I put in PV for electricity and separately also put in solar thermal for hot water both went in service in 2009.  I live in NY state and my question is whether the tax credit has to be claimed in the year the project went in service.  Since the cap in NY is $5000 per year I will reach that in just the PV project alone.  If I have to claim both projects in the same year I will miss out on the credit for the solar thermal project.  Can I claim one project on the 2009 return and then claim the other on the 2010 return?  Also do they need to be consistent with the years they are claimed on the federal return?

No idea about New York, but the federal tax credit should be claimed in the year the systems were originally 'placed in service', however I do believe that if you have insufficient income to take advantage of the full federal tax credit that you can carry the credit forward to subsequent years.

The dsireusa.org is a great resource for information about state and federal renewable energy incentives:

http://www.dsireusa.org/incentives/incentive.cfm?Incentive_Code=NY03F&re=1&ee=1

Finally,  I'll note that i am neither an attorney nor a CPA and therefor, I don't give tax advice and the above should not be construed as such....

~Fortunat
www.revisionenergy.com

I got my answer for this on the NYS tax site. The credit is for the year the equipment was placed in service.