SearchLearning | Valuation Pricing Analytics
How to Value Tolling Agreements
Introductory Summary
A tolling agreement gives its holder the contractual right to control the commercial operation of a generating asset under agreed contractual terms, without owning the underlying power station.
Rather than simply purchasing electricity, the holder acquires contractual control over how the generating asset is commercially operated. Depending on the agreement, this may include responsibility for fuel procurement, operating costs, dispatch decisions, or other commercial obligations associated with the plant.
For a broader explanation of how these agreements work, see What is a Tolling Agreement?
Whether the plant should operate at any point in time depends on continually changing market conditions.
The central valuation challenge is therefore not determining the value of a fixed series of cashflows. It is determining when the plant should operate, how much it should generate, and whether operating today creates more value than preserving flexibility for tomorrow.
For this reason, tolling agreements are fundamentally optimisation problems that combine electricity prices, fuel costs, operational constraints, and market uncertainty to determine the economically optimal dispatch strategy.
Understanding these optimisation techniques is essential for organisations involved in electricity generation, structured energy contracts, virtual power plants, and flexible energy portfolios.
Objective of Tolling Agreement Valuation
The objective of tolling agreement valuation is to determine the operating strategy that maximises the commercial value of the agreement over its remaining life.
Unlike many financial contracts, the value does not arise from predetermined payments. Instead, value is created by making a sequence of operating decisions as market conditions evolve.
Each dispatch decision affects future opportunities, fuel consumption, operating costs, equipment availability, and the flexibility available in subsequent periods.
Valuation therefore requires identifying the operating strategy that delivers the greatest overall economic outcome while respecting both contractual obligations and the physical characteristics of the generating asset.
Why Tolling Agreements Are Different
Although tolling agreements are often described as contracts, they behave much more like operating assets. Rather than valuing contractual cashflows, practitioners are effectively valuing the right to control the operation of a power station.
This introduces decisions that do not arise in simpler contracts. Typical considerations include:
- whether to start or shut down the plant;
- whether to remain offline;
- ramp-rate constraints;
- how much electricity to generate;
- how rapidly output can change; and
- how today’s operating decision affects tomorrow’s opportunities.
These decisions depend on continually changing electricity prices, fuel prices, emissions costs, and the physical capabilities of the generating unit.
The valuation therefore becomes an optimisation of dispatch rather than simply a pricing exercise.
The Spark Spread Drives Commercial Value
One of the most important concepts in tolling agreement valuation is the spark spread. The spark spread represents the economic margin available from converting fuel into electricity. In simple terms, it compares the revenue earned from selling electricity with the cost of purchasing the fuel required to produce it.
When this margin is sufficiently positive, operating the plant may be economically attractive. When it is negative, remaining offline may be the better commercial decision.
In practice however, modern valuation models extend this concept considerably further. Additional factors commonly incorporated include:
- variable operating costs;
- carbon or emissions costs;
- start-up fuel consumption;
- auxiliary power requirements;
- maintenance impacts; and
- other plant-specific operating costs.
Rather than asking whether electricity prices are ‘high’, practitioners ask whether operating the generating unit creates greater economic value than waiting for potentially better market opportunities.
Dispatch Optimisation Sits at the Centre of Valuation
The commercial value of a tolling agreement is determined by the quality of its dispatch decisions. Every potential operating period requires the optimisation model to evaluate multiple alternatives.
For example:
- start the generating unit;
- continue operating;
- increase output;
- reduce output;
- temporarily idle the plant; or
- shut the unit down completely.
Each decision influences future operating flexibility. The optimisation therefore evaluates the entire operating horizon rather than making isolated decisions period by period. This sequential decision-making process is one of the defining characteristics of tolling agreement valuation.
Physical Constraints Matter
Unlike purely financial derivatives, generating assets operate within physical limits that strongly influence commercial value. Common operational constraints include:
- minimum stable generation;
- maximum generation capacity;
- ramp-rate limits;
- minimum up-times;
- minimum down-times;
- start-up costs;
- shut-down costs;
- heat-rate characteristics;
- maintenance schedules; and
- plant availability.
These constraints mean the economically optimal dispatch is not always the one suggested by prices alone.
For example, a brief period of favourable electricity prices may not justify starting a generating unit once start-up costs, minimum run-times and expected future market conditions are considered. Likewise, technical limitations may prevent a plant from immediately increasing output to capture short-lived price spikes.
Representing these physical characteristics accurately is therefore essential for realistic valuation.
Common Valuation Approaches
Although every methodology seeks to identify the optimal dispatch strategy, the techniques used vary according to the level of sophistication required.
Intrinsic Valuation
Intrinsic valuation assumes today’s forward curve represents the future with certainty. Using current forward prices, the optimisation determines the dispatch schedule that maximises value while respecting all operating constraints.
The result provides an important benchmark because it reflects the value available if market expectations never changed. However, intrinsic valuation cannot capture the additional value created by future price uncertainty.
Rolling Intrinsic Valuation
Rolling intrinsic valuation recognises that forward curves evolve through time. Rather than relying on a single optimisation, the dispatch schedule is recalculated as market information changes.
Although each optimisation remains deterministic, repeated re-optimisation allows operating decisions to adapt to changing market conditions and generally provides a more realistic approximation of practical plant operation.
