LT Plan Class

See also LT Plan Property Reference for a detailed list of properties for this class of object.

The settings that control the capacity expansion planning function in the simulator are defined on LT Plan objects. Below is a comprehensive guide to LT Plan.

Introduction

The term "capacity expansion" refers to the problem of finding the optimal combination of generation new builds and retirements and transmission upgrades (and retirements) that minimizes the net present value (NPV) of the total costs of the system over a long-term planning horizon. That is, to simultaneously solve a generation and transmission capacity expansion problem and a dispatch problem from a central planning, long-term perspective.

Capacity expansion is implemented via the LT Plan class of objects. The purpose of the LT Plan is then to solve the capacity expansion problem over the planning horizon-typically expected to be in the range of 10 to 30 years, though any horizon is possible. LT Plan appropriately deals with discounting and end-year effects.

LT Plan runs before the PASA/MT Schedule/ST Schedule phases. It is fully integrated with these other simulation phases. Thus, LT Plan can be run either separately or in sequence with these other simulation phases in a single simulation. In the latter role, the long-term build/retirement decisions made by LT Plan will be automatically passed down to the other phases, providing a seamless solution. In either role, the output of LT Plan can be accessed using the solution viewing functions. In addition the LT Plan build/retire decisions can be written to text file for use in subsequent simulations-see the setting Write Expansion Plan Text Files.

LT Plan can output the optimal expansion solution and optionally a hierarchy of sub-optimal solutions starting working down in solution quality.

LT Plan uses the same generic Constraint facility as other simulation phases. This means that complex unit staging, and other constraints can be modelled. Further, LT Plan provides the same capabilities as MT Schedule in modelling Emissions, Fuel constraints and Reserve. Like MT Schedule LT Plan can run in chronological mode or use Load Duration Curves (LDC) according to the LT Plan Chronology setting. In chronological mode LT Plan will capture the dynamic effects of intermittent generation and load uncertainty on generator cycling. Finally, LT Plan can be run in deterministic or stochastic modes. In stochastic mode it can be used to find the single optimal set of build decisions in the face of uncertainties in any input e.g. load, fuel prices, hydro inflows or wind generation.

The following types of expansion/retirement and features are supported:

Electric

• Building new generators
• Retiring existing generators
• Building new ac or dc transmission lines
• Retiring existing ac or dc transmission lines
• Adding new transmission flow control devices
• Expanding the capacity on existing transmission interfaces
• Taking up new physical generation contracts
• Taking up new physical load contracts
• Adding battery electric storage systems

Gas

• Developing new gas fields
• Building gas processing plants
• Building new gas pipelines
• Developing new gas nodes
• Adding gas storage

Water

• Building water processing plants
• Building new water pipelines
• Developing new water nodes
• Adding water storage

See:

• LT Plan - Formulation
• LT Plan - Problem Size
• LT Plan - Turning on LT Plan
• LT Plan - Expansion Candidates
• LT Plan - Timing and Staging Constraints
• LT Plan - Capacity Zones
• LT Plan - Capacity Interchange and Coincidence of Peak Loads
• LT Plan - Revenue Adequacy
• LT Plan - Monthly Build Decisions
• LT Plan - Depreciation Benefits
• LT Plan - Ancillary Services
• LT Plan - Stochastic Optimization

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