Background
A national transmission owner and system operator in a semi-arid country was responsible for maintaining grid reliability, economic dispatch, and integration of new generation capacity. In recent years, the system experienced rapid growth in wind and solar generation, driven by energy security objectives and declining renewable costs.
As renewable penetration increased, system operations became more complex, requiring new tools and approaches to manage variability while maintaining reliability and cost efficiency.
Challenge
The rapid expansion of wind and solar generation introduced high variability, steep ramp rates, and limited visibility of distributed (“hidden”) renewable output across the grid.
This resulted in:
- Inaccurate forecasting of net load and renewable generation
- Inefficient dispatch decisions
- Increasing renewable curtailment
- Escalating financial exposure under take-or-pay power purchase agreements (PPAs)
At a system level, the utility was increasingly paying for energy it could not efficiently utilize
Without improved forecasting, operational visibility, and system flexibility, the grid faced:
- Reduced reliability
- Higher production and balancing costs
- Constraints on further renewable integration
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Solution
EPE implemented a phased advisory programme focused on improving both operational decision-making and long-term planning capability.
The approach combined forecasting, modelling, and commercial advisory to directly address curtailment and cost exposure.
Key elements included:
- Enhanced net-load and renewable forecasting methods
- Centralised data and telemetry improvements to improve system visibility
- Security-constrained unit commitment (SCUC) production cost modelling
- Curtailment quantification and financial exposure analysis
- Operational mitigation strategies, including reserve optimisation and dispatch improvements
- PPA technical and commercial advisory to address contractual inefficiencies
- Development of a benefit-cost-based energy storage roadmap, including sizing, siting, and pilot project recommendations
This integrated approach linked system operations, market dynamics, and infrastructure planning into a unified decision-making framework.
Key Insight
The primary constraint was not renewable capacity itself, but the system’s ability to forecast, dispatch, and absorb variable generation efficiently.
Curtailment and cost exposure were symptoms of limited visibility and operational flexibility, rather than insufficient generation or infrastructure.
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Result
The utility gained improved forecast accuracy, enhanced operational visibility, and data-driven planning tools to manage renewable integration more effectively.
This enabled:
- Reduction in unnecessary renewable curtailment
- Improved dispatch efficiency and reserve management
- Quantification and mitigation of financial exposure under PPAs
- Establishment of a practical, phased energy storage investment strategy
Collectively, these improvements:
- Reduced system-level inefficiencies
- Lowered operational costs
- Strengthened grid reliability
- Created a scalable pathway for integrating higher levels of renewable energy
Why It Mattered
As renewable penetration increases, grid operators must balance variability, cost, and reliability in real time.
This engagement enabled the utility to move from reactive operations to proactive, data-driven system management, improving both economic performance and the grid’s ability to absorb future renewable capacity.