---
title: "Interval Calculations"
slug: "interval-expressions"
updated: 2025-07-16T14:07:04Z
published: 2025-07-16T14:07:04Z
canonical: "docs.bazefield.com/interval-expressions"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bazefield.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Interval Calculations

## Overview

**Interval Calculations** are a type of **Calculated Point** in Bazefield that compute values at fixed time intervals using the **Bazefield Calculation Service**. These calculations are ideal for generating **time-based KPIs**, summaries, and performance metrics that are stored for historical analysis and reporting.

---

## Key Characteristics

- **Scheduled Execution**: The calculation runs at regular intervals (e.g., every 5 or 15 minutes).
- **Expression-Based Logic**: Uses arithmetic, built-in functions, and references to other points.
- **Recalculable**: Logic can be updated and recalculated at any time, over any time period.
- **Long-Term Storage**: Results are saved to the **Bazefield IMATIS database** or an **external database** like PostgreSQL.

> [!WARNING]
> Interval Calculations provide enough functionality for most KPIs but if more complexity is required for the use case, a [Calculation Model](/product/docs/calculation-models) may be a better fit.

---

## Examples

### ℹ️ Average Active Power (5-minute interval)

A point named **ActivePowerAvg** is configured for a Wind Turbine model as follows:

- **Point Type**: `CALCULATED_POINT`
- **Script Type**: `Interval_Calculation`
- **Expression**: `([@ActivePower]) == 0 ? Double.NaN : TagTimeAvg([@ActivePower]:[Double.NaN])`
- **Interval**: `300 seconds` (5 minutes)
- **SaveAtIntervalStart**: `True` (to log the output timestamp at the beginning of the interval)
- **Data Template**: `IMATIS` (interval data should be stored in the Bazefield IMATIS database)

This configuration will output NaN if there are no raw ActivePower values in the last 5 minutes, and the time-weighted average of the raw ActivePower values in the last 5 minutes otherwise.

![](https://cdn.document360.io/a0786c0f-b171-4b24-8860-c32eb7ef2738/Images/Documentation/image(219).png?sv=2026-02-06&spr=https&st=2026-11-06T20%3A45%3A47Z&se=2026-11-06T21%3A45%3A47Z&sr=c&sp=r&sig=FY6U8lCPAlKaX2RtEWMyv%2FU4FGIvWrH%2BDKURVDaX4vs%3D)

### ℹ️ Energy Produced in Last 5 minutes

A point named **TotalEnergyProduced.5m** is configured for a Wind Turbine model as follows:

- **Point Type**: `CALCULATED_POINT`
- **Script Type**: `Interval_Calculation`
- **Expression**: `{TagTimeAvg([@ActivePower]:[Double.NaN])/12}`
- **Interval**: `300 seconds` (5 minutes)
- **SaveAtIntervalStart**: `True` (to log the output timestamp at the beginning of the interval)
- **Data Template**: `IMATIS` (interval data should be stored in the Bazefield IMATIS database)

This configuration will compute the time-weighted average of the raw ActivePower values in the last 5 minutes, then divide by 12 to convert from kW to kWh (there are 12 5-minute periods in 1 hour). This is an estimation but a rather accurate one.

![](https://cdn.document360.io/a0786c0f-b171-4b24-8860-c32eb7ef2738/Images/Documentation/image(221).png?sv=2026-02-06&spr=https&st=2026-11-06T20%3A45%3A47Z&se=2026-11-06T21%3A45%3A47Z&sr=c&sp=r&sig=FY6U8lCPAlKaX2RtEWMyv%2FU4FGIvWrH%2BDKURVDaX4vs%3D)

### ℹ️ Turbine Capacity Factor

A point named **Capacity** is configured for a Wind Turbine model as follows:

- **Point Type**: `CALCULATED_POINT`
- **Script Type**: `Interval_Calculation`
- **Expression**: `{100 * Max(TagLast([@ActivePowerAvg]:[Double.NaN]), 0) / GetAttribute(“ratedPower”)}`
- **Interval**: `300 seconds` (5 minutes)
- **SaveAtIntervalStart**: `True` (to log the output timestamp at the beginning of the interval)
- **Data Template**: `IMATIS` (interval data should be stored in the Bazefield IMATIS database)

This configuration build on the ActivePowerAvg point by retrieving its last value (setting it to 0 if it is negative), then dividing this by the Turbine’s ratedPower attribute. Finally, this value is multiplied by 100 to get a percent Capacity Factor.

![](https://cdn.document360.io/a0786c0f-b171-4b24-8860-c32eb7ef2738/Images/Documentation/image(222).png?sv=2026-02-06&spr=https&st=2026-11-06T20%3A45%3A47Z&se=2026-11-06T21%3A45%3A47Z&sr=c&sp=r&sig=FY6U8lCPAlKaX2RtEWMyv%2FU4FGIvWrH%2BDKURVDaX4vs%3D)

---

## Key Benefits

✔️ **Historical Insight**: Enables trend analysis and long-term performance tracking.

✔️ **Custom KPIs**: Tailor calculations to your operational goals.

✔️ **Database Integration**: Store results in the Bazefield database or external systems for BI/reporting.

✔️ **Scalable**: Apply across fleets, technologies, and vendors.

---

## When to Use Interval Calculations

Use Interval Calculations when:

- You need **aggregated values** over time (e.g., averages, totals).
- You want to **store regularly-spaced results** for dashboards, reports, or compliance.
- Real-time updates are **not required** for the use case.