physics

Spark spread

Spark spread is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Spark spread rather than just read about it. In short: The spark spread is the theoretical gross margin of a gas-fired power plant from selling a unit of electricity, having bought the fuel required to produce this unit of electricity. All other costs (operation and maintenance, capital and other financial costs) must be covered from the spark spread.

Key takeaways

Spark spread belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Spark spread to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Spark spread from memory before moving on to harder problems.

Reference excerpt

The spark spread is the theoretical gross margin of a gas-fired power plant from selling a unit of electricity, having bought the fuel required to produce this unit of electricity. All other costs (operation and maintenance, capital and other financial costs) must be covered from the spark spread. The term was coined by Tony West's trading team on the trading floor of National Power Ltd in Swindon, UK during the late 1990s and quickly came into common usage as other traders realised the trading and hedging opportunities. The terms dark spread, quark spread and bark spread refer to the similarly defined differences ("spreads") between cash streams for coal-fired power plants, nuclear power plants and bio-mass power plants, respectively. These indicators of power plant economics are useful for trading energy markets. For operating or investment decisions published "spread" data are not applicable. Local market conditions, actual plant efficiencies and other plant costs have to be considered. A higher dark spread is more economically beneficial to the owner of the generator; an IPP with a dark spread of €15/MWh will be more profitable than a competitor with a dark spread of only €10/MWh. Further definition of clean spread indicators include the price of carbon dioxide emission allowances (see: Emission trading).

Definition of spark spread Conceptually, the spark spread (SS in megawatt-hours) equals:

Electricity total value minus fuel total cost, divided by the megawatt-hours of electricity delivered, equals spark spread in $/MWh A more refined version of this calculation may be:

S S = p E − p G η e l = p E − H R ⋅ p G {\displaystyle SS=p_{E}-{\frac {p_{G}}{\eta _{el}}}=p_{E}-HR\cdot p_{G}}

with pE as price of electricity in MU/MWh pG as price of natural gas in MU/MWh or MU/Btu ηel as electrical efficiency resp. HR as heat rate in Btu/MWh While the above equations may be sufficient for a single power plant or electricity provider, more detailed calculations may needed depending on the analysis being performed. If the data is sourced from futures contracts for fuels and over-the-counter contracts for electricity, further calculations must be made to determine the appropriate hedge ratio of electricity to fuel. A precise definition of a spark spread has to be given by the source publishing such indicators. Definitions should specify energy (electricity and fuel) prices considered (delivery point & conditions) and the plant efficiency used for the calculation. Also, any plant operating costs that may be included should be stated. Typically, an efficiency of 50 % is considered for gas-fired plants, and 36% for coal-fired plants. In the UK, a non-rounded efficiency of 49.13% is used for calculating the gas conversion. In reality, each gas-fired plant has a different fuel efficiency, but 49.13% is used as a standard in the UK market because it provides an easy conversion between gas and power volumes. The spark spread value is therefore the power price minus the gas cost divided by 0.4913, i.e. Spark Spread = Power Price – (Gas cost/0.4913). As of August 2006, UK dark spreads were in the range of 10–30 £/MWh, while UK spark spreads were in the range of 4–9 £/MWh. It is well-known that these values substantially understate the actual efficiency of modern plants. Best-in-class efficiencies (as of 2019) are near 64%, and commercial development is rapid.

Clean spread In countries that are covered by the European Union Emissions Trading Scheme, generators have to consider also the cost of carbon dioxide emission allowances that will be under a cap and trade regime. Emission trading has started in the EU in January 2005. The Clean Spark Spread is calculated using a gas emissions intensity factor of 0.411 tCO2/MWh. Therefore, the clean spark spread is calculated by subtracting the carbon price per tonne (multiplied by 0.411) from the ‘dirty’ spark spread, i.e. Clean Spark Spread = Spark Spread – (Carbon Price*0.411). Clean spark spread or "spark green spread" represents the net revenue a generator makes from selling power, having bought gas and the required number of carbon allowances. This spread is calculated by adjusting the cost of natural gas for the efficiency of the generation and subsequently applying the market cost of procuring or opportunity cost of setting aside an emissions allowance such as a European Union Allowance (EUA) in the European Union Emissions Trading Scheme (EU ETS). Let S: spark spread, E: electricity price, G: gas cost, Ng: number of carbon credits necessary to cover gas operation, Pcc: price of a carbon credit. Then the Clean spark spread is defined as

C l e a n S p a r k S p r e a d = p E − p G η e l − N g ∗ P c c {\displaystyle CleanSparkSpread=p_{E}-{\frac {p_{G}}{\eta _{el}}}-Ng*Pcc}

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Spark spread

Start with the simplest possible case. Write down what Spark spread claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Spark spread before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Spark spread ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Spark spread

In research: Spark spread appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Spark spread in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Spark spread is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electric power generation, Electricity economics, Energy in the United Kingdom, so understanding it makes those chapters shorter.
In everyday life: Look for Spark spread outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Spark spread in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Spark spread means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Spark spread out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Spark spread in simple terms?

Why does Spark spread matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Spark spread?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Spark spread.