The Prince of Wales's private income rose by 7% to more than £16m last year, according to Clarence House figues.
The money generated by the Duchy of Cornwall - the landed estate given to the heir to the throne - increased by just over £1 million to £16,273,000 during the last financial year.
The amount of carbon dioxide (CO2) produced by Charles fell by 18% or 630 tonnes to 2,795 during 2007-08, the accounts revealed.
Clarence House officials said the cut was due to a switch to "green" electricity supplies and a further reduction in travel-related emissions.
The accounts also revealed the cost of the Prince's official travel by air and rail fell 22% from £1.4 million to £1.1 million.
The journeys by plane and train are paid for by the taxpayer through grants-in-aid.
It was revealed that five controversial helicopter flights Prince William made while training with the RAF cost more than £50,000.
The trips, which included journeys to a stag-do and the family home of William's girlfriend, Kate Middleton, were criticised as an alleged abuse of military training.
The accounts also showed that Charles's personal costs, referred to as "non-official expenditure", fell from £2.6 million to £2.2 million.
The amount of tax the heir to the throne paid to the inland revenue dropped by £5,000 to £3,429,000.
