Intermittent Generation

The intermittent generation technology in DER-VET is modeled most closely after a solar photovoltaic (PV) system, though can be used to represent a wind generator or other intermittent generation.

The PV technology option (with optional curtailment) generates electricity according to a dimensionless time series generation input (kW/kW_rated) multiplied by its rated capacity, which can be a user input or can be determined by the optimization.

Inputs

Curtailment

Tag	Key	Description
PV	curtail	This binary (0 or 1) input determines whether the solar can be curtailed (1) or not (0). When solar can be curtailed the solar generation will be an optimization variable instead of a parameter. This optimization variable will be constrained between 0 and the maximum generation enabled by the current weather conditions. Curtailment is useful to avoid infeasibilities that can arise from requiring a storage system to charge beyond 100% SOC to meet an interconnection constraint.

Inverter Size

Tag	Key	Description
PV	inv_max	The inverter maximum will limit the solar generation (in AC kW). If a storage system is DC-coupled with the solar system, the inverter maximum will limit the combination of solar and storage power.

Location

Tag	Key	Description
PV	loc	This input determines whether any storage systems present are AC-coupled (ac) or DC-coupled (dc) with the solar system. Note: This input should be 'ac' to model a wind generator.

Rated Capacity

Tag	Key	Description
PV	rated_capacity	The rated capacity (in AC kW) of the solar system is multiplied by the dimensionless generation input (kW/kW_rated) to determine the maximum AC power generation from the solar system before curtailment.

Grid Charging

Tag	Key	Description
PV	grid_charge	This binary (0 or 1) determines whether any storage systems in the DER mix can charge from the grid (1) or only from local generation (0).

Growth

Tag	Key	Description
PV	growth	Is the PV generation growing over time? For a fixed-size PV array, this should be 0. This can be non-zero in the case where the PV technology is meant to represent an aggregation of customers, some of whom may install PV during the analysis window or other similar scenarios.

PV Power Variability

Tag	Key	Description
PV	nu	Minimum percent of PV generation one can expect within a timestep. This is used exclusively in reliability calculations and ensures the microgrid will always have enough power capacity to meet critical load, even during momentary PV generation dips caused by clouds, etc.

PV Energy Variability

Tag	Key	Description
PV	gamma	Percent of the timestep for which PV is at its minimum generation (nu). This is used exclusively in reliability calculations and ensures the microgrid will always have enough energy stored/available to cover critical load, even during momentary dips in PV generation.