sought in order to accumulate energy in periods of lower power demand and produce excess power in periods of increased demands. In the present paper the application of the steam accumulator is evaluated to provide the thermal energy storage in the coal-fired thermal power plant and to increase its flexibility under the demand for the variable load changes. The steam accumulator is charged during periods of lower power demand, as during the night hours, and discharged during peak load demands. The steam accumulator is charged by the steam extracted from the steam turbine. The steam discharged from the steam accumulator increases the steam flow rate through the turbine and the turbine power. Investigated are possible technical solutions with the steam accumulator installations in the power plant. The upgrade of power plant flexibility by steam accumulator is demonstrated. The corresponding operating parameters and energy benefits are calculated.