POWER GRIDS CAN ACCOMMODATE SUBSTANTIAL LEVELS OF WIND & SOLAR POWER
The purpose of the Hawaii Rewnewable Portfolio Standards (RPS) Study was to use modeling tools to identify and evaluate cost-effective pathways that support the growth of renewables on Oahu and Maui with a goal of achieving RPS targets and maintaining grid stability and reliability.
Based on the study results the following changes will need to be made to the current system in order to improve grid stability and reliability:
1. Include reserves to handle wind and solar variability
Grid operators carry “regulating reserves”, to offset potential short-term variability in renewable power, helping ensure grid stability. This reserve can come from thermal plants, demand response, storage and even wind and solar.
2. Reduce minimum operating levels on thermal power plants
As wind and solar generation increase, the output of other conventional generators is backed down to accommodate the renewable output. Modifications and upgrades that allow thermal units to operate at lower levels can save up to $80 million/year and accommodate up to an additional 110 MW per hour of renewables.
3. Remove must-run constraints and allow cycling of baseload units
As wind and solar penetration increase, in some scenarios, it could be more economical to turn thermal generation off. Unit cycling could reduce curtailment by up to 40% and save approximately $19 million per year in a high renewable scenario.
4. Use wind and solar to provide reserves
When a part of the grid trips offline, power plants have to adjust to keep the grid stable. Allowing renewables to provide reserves, the grid can save up to $50 million per year and integrate an additional 200 GWh of wind and solar. More