> For the complete documentation index, see [llms.txt](https://docs.voltmasters.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.voltmasters.io/voltmasters-platform/10.-project-settings/10.11-energy-contracts.md). # Energy contracts The energy contract tells the EMS how the market translates into the prices it actually plans against. The EMS never acts on a raw market price directly: your contract determines how each quarter-hour becomes a **net consumption price** (what you pay to import) and a **net injection price** (what you earn or pay to inject). Those two net prices drive every price-based decision, including [curtailment](/voltmasters-platform/10.-project-settings/10.3-curtailment.md) and [cost optimization](/control-algorithms/cost-optimization.md). You configure the contract under **Configuration → Grid & market → Energy contract** (see [Project settings](/voltmasters-platform/10.-project-settings/10.5-project-settings.md#energy-contract)). {% hint style="info" %} When you save a new contract, the platform recalculates the upcoming energy prices for this project. Prices already in the past keep the values they were calculated with, so a chart can show market-following prices up to the switch and the new contract's prices afterwards. {% endhint %} ### Contract types | Type | How prices are determined | | ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **Dynamic** | Follows the quarter-hourly / hourly day-ahead market (EPEX spot). Net prices are derived from the market price via scaling factors and fixed cost components. Best suited for the [Cost Optimisation](/voltmasters-platform/10.-project-settings/10.5-project-settings.md) strategy. | | **Flexible** | A fixed price per MWh that your supplier revises periodically (for example monthly or quarterly). Between revisions it behaves like a fixed contract. | | **Fixed** | A single price per MWh agreed in advance for the whole contract and independent of the market. | | **Fixed (Spain — time-of-use)** | A Spanish access tariff (3.0 TD / 6.1 TD / 6.2 TD) with a different fixed price per **tariff period** (P1–P6). Only available for projects located in Spain. | ### Dynamic The net prices are computed from the market price with your scaling factors and per-MWh costs. The exact formulas and a worked example are documented in [Energy price calculation](/voltmasters-platform/10.-project-settings/10.8-energy-price-calculation.md). If you leave a parameter blank, the EMS falls back to default values. ### Fixed and Flexible You enter a single **consumption price** and **injection price** in €/MWh. Every quarter-hour uses the same value, so the price line is flat and independent of the market. A *Flexible* contract works identically; re-enter the price whenever your supplier revises it. ### Fixed (Spain — time-of-use) In Spain, fixed tariffs are not a single price. Under CNMC Circular 3/2020 (Iberian Peninsula), every quarter-hour is classified into one of six **tariff periods**, from **P1** (most expensive) to **P6** (cheapest), and each period has its own price. This contract type lets you enter one fixed price per period; the platform automatically applies the correct period to each quarter-hour based on the date and time. {% hint style="info" %} This contract type only appears in the dropdown for projects whose country is set to Spain. {% endhint %} You enter **six prices** (€/MWh), one per period P1–P6. The period that applies to a given quarter-hour depends on three factors, evaluated in Spanish local time (Europe/Madrid): **1. Day type** * **Weekends and national holidays** → the whole day is **P6**. * **Working days** → the period depends on the season and the hour (below). **2. Time block (working days)** | Block | Hours | Result | | ------------ | ---------------------------------------- | ------------------------------ | | **Peak** | 09:00–14:00 and 18:00–22:00 | Peak period for the season | | **Shoulder** | 08:00–09:00, 14:00–18:00 and 22:00–24:00 | Shoulder period for the season | | **Valley** | 00:00–08:00 | Always **P6** | **3. Season (by month)** | Season | Months | Peak block → | Shoulder block → | | ----------- | --------------------------------- | ------------ | ---------------- | | High | January, February, July, December | **P1** | **P2** | | Medium-high | March, November | **P2** | **P3** | | Medium | June, August, September | **P3** | **P4** | | Low | April, May, October | **P4** | **P5** | In practice this means a working day uses **three** prices — the night/valley (P6) plus the season's peak and shoulder period — while a weekend or national holiday uses a **single** price (P6). The national holidays that count as all-day P6 are the fixed-date Spanish electrical holidays: | Date | Holiday | | ----------- | --------------------- | | 1 January | New Year's Day | | 6 January | Epiphany | | 1 May | Labour Day | | 15 August | Assumption | | 12 October | National Day | | 1 November | All Saints' Day | | 6 December | Constitution Day | | 8 December | Immaculate Conception | | 25 December | Christmas Day | {% hint style="warning" %} Movable feasts without a fixed calendar date (Good Friday, Holy Thursday, etc.) and regional/local holidays are **not** treated as P6 — they follow the normal working-day rules, in line with the CNMC fixed-date definition. {% endhint %} **Injection.** Under these Spanish contracts, energy is not sold back to the grid, so the **injection price is always 0**. {% hint style="info" %} The underlying spot data for Spain is sourced from the ENTSO-E transparency platform (the Spanish bidding zone), which reflects the same day-ahead market outcome as OMIE. For a *fixed time-of-use* contract the spot price is not used for pricing — only the tariff period of each quarter-hour matters. {% endhint %} ### Where these prices are used * [**Curtailment**](/voltmasters-platform/10.-project-settings/10.3-curtailment.md): PV production is limited when the net injection price is negative. * [**Cost optimization**](/control-algorithms/cost-optimization.md): the battery is charged and discharged based on the net consumption and injection prices across the forecast. * [**Energy price calculation**](/voltmasters-platform/10.-project-settings/10.8-energy-price-calculation.md): the formulas that turn a dynamic contract's market price into net prices. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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