This release includes several new features, most notably implementation of
pumped storage hydro. It also renames one output file and changes the balancing
rules for hydro systems when there are multiple timeseries in the same
investment period.
The updates are summarized below. For more details, see the
git commit log.
Changes that may affect existing models and results
The switch_model.generators.extensions.hydro_system module now tracks hydro
reservoir levels separately for each timeseries instead of linking them together
across the whole period.
Previously the hydro_system module tracked levels of reservoirs across all
the timepoints in a period, as if each timeseries was linked to the one
after it. This was an error, and in models with multiple timeseries with
different weights, Switch could retain water during low-weight timeseries,
then release it during high-weight timeseries, effectively producing free
energy.
The new approach matches the general principle in Switch that each
timeseries is independent and it must be possible to repeat each timeseries
many times in a row if necessary. Although this is more correct than the
previous approach, it is also more conservative: hydro networks must now
reach the same level (or a prespecified level) at the start and end of each
timeseries, instead of the start and end of each period.
Users should now set res_initial_vol and res_final_vol for each
timeseries in reservoir_ts_data.csv instead of setting initial_res_vol
and final_res_vol for each period in reservoirs.csv. The standard upgrade
script will automatically rename and move these columns if needed. It will
also interpolate between the previous full-period reservoir volumes to set
the reservoir volumes at the start and end of each timeseries.
For models with a single, long timeseries for each period (the most common
use case for this module), this change won't affect results. However, for
models with multiple timeseries in each period with different weights, this
update may change the model results.
The res_initial_vol and res_final_vol inputs are now optional. If
res_initial_vol is set but not res_final_vol, Switch will set the final
level equal to the initial level. If neither is set, Switch will choose an
optimal initial volume for each timeseries and also return to that level at
the end of the timeseries. (For most models, it is best not to set
res_final_vol, so Switch will return the reservoir to the starting level.
This makes it possible to have an arbitrary number of repetitions of each
timeseries.)
The gen_project_annual_summary.csv output file has been renamed to
dispatch_gen_annual_summary.csv. The new name is more consistent with the
other dispatch summaries, such as dispatch_zonal_annual_summary.csv or
dispatch_annual_summary.csv.
New features
The switch_model.generators.extensions.hydro_system module can now model
pumped storage hydro systems.
To use this feature you must also add
switch_model.generators.extensions.storage somewhere above
switch_model.generators.extensions.hydro_system in modules.txt.
Hydro generators can be designated as reversible (able to do pumped hydro
storage) by setting gen_storage_efficiency in gen_info.csv to a numeric
value (generally 0.5 - 1.0).
When generators are identified as reversible, water can be pumped from the
node below the generator to the one above, with the specified round-trip
efficiency. The nodes above and below the generator should have reservoir
data in reservoirs.csv to indicate the amount of storage available. If you
currently have a sink node below the dam, you may need to add a reservoir
with a fixed size for the lower pool, then connect the sink node downstream
of that.
The storage module now defines a new set called ALL_STORAGE_GENS, which will
rarely be used. This is the union of pumped-storage hydro generators and
standard storage generators (usually batteries), which are still listed in
STORAGE_GENS.
If you have installed pulp (easy to do via pip or conda), you can use the
cbc solver bundled with it by specifying --solver pulp_cbc when running
Switch. CBC is a fairly fast solver and can be difficult to install on
Windows, so this may be a convenient way to use it.
The switch_model.balancing.diagnose_infeasibility module now relaxes
bounds on variables in addition to constraints. These will show up in the
reporting as VariableName_bounds, and can be turned back on via
--no-relax VariableName_bounds. This can give a clearer picture of which
constraints and/or bounds are interacting to make a model infeasible.
The switch_model.hawaii.ev module now balances EV charging by date instead
of timeseries, if the tp_date column is provided in timepoints.csv. This
forces full charging every day when using multi-day timeseries, rather than
allowing EVs to delay charging multiple days, possibly exceeding their storage
capacity.
This release includes several new features, most notably implementation of pumped storage hydro. It also renames one output file and changes the balancing rules for hydro systems when there are multiple timeseries in the same investment period.
The updates are summarized below. For more details, see the git commit log.
Changes that may affect existing models and results
switch_model.generators.extensions.hydro_systemmodule now tracks hydro reservoir levels separately for each timeseries instead of linking them together across the whole period.res_initial_volandres_final_volfor each timeseries inreservoir_ts_data.csvinstead of settinginitial_res_volandfinal_res_volfor each period in reservoirs.csv. The standard upgrade script will automatically rename and move these columns if needed. It will also interpolate between the previous full-period reservoir volumes to set the reservoir volumes at the start and end of each timeseries.res_initial_volandres_final_volinputs are now optional. Ifres_initial_volis set but notres_final_vol, Switch will set the final level equal to the initial level. If neither is set, Switch will choose an optimal initial volume for each timeseries and also return to that level at the end of the timeseries. (For most models, it is best not to setres_final_vol, so Switch will return the reservoir to the starting level. This makes it possible to have an arbitrary number of repetitions of each timeseries.)gen_project_annual_summary.csvoutput file has been renamed todispatch_gen_annual_summary.csv. The new name is more consistent with the other dispatch summaries, such asdispatch_zonal_annual_summary.csvordispatch_annual_summary.csv.New features
switch_model.generators.extensions.hydro_systemmodule can now model pumped storage hydro systems.switch_model.generators.extensions.storagesomewhere aboveswitch_model.generators.extensions.hydro_systeminmodules.txt.gen_storage_efficiencyingen_info.csvto a numeric value (generally 0.5 - 1.0).--solver pulp_cbcwhen running Switch. CBC is a fairly fast solver and can be difficult to install on Windows, so this may be a convenient way to use it.switch_model.balancing.diagnose_infeasibilitymodule now relaxes bounds on variables in addition to constraints. These will show up in the reporting asVariableName_bounds, and can be turned back on via--no-relax VariableName_bounds. This can give a clearer picture of which constraints and/or bounds are interacting to make a model infeasible.switch_model.hawaii.evmodule now balances EV charging by date instead of timeseries, if the tp_date column is provided in timepoints.csv. This forces full charging every day when using multi-day timeseries, rather than allowing EVs to delay charging multiple days, possibly exceeding their storage capacity.