The 10th auction in the Regional Greenhouse Gas Initiative (RGGI) was held on December 1st. In honor of this significant round number, I give you the top 10 interesting facts about the 10th RGGI Auction, all of which are based on today's market monitor report:

10) In the Auction, 24,755,000 allowances from the 2009-2011 compliance period sold for $1.86 each (the floor price);

9) That amount is only 57% of the 2009-2011 allowances offered for sale, the lowest yield from a current compliance period auction;

8) 38 entities bid on these current compliance period allowances, down from 45 in September and 51 in March;

7) The generators subject to RGGI compliance and their affiliates (collectively "compliance entities") purchased 97% of the current compliance period allowances sold;

6) 1,172,000 allowances from the second compliance period (2012-2014) were also sold at $1.86 (the floor price);

5) That amount is 57% of the 2012-2014 allowances offered for sale -- the lowest yield to date for this vintage of allowances -- and 100% of them were bought by just 4 compliance entities;

4) In the 10 RGGI auctions, taken together, compliance entities have purchased 85% of all allowances sold;

3) Due to trading on the secondary market, after the 10th auction purchases are settled, compliance entities will hold 95% of all RGGI allowances in circulation;

2) All together, the 10 RGGI auctions have brought in more than $777.5 million for the 10 RGGI states;

and

1) The RGGI states have collectively invested about 80% of the RGGI funds in strategic energy programs, most of which involve energy efficiency improvements in homes and businesses. RGGI has created a website compiling the states' announcements on the success stories from these investments.

The next RGGI auction will be held March 9, 2011.