Wind &
Solar Capacity Market deratings

Case studies


In 2018 National Grid commissioned LCP to develop an approach to calculating the incremental EFCs (equivalent firm capacities) for wind and solar plants, with a view towards setting deratings for their participation in future capacity auctions.  

Our Unserved Energy Model (UEM) is a capacity assessment tool used by National Grid and BEIS for security of supply analysis. It stochastically simulates outages, demand and renewable generation across many thousands of simulations to provide a view on the likelihood, duration and severity of system security events.

Our solution

This project involved the development and implementation of a methodology within the UEM to calculate the contribution to system security provided by an incremental amount of different intermittent technologies. Separate EFCs are calculated for onshore wind, offshore wind and solar, and the data behind the calculation accounts for the geographic distribution of these plant.

The EFC for an incremental amount of capacity is typically lower than the average EFC of the fleet, as the contribution to system security diminishes as the penetration of an intermittent technology increases. For example, the twentieth GW of offshore wind has a lower contribution than the first GW, due to system security events on a system with 20GW of offshore wind being heavily driven by periods where there are low levels of wind.

The results

The results of this modelling were used to produce the "EMR Delivery Body Consultation - De-Rating Factor Methodology for Renewables’ Participation in the CM” final report by National Grid in January 2019.

We can help our clients with a wide range of issues from whole system modelling to individual power plant and policy impact analysis.

Strategic advice aimed at maximising the benefits and minimising the risks associated with the Capacity Market and Contracts for Difference.

We advise on the optimal dispatch of assets within the wholesale market, forward planning of maintenance activities and valuation of commercial upgrades to plant.

We provide detailed forecasts of the GB and Irish power markets, using our EnVision modelling framework. This can provide both short-term and long-term forecasts of all key system metrics, from system wide to individual assets.

We work extensively in the Irish market, providing market modelling and analysis to investors, generation owners and governments.

Our understanding of market dynamics and modelling experience allow us to offer evidence-based recommendations on complex policy and regulatory issues that allow fully informed decision-making.

We combine bottom-up unit-level modelling with market and policy insights to quantify the value and understand the risk associated with any generation asset. 

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