Bundesumweltamt (the German Federal Environment Agency) has just published a new study on the costs and benefits of the transition to a 100% renewable electricity system.
I recommend reading this (it is in German language). I learned the following interesting facts, among others.
McKinsey estimates the potential for rooftop solar beating the price of buying electricity from the grid and solar beating other generation methods like diesel until 2020 as over 1 TW. In contrast, in 2010 only 40 GW was installed world wide, which is only a fraction of the potential (page 18 of the report).
They expect capital cost per kW for solar PV to come down to below 500 euros by 2050, which is the lowest value of all renewable options (page 17). They see onshore wind at about 600, offshore wind at about 900, solar thermal at about 1,700, and biomass at about 1,400 (all in 2050). Of course these are statements looking forward a couple of decades, so there is some uncertainty. But with these numbers it would be hard to see how fossil fuel had any chance to survive as a electricity generation method until 2050.
They also present own estimates on the real cost of fossil fuel generation (page 26). Lignite coal has external costs of 10.75 cents euro per kWh, coal 8.94, oil 8.06, and gas 4.71.
They also explain that while building renewable capacity costs some money in the short term, in the long term it saves money compared to just sticking to fossil fuel.
Leaving massive renewable generation capacities and still further reduced capital costs to the next generation does not only help them with avoiding global warming. It also reduces their energy costs massively.
The report closes with a list of recent publications for further reading.