Impact of demand response and wind generation on reserve requirements in the US Pacific Northwest

As the global movement towards the implementation of large-scale renewable energy sources proceeds, wind power has continued to remain a leading resource. Unlike other traditional generation sources, the fuel cost for wind is zero; nevertheless, the impacts of adding wind generation to an existing power system are generally non-negligible. One of the key indicators of the variability of a renewable resource is the amount of reserve generation required to back up that resource. The variable nature of wind generation can stress many different elements of a power system, including both transmission and the operation of other generation resources. In the US Pacific Northwest, much, if not all, of the reserve is provided by the plentiful hydropower resource that makes up the majority of traditional generation in the area. In order to reduce the additional stresses that wind power places on the hydro system, other sources of reserves will be required in the future. This paper explores the impact of combining demand response with the increasing penetration of the wind resource on reserve requirements. Utilizing a variety of simple demand response implementations with varying wind penetration, the results demonstrate that demand response can play a part in mitigating the stresses that increasing variable renewable generation places on the power system. The results show that with 15 percent of the load participating in demand response, approximately 10 percent wind penetration can be achieved with no change in reserve requirements.