Compressed Air Storage and Wind Energy for Time-of-day Electricity Markets

As renewable energy generating capacity increases on electricity grids, technology is needed to balance the supply and demand of energy. In order to manage the demand side of electricity, time-of-day (TOD) tariffs are a simple economic mechanism that encourages consumers to smooth the diurnal demand profile by shifting consumption to off-peak times. The management of supply by renewable energy generators can be achieved using energy storage. This study investigates the use of compressed air energy storage (CAES) to de-couple a wind energy converter (WEC) from the electricity grid and manage its power output. Numerical and thermodynamic models simulate the operation of the system. One year of operation is simulated using 10 minute WEC time-step data for varying CAES capacities in order to optimize the economic performance of the total system. By selling electricity according to TOD tariff schedules, the income generated by a 0.8 MW WEC using a 4 MWh CAES system is increased by 30%. The CAES has a round-trip efficiency of 66% and annually experiences 450 deep cycles as it stores 25% of the energy generated by the WEC.