Subject: What are the costs in constructing solar tower & line focused solar collectors?

From: Wally Bently <[email-masked]>
Date: Sat, 18 Jan 1997 20:19:11 -0600

1997 January 18th. 

I recently looked at the home page by Sandia corporation in regards to
the solar tower they constructed in the late 1970's.  I am trying to 
establish current 1990 realistic numbers and where further cost
reductions are needed.  

    The following were some costs for the 222 helio-stat mirror
Solar Tower system which produce about 5 megawatts (thermal heat)
under maximum sunlight.  This thermal heat generates about 1.5 million
electrical watts.  

Technology                                       Capital
Era                                               Cost? 
-------   ----------------------   -----------  -------------- 
1970's    Helio stat cost (each)   $35,000      $4.50/electrical-watt
	  Computer cost            $1 million  
          Total system cost        $22 million $13.20/electrical-watt 

1980's    Helio stat cost (each)   $17,000      $2.16/electrical-watt 
          Total system cost        $ ?          $6.10/electrical-watt?
          Computer cost            $100,000         ? 

1990's    Helio stat cost (each)     ?              ?
          Computer cost              ?              ?  
          Total system cost        $20,000?         ?

Of course from this home page, recurring and non recurring
(development, research, and manufacturing one time costs) cannot be
determined.  At least 33% of the costs ($1.35/thermal-watt) are
thought to be composed of overhead management, research, public
relations, and other such items.   

What portion of the (recurring costs only) for each heliostat is
composed of pointing electronics and computer control?   I personally
can't see more than $1,000/heliostat for electronics and probably is
closer to $500/heliostat.   

What was the hardware technology used to control the helio stats? 
More specifically how did the central computer transmit
(via radio or cable?) the pointing information and in what form 
(analog or digital?) to each heliostat.  What type of servo system
for moving the mirrors (in some detail) were used?   

I would like to know the answers to the same questions for the 
California located Solar Electric Gas Generation System SEGGS
which are line focused (one axis rotation) solar collectors. 

I personally believe, that capital costs can be brought down within
this decade to $5 electrical-watt (about the same as current
photovoltaic panels prices and nuclear reactors.   

Is there some way of getting a detailed break-down of current
costs for building a 1990's technology solar tower system. 

Any additional information would be be appreciated.  

Thank you,

Wally Bently
E-mail [email-masked]