Review Of International Experience Integrating Variable Renewable Energy Generation

April 2007

A report released by the California Energy Commission (CEC) on the international experience with renewable energy integration found that integration costs tend to be less when wind resources are spread across larger areas.

The report, “Review of International Experience Integrating Variable Renewable Energy Generation,” was prepared for CEC by the firm Exeter Associates. The study referred to the cost of integrating wind as “non-zero”; that simply means, according to author Kevin Porter of Exeter Associates, who spoke to Wind Energy Weekly, “These costs are relatively modest—just not zero.”

According to the report, reserve costs attributed to wind integration (i.e., the need for backup resources, quick and unexpected ramp-up capabilities of an overall system, etc.) are relatively small at wind penetration levels of less than 20%. Wind integration costs are lessened when resources are spread across a wider area, such as in power pools and regional transmission organizations, the report said.

Porter also noted that while Europe is often thought of as a single entity with a unified experience, policies and electricity systems do vary significantly from country to country. For example, Denmark, a leader in wind power in terms of penetration, is part of a regional power pool, while other countries such as the island nation of Ireland have limited interties.

The report concludes that the U.S. and European experience is increasingly similar as renewable energy generation gains in market penetration. “These similarities are sparking information exchange and transfer through forums such as the [International Energy Agency], the Institute of Electrical and Electronics Engineers, and the Utility Wind Integration Group,” the report noted. “That, in turn, can help elevate prominent issues and make the task of developing solutions and options for integrating variable renewable energy generation easier.”