419 



Note that in this 1991 POWER PLAN "costing model-, 

 higher efficiency goals are favored, apparently 

 awaiting a very unlikely 25X flat-plate efficiency in 

 $52/m* modules for 9</kHh cost of energy in order to 

 approach a 'regional avoided cost in the year 2000' of 

 8t/kWh compared to the present 2.6«/kWh. This DOE '83 

 Nomograph that has been used over the past decade to 

 prompt the 'efficiency race" and to send large-scale 

 solar photovoltoics back to research and development in 

 PV cell and PV module EFFICIENCY. 



Improved efficiency is good, fewer unit generators 

 being needed for a specific plant capacity. Since 

 solar-fuel is zero-cost delivered at the site, there 

 isn't the same persuasion toward efficiency or heat- 

 rate improvements as for expensive fossil and mineral 

 fuels with expensive pollution content. If saving 

 fuel and pollution limitation doesn't drive PV 

 efficiency, what does? In the 1991 POWER PLAN 

 'fundamental solar equation" the high Plant cost of 

 $2822/kW is largely dependent on per square meter costs 

 of the balance-of-plant required to support a given 

 capacity of solar photovoltaic generator modules. 

 However, if the balance-of-plant is a low cost, say 

 less than $160/kW, then a SOX improvement in unit 

 generator fuel-rate, e.g., from 0.1 to 0.15 (lOX to 15X 

 efficiency), yields a balance-of-plant less than 



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