WIND TURBINES AT Hamerton Zoo exceed its energy needs, so it sells the surplus power to Opus Energy. The firm supplies gas and electricity, obtained from renewable sources where possible, to more than 200,000 businesses across the country, ranging in size from local newsagents to Cambridge city council. Charlie Crossley Cooke, the chief executive, founded the business in 2002 and it now employs 588 people at its offices in Northampton and Oxford. Most of them work in sales and customer service, but there is also a risk-management team responsible for power and gas purchasing, pricing and demand forecasting. After a young employee's death from bowel cancer last year, Crossley Cooke decided to provide private medical cover for the entire workforce. As well as offering regular health checks, the scheme sets lifestyle goals that, if met, reward individuals with discounts on spa breaks and sporting goods. An annual wellbeing day combines fun and games with health advice, while a corporate challenge sees everybody given a pedometer and invited to walk as far as possible over a two-week period. Such initiatives ensure people don't feel their health is suffering because of work (a 76% positive score). They are also happy with the balance between work and home life (68%). www.opusenergy.com