CCL is a government-imposed tax to encourage reduction in gas emissions and greater efficiency of energy used for business or non domestic purposes. CCL is chargeable only on units/kWh used and not on any other component of the bill, e.g. standing charge. The rate of CCL is now index-linked and therefore likely to increase on 1 April each year. Under current legislation: Where VAT is charged at the standard rate, CCL (plus VAT on CCL) will usually be added to the bill, Where VAT is charged at the reduced rate, the supply is automatically excluded from CCL, Green energy (i.e. from renewable sources) is automatically exempt from CCL.