That is, if last year’s record as reported by Bloomberg New Finance ($268.7 billion) is an indication for the average of these 23 years.
That would be a low scenario, and clearly an insufficient one.
A new report by REN21 and ISEP about the future of clean energy discusses predictions by various groups on the level of finance to be expected over the next couple of decades on page 33. Greenpeace calls for the highest number ($1 trillion a year average), but Bloomberg New Finance also expects $400 billion by 2020 and $460 billion by 2030. The International Energy Agency is rather conservative in their estimate, they expect only $6.4 trillion until 2035, which would mean $280 billion (about present levels) over the whole period.
With global warming becoming clearer and more urgent by the minute and fossil fuel going up in price over the long term, I don’t expect that to happen. For the very least the Bloomberg New Finance scenario of $400 billion by 2020 needs to get realized.
As far as large scale desert projects are concerned, the most important trick is to make investing in Mongolia a largely risk-free option with at least an “AA” rating by the agencies. That is difficult to do, and quite impossible if one were to depend only on what Mongolia can offer on its own.