In July, several experts in the operation of the power systems of Denmark, Germany, and Spain gave presentations on how their countries handle integrating large amounts of wind and solar power. Because of their variable nature, these renewable resources can present unique challenges for power systems.
These countries have aggressive government policies to develop renewable resources and reduce carbon emissions, and as a result, they've achieved a high degree of renewables in their energy mix. Wind and solar represent 24 percent of the total installed generating capacity in Spain; 27 percent in Germany, and 28 percent in Denmark. In comparison, the Bonneville Power Administration's balancing authority has 10 percent, and for the Pacific Northwest as a whole, 9 percent.
Some key features that have helped integrate variable resources into their systems are:
- Robust and fluid power exchange markets that access the full balancing capability of these systems
- Strong interconnections and common business practices among transmission system operators enabling them to share balancing reserves
- Wide geographic distribution of wind and solar facilities resulting in less volatility than in the Pacific Northwest
- Sophisticated wind forecasting
While these TSOs have been successful in integrating large amounts of renewables, some of the emerging issues as more variable resources come on line include:
- Increasing episodes of over-generation
- Increasing frequency of negative wholesale prices
- Increasing volatility of wind and solar output
- Transmission congestion
- Increasing penetration of uncontrolled generation
- High wholesale power prices compared to the Pacific Northwest
While we're unlikely, in the short term, to duplicate the institutional structures that have helped these TSOs successfully integrate variable renewable resources, we can work to improve things like our forecasting, transmission, access to balancing reserves, and the geographic diversity of facilities that will help accommodate increasing renewable development.
The wind integration forum has the latest information on how the region plans to do this.