the period to corresponds to the period where major reductions in the cost of renewable technologies for electricity generation such as solar pv geothermal and wind are expected while not infeasible such an amount is clearly very high and not currendy in the range of discussion of what developed countries might be willing to commit without hard negotiations on the other hand it is highly plausible that not all countries would be able to reach the threshold we have used for our calculations by so that the subsidy that would need to be actually disbursed would be lower however many other issues would probably arise in the implementation process