Bill Joy helped develop the climate change and sustainability investment strategy at the venture capital firm Kleiner Perkins Caulfield & Byers, which is known mainly for its investments in companies such as Amazon.com and Google.

Joy is also famous for building BSD Unix, a computer operating system that has had a big impact on the computer industry and the development of the Internet. As a cofounder and chief scientist at Sun Microsystems, he developed key technologies such as the programming language Java.

As an investor, Joy has backed several high-risk solar power companies. Technology Review talked to him about lessons learned from failed investments in solar companies, and what it will take for innovative solar companies to succeed.

TR: With the failure of Solyndra, and hard times for many other solar companies, solar investments have come under scrutiny. What's gone wrong?

Joy: Many have been badly managed, or badly conceived. The trouble comes if you're not good enough to make a difference. I think a lot of the solar ventures haven't had enough differentiation. They haven't been enough better than the trajectory of the incumbents.

[At Kleiner Perkins Caulfield & Byers] we've had some failures, but that's because we've been aiming well ahead of where the conventional technology was going to go. The alternative is that you can try to do something that isn't as far ahead. So then what's the point? You're just doing almost the same thing using immature manufacturing that everyone else is doing using mature manufacturing. That's no recipe to win.

You mentioned failures at KPCB—what went wrong there?

Solasta was an attempt to build a three-dimensional nanostructure [for solar panels] that would've had better physics, and the difficulty there, I think, was fabrication. We were unable to come up with a technique for making the devices that we wanted. We didn't have the time to wait for the new technology to make it work.

Intel's new transistors—they're turned up in the third dimension—I heard they spent something like $7 billion and had a thousand PhDs. It was an extremely large program, and went on for a long time. We can build patterns that are planar, but to build structures that are vertical, and that fine-scale, is very difficult. Solyndra was trying to deposit on a nonplanar surface. Doing stuff on a planar surface is easy. Anything beyond that is difficult.