Integration Costs: Are They Unique to Wind and Solar Energy

In the past several years there has been considerable interest and effort in assessing wind integration costs (solar integration costs have not been as rigorously pursued but this is expected to change with increasing solar energy penetration). This interest is understandable, because wind energy does increase the variability and uncertainty that must be managed on the power system. Measuring this integration cost can be challenging. In addition to wind and solar energy (and load), there are other sources of variability and uncertainty that must be managed in the power system. In this paper we describe some of these sources, which can include the performance of thermal plants. We also show that even the introduction of baseload generation can cause additional ramping and cycling, along with lower capacity factor, of at least some thermal units. The paper concludes by demonstrating that integration costs are not unique to wind and solar, and should perhaps instead be assessed by power plant and load performance instead of technology type.