Best way to manage utilities

[Alberto Dante]

The question is:

Which is the best way to manage utilities (electricity, PV panel 
electricity production, gas, water, ...) registering the consumpion 
(quantity: kWh, mc, ...), the price per unit and the total price, having 
reports and graphs (i.e. price per unit over the time) and export features?

I had a discussion with the developers (bugzilla Bug # 728829 " Quantity 
and price per unit transaction fields"), and they suggested me to ask to 
the community.
Thanks in advance for your contributions.
Alberto