If you have been told there is no tax involved someone is lying to you. The cost of maintaining the grid and providing power is not as high as you quote as far as I am aware.
Are you sure? Does electricity in Portugal cost 10 to 20 cent before tax? Why is it so expensive? We pay 6 cent/kWH before tax in the Netherlands.
Because we had a government owned company with a monopoly that the EU forced us to sell. So now we have a private monopoly instead of a public one.