NVRAM-based Burst Buffers are an important part of the emerging HPC storage landscape. The National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory recently installed one of the first Burst Buffer systems as part of its new Cori supercomputer, collaborating with Cray on the development of the DataWarp software. NERSC has over 6500 users in 750 different projects spanning a wide variety of scientific applications, including climate modeling, combustion, fusion, astrophysics, computational biology, and many more. The applications of the Burst Buffer at NERSC are therefore also considerable and diverse. We describe here experiences with the first year of the NERSC Burst Buffer. A number of research projects have had early access to the Burst Buffer and exercise its different capabilities to enable new scientific advancements. We present in-depth performance results and lessons-learned from these real applications as well as benchmark results and system configuration experiences.