2/ Determining H, E and R

Obtaining data for hash and revenue is straightforward. I downloaded it from http://blockchain.com. The data for efficiency was more tricky to derive.  I was only able to find efficiency data in terms of energy i.e. TH/J, from https://ccaf.io/cbnsi/cbeci.  Converting from TH/J to TH/$ requires an assumption on the electricity costs of mining.

Fortunately, electricity price does not scale as much as energy efficiency of the mining rigs themselves, so it is not too critical a parameter for modeling the overall trend. Only a small correction is needed to account for the improved price of electricity secured by the miners over time. 

To this end, I propose two heuristic models for electricity price:

Model 1: Electricity price is fixed at 0.1 dollar per kWhr
Model 2: Electricity price is modeled as 0.24/sqrt(year-2009) dollars/kWhr*

*This model is only applicable for years >2010.

https://m.primal.net/KQfc.png