Is it possible for all the S-RECs in world to get used up, and if that happens, then what?

In practical terms, this is impossible. Every day, S-RECs are continually being generated by grid-tied solar panels that are exposed to sunlight. As long as the sun keeps shining, more S-RECs get created day after day. The problem has been the opposite, which is that not enough S-RECs have been used up because there has not been a functioning consumer market for them. The whole point is to get people to become intentional consumers of solar.

SunPort’s objective is to create and expand solar energy market to the point that aggregated consumer demand for S-RECs can become a factor in driving solar forward. We can’t really use up all the S-RECs but we can make the market tight enough that they become more valuable, which will in turn make owning solar production equipment more economically worthwhile. If we can cause high demand for S-RECs, this should be a sufficient market signal for much more solar to be built, thereby guaranteeing that plenty of S-RECs will be available.