CALCULATORS / SOLAR AND RENEWABLE ENERGY

Solar-panel power and energy estimate calculator

Irradiance-scaled nameplate output with supplied aggregate derating.

solar-pv-output.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	outputW
	192
	153.6

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

power target192.00 W✓ passes

BASELINE INPUTS

ratedPower300 Wirradiance800 W/m^2reference1000 W/m^2derating0.8

CALCULATED

output192 W

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Solar-panel power and energy estimate
# Scope: Irradiance-scaled nameplate output with supplied aggregate derating.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

ratedPower = 300 W
irradiance = 800 W/m^2
reference = 1000 W/m^2
derating = 0.8

output := ratedPower*irradiance/reference*derating [W]

check power target: output >= 150 W

scenario alternative: ratedPower = 240 W

Calculated from your source · not saved

Baseline · Baseline

power target192.00 W ✓ passes

alternative · alternative

power target153.60 W ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

output: output = ratedPower*irradiance/reference*derating [W]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

rated power: 300 W
irradiance: 800 W/m^2
reference: 1000 W/m^2
derating: 0.8

Calculated

output: 192 W

Assumptions and limits

Irradiance-scaled nameplate output with supplied aggregate derating.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Solar-panel power and energy estimate. Inputs: rated power; irradiance; temperature; losses. Outputs: power; daily energy estimate. Model scope: Location/weather inputs or explicitly selected irradiation assumptions. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: rated power, irradiance, temperature, losses
Outputs: power, daily energy estimate
Modes: calculate, compare, sweep
Drawing: Energy and resource plots

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS