The cost of “going green” is the delta between the cost of green power and the cost of providing electricity without going green. That’s nowhere close to 500B by 2025.
Prematurely shutting down nuclear looks like a dumb decision, but Germany has been mismanaging their electric grid for decades.
https://www.statista.com/statistics/1267541/germany-monthly-...
Part of this discrepancy was them paying off an extremely premature investment in PV solar in attempt to kick start domestic production. Back in 2009 they setup 39 euro cents/kWh feed in tariffs for solar. Those subsidies where quickly cut on new installations but as I understand it they are still paying it on those early installs. The good news is those will be expiring fairly soon and arguably those initial investments are paying dividends in current rock bottom prices for new installations.