Using Power Monitor

Power Monitor's daemon runs in the background and measures power consumption every 5 seconds. You can launch the “Power Monitor” application to see the visualizations of the collected power consumption data. You will see the current system power consumption of your Mac, as well as the highest and an average value, and the current time that is being used for these calculations.

Settings

You can configure Power Monitor in the app's settings. In the General section you can set the app to run in background or to be opened automatically at login, set the energy price for a kilowatt hour (kWh) and delete all measurements.
If you choose to run Power Monitor in the background you have a permanent icon of a thunderbolt in the menu bar the displays the current and average system power used.

You can enable or disable Power Nap in the Power Nap section. Here you can also specify if you want Power Monitor to ignore Power Naps and not measure power consumption during these periods.

In the View Options section you can also customize Power Monitor's appearance. So you can hide/unhide the average line and markers for a day, highlight times your Mac took a Power Nap and customize the graph that is visualized.

You can show the carbon footprint of your Mac's power consumption too. This can be enabled in the Carbon Footprint section.

You can either import carbon intensity data using a CSV file as described or provide API keys for real-time data. This requires that you approve Location Services for the app. Power Monitor currently supports API keys from Electricity Maps. Please refer to the Managing Power Monitor section to read how to manage carbon intensity data using a macOS configuration profile.

The Journal section allows you to enable the journal function, which logs power consumption over a longer period of time. The automatic deletion of journal entries can also be configured here.