BREOS - Building Renewable Energy Optimization Software

BREOS is a Python library for simulating and optimizing household PV + battery energy systems (weather, PV production, battery aging, economics, emissions, and multi-objective sizing) behind one stable breos.App facade, with lower-level modules for building custom study pipelines.

📖 Full documentation: breos.readthedocs.io

Features

• Weather — TMY from PVGIS/NSRDB and historical data from Open-Meteo, at hourly or 15-minute resolution.
• PV production — pvlib CEC single-diode model, with a small example module catalog to get started.
• Multi-array roofs — combine multiple faces/orientations (e.g. east-west) at the DC stage instead of one representative tilt.
• Battery — energy balance with calendar + cycle aging (Naumann 2020, Lam 2025) and field-calibrated LFP parameters.
• Economics — NPV, LCOE, breakeven, and cost projections with configurable tariffs and inflation.
• Monte Carlo — weather-year and demand resampling for NPV, payback, grid-independence, LCOE, and SoH distributions.
• Optimization — multi-objective PV/battery sizing (pymoo NSGA-II), tilt optimization, and sizing sweeps.
• Emissions — CO₂ savings and projections.
• Visualization — publication-ready plots for energy balances, degradation, breakeven, and Pareto fronts.
• Bring your own data — every layer accepts custom inputs: PV module parameters, battery degradation coefficients, weather CSVs, residential load profiles, and cost/tariff/emissions assumptions. The packaged presets are starting points, not fixed defaults.

Installation

pip install breos

Or with uv:

uv add breos          # as a project dependency
uvx breos --version   # run the CLI without installing

The default install is a lean core. Some workflows need optional extras (e.g. optimization, historical weather, plots):

pip install "breos[optimization,weather,plots]"

See the installation guide for the full list of extras and a source/uv setup.

Quick Start

import breos

app = breos.App({
    "location": "porto",              # preset or {"latitude": ..., "longitude": ..., "timezone": ...}
    "n_modules": 10,
    "annual_consumption_kwh": 4000,
    "battery_kwh": 5.0,               # 0 for no battery
    "cost_preset": "residential_pt",
    "emissions_country": "PT",
})

app.simulate()
result = app.result()

print(f"Grid independence: {result['grid_independence_pct']:.1f}%")
print(f"Payback: {result['payback_year']} years")
print(f"NPV savings: {result['npv_savings_eur']:,.0f} EUR")

result() returns a plain JSON-serializable dict. The configuration reference lists every option, and interpreting results documents every output field.

For real studies, bring your own weather/API access where required (NSRDB needs an NREL API key; PVGIS and Open-Meteo do not), licensed load profiles, and your own cost/tariff assumptions. The packaged defaults make the tool runnable, not project-grade.

Command Line

Run a simulation without writing Python:

breos run --location porto --n-modules 10 --annual-consumption-kwh 4000 \
  --battery-kwh 5.0 --cost-preset residential-pt --emissions-country pt \
  --output result.json

The CLI also drives config files, parameter sweeps, and Monte Carlo studies, and breos list <category> shows bundled presets (locations, modules, cost presets, …). See the CLI recipes.

Citation

If you use BREOS in your research, please cite the preprint:

@misc{rodrigues2026breos,
  author = {Rodrigues, L. and Delgado, J. M. P. Q. and Mendes, A. and Guimar{\~a}es, A. S.},
  title  = {A Modular, Open-Source Python Framework for Household PV-Battery Sizing: Validation, Multi-Objective Optimisation, and Uncertainty Analysis},
  year   = {2026},
  doi    = {10.2139/ssrn.7032064},
  url    = {https://papers.ssrn.com/sol3/papers.cfm?abstract_id=7032064},
  note   = {SSRN preprint}
}

Contributing

See CONTRIBUTING.md. Feature work happens on branches off develop and merges via pull request; main tracks stable releases only.

Contact

For questions, collaboration, or access to additional modules: lrodrigues@fe.up.pt.

License

BSD 3-Clause. See LICENSE.