The car sharing heavyweight Zipcar filed for an IPO this week, looking to raise $75 million. With a fleet of 7,000 vehicles, more than 400,000 members (who can rent the car by the hour or day), Zipcar relies on the web, software, data centers, GPS, mobile networks and other communication tools to provide mobility as a service.

The founder of, and former owner of, Gary Kremen, is now an investor in early stage greentech startups. Kremen told Earth2Tech that he “wanted to do something positive for society after doing evil porn for so many years.”

The new battle between phone companies AT&T and Verizon is over the power grid. Both telecom firms are looking at convincing utilities to sign up to run smart grid services over their cellular networks.

The semiconductor industry has been seeding greentech startups with executive leaders that want to do something good for the world and move into a growing market. Here’s 10 executives that left the chip biz to run greentech startups.

General Motors wants do be a venture capitalist. This week the automaker announced it has created a $100 million fund to invest in green transportation startups.