SUMR-D horizontal (IMAGE) University of Colorado at Boulder Caption The two-bladed, 53.38 kilowatt demonstrator (SUMR-D) at the National Renewable Energy Laboratory’s (NREL) Flatirons Campus, just south of Boulder, Colorado. Credit Kelsey Simpkins / CU Boulder Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.