Photo of Andy Walker

Andy Walker

Senior Research Fellow I-Mechanical Engineering


As a senior research fellow, Dr. Andy Walker helps inform the strategy of the lab and serves as a resource for helping staff develop ideas and ensure quality. He develops new methods for engineering and economic analysis of energy efficiency and renewable energy projects. His patent on the Renewable Energy Optimization method of planning renewable energy projects across a portfolio of properties based on economic value was awarded the Thomas A. Edison Patent Award in 2015 based on innovation and impact. He teaches as an adjunct professor at the University of Colorado at Boulder, Colorado School of Mines, and Metropolitan State University of Denver. He has led the Solar Energy Division of the American Society of Mechanical Engineers (ASME) and is an ASME Fellow.

Walker conducts engineering and economic analysis of energy efficiency and renewable energy projects for federal agencies, such as national parks and military bases, and for commercial and industrial clients. He has helped plan projects for:

  • 42 Anheuser-Busch facilities
  • Seven Frito Lay factories, which resulted in a 5,200-m2 solar thermal system in Modesto, California, and a "net zero" manufacturing plant in Casa Grande, Arizona, incorporating solar thermal, biomass, and photovoltaics
  • An engraving and printing plant where U.S. currency is manufactured
  • International shoe and garment manufacturers
  • Other manufacturing facilities considering renewable energy (photovoltaics and solar thermal).

Research Interests

Derivation of probabilistic cost modeling

Subinterval distribution function for time-series simulation

Analytical and numerical optimization

Project delivery with photovoltaics, solar thermal, and building energy


Ph.D., Philosophy, Mechanical Engineering, Colorado State University

M.S., Mechanical Engineering, Colorado State University

B.S., Mechanical Engineering, Energy Conversion and Bioengineering, Colorado State University

Featured Work

Sustainable Energy Technologies, Chapter 5, Integration of Renewable Energy Technologies in Buildings and Cities (2018)

REopt: A Platform for Energy System Integration and Optimization, NREL Technical Report (2017)

Large-Scale Power Production Potential on U.S. Department of Energy Lands, NREL Technical Report (2017)

Best Practices in Photovoltaic System Operations and Maintenance: 2nd Edition, 2016, NREL/Sandia/Sunspec Alliance SuNLaMP PV O&M Working Group, NREL Technical Report (2016)

Integration of Renewable Energy Systems, American Society of Mechanical Engineers Technologies for Sustainable Life (TSL) — Concise Monograph Series (2016)

Solar Energy: Technologies and Project Delivery for Buildings, Published by John Wiley and Sons Inc. (2013)

District/Central Solar Hot Water Systems Design Guide, Published by American Society of Heating Refrigerating and Air Conditioning Engineers Inc. (2013)

Implementing Solar PV Projects on Historic Buildings and in Historic Districts, NREL Technical Report (2011)

Green Building: Project Planning and Cost Estimating, RS Means and Co. (1st Edition 2002, 2nd Edition 2006, 3rd Edition 2010)

Procurement of Architectural and Engineering Services for Sustainable Buildings-A Guide for Federal Project Managers, DOE FEMP Publication (2004)