Stochastic Valuation
Where operational flexibility represents a significant source of commercial value, stochastic valuation often provides the most complete representation. Rather than assuming one future market outcome, stochastic methods evaluate many possible electricity and fuel price paths.
Depending on the valuation framework, these future market states may be represented using lattice techniques such as binomial or trinomial trees or through large-scale Monte Carlo simulation.
Across every possible market scenario, the optimisation determines the dispatch strategy that maximises commercial value while satisfying all operational constraints.
Because operating decisions adapt to changing market conditions, stochastic valuation captures both the intrinsic value visible in today’s forward curve and the additional ‘extrinsic’ value created by future uncertainty.
The Questions the Valuation Model Must Answer
Every tolling agreement valuation ultimately attempts to answer a series of interconnected operational and commercial questions. What market information is available today? What operating flexibility remains? Which dispatch decisions are physically feasible? Which sequence of decisions produces the greatest economic value?
Although different valuation methodologies answer these questions in different ways, they generally require the same core analytical inputs.
Step 1: Define the Commercial Agreement
The valuation begins by identifying the commercial structure of the tolling agreement.
Typical inputs include:
- contract term;
- fuel supply arrangements;
- electricity delivery obligations;
- pricing mechanisms;
- operating responsibilities;
- emissions obligations;
- maintenance provisions; and
- contractual operating restrictions.
These commercial terms establish the rights, obligations, and operating flexibility available throughout the life of the agreement.
Step 2: Model the Generating Asset
The physical characteristics of the generating plant must then be represented within the valuation model.
Depending on the generating technology, these may include:
- generating capacity;
- heat-rate characteristics;
- minimum stable generation;
- ramp-rate constraints;
- minimum up-times and down-times;
- start-up and shut-down costs;
- auxiliary consumption;
- maintenance schedules; and
- plant availability.
Together, these characteristics determine the operational decisions available to the optimisation engine.
Step 3: Construct the Market View
The valuation then combines the physical model with current market information.
Typical market inputs include:
- electricity forward curves;
- fuel forward curves;
- emissions prices;
- interest rates (where applicable);
- volatility assumptions for stochastic valuation; and
- other market calibration data.
The quality and consistency of these inputs have a direct influence on valuation quality.
Step 4: Optimise Plant Dispatch
The optimisation engine determines the economically optimal operating strategy across the remaining life of the agreement.
Rather than assuming a fixed generation schedule, the model continually evaluates whether the plant should:
- remain offline;
- start generating;
- continue operating;
- adjust output; or
- shut down.
For intrinsic valuation, this optimisation is performed using today’s observable forward curves. For stochastic valuation, the optimisation is evaluated across many possible future market scenarios.
The resulting dispatch strategy determines both the operational behaviour of the plant and the commercial value of the tolling agreement.
Matching the Valuation Method to the Commercial Problem
Different valuation approaches answer different commercial questions.
Intrinsic valuation is often sufficient when the objective is daily reporting, benchmarking, or understanding the value implied by today’s observable forward curves.
Where commercial decisions depend heavily on future market uncertainty, more sophisticated stochastic approaches provide additional insight by recognising that dispatch strategies can adapt as prices evolve.
Rather than asking which methodology is ‘best’, experienced practitioners usually ask which approach is most appropriate for the decision they are trying to support.
Common Pitfalls and Misconceptions
Tolling Agreements Can Be Valued Like Forward Contracts
Forward contracts have predetermined cashflows. Tolling agreements create value through operational decision-making.
Treating a tolling agreement as a simple financial contract ignores the operational flexibility that creates much of its economic value.
High Electricity Prices Always Mean the Plant Should Operate
Not necessarily. Dispatch decisions depend on the complete economic margin after considering fuel costs, emissions costs, operating costs, start-up costs, and the technical capabilities of the generating unit.
The highest electricity price does not always produce the highest commercial outcome.
Dispatch Optimisation Is Separate from Valuation
For tolling agreements, optimisation and valuation are inseparable. The value of the agreement is determined by identifying the operating strategy that maximises commercial value over the remaining life of the contract.
Managing Tolling Agreement Valuation in Practice
Developing an accurate valuation model is only part of the challenge.
Organisations also need confidence that valuations remain consistent as market data changes, forward curves are updated, new generating assets are introduced, and commercial assumptions evolve over time.
Maintaining that consistency across trading, risk, finance, and commercial teams becomes increasingly important as portfolios expand and analytical requirements become more sophisticated.
Applications such as Lacima Trader enable traders, analysts, and quantitative teams to perform sophisticated dispatch optimisation, valuation, and scenario analysis efficiently within Microsoft Excel using existing market data, forward curves, and plant models.
One-Sentence Takeaway
Tolling agreement valuation is fundamentally an optimisation problem that determines the operating strategy which maximises the commercial value of a generating asset while respecting its physical constraints and responding to changing market conditions.
Related Learning Resources
Understand how tolling agreements transfer operational control of a generating asset without transferring ownership.
Learn how spark spreads measure the economic margin between electricity prices and fuel costs, and why they underpin thermal generation economics.
What is Monte Carlo Simulation?
Discover how Monte Carlo simulation represents uncertain future market conditions when valuing assets with embedded optionality.
What is a Trinomial Tree Model?
Explore how trinomial trees evaluate optimal operating decisions across many possible future market states.