Be that as it may, it's most likely more expensive. This is purely my personal guesstimate, but gas tends to be much cheaper in Poland than electricity. More efficient, maybe, but I'd be very surprised if it was cheaper given the prices.
Yes, I assume it's more expensive. Gas is cheaper than electricity in Poland, but then again, electricity also isn't that expensive for preboiling in a kettle to make a big difference.
On a related note, I was surprised when I did calculations on how much it actually costs us to bake our own bread. We started doing that a lot during this pandemic. It turns out, the cost of ingredients + electricity adds to slightly less than what it would cost to buy the same products from a bakery. This doesn't price in time spent on preparing and baking, but it's not like we could actually use that time to make money, we're having fun, and going to a store also takes time (and/or fuel). Electricity is cheap.
Be that as it may, it's most likely more expensive. This is purely my personal guesstimate, but gas tends to be much cheaper in Poland than electricity. More efficient, maybe, but I'd be very surprised if it was cheaper given the prices.