Storage technology optimization

Energy storage allows us to synchronize energy supply (whether from a renewable resource or a vehicle charging station) and energy demand. The development of future storage technologies requires an understanding the dynamics of energy consumption. Here we analyze energy consumption in order to determine lab-scale performance targets for storage technologies.

Design rules for electric vehicle batteries: By studying patterns of travel and energy consumption in the transportation sector, we are identifying requirements for electric vehicle batteries. In addition, we have uncovered several surprising patterns in commuting across cities of various sizes, shown in Figure 1.

Figure 1. Comparison of driving patterns between four major US metro areas. Driving patterns, as characterized by the distance and duration of vehicle trips, are more similar than anticipated between cities with disparate population densities and road networks. Because of this, identifying broad performance requirements for electric vehicle batteries may be possible. Black dots represent the nation-wide distribution of trip distances, red dots represent the city listed. “M/M/M” corresponds to mean, median, and mode values, “n” is the survey sample size. Data has been filtered to reduce rounding bias in survey data. Data from 2009 US National Household Travel Survey.

Stationary, large-scale energy storage optimization: We are studying patterns of electricity consumption and comparing them to changes in solar and wind availability throughout the day (Figure 2). From this analysis we are able to identify optimal properties for future storage materials and devices, and compare current technologies to these performance targets.

Figure 2. Price, energy resource dynamics, and the impact of storage. A) Cumulative distributions of hourly solar and wind capacity factors, and electricity prices. B) The frequencies and amplitudes of resource and price peaks. C) Energy resource and price time series, and the impact of storage in shifting generation to times of peak price (dotted to solid lines).

  • Braff, W. A., Trancik, J. E., Guidelines for Stationary Energy Storage Technology Development, in final preparation for submission.