Welcome to the world of the BSCP504 my friend lol This will
Burn the back of your eyes out
In short an energy supplier buys say 1,000,000 KWH of energy at a set price based on what its forcasted (based on the estimated annual consumption figures) to sell to its customers.
If it sells 900,000 for that period it then has to sell the over procured Kwh back to the grid for a reduced rate which loses money
if it sells 1,100,000 Kwh it will have to buy more to cover but at a different and often more expensive price.
By allowing more accurate buying the theory is the cost is lower so the price to the consumer should be lower. (I know what your thinking... more profit....

)
On the flip side as well is energy suppliers have to be i think 98.4% accurate with its purchase of energy vs its sales of energy to its customer. if its under this regulation state they have to pay more per unit it buys as a penalty. if its over this its cheaper to buy each unit. if it falls below 90 or 94% i think, they get put on special measure and targets are set to get it up to standard otherwise theycan lose their supplier license which means no more energy supplier!