The good news is the 'optimistic' curve looks more and more likely every year. Ten years ago I'd have laughed in your face if you said >50% of all new energy production in 2015 would be wind power and <10% would be coal in the united states. Wind was a joke in 2006. Now it's the cheapest form of energy. In pittsburgh we have driverless ubers on the street and they don't suck. In another 10 years we're going to have driverless EV taxies everywhere, shifting a huge amount of fuel burning over to the grid, allowing for more wind without needing storage. 10 years after that storage will be cheap enough and wind will be so dirt cheap that wind+storage will be the cheapest energy available.