Wind power, like many forms of renewable energy, suffers from intermittence that weakens its potential as a baseload power source. Pumped hydroelectric energy storage can mitigate the variability associated with wind power; however, it is not always available. When energy storage is not an option and wind conditions are sub-optimal, conventional power plants are used to supply the grid. These conventional power plants run less efficiently when they are forced to change output on the basis of wind intermittency, creating decreasing marginal reductions of CO2 emissions (ESB 2004). In order to avoid the problems associated with intermittency, Fusco et al. (2009) propose using wind power in combination with wave energy. Since these two resources have an inverse correspondence in some areas, together they could reduce the need for energy storage and CO2 emitting, backup power plants. Noah Proser
ESB National Grid. Impact of wind power generation in Ireland on the operation of conventional plant and economic implications. February 2004.
Fusco, F., Nolan, G., Ringwood, J.V., 2009. Variability reduction through optimal combination of wind/wave resources – An Irish case study. Energy 35, 314–325.
The researchers focused on the ability to combine wind and wave power in Ireland in order to meet the country’s new goal of 33% renewable energy. They used data on wind speeds, wave periods, and wave heights collected from weather buoys by the Irish Marine Institute. Energy potentials were calculated based on 3.5 MW offshore wind turbines and the 750 kW Pelamis wave energy converter. The researchers considered the West, Southwest, South, and East coasts of Ireland separately since wind/wave correlations differ geographically.
Fusco et al. found that the West and South coasts of Ireland experienced winds and waves that were not highly correlated, while there was a high correlation on the East coast. Since the East coast is harbored from the Atlantic, wave energy is largely dependent on local winds, thus creating a high correspondence. On the other hand, the West and Southern coastlines can utilize wave energy created in the open ocean. These higher energy swells provide power when local wind power is insufficient.
In combination, wave and wind power can significantly reduce renewable power variability. Though more dependable power sources will still be necessary without significant energy storage options, this reduced variability will allow these plants to run more efficiently. Fusco et al. also emphasize that wave power is relatively predictable, making grid management easier. Though more research is needed in order to identify the best arrangements of wind and wave power systems, it is clear that grouping these technologies will make Ireland’s energy goals more feasible and efficient.