energyintensive firms can receive up to an discount if they join a climate change agreement cca which requires meeting energy efficiency or carbonsaving targets renewable electricity suppliers are exempt from the ccl receipts from the ccl amounted to billion in the ro requires electricity endsuppliers to purchase a certain fraction of their annual electricity supply from producers using specific renewable technologies and they receive tradable renewables obligation certificates rocs for doing so the supplier can also buy out the obligation by paying a set price per mwh the buyout revenue is recycled to participating suppliers in proportion to their rocs