Tarpenning was raised in Sacramento, Calif., and earned a bachelor’s degree (1985) in computer science from the University of California, Berkeley.
He began his career working for the conglomerate Textron in Saudi Arabia. Tarpenning then developed software and firmware products for several companies, including Seagate Technology and Bechtel, and later served as vice president of engineering at Packet Design, a network technology company.
In 1997 Eberhard and Tarpenning cofounded NuvoMedia, an e-book venture that produced the Rocket eBook (1998). Eberhard served as CEO and Tarpenning led development until 2000, when NuvoMedia was sold to Gemstar–TV Guide International for $187 million. In 2003 Eberhard and Tarpenning teamed up again to launch Tesla Motors, a company dedicated to developing an electric sports car. Funding for the company was obtained from a variety of sources, most notably PayPal cofounder Elon Musk, who contributed more than $30 million to the new venture and served as chairman of the company.
In 2006 Tesla Motors announced that its innovative, completely electric Tesla Roadster prototype had achieved an unprecedented range of 245 miles (394 km) on a single charge in company tests. Additional tests showed that the then $98,000 (later $109,000) sports car could accelerate from 0 to 60 mph (96 km/h) in less than four seconds and could reach a top speed of 125 mph (200 km/h). The lightweight car body was made of carbon fiber. The roadster produced no tailpipe emissions, as it did not use an internal-combustion engine. Tesla Motors found that the car attained efficiency ratings that were equivalent to a gasoline mileage of 135 miles per gallon (57 km per liter). The vehicle’s electric motor was powered by lithium-ion cells—often used in laptop-computer batteries—that could be recharged from a standard electric outlet. The initial roadsters were delivered to owners in 2008. Following the success of the roadster, the company diversified its product line by developing prototypes for more affordable electric cars.
Tarpenning was vice president of electrical engineering, supervising the development of electronic and software systems for the roadster, and was CFO for several years. He also left the company in 2008.