You will be billed every quarter for all the gas, electricity and oil you have used in the business.
If you ran your farm before converting it to organic, you will have a good idea of the amount that you will be billed for your heat and light. If not, it will probably take a few months before you know exactly how much energy the farm will use. Depending on the nature of your farm, you may use a large amount of energy. For example, indoor pig units (organic pigs are allowed to spend a certain amount of time indoors) and dairy milking parlours can be expensive to run.
It is possible that your energy supplier may be able to give you some guidance on likely consumption depending on the type of equipment you're planning to use. You can adjust the figures once you have been in business for a few months.
It's worth shopping around the different energy companies to get the best deal for your business, particularly if you're going to be a heavy energy user.
It is possible that your farm could benefit from local energy initiatives - you may be eligible for grants to convert to 'greener' forms of energy.