I'm not going to give my roommate my half of the electricity bill
What makes you not want to pay your half of the electricity?
I've been living with her for years. She has never thought about sharing the electricity bill before.
Typically roommates always split the expenses. It's wrong to not honor your half of the deal.
Wow, you are being a killjoy.
If you've agreed to split the electricity, then you should pay your half, as that's what roommate's generally do. If you don't pay your share you risk the electricity being turned off.