The Sienna modeling framework effectively builds, solves, and analyzes the scheduling problems and dynamic simulations of quasi-static infrastructure systems.

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To meet the needs of evolving energy infrastructure systems, Sienna develops a foundation to fundamentally advance the nation's ability to model individual and integrated infrastructure systems at a range of spatial and temporal scales. 


The Sienna model applies NREL's capabilities in advanced computer science, visualization, applied mathematics, and computational science to create a first-of its-kind flexible modeling framework that incorporates new solution algorithms, advanced data analytics, and scalable high-performance computing.

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Open-Source Software Suite

Sienna, formally known as SIIP, is a modular framework to answer different questions about future energy systems and consists of open-source software packages that are available on the Sienna GitHub.

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Enables efficient intake and use of energy systems input data. Sienna\Data supports reading from multiple different file formats, consistent representation of millions of devices, time series representations of any device parameters, unit system conversions, and a well-defined user interface.

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Supports the simulation of system scheduling, including unit commitment and economic dispatch, automatic generation control, and nonlinear optimal power flow—along with sequential problem specifications to enable production cost modeling techniques.

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Enables the simulation of power system dynamic response to multiple perturbations and contingencies with large shares of inverter-based resources. Sienna\Dyn has the flexibility to simulate both phasor simulations and balanced electromagnetic transients with different levels of modeling complexity for system components. It also supports small-signal stability and parameter sensitivity calculations with automatic differentiation.

Future Development Plans

Ongoing development will integrate problem decomposition and parallel optimization capabilities to further enhance the computational performance of Sienna software packages. Enhanced connections to NREL's WIND Toolkit and National Solar Radiation Database renewable energy data will ease the lift to create new data sets.

NREL is also working to expand Sienna to represent other infrastructure systems and sectoral interdependencies in the future.

Related Publications

A Multi-Stage Stochastic Risk Assessment With Markovian Representation of Renewable PowerIEEE Transactions on Sustainable Energy (2022)

AGC Simulation Model for Large Renewable Energy Penetration Studies, 52nd North American Power Symposium (2021)

Transient Simulations With a Large Penetration of Converter-Interfaced Generation: Scientific Computing Challenges And Opportunities, IEEE Electrification Magazine (2021)

PowerSystems.jl — A Power System Data Management Package for Large Scale ModelingSoftwareX (2021)

Computational Experiment Design for Operations Model Simulation, Electric Power Systems Research (2020)

Grid Forming Inverter Small Signal Stability: Examining Role of Line and Voltage Dynamics, 46th Annual Conference of the IEEE Industrial Electronics Society (2020)

Grid-Coupled Dynamic Response of Battery-Driven Voltage Source ConvertersIEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids (2020)


Slack: @NREL-Sienna