By Mathew Carr

From Bloomberg – May 19 2010 –  Emission traders’ most-profitable credits, linked to greenhouse gases considered more harmful than carbon dioxide, are dragging the United Nations carbon market to its biggest discount in a year.

The UN faces a devaluation of the tradable credits it gives investors that pay for projects to reduce hydrofluorocarbons, or HFCs, because the European Union may favor alternatives such as windfarms to combat global warming. UN offsets for 2012 traded yesterday at 4.11 euros ($5.04) a metric ton less than comparable EU permits, twice the spread at the end of last year.

Goldman Sachs Group Inc. and Royal Dutch Shell Plc are among investors that may get lower returns amid a clampdown on HFCs, which are known as “super gases” because they trap 11,700 times more heat per molecule than CO2. Bloomberg New Energy Finance said the UN market may develop two tiers by 2013, with “low quality” offsets dropping to about 7 euros versus 11 euros for credits eligible for EU compliance. Read the whole story