Sustainable Energy Transition

Ugo Bardi offers a "back of the envelope" calculation for what it would take to replace fossil fuels with renewable sources of energy. It won't be easy.

[W]e need to increase the installation rate [by] about a factor of 8 in energy terms. Assuming that the cost of renewable energy won't radically change in the future, we need to increase monetary investments of about the same factor. It means that we need to go from the present value of about 280 billion dollars per year to some 2 trillion dollars per year. This is a lot of money, but not an unthinkable investment rate. If we sum up what we are investing for fossils (about $1 trillion/year), for renewables ($300 billion/year) and nuclear (perhaps around $200 billion/year) we see that we are not far from there.