The theorem was published in the Proceedings of the National Academy of Science (PNAS) today (Monday 6 November 2017) with the title «Scale - dependent portfolio effects explain growth inflation and volatility reduction in landscape demography». (sciencedaily.com)
In short, the market has heated up to a point where the CPIs (cost per install) are so high that even a strong portfolio effect doesn't result in a positive LTV (lifetime value). (deconstructoroffun.com)
This we attribute to an unwitting renewable energy portfolio effect with the increase in solar PV and solar water heating. (mpra.ub.uni-muenchen.de)