ESOS is a mandatory energy assessment scheme for large UK businesses aimed at reducing energy usage and improving efficiency. Around 7,000 large businesses are affected by ESOS, but by mid-2015 only 85 had notified authorities about their compliance, suggesting many struggled to meet the original deadline. ESOS assessments must provide a complete review of a business's energy usage and intensity, and identify effective energy saving opportunities. Qualifying businesses are those employing over 250 people or with an annual turnover over 贈38 million, and assessments can only be conducted by approved assessors.