In 2007 the total cost to cover consumption with renewable in an Efficiency Scenario would be very similar to the cost of covering consumption with dirty energy in a Business-as-Usual Scenario. In 2050 the difference becomes much greater, so the cost to cover consumption with renewable in an Efficiency Scenario is only 9% of the cost to cover consumption in a BAU Scenario with dirty energy, and 22% if the latter is covered exclusively with renewable. This leaves a very large economic margin to spend on efficiency and intelligence measures. The smart use of these freed resources is what defines a sustainable economy.
Speeding up the transition from one model to the other provides huge economic savings. A 20-year delay in taking action (delayed transition) leads to costs 2.11 times higher compared to a responsible transition (which is accelerated in the early years). If the process were in linear time, it would lead to costs of 49% above the corresponding cost in a responsible transition scenario.