Weinberg is the principal of Weinberg Associates, which he founded in 1993 after 19 years with the Pacific Gas and Electric Company where he effectively managed and grew an internationally respected energy research and development program. Weinberg Associates was formed with the primary objective of accelerating the introduction of renewable and distributed power systems.

He is a recognized and respected spokesperson with a comprehensive view encompassing and integrating technical, regulatory, policy and environmental perspectives. Most recent activities involve policy issues and their technical considerations in the restructuring of the utility industry, with particular emphasis on the concept of sustainability in a competitive framework, and the introduction of distributed resources. He serves on the boards and working level committees of numerous energy efficiency and renewable energy organizations in the public and private sector. He was a member of the review panel for California's Public Interest Energy Research Program.