Alexander Farrell, renowned researcher, professor, and director of the Transportation Sustainability Research Center at the University of California at Berkeley has died at the age of 46. He was found by police in his home on Tuesday, but the cause of death is yet unknown.

Professor Farrell’s work was highly influential in the world of green transportation and its relationship to global warming. His research spanned in the areas of biofuels, hybrid technologies, and hydrogen fuel cells. He worked directly with the California Air Resources Board and played a key role in the search to find methods to reduce greenhouse gas emissions from vehicles. So much so, that he was selected last year by Governor Arnold Schwarzenegger to co-author the state’s low-carbon fuel standard. “We’re very upset, sad and regretful about Alex’s death,” Mary Nichols, chairwoman of the California Air Resources Board told the San Francisco Chronicle. “He was a tremendously important member of our team working on low-carbon fuels and biofuels.”

Perhaps his most important contributions came in the field of biofuel research and the environmental effects of ethanol. Farrell analyzed the overall impacts of fuels throughout their lifecycles, and their effects on the individual ecological components; air, water and land. His work in this area was considered ground breaking by others in the energy community. “He was one of the leading lights in the area of low-carbon fuels and energy systems, and his career was on a dramatic rise,” Dan Kammen, a professor in the Energy and Resources Group told UC Berkeley News.

Farrell was heavily published and served on various scientific advisory committees and consultancies. After starting his career in the Navy, he earned a PhD from the University of Pennsylvania in Energy Management and Policy and was a fellow at Harvard University’s John F. Kennedy School of Government.

Farrell is survived by his mother, two brothers, a sister, two nieces, and a nephew.