By Nicholas Earl A rival supplier has slammed the two prospective bids for fallen firm Bulb Energy (Bulb), labelling them a “significant risk to all energy bill payers.” It has told City A.M. it wants both Octopus Energy (Octopus) and Ovo Energy (Ovo) to commit to ring-fencing the customer credit balances of Bulb’s 1.6m customers. A source at the supplier warned that, without ringfencing, the takeover deal could become a risk to its customers and the taxpayer. It also questioned why any deal for Bulb needed “state aid” in the form of £1bn hedging support amid the “prevailing economic environme…