“Start preparing now,” the Department of Energy (DOE) says in a recently released report intended to provide practical guidance to utilities seeking to integrate intermittent resources onto their systems. The report, entitled Voices of Experience | Integrating Intermittent Resources: What Utilities are Learning, was prepared for DOE by the National Renewable Energy Laboratory, and lays out the challenges, solutions, and lessons learned from integrating variable generation based on the experiences of utilities on the leading edge of integrating intermittent resources. Drawing on information collected from a 90-utility working group including San Diego Gas and Electric, Pepco, Vermont Electric Power Company, and the Salt River Project, the report offers utilities currently facing low levels of intermittent resource penetration the following advice:
Keep up with the Joneses. The report warns utilities that penetration growth rates, particularly those associated with residential solar installations, are likely to follow an exponential growth pattern, with neighbor influence and peer pressure driving growth. According to the report, one neighbor with a solar array increases other neighborhood residents’ likelihood to “go solar” by almost threefold; that figure jumps to nearly sixfold if there is a second solar household in the neighborhood. As a result of this effect, the report cautions that “even if [a utility’s] growth rate is slow and steady now, [the utility] could quickly become inundated with interconnection requests.”
Data, data, data. The report also urges utilities to “[c]apture [their] load profiles.” Because customer-sited rooftop solar can impact load shapes significantly, the report advises utilities of the need to collect and manage newer, more granular data to assist in modeling their systems and studying customer energy usage and hosting capacity.
Have the right tools. Given that “[g]rids are now dynamic and require integrated models that enable operators to look beyond one section at a time,” the report advises utilities of the need to develop system models that can rise to the challenge. Those models should be capable of reflecting equipment characteristics such as phasing, line impedance, generator characteristics, the location of distributed resources, and inverter information, and should be incorporated into the utility’s toolset early on.
Other key topics covered in the report include operational impacts, the interconnection process, planning and forecasting, and customer engagement.