Well, it appears it's finally happened -- energy efficiency is now the hot sector in cleantech venture capital.  That's based upon the writeup of Q1 as reported by The Cleantech Group and Deloitte, who put out their numbers today.

Overall, the picture is one of continued return to healthy dealflow in the sector.  They tallied $1.9B in global cleantech venture dollars, across 180 disclosed deals.  On a dollar basis, this is their largest quarter since 2008, but in terms of deals they claim it was the largest quarter ever.  With Project Better Place providing $350M in one single tracked deal, this implies that deal sizes are relatively down.  

As I have said for a while, it's important to track the number of deals, not just the dollars.  And this Q1 tally illustrates this well. 

Thanks to PBP, the transportation sector had the highest dollar totals.  But in energy efficiency they counted 39 deals totaling $217M, versus 27 each in transportation and solar. 

What's interesting to me is to look at those three sectors in comparison to recent history.  For this, let's look at annual totals, not the ups and downs of quarters. 

• Solar:  In 2008, 110 tracked deals.  In 2009, 86 tracked deals.  In Q1 2010, 27 tracked deals for an annualized rate of 108 deals.
• Transportation (which I assume is their catch-all for both Vehicles and Advanced Batteries):  In 2008, 40 tracked deals.  In 2009, 60 tracked deals.  In Q1 2010, 27 tracked deals for an annualized rate of 108 deals.
• Energy efficiency:  In 2008, 87 tracked deals.  In 2009, 120 tracked deals.  In Q1 2010, 39 deals for an annualized rate of 156 deals.

So energy efficiency indeed leads the way and has been coming on strong. 

But transportation has been growing quite rapidly as well.  And the venture capital love affair with solar is still far from over.  I see plenty of anecdotal evidence, in my conversations with colleagues among VCs, that folks are starting to turn against solar and vehicle and battery deals to an extent, but that may be a biased sample.  And also, the rapid growth of corporate venture dollars into the sector, and the need for follow-ons into existing portfolios may also be the reason why VC attitudes may be shifting but the dealflow isn't yet.

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On another topic, I had the opportunity to review the recent Greentech Media report on Ultracapacitors, and it's a quite good report.  Not just the usual market overview, but some good meaty explorations of specific innovations and specific companies.  Tactically useful information for investors and industry participants.  Definitely recommended.