DISCO (Distribution Integration Solution Cost Options) is an NREL-developed, python-based software tool for conducting scalable, repeatable distribution analyses. While DISCO was originally developed to support photovoltaic (PV) impact analyses, it can also be used to understand the impact of other distributed energy resources (DER) and load changes on distribution systems. Analysis modules currently included in DISCO are:
Snapshot hosting capacity analysis, in which hosting capacity is based on a traditional definition of if operating thresholds are exceeded for worst-case/bounding snapshots in time
Snapshot impact analysis, which calculates the same impact metrics as hosting capacity, but for specific user-defined PV deployment scenarios
Dynamic hosting capacity analysis, in which hosting capacity is calculating using quasi-static time-series (QSTS) simulations and dynamic impact metrics for voltage and thermal loading. PV curtailment, number of device (voltage regulator, capacitor switch) operations, and energy losses are also calculated as part of this analysis because excessive PV curtailment, increases in device operations and associated replacement cost increases, and energy losses can also serve to limit how much PV can be economically interconnected to a given feeder.
Dynamic impact analysis, which is to dynamic hosting capacity analysis as snapshot impact analysis is to snapshot hosting capacity analyses.
DISCO analysis is based on power flow modeling with OpenDSS used as the simulation engine. PyDSS (https://nrel.github.io/PyDSS) is used to interface with OpenDSS and provide additional control layers.
The benefit of using DISCO instead of just directly using OpenDSS or PyDSS is two-fold:
DISCO provides the infrastructure required to run a large number of analyses by managing job submission and execution through JADE (https://nrel.github.io/jade/).
DISCO provides ready-made, tested code to calculate snapshot and dynamic impact metrics, allowing for repeatable analyses across projects and teams without having to re-create code to process OpenDSS results.
Examples of how DISCO has been or is currently being used are:
Evaluating curtailment risk associated with using advanced inverter controls and flexible interconnection options for PV grid integration on 100’s of circuits.
DISCO does not yet have the ability to conduct end-to-end techno-economic analyses of different distribution integration solutions, including looking at impact on customer bills, utility revenue, or the economic impact to customers and utilities of reduced electricity demand. Thus, this is not a tool for comprehensive techno-economic analysis.