Determine construction power costs / eOn charges too much

Dear community, things are getting serious for us. We addressed the issue of "construction electricity" very early on and our general contractor gave us a "rough estimate" of an amount between 3,500 - 6,000 euros for construction electricity and construction water. After reading this thread, that seems very generously calculated to me. The highest amounts are around 3,000 euros. We are building three floors on a slope; earthworks are supposed to start this month. What do you think about the estimate of 3,500 - 6,000 euros for construction electricity and construction water?

The whole thing depends on how you do your construction drying or what you use for heating. We paid 360 € for construction electricity but dismantled the construction electricity box when the screed was finished. From that point on, we used house electricity, which was 25% cheaper. Connections in the basement were available. Using house electricity from then on, we paid another good 400 €, BUT: we were already heating with gas at that time. We only needed electricity for the construction dryers. The price at that time for one kWh of gas was 5.5 cents, electricity was 25 cents. That’s a difference like day and night. Gas for heating the screed then cost 500 €. For electricity, we would have paid five times as much (this was the case with neighbors who had electric mobile heating).

By the way, construction water was cheap: the shell builder had set up a tank but only used Poroton with thin-bed mortar, so not much water was needed. For plaster and screed, we rented a standpipe (1.40 € rent per day plus 1.80 € per cbm of water). But it was only 25 cbm of water in total and we paid a total of 180 €.