Behind the curve but still willing to blow a morning showing everyone what I wished I had done before anyone else

Inspired by Energy Outlook and the TerraPass Footprint I decided to make my own calculations of the climate auction revenue in Obama's budget (budget image from TerraPass):

Not to be outdone, here is how I blew half my morning yesterday:

1. Get greenhouse gas estimates from EIA
2. Convert from metric to short tons (MT*1.1 = ST)
3. Project GHGs out to 2050
4. Assume GHG auction begins in 2010
5. Assume campaign pledge refers to 80% reduction of GHGs by 2050 relative to 2007 baseline
6. Assume GHGs fall linearly out to 2050
7. Multiply GHGs by $10 permit price/ton
8. Figure that auction revenue is $81 billion in 2010 and stays roughly constant with an elasticity of demand equal to 1.
9. Permit prices rise from $10/ton to $46/ton in 2050.

Below is a graph of the business-as-usual (in blue) and 80% reduction by 2050 (in green) time path of GHGs.

Here is my spreadsheet (Co2-auction-revenue.xls). Download, change some assumptions and blow your own dang morning if you'd like!