Hi I'll be wrapping up my undergrad in physics in about a year, and I'm starting to seriously think about grad school. What I'd like to be doing eventually is applying physics to issues of sustainability, particularly energy sustainability. At the moment, I'm trying to decide what areas of physics are most applicable to these issues and how much appeal they hold for me. Ideally, I'd like do grad school somewhere that is actively using physics for developing sustainable technologies, not just doing pure research in an area that *may* have potential applications down the road. I prefer a hands-on approach and would much rather work towards a tangible result rather than do theoretical work. So my questions are: What are areas of physics that have immediate applications to sustainable technologies? What are some of the research groups in these areas and where are they located? Photovoltaics and plasma physics come to mind - what are some others, no matter how obscure? Anything going on in biophysics? What about better batteries - what areas are used for these? Please be specific: "semiconductor physics for photovoltaics" isn't as enlightening as "applying quantum tunnelling seen in photosynthesis to photovoltaics". And finally, thank you!