I don't know that "subsidy" is here a useful metaphor of the externalized costs of fossil fuel exploration, extraction, combustion. You mention adverse health effects but don't really elaborate on price of CO2 volume. Environmental toxicity in arable land and human bodies attributable to these activities is the loss center closest to present tensions. Morbidity could be the ring that binds people to demand destruction --or "climate change" action-- except I can't recall one expert in this country, the US, willing to connect pathogenic defects to particulate and heavy metals pollution.

You may well ask yourself, Who is my reader? The dollar amounts would be meaningful to Ratepayer, if they were associated with particular mining and NG companies as well as utilities. The dollar amounts are not meaninful to Investor, as by definition they aren't attributed to operations. One means to bridging the gap between winners and losers is selecting trade data to answer the question, How does fuel cost encourage or discourage vertical integration and combinations that predicate price fixing per kWh? Look at National Grid, for example: It's subsidiary NG distribution and transmission businesses are pertinent factors in the state's evaluation of Deepwater's offshore wind farm equity offer and expected rate of return.  

I admit, separating operating expenses from state and federal taxes --the top line "subsidies" which vary by utility service area -- is a tall order; but someone's got do it before advancing any generalizable valuation of externalities. I might be impressed, if the money my electric company "saves" by burning x tonnes or x cu.ft appeared in my monthly statement of customer profitablity.  

Speaking of Rhode Island and RGGI, what can you tell us about CCX --a pure play exchange-- its carbon credit trading history and certification protocols? Its US domestic and international membership is quite diverse, in terms of their marketable assets.

Diversity is the key to economic and political evolution.