Economic Analysis Of Photovoltaic System Based On Small Scale Compressed Air Energy Storage

The small scale compressed air energy storage can be used as an environmental friendly method for energy storage without the combustion of the fossil fuel.In this method,compressed air is injected into the air vessel in liquid form,thus storing the energy which is absorbed in the process of condensation.It is a promising method with its characteristics such as flexibility,convenience,durability,etc.Utilizing the small scale compressed air energy storage in photovoltaic power generation can solve the problems such as the photovoltaic power generation intermittence and fluctuation.On one hand,the system can form an independent system to realize the power supplement on the island,mountain and other remote areas to assure the reliability of power supplement.On the other hand,the system can be utilized in grid-connected system as the power storage unit,making the power flowing more flexible and provide more convenience to the users.However,economy is an important factor that restricts the use and development of energy storage and photovoltaic system.The economic performance of the system from the angle of investors and users is mainly studies.First,the mathematical model of photovoltaic power generation and small scale compressed air energy storage device is introduced.In the stand-alone photovoltaic system,an economic model is established considering load power shortage rate and energy overflow rate and the initial investment in equipment,operation and maintenance cost,salvage value and the part of the proceeds.The relationship between the PV capacity and the energy storing capacity which meet the index is established considering the load power shortage rate and the energy overflow rate,and calculating the optimal PV capacity aiming at minimize the annual cost.In order to improve the economic performance under the TOU power price strategy for the grid connected photovoltaic system of “Main for self-use,remains for grid”,an energy management method is proposed to optimize the exchange power and the efficiency of storage charging and discharging.The optimal storing capacity under some certain photovoltaic power capacity and loading capacity is calculated by establishing the economic model and using particle swarm optimization to solving it.In order to further improve the economic performance,the demand response to the photovoltaic system of “Main forself-use,remains for grid ” in large enterprises or residential areas is introduced.By providing a certain compensation,the method proposed in this paper can guide the users to reduce and transfer the load,fitting the PV curves and loading curves more better,then re-allocate the capacity and study its economic performance.Users is the consumer in the power market,as well as the power supplier utilizing the proposed system,the power supply satisfaction and purchase electricity satisfaction from users should be taken a full consideration.As is demonstrated in the case mentioned below,introducing the demand response can reduce the energy storage based on the containing power supply satisfaction and purchase electricity satisfaction from users,and further improve the economic performance.In conclusion,the economic performance of the proposed system is influenced by the reliability of power supply,capacities,load’s characteristics,etc.Taking a full consideration among these factors can further promote the economic performance.Small scale compressed air energy storage is suitable for photovoltaic power generation,it can become a new choice of storage battery and super capacitor.An energy storing strategy is considered in the proposed system and can versatilely benefit the grid as well as the social environment,although the relatively high initial investment of the proposed system may hinder the process of generalization,the initial compensation is once given to the investors,the popularization of the proposed system is well in sight.