I saw a post somewhere recently that mentioned using the factorization solar boiler attached to a hobbyist engine. It works pretty good. I found a vein of silver, and was able to make 7 mirrors initially. You get .2MJ for every mirror. I have 8 at the moment and 1.6MJ continually during the day. "Free" MJ for the win. Of course it only works during the daytime, but attach a couple chutes to the top of the pulverizer and you are good to go. Put this in with the new conductive pipes in buildcraft, and you have a nice easy no maintenance energy network. Great for
slowly processing your ores.
At .2MJ for each mirror, it takes a lot of silver to scale, and there are other better power systems later on, but it's a good start.
Here's a link to the updates on the BC power system. Highlights - No loss of power, no more exploding pipes, the materials used limit the total MJ that can traverse them.