iconOur Leaders


Peter Lilienthal

Peter Lilienthal, Ph.D., Chief Executive Officer

Dr. Peter Lilienthal is the original developer of the HOMER® software and founded HOMER Energy in 2009 to enhance and commercialize the software. He has a Ph.D. in Management Science and Engineering from Stanford University.  Peter has been active in the field of renewable and distributed energy and energy efficiency since 1978. Before founding HOMER Energy, he was president of Green Island Power, which provided analytical services for renewable and distributed power projects. From 1990-2007 he was Senior Economist with the International Programs Office at the National Renewable Energy Laboratory. His experience has included project development of distributed power projects, designing and teaching courses at the university level, and consulting to industry and regulators. His technical expertise is in utility modeling and the economic and financial analysis of renewable and distributed power projects. He was the lead analyst and one of the creators of NREL’s International and Village Power Programs.

Marilyn Walker

Marilyn Walker, Ph.D., Chief Operating Officer

Dr. Walker is a serial entrepreneur and experienced technologist. She started her career in academia, earning a Ph. D in Biology from the University of Colorado and publishing over 50 technical publications on modeling and environmental analysis. In the university setting, she raised over 12 million dollars to make her programs financially sustainable and gained valuable knowledge in the fields of software, databases, modeling, and analysis. After 20 years in academia, she became an entrepreneur by purchasing, managing, and selling a successful business, PlayFair Toys. She founded and built two e-commerce companies, and has led multiple international and multidisciplinary teams. Dr. Walker brings her unique, in-depth experience in environmental systems and business operations to her role as COO.

Andy Kruse

Andy Kruse, VP of Business Development

For nearly 30 years Andy Kruse has been involved in international marketing, sales development of certification standards and public policy. Andy was a co-founder of Southwest Windpower, a start-up small wind company that grew to be an internationally recognized brand within the clean energy industry. Southwest Windwopower sold more than 180,000 wind generators worldwide. Later he joined Endurance Wind Power and established one of the first small wind leasing programs in the U.S. Just before joining HOMER Energy, he worked as a consultant to a number of wind and solar companies in Europe. Andy was awarded Exporter of the year by the US Export-Import Bank, and he received the President’s E award from the US Department of Commerce. The American Wind Energy Association awarded him Small Wind Person of the Year in 2009.

Diane Rieck

Diane Rieck, Controller

Diane has long been involved and interested in the environmental sector and serves as HOMER Energy’s Controller. She was a founding member of Wildlands Restoration Volunteers in Boulder, later taking over their accounting operations and in addition has worked with multiple local accounting clients over the last decade. Previously, Diane worked for American Express in New York City. She has an MBA from New York University and was an active volunteer for NRDC. Diane loves balance, a theme she sees compatible and necessary in both accounting and nature. She enjoys biking, hiking, gardening, knitting, cooking, reading, the list goes on and on…

Steffi Klawiter

Steffi Klawiter, Product Manager

With a Masters in Renewable Energy Management, Steffi applies her experience with various renewable systems to the HOMER world including: feasibility analysis and modeling distributed generation. Working at HOMER continues to inspire her interests in distributed energy, microgrids, and solar energy on the international level.

Jack Clayton

Jack Clayton, Director of Information Technology

Jack Clayton brings a unique perspective to our IT infrastructure and websites. With an MBA, a physics degree, and over 20 years of web development experience in everything from multi-million dollar online retailers to greenfield start-ups, Clayton enjoys finding economic solutions to everyday problems, and he helps implement our marketing strategy in the most effective way possible. He also enjoys dark beer, cycling, and dogs.