more on shadow price following yesterday's discussion

I came across a document with a good clear description (to my mind) of
shadow price and it's relationship to balancing price and congestion
pricing: www.ercot.com/content/mktinfo/prices/MCP.pdf

Also from the UK Dept. of Energy, interesting document detailing their
rationale to move from using 'Social Cost of Carbon' to 'Shadow Price of
Carbon' in determining policy and economic investment appraisals:
http://www.decc.gov.uk/en/content/cms/what_we_do/lc_uk/valuation/shadow_price/shadow_price.aspx
(click on link in para 4)

Best,
Anne