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

# Blocks

> Blocks help you organize project models by grouping related inputs, outputs, and functions into reusable, modular components.

## What is a Block?

A block is a container that includes two or more [terms](/docs/terms) (inputs or outputs) and may also contain one or more functions. Blocks help structure complex project models by grouping related logic together.

Blocks can represent:

* A subsystem (e.g., battery, solar panel, electrolyzer)
* A financing structure (e.g., tax equity, project finance, grants)
* A business model configuration (e.g., PPA, merchant, hybrid)

## Why Use Blocks?

Blocks are optional but recommended. They help you:

* **Stay organized**: Group related terms and functions together
* **Reuse logic**: Apply blocks across multiple projects or scenarios
* **Compare configurations**: Create and analyze cases of blocks
* **Work efficiently**: Reduce duplication and make updates easier

You can build blocks as you go, or restructure your model into blocks at any point in your workflow.

## Blocks in Scenarios

When you create a [scenario](/docs/scenario-analysis), anything in a block can differ from the base — term values, formulas, or structure. You can change a single input, rewire the logic entirely, or add blocks that don't exist in the base. The scenario is its own version of the model.

## Example: Solar Array Block

A solar array block might include:

* **Inputs**: System Size (MW), Panel Efficiency (%), Inverter Capacity (MW), Tilt Angle (degrees)
* **Outputs**: Annual Generation (MWh), Capacity Factor (%), Levelized Cost (\$/MWh)

You might compare bifacial versus monofacial panels, fixed-tilt versus tracking systems, or different module manufacturers by creating [scenarios](/docs/scenario-analysis) that vary the relevant terms—all while maintaining consistent block structure.

## Flexibility by Design

Blocks support multiple workflows. Some users start with fully modularized models, while others introduce blocks later as complexity grows. Both approaches work. You can:

* Add [terms](/docs/terms) directly to a project without blocks
* Group related terms into a block when structure helps
* Nest blocks within other blocks for complex systems
* Edit terms within or outside of block views

This flexibility lets you balance structure and speed depending on your project phase and modeling style.