The Value of Diversifying Uncertain Renewable Generation through the Transmission System
The true value of transmission for renewable generation
By Kai Van Horn (National Grid USA), Johannes Pfeifenberger (ISE, The Brattle Group), and Pablo Ruiz (ISE, NewGrid)
September 2020
Integrating the electric grid across broader geographic regions is widely seen as a cost-effective approach to incorporate large-scale wind, solar, and other forms of variable renewable energy. This study sought to achieve the difficult task of estimating the magnitude of those geographic diversification benefits as U.S. operators, planners, and policymakers prepare for an unprecedented increase in renewable energy production.
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Key Findings
- Transmission expansion can play a critical role in successfully integrating large-scale renewable generation under both forecasted day-ahead and real-time market conditions.
- The results of the analysis show the benefits of transmission expansion between areas with diverse renewable generation resources are substantial, with significant reductions in system-wide costs and renewable generation curtailments.
- For renewable generation levels from 10 percent to 60 percent of annual energy consumption, interconnecting two power market sub-regions with different wind regimes through transmission investments can reduce annual production costs up to 23 percent and annual renewable curtailments by as much as 90%.
- When real-time uncertainties of renewable generation and loads relative to their day-ahead forecasts are taken into consideration, the benefit of geographic diversification through the transmission grid is two to 20 times higher than benefits typically quantified based only on “perfect forecasts.”