I'm just starting a MSc in Engineering at the OU, after 10 yrs as a senior website developer (also have a BEng in Elec Engineering from 1997). I'm pretty keen on the idea of doing a PhD as I feel research will keep me motivated day to day. At present I'm very interested in Renewable Energy but this is a very wide field.
My question is, at this stage, should I have more specific areas of interest or indeed, an actual idea for a project? To be honest, I feel I could find myself absorbed in ANY aspect of this field, as long as I play some small part in increasing the use of Renewable Energy.
Also, is it best to try for a PhD straight after the MSc or work in industry first? (bearing in mind I'm 40, not getting any younger!)

This probably comes across as a bit vague, but various opinions would be very welcome.
Thanks,
Ross.

Go straight into the PhD. You'll probably find it easier than getting a job in industry given that you have no background in energy.

I'd think if you were going to do a PhD do it straight after the MSc. I've known people in renewables, and I don't think you'd need a PhD to do most jobs in renewables industry (obviously, if the PhD is its own reward then great)
There is renewables research in a few UK universities, but there is also still plenty in how to get more out of carbon energies.
Cheers