Peak load matching and the offshore wind resource

Coastal and offshore locales are favored regions for wind power utilization because of the generally high wind resource, proximity to major load centers, and existing transmission infrastructure. Since the heaviest power loads in the U.S. occur during the warm season, when sea and lake breezes are most prevalent, understanding the climatology and dynamics of these local circulations is key to accurately depicting and matching potential offshore wind power production with onshore energy demand. The sea (or lake) breeze circulation is an adjustment to the local pressure gradient driven by temperature differences between the onshore (warmer) air-mass and the (cooler) offshore waters From an energy production perspective, sea (or lake) breeze circulations produce wind speed/wind power maxima during high load periods of hot summer afternoons. Although winds well inland may remain light, wind speeds in the near and offshore waters can exceed 10 m/s during the mid and late afternoon hours, co-incident with the time of peak load demand (Figure 1). However, small differences in the characteristic onset time between locations may have a considerable impact on the load matching performance of wind generation between the sites. Furthermore, changes in coastal morphology over even short distances (several km or less) can significantly affect the extent, strength, and timing of the sea breeze circulation. The goals of this study are to: (i) understand the dynamics and climatology of the local sea breeze circulation as applied to wind power production; (ii) provide an awareness of how subtle variations in the characteristics of the sea breeze circulation can significantly change the load matching characteristics between nearby offshore sites; and (iii) develop a time-evolution composite of the sea breeze circulation and load demand for various locales along the mid-Atlantic and northeastern U.S. coast. Long-term observations along the northeastern coast of the U.S. and high resolution measurements from a recently completed field study in the near and offshore waters south of New York and east of New Jersey were used to assess the climatology of the sea breeze circulation. Simulations with a coupled mesoscale-ocean wave modeling system were also performed to examine local influences on the sea breeze circulation.