Introduction
The integration of renewable energy into the PJM Interconnection system has increased steadily in the past several years, primarily as a result of renewable energy goals in most of the states within the PJM footprint. At the request of its stakeholders, PJM commissioned a study in May 2011 to understand the impacts to grid operations if renewable energy goals over the next 15 years are achieved or exceeded. An Executive Summary for the study is now available on the PJM website.
GE Energy, along with AWS Truepower, EnerNex, Exeter Associates, Intertek Asset Integrity Management, and PowerGEM led the study. The team used a combination of publicly available and confidential data to model the Eastern Interconnection PJM and the generating plants within PJM. Ten scenarios were chosen, ranging from a business-as-usual reference case with wind and solar resources at 2011 levels, to a scenario with 30% of energy over a year provided by wind and solar resources.
Characteristics explored
- Load, wind and solar profiles
- Regulating and operating reserves
- Transmission system upgrades
- The impact of renewables on annual PJM operations
- Sub-hourly operations and real-time market
- Capacity value of wind and solar
- Impact of cycling duty on Variable Operation and Maintenance (VOM) costs
- Power plant emissions
- Industry practices and experience on renewables integration
- Methods to improve system performance.
The study presented conclusions and recommendations, and identified topics for further study. It also assumed that the penetration of renewable resources would increase and investigated how the PJM system would be affected. The economics of renewable resources and quantifying the capital investment required to install additional wind and solar infrastructure were beyond the scope of this study and were not investigated. Similarly, the study did not evaluate distribution system impacts, potential voltage and frequency control issues, and costs to maintain resource adequacy (reserves).
Key Findings
The study mainly concluded that the PJM system, with adequate transmission expansion (up to $13.7 billion) and additional regulation reserves (up to an additional 1,500 MW), would not have any significant reliability issues operating with up to 30% percent of its energy (as distinct from capacity) provided by wind and solar generation. PJM has long held that ISOs and RTOs are better able to integrate variable energy resources because of their organized markets and regional infrastructure planning processes, but the study found that PJM’s large geographic footprint also provides significant benefit for integrating wind and solar generation because it greatly reduces the magnitude of variability-related challenges.
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