Small-scale energy storage solutions for distributed applications, with or without connection to the grid, have been recognized as a valuable and sometimes indispensable complement to local energy production based on renewable energy sources. In the case of grid-tied energy storage units, the possibility to operate in peak shaving mode, mitigating contingencies and providing backup power, reducing transmission losses, and generally giving larger utility control on renewable energy generation makes distributed energy storage a necessary prerequisite for the wider deployment of renewable energy systems and their deeper penetration into utilities’ portfolios. Thermodynamic energy storage in the form of compressed air can be applied at small scales as an alternative to electrical batteries.
Distributed compressed air energy storage (DCAES) units combined with small-scale solar or wind energy converters installed at residential homes or small commercial buildings do not present any major technical challenges, and promise lower specific investment than batteries if mass produced. Flexible control methods can be applied for optimizing the behavior of the energy storage system and maximizing the benefits from its utilization.
This study aims at presenting a devised operational control strategy applied to distributed compressed air energy storage systems, as well as assessing the best scenario for optimal utilization of grid-integrated renewable energy sources at small scales in dynamic electricity markets. Profit maximization for the end consumer is the major goal.
Results show that profits can be achieved even without integration of local power generation, if optimal charge and discharge strategy is found as a function of electricity price and various restrictions. A monthly benefit of $ 77 is expected during times of generally high consumption levels for an aggregated group of several residential houses, growing to $ 82.5 /month if a 15 kW renewable energy capacity is installed in the locality. Smart load management approximating a quasi-dispatchable behavior of the energy storage can bring additional benefits to the transmission system operator, leading to improved grid stability.