Gas-Fired Power Plant Optimization (MILP)

This repository contains a mixed-integer linear programming (MILP) model for optimizing the operating schedule of a gas-fired power plant under operational constraints and uncertain future prices.

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Problem Description

We model a gas-fired power plant operating in the period December 31, 2021 – February 1, 2022, after which the unit enters a long-term maintenance outage.

Given multiple simulated forward price scenarios for:

• Power (€/MWh)
• Gas (€/MWh)
• CO₂ (€/ton)

the objective is to maximize total profit while respecting strict operational constraints, including:

• Limited number of starts
• Limited total running hours
• Minimum and maximum generation levels
• Start-up costs and energy consumption depending on downtime duration

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Key Technical Parameters

• Maximum capacity: 400 MW
• Minimum stable generation: 220 MW
• Remaining starts available: 15
• Remaining running hours available: 250
• Initial condition: plant is running at the beginning of the horizon

Start-up Types

Start-up behaviour and resource consumption depend on the number of hours the unit has been offline:

Hours offline	Start Type	Power produced during start (MWh)	Gas consumed during start (MWh)	CO₂ emitted during start (t)
≤ 10	Type 1	75	190	35
11 – 35	Type 2	190	700	130
> 35	Type 3	210	800	150

Start-up energy, gas and CO₂ emissions are accounted for in the hour before the unit reaches minimum stable generation.

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Model Overview

The problem is formulated as a Mixed-Integer Linear Program (MILP) and solved using PuLP + CBC solver.

Main Decision Variables

• is_on[t] – binary: plant is producing power in hour t
• start[t] – binary: plant starts in hour t
• start_type_1[t], start_type_2[t], start_type_3[t] – mutually exclusive start type indicators
• gen_above_min[t] – continuous: generation above minimum stable level (MW)
• consecutive_off_hours[t] – auxiliary variable for tracking downtime

Objective Function

Maximize total profit over the horizon:

Profit = Power revenue − Gas cost − CO₂ cost

Revenue and cost terms include:

• Hourly generation revenue (including start-up power if credited)
• Start-up fuel and CO₂ costs
• Running fuel and CO₂ costs

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