What if transition projects could pay for itself, and dramatically reduce spending on negative externalities. For example, the Community Land Trust movement in France, Terre des Liens, which takes land outside the market to provide low rents for organic farmers, told me that their system of organic production dramatically reduces water purification costs for public authorities, as well as dramaticall improving health outcomes. In this way, part of the savings could be invested in transition projects, creating a virtuous cycle.
A similar concept is Transition Trade, proposed by Chris Cook.
"The greater prize – where the UK has barely scratched the surface – is to reduce energy consumption through the use of what is called the 'Fifth Fuel' (ie intellectual value), embedded in smart technology and solutions. In fact, an example of the necessary reality-based energy policy may be identified - back to the future- in 1778, when James Watt supplied the use of his new steam engine to Cornish tin mines to pump out water in return for a third of the coal saved: Pumping as a Service. Such savings of energy as a service are made at the retail price and this often gives rise to a compelling conventional economic case.
So in a nutshell, I believe one of the great reality-based trades of the 21st Century will be the exchange of smart/intellectual value (the Fifth Fuel which the UK possesses in abundance) for the value of fossil fuels and other finite resources saved – the Transition Trade." (https://www.thealternative.org.uk/dailyalternative/2017/3/7/the-policy-makes-the-party)