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HOMER Pro 3.9

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Required Operating Reserve

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Required operating reserve is the minimum amount of operating reserve that the system must be capable of providing. HOMER calculates the required operating reserve for each time step based on the values that you enter on the Constraints window. Whenever possible, HOMER ensures that enough dispatchable capacity is available to keep the operating reserve equal to or greater than the required operating reserve. HOMER records any shortfall as a capacity shortage.

Because operating reserve guards against increases in the load or decreases in the renewable power output, the required operating reserve is a function of both the load and the renewable power output (specifically, the solar and wind power output, since the hydro power output typically experiences little short-term variability). The amount of required operating reserve therefore typically changes from one time step to the next. In each time step, HOMER calculates the required operating reserve on the AC and DC buses using the following equations:

equations_L_res,AC

equations_L_res,DC

where:


 

 

Lres,AC

is the required operating reserve on the AC bus

 

Lres,DC

is the required operating reserve on the DC bus

 

rload

is the input 'operating reserve as a percent of load in the current time step'

 

Lprim,AC

is the average AC primary load in the current time step

 

Lprim,DC

is the average DC primary load in the current time step

 

rpeakload

is the input 'operating reserve as a percent of annual peak load'

 

symbols_Lhat_prim,AC

is the highest AC primary load experienced by the system during the year

 

symbols_Lhat_prim,DC

is the highest DC primary load experienced by the system during the year

 

rwind

is the input 'operating reserve as a percent of wind power output'

 

Pwind,AC

is the average AC wind power output in the current time step

 

Pwind,DC

is the average DC wind power output in the current time step

 

rsolar

is the input 'operating reserve as a percent of solar power output'

 

PPV

is the average PV array output in the current time step

See also

Maximum Annual Capacity Shortage

Total Capacity Shortage

Capacity Shortage Fraction