Because I have my summer & winter readings (units used), I can accurately forecast my consumption per 61 day billing cycle (we get 6 ESB bills per year) in any year and produce the resulting invoices to within a euro or two of the actual bill. ESB in winter grossly underestimate consumption in my experience, sometimes by in excess of €100. The numbers they use for consumption figures on "estimated" bills seem to come from a random number generator!
Joking aside, the implications for consumers receiving grossly underestimated energy bills can be catastrophic, financially and emotionally. Pre-pay meters and the averaging of bills over a year are not the answers either, any more than smart-meters. If ESB staff can't use their own existing, simple technology available in-house now, what are the odds they'll mess up again with the new stuff?
Pre-pay meters result in higher costs for the consumer and the "averaged out over the year" billing, aka budget billing paid by direct debit of course, has caused problems for neighbours (over-payments difficult to get back, under-payments causing worry).
If I get an estimated bill I phone customer services, give them the new reading and ask for a new bill. I don't pay by direct debit and I get paper bills. Hard-copy utility bills are very handy and given their ineptitude with calculators or simple spread-sheets, would you want ESB (other re-branded energy suppliers may operate in your area) to have access to your bank account?
An early version of my simple ESB template is available as a
key post (rates are well out of date by now)
I'll update it when I get a chance.