If you're looking at distributing alternative energy in Nigeria, for instance, what gets in your way is not people's ability to pay, not people's desire for a clean solar lamps or biomass opportunities. But there is a strong status quo that really depends on selling diesel.

Human beings want to see each other. We want to be heard by each other.

I think we so often equate leadership with being experts - the leader is supposed to come in and fix things. But in this interconnected world we live in now, it's almost impossible for just one person to do that.

The best change that comes to the world is when all parties are seeing each other as equal, and all parties have the opportunity to be transformed. That really goes back to the idea of dignity.

When we were walking through the narrow alleys [of the Mathare Valley slums], it was literally impossible not to step in the raw sewage and the garbage alongside the little homes. But at the same time it was also impossible not to see the human vitality, the aspiration and the ambition of the people who live there.

Failure can be an incredibly motivating force.

What we really yearn for as human beings is to be visible.