KiOR cost Vinod Khosla tens of millions and was extremely embarrassing as the company was sued by the SEC for fraud, the total loss was something like $650M. Craig Ventor doesn't even mention Synthetic Genomics any more, total loss there was close to $100M. Solazyme IPOed a few years back, has since lost 90% of their stock's value and have an accumulated deficit approaching $700M. Aurora Algae lost $150M and went out of business. Algenol has spent about the same without any revenues of note. Sapphire raised something like $350M, including $100M from the DOE for biofuels but have slowed operations significantly and are now focusing on fish oil. LS9 raised $81M and was eventually sold for $40M. Amyris went public awhile back as well and has since lost over 95% of their market cap. Their accumulated deficits are well over a billion dollars now.
If I had to guess, I'd say in the biofuels space, about $3-$4 billion has been set on fire in the past decade.
But you can't fault them for trying, and it sounds to me like this fund isn't investing necessarily with a high likelihood of making money, hence the 20 year time frame.
At least one company that I know of, Loop Energy, has proven (independently verified) fuel cell tech that will soon make cargo trucks 0-emissions. (Note: My brother was the lead engineer and basically developed this)
Sure it has taken a while, but things like this would not have been possible without that initial investment in fuel cells.