I also didn't understand. Also I think the author misses a vital point that voluntary computing is practiced on many computers that are already running, like a computer used for word processing, or browsing the web... That is actually what makes the computation environmentally friendly, because it uses an already fired up machine, instead of spinning up a designated HPC that can sometimes sit idle (e.g. Christmas Holidays)
RE: Multi-Currency Economy and Gridcoin as the World's Largest, Decentralized, Green-Energy Powered Supercomputer