 I conceive of this whole area of energy as a triangle of technology, policy, and finance. And technology is at the top. That is because policy and finance in our minds exist to drive technology out of the labs and into full-scale cost-effective deployment. When I talk about clean energy, I'm talking about lower-carbon and zero-carbon technologies. It's all of the renewables, not just solar and wind, but hydropower and biomass and geothermal. Nuclear power figures into this. Policy looms large in so many different ways in the energy context, and I truly do believe that it can make or break many energy technologies. We incentivize clean energy through policy, particularly through the U.S. federal government, in a whole host of ways. Policy determines how efficient your refrigerator is in your house. That's set by regulators. We've seen dramatic improvements in energy efficiency technologies. We went from the incandescent light bulb to the compact fluorescent light bulb to the LED. Finance looms large in the development and the deployment of all energy technology. It is a highly capital-intensive business. And the challenge with clean energy technology is that a fair amount of it, when you first deploy it, is often risky. You've got to make sure we tune things up well enough when it comes to clean energy that we can make this jump from the current investment levels of three-quarters of a trillion dollars to more than two trillion dollars each and every year. Where that capital is going to come from is a very naughty question. So one of the areas that I'm interested in is this intersection between policy and finance. In other words, how can policy mechanism drive more capital, lower cost capital, towards clean energy? It starts with basic R&D, basic science. From there, the federal government can get involved in actually helping to commercialize the technology. That is, how do you get the first couple of commercial-scale projects built? This is something that, for example, we use a technique called loan guarantees. One of the largest areas of federal policy when it comes to clean energy involves tax credits for renewable energy. Tax credits can help cut the cost of getting that technology to scale. I believe that all of this that we're talking about in the triangle of technology, policy, and finance is working in many respects. We've seen dramatic drops in the cost of various renewable energy technologies. But having said all that, we still have a long way to go on a whole host of technologies. We really measure our success in the likelihood that a technology is going to get developed and ultimately get deployed. And policy and investment have a lot to say about whether or not that happens.