It is often claimed that renewables are still too costly and not yet competitive with conventional energy sources. But what costs are incurred when renewable energies are not used? Every day during which potential renewable energy sources are not utilised but exhaustible fossil fuels burnt instead speeds up the depletion of these non-renewable fuels. Using burnt fossil fuels for nonenergy related purposes (e.g. in the petro-chemical industry) in the future is obviously impossible. Thus, their burning – whenever they could have been replaced by renewables – is costly capital destruction. This study concludes that, estimated conservatively, the future usage loss resulting from our current oil, gas and coal consumption is between 3.2 and 3.4 trillion US Dollars per year.