Dear HN,
My lab is looking for ideas, particularly in relation to developing countries. What sort of problems have you seen that we might be able to solve through technology?
About us:
We are the Sustainable Engineering Lab at Columbia University (http://sel.columbia.edu/). We are a team of students, engineers, programmers and experts in renewable energy.
We've done work in Nigeria, Indonesia, Myanmar, India and a whole bunch of other places (http://sel.columbia.edu/projects/).
In a country like India, there is a huge problem to solve when it comes to basic necessity like Electricity for everyone. Specially in smaller towns and villages. Since you mentioned renewable energy, I am sure there is a huge potential there.
The problem is that the electricity grids (or transformers) are just not enough for everyone. So in many small towns/villages, they do something called "load shedding" and power cuts are frequent even if there is electricity available. Hardly there are areas where there are no transformers or grid but most of the times, they are not functional or just badly managed.
Find a way to create enough energy AND then channel it efficiently as well. You have a winner right there.