Forced by the Enron ripoff ?
http://news.yahoo.com/s/nm/20060821/pl_nm/energy_california_solar_dc_1
This is just a part of his new campaign to reduce carbon emissions and was probably talked about when Blair visited him earlier this year.
It isnt done on his own either, several other states are going to be in on the act too.
TBH it seems like Dubya has managed to pee him off a bit and it might be the reaction to that.