The real-time methane leak counter was stopped on Feb. 11, 2016, when SoCalGas announced the leak had been temporarily stemmed. The total amount of methane leaked now shown on the counter is based on this paper in the journal Science.
Here are the assumptions and sources for the each calculation used to power the counter:
- Methane emissions estimate: Updated to reflect the final estimate from the California Air Resources Board.
- Gasoline volume equivalency: Calculated by converting the amount of carbon dioxide pollution from the leak to that that comes from combusting gasoline, using rates provided by EPA.
- Value of wasted gas: Calculated using a price of $3/mcf of gas, which is the monthly average Henry Hub spot price for October 2014-October2015 according to available EIA data.
- Carbon dioxide equivalency: Calculated using a formula from the International Panel on Climate Change's 5th assessment report (Chapter 8, page 714).