Hi. I'm the author of this blog post. Happy to answer questions people have, as time allows, on Wednesday. Upcoming posts will look at the future of wind power, the future of energy storage, and what the missing pieces are. If you don't want to wait, you can read my thoughts on energy storage here: http://rameznaam.com/2015/04/14/energy-storage-about-to-get-...
When we look at figure-1(levelized PPA), we see steady price reductions until mid-2013 , and than none. That is probably due to soft costs starting to dominate. So since the cost drivers changing - why does it make sense to model future price on old cost drivers ?
I initially set out to model soft costs on their own, separate from module costs. However, that effort revealed other factors. Solar capacity factor is rising and operational costs (which are not included in soft costs are dropping. There are more variables at play. For some of those variables, there isn't robust data available over lon times.
All of those variables ultimately feed into electricity prices, in the end, which is why I chose that modeling approach.