If you have any business premises you will be billed every quarter for any electricity (and perhaps gas) you have used in the business.
Until you have been trading for a few months you will not know exactly how much - if any - energy the business will use. However, you could contact energy suppliers who may be able to give you an idea of likely consumption. You can adjust your estimated 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 businessif you are going to be an energy user.