PRECISE: PREconfiguring and Controlling Inverter SEt-points

2019 R&D 100 Winner

NREL’s PRECISE™—PREconfiguring and Controlling Inverter SEt-points—helps utilities seamlessly interconnect distributed solar energy, cutting the wait time and costs for customers and their utilities.

PRECISE combines detailed distribution system modeling with analyses of grid conditions to provide custom solutions tailored to fit each utility’s unique local needs. This functionality has won PRECISE an R&D 100 award and has helped customers safely install more solar energy across the world.

Solar power is arriving fast—sometimes faster than it can be managed. Each new solar photovoltaic (PV) system involves a new technical configuration, which is currently being assessed manually, increasing demand on utilities' already-burdened planning engineers.

PRECISE is the industry's one-stop solution for this challenge, and it is available for license. The tool performs fast and automated interconnection assessments and seamlessly integrates with each utility's existing business interconnection workflow.

Customizable Automation Tool for Interconnecting Customer Solar

With PRECISE, as soon as a customer applies for rooftop PV system installation, the platform can identify exactly where the interconnection is located on the network based on the customer's interconnection address. PRECISE then models the distribution feeder and preconfigures advanced inverter modes that provide grid support and minimize energy curtailment, enabling seamless interconnection with much less wait time.

New customers can interconnect their solar quickly, and utilities can automate a process that would take twice as long otherwise.

Graph illustration that shows the Precise Tool operating in the optimal range between customer loss and utility loss.

PRECISE creates value for both customers and utilities. Optimal inverter settings strike a balance between curtailing customer energy and cost-effectively using customer devices for grid stability.

By programming the best settings for each circumstance, utilities can keep solar running  without risking stability issues.

Novel Features and Capabilities

PRECISE includes the following features and capabilities:

Distribution Power Flow

Utilities can interface with local distribution system detail using PRECISE. Select features include:

  • Visibility of network topology and geographic location of solar systems
  • Capability to perform power-flow analysis
  • Conversion tool from GIS/Synergi to OpenDSS
  • Choice of advanced inverter modes for analysis.

Inverter Optimization

The tool uses quasi-static time series simulations, alongside mathematical optimization, to identify optimal inverter modes. Users can program the constraints and physical hardware limitations, which lead to PRECISE’s identification of those advanced inverter modes. Features include:

  • Adherence to grid interconnection standards
  • Adherence to limitations from power-factor limits or reactive power limits
  • Parameterization of weather events and local grid conditions.

Personalized Deployment Options

PRECISE seamlessly integrates with utilities’ existing business interconnection workflow. Utilities can choose to deploy the tool in-house under the security of their private networks, deploy via the cloud, or choose a hybrid option in which PRECISE APIs get deployed in the cloud and connected to existing in-house infrastructure.

Visualization and Data Ingestion

PRECISE is equipped with a user platform that makes data input–such as customer solar interconnection applications–easy. Users can visualize the effects of specific inverter modes and device management decisions.

Seamless Technology Integration

PRECISE can integrate with a diverse range of technologies including PowerClerk, Oracle, Microsoft’s SQL Server, Apache Hadoop, OpenDSS, Docker, Control-M, and more.

Download the PRECISE white paper to learn more.


PRECISE™ Launches

Aerial view photo of Sacramento's Tower Bridge and the Sacramento River, looking towards the Capitol mall and building.

Sacramento Municipal Utility District

The Sacramento Municipal Utility District (SMUD)—a leading utility in California—reached out to NREL to help solve pain points in its interconnection processes given rising customer solar requests. PRECISE went live at SMUD in 2022 and processed an average of 13 applications per business day and as high as nearly 30 applications in one day. The tool itself can scale to process any number of applications—through automation, data integration, and fast computing techniques, PRECISE can easily handle hundreds of applications daily. Close collaboration between NREL engineers and a diverse SMUD team was vital to the success of the project, which enabled the full integration and automation of PRECISE. The project was the first automation of the technical interconnection evaluation process of its kind, and one that could serve as a template for many utilities that wish to automate the increasing challenge of evaluating new interconnection requests.

Future Development Plans

NREL is exploring applying PRECISE's automated evaluations to other inverter-based distributed energy resources, such as battery energy storage and electric vehicles.


Studies on the Effects of High Renewable Penetrations on Driving Point Impedance and Voltage Regulator Performance: National Renewable Energy Laboratory/Sacramento Municipal Utility District Load Tap Changer Driving Point Impedance Project, NREL Technical Report (2018)

In the News

NREL and SMUD Launch Groundbreaking Automation Tool for Interconnecting Customer Solar to the Grid, NREL (2022)

NREL's PRECISE Helps Interconnect SMUD Customers' Solar PV for Better Performance, in Half the Time, NREL (2018)

Licensing and Demos

Are you interested in licensing or a demo of the tool's capabilities? Reach out to the PRECISE team.


Killian McKenna

Senior Research Engineer, Grid Planning Analysis