Units of measure
NEMO uses units of measure in the following categories:
- Energy
- Power
- Costs
- Emissions
When you define a scenario, you choose units in these categories and must employ them consistently across parameters. Each scenario can have one cost unit and one emissions unit. Energy and power units can vary by region within a scenario, but it's generally easier to select a single energy unit and a single power unit for all regions.
Typical units for a national-scale NEMO model are petajoules for energy, gigawatts for power, million $ for costs, and metric tonnes for emissions. These are the units LEAP uses with NEMO.
Two parameters define the relationship between power units and energy units.
CapacityToActivityUnit: For a given region, the power unit * 1 year, expressed in terms of the energy unit. For example, if the power unit is gigawatts and the energy unit is petajoules, this parameter should be 1 GW-year expressed in PJ, or 31.536 PJ/GW-year. NEMO uses CapacityToActivityUnit when translating between the capacity of technologies and their energy outputs and inputs.
TransmissionCapacityToActivityUnit: For a given region, one megawatt-year expressed in terms of the energy unit. For example, if the energy unit is petajoules, this parameter should be 0.031536 PJ/MW-year. NEMO uses TransmissionCapacityToActivityUnit when converting energy flowing over transmission lines into the appropriate energy unit. The power unit for transmission lines is always megawatts in NEMO.