no doubt the biggest factor holding back rampant increases in solar installs is cheap natural gas from fracking. i'm a huge proponent of energy independence here in the u.s. but i believe 'fracking' will come under further and further scrutiny as more and more contaminated water wells come to the forefront of public attention. not disclosing the chemical mix used in most fracking operations due to 'trade secret' protections is a hoax at best. the chemicals are very toxic..that's the main reason for non-disclosure.
more regulations on the fracking process will drive up costs making solar once again a must have source in everyone's energy mix. not that the global outlook for solar is hurting at the moment