Available Capacity: A Guide to Understanding Transfer and Offtake Capacity Calculations

When planning large-scale energy or data center projects, understanding transfer and offtake capacity is critical. These calculations determine how much power can flow efficiently through the grid or be utilized on-site without exceeding infrastructure limits. Yet, for many developers, navigating the complexities of available capacity can feel overwhelming.

This guide breaks down the essentials of transfer and offtake capacity calculations, giving energy and data center developers the clarity they need to make informed decisions. Whether you're assessing grid connection options or planning for future scalability, we’ll walk you through the key concepts step-by-step.

Available Capacity: A Key Factor in Grid-Connected Projects

Available capacity is a critical consideration when developing projects intended to connect to the power grid. For generation projects like Solar, Wind, and Battery Energy Storage Systems (BESS), Available Transfer Capacity is essential for injecting additional electricity into the grid. Similarly, large energy-consuming projects such as Data Centers and Crypto Mining facilities need Available Offtake Capacity to secure the necessary power for their operations.

Available Transfer Capacity vs. Available Offtake Capacity

While Available Transfer Capacity and Available Offtake Capacity are similar calculations, they serve different purposes depending on the nature of the project.

For developers of generation projects, the focus should be on Available Transfer Capacity at the nearest substation. This capacity refers to the maximum amount of additional power that can be transferred through the network without violating grid constraints. If a project exceeds the available transfer capacity, the developer may be required to fund network upgrades, which can significantly increase project costs. These potential upgrade costs are estimated through platforms like LandGate, which can also provide information on multiple transfer limits for each substation.

On the other hand, projects with high energy demand, such as data centers and crypto mining facilities, focus on Available Offtake Capacity. This value indicates the maximum amount of power that can be reliably sourced from the grid at a particular interconnection point. Unlike generation projects, these energy-intensive developments are typically not responsible for covering the costs of network upgrades. However, delays in network upgrades can affect the interconnection timeline, potentially pushing back project development. Therefore, securing sufficient Available Offtake Capacity is essential for ensuring a smooth and timely project rollout.

How Are These Capacity Values Calculated?

Calculating Available Transfer and Offtake Capacity across the country is a complex and lengthy process. Both calculations start with mapping the transmission network, which includes substations, transmission lines, transformers, and other essential components. Each Independent System Operator (ISO) or Regional Transmission Organization (RTO) sets different load demand and generation base-case scenarios for multiple future years.

Power engineers at LandGate then run sophisticated simulations for both Transfer and Offtake Capacity. These simulations account for potential contingencies, ensuring the system remains stable even in the event of unexpected failures like line outages or generator trips.

The final calculations yield two distinct values:

• Available Transfer Capacity: This represents the maximum additional power that can be safely transferred between different areas of the grid without violating operational constraints.

• Available Offtake Capacity: This value indicates the maximum load that can be reliably supported at each interconnection point on the grid, ensuring the system can handle increased demand without compromising reliability.

Impact of Available Capacity

Understanding Available Transfer and Available Offtake Capacity is crucial for the success of any project connected to the power grid. Developers of generation projects must ensure they have sufficient Available Transfer Capacity to avoid costly network upgrades. Meanwhile, high-demand projects like data centers and crypto mining facilities must prioritize securing enough Available Offtake Capacity to avoid delays and ensure timely project completion. By understanding and planning for these capacities, developers can navigate the complexities of grid connection and optimize their projects' success.

To learn more, book a demo with our dedicated energy markets team.