45 PV System Capacity Credit

PV systems differ from other DG systems in that they are not dispatchable unless equipped with storage. For that reason, they have been viewed as generator fuel saving. However, recent work has shown that there is significant PV capacity credit for grid penetrations of 20% or less. Using the standard Institute of Electrical and Electronic Engineers (IEEE) load duration curves, Rahim and Kreider (1992) showed, using an hourly simulation, that the equivalent load carrying capacity (ELCC) of a PV plant connected to the IEEE-standard grid was approximately equal to the average electrical output of the PV plant. Recall the earlier key distinction between the peak and average PV system outputs. As a general rule, in sunny climates the average output is about half the peak output under standard rating conditions. This rule of thumb obviously does not apply to overcast or hot climates because both of these factors diminish plant output when compared to the output in a sunny, cooler climate.

The ELCC is defined as the amount of standard fossil generation capacity that can be avoided by connecting PV systems to the grid. Therefore, the net installed cost of a PV system is its initial capital cost reduced by the cost of the avoided conventional plant. Since conventional plants cost about $600 to 1400/kW, depending on the size and type, the net PV system cost (expressed in $/kW) is reduced by this amount multiplied by the average to peak plant output ratio noted above to be about 50% in sunny locations. Therefore, a PV plant that has a gross installed cost of $5000/kW would have a net installed cost of $4300/kW if its installation resulted in avoided capacity installation. The prevailing mode for PV system economic analysis rarely addresses capacity displacement. However, with the new financial markets in electric power, this issue becomes moot since the several types of generation will each ultimately need to charge their full costs.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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