Trying to decide if you should buy a hybrid to do your bit for the environment? The decision just got more complicated.

A new study shows that over the lifetime of a vehicle-from the moment it is conceptualized at a design studio until it ends up in the scrap heap-hybrids actually consume a lot more energy than even big SUVs. One reason is that hybrids contain more moving parts than conventional vehicles, which require more energy to manufacture and process. In addition to an internal combustion engine, for instance, hybrids also have an electric motor and a sizable battery pack. That adds to disposal costs, too, once the car has run its last mile-especially for the lead-acid batteries.

The study, by consulting firm CNW Marketing Research in Bandon, Ore., analyzed hundreds of variables that contribute to energy costs-including the fuel they burn while being driven