Utility Scale Solar Power Generation
When it comes to produce power at utility scale and network a whole country, PV technology presents three serious limitations and drawbacks:
- Land utilization: The efficiency of a CSP plant (35-45%) is twice as much as the efficiency of the best PV system and therefore the collecting area required is half.
- Dispatchability: PV modules convert light into power instantaneously and therefore electricity not consumed between sunrise and sunset is lost. Battery storage is still very expensive, voluminous and heavy. A CSP solar field augmented with heat storage capability can double the number of hours the field is operational as compared to a field without storage. The CAPEX increased is well offset by the increase of kWh produced.
- Gas backup can further increase the time of operation up to 24/7 pending its availability and cost thus enabling the lowest possible cost of kWh.
- All those characteristics explain and justify why power plants of dozens or hundreds of MW are doable with CSP and impossible to realize with PV.
For sake of balanced comparison, PV technology has three major advantages over CSP:
- It is easily scalable from few Watts to MWs and can be installed on any surface or roof top.
- PV is effective with both diffuse and direct light while CSP (parabolic trough) is effective with direct light only. This limit the use of CSP to the Sun Belt (+/- 5-10o around the equator).
- PV has very low maintenance costs of the lifetime of the system when compared to CSP.
An exhaustive comparison of bCell, standard CSP and PV can be found here.