Bug fixes and maintenance:

• NaturalNameWarning while saving
• Paranthesis in transmission constraint
• Plotting of all commodity types

• Maintenance: Modularity (only features which are used are built)
• Maintenance: New structure of documentation
• Feature: Time variable efficiency
• Feature: Objective function can be changed to CO2
• Feature: Intertemporal feature (expansion between years)
• Feature: Input validation (having easier to understand error messages due to Excel file)
• Feature: Reconstruction of partial feature
• Feature: Global constraints instead of Hacks
• Bugfixes: Many

• Bugfix: Buggy startup feature removed
• Bugfix: Part-load behaviour fixed
• Bugfix: Consistent CO2 tracking in part-load
• Bugfix: Pyomo/Numpy errors fixed via reordering of equations
• Bugfix: CO2 level of zero possible
• Bugfix: Path creation for copying files fixed
• Maintenance: Simplification of input logic of buy/sell
• Maintenance: Speed up of model building
• Feature: Input Validation
• Feature: Report/plot sites names (set another name for multiple site plot)
• Feature: Multiple sites summed in report

• Bugfix: area_feature, dsm
• Maintenance: Updates in doc
• Maintenance: Major speedup in model creation
• Maintenance: 'Hacks' renamed to global in input file
• Feature: Self-discharge of storages added
• Feature: Multi-commodity plots in comp.py

• Maintenance: Model file urbs.py split into subfiles in folder urbs
• Feature: Usable area in site implemented as possible constraint
• Feature: Plot function (and get_timeseries) now support grouping of multiple sites
• Feature: Environmental commodity costs (e.g. emission taxes or other pollution externalities)
• Bugfix: column Overproduction in report sheet did not respect DSM

• Removed support for Pyomo 3 (a.k.a. coopr). Please upgrade your Pyomo installation before using this release.
• New feature: retrieve dual variables for Constraint objects using get_entity(). See new rundual.py script for a usage example.
• New features: added linear formulation of startup costs and partial load efficiencies to conversion processes. See documentation about Partial & Startup Process Constraints for more details.

• Support for Python 3 added
• Support for Pyomo 4 added, while maintaining Pyomo 3 support. Upgrading to Pyomo 4 is advised, as support while be dropped with the next release to support new features.
• New feature: maximal power gradient for conversion processes
• Documentation: Buy-Sell Documentation long explanation for Buy and Sell commodity types
• Documentation: Mathematical Documentation full listing of sets, parameter, variables, objective function and constraints in mathematical notation and textual expanation
• Documentation: updated installation notes in README.md
• Plotting: automatic sorting of time series by variance makes it easier to read stacked plots with many technologies

• Additional commodity types Buy and Sell, which support time-dependent prices.
• Persistence functions load and save, based on pickle, allow saving and retrieving input data and problem instances including results, for later
• re-plotting or re-analysis without having to solve them again.
• Documenation: Workflow tutorial added with example "Newsealand"

• Processes now support multiple inputs and multiple output commodities.
• As a consequence plot() now plots commodity balance by processes, not input commodities.
• urbs now supports input files with only a single site; simply delete all entries from the ‘Transmission’ spreadsheet and only use a single site name throughout your input.
• Moved hard-coded ‘Global CO2 limit’ constraint to dedicated “Hacks” spreadsheet, while the constraint is add_hacks().
• More docstrings and comments in the main file urbs.py.