Obviously the answer to this varies on the size of the business. The average gas/electric usage in the UK is:
Microbusiness: 10 000 kWh per year / 5,000 – 15,000kWh
Small businesses: 25 000 kWh per year / 15,000-30,000 kWh
Medium businesses: 45 000 kWh per year / 30,000 – 50,000 kWh