This is already a feature. Just click on the module and it gets "greyed out" while the power draw is updated below for the modules you turn off. It may not be immediately apparent that you can click the moduels esp. if you come from using ED Shipyard where each module has an obvious checkbox.
Hmm, I'll try on Windows tomorrow, but it doesn't work on Mac. When I click on a module, it just expands the box when I can select the item type and/or class, but I can't find a way to disable the modules.
Edit: ah, got it! You have to clic on the items in the list, of course. Thank you!
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