With the rapid development of wind power, electric grid faces significant challenges from the variable nature and anti-peak-regulation characteristic of wind power. In order to mitigate the impact of wind power, large capacity electrochemical energy storage is proposed to solve this problem. This study establishes a unit commitment (UC) model with large capacity electrochemical energy storage given the specific characteristics. Meanwhile, wind forecast deviation and curtailment are considered. Case studies with modified IEEE 39-bus system are employed to validate the proposed method. The impact of electrochemical energy storage system on economics, peak load shifting and accommodating wind power is analyzed.