Researchers at Stanford University have published a feasibility study to convert 143 countries world-wide to 100% zero-carbon energy by 2050 using wind, solar, water (WWS) storage systems. They say it could be done by 2030 but for a variety of reasons have chosen the later date. They estimate such a system would cost $73 trillion to implement, but would recoup the entire cost in 7 years. According to the Stanford researchers, building the new WWS system would incur a carbon emission footprint less than 1% of the current energy system. It would create millions of jobs and save many of the 7 million lives lost yearly to pollution.
https://www.cell.com/one-earth/fulltext/S2590-3322(19)30225-8
However, they devote little attention to funding sources, implementation mechanisms, or ways to overcome political and corporate resistance to their ambitious plan. They do provide a country by country breakdown of how it could be achieved.