A lot of people with disabilities need reliable access to electricity. If you don’t make electricity continuously available at your event, your event is not accessible.
Some people need electricity in order to breathe. Some people need electricity to be able to move across a room. Some people need electricity for life sustaining medical treatments. Some people need electricity to communicate.
All of these people, and anyone else with an access need for electricity, should be welcome at your event. They can be, if you make proper plans and make sure that electricity will be reliably available.
(For further details, see this post.)