- $1: Cinder block
Not what I used, but close enough.
- $1: Concrete
I used about 1/4 of a 50 lb bag to make one stat
- $3: 24” length 1/2”-13 threaded rod
- $1: 1/2”-13 nuts (3), washers (4)
Cost is a guess
- $9: 24” length 1 1/2" perforated angle iron and 12” length 1 1/2" angle iron
- $10: Motors (2)
$5 each in quantities >50.
- $2: 1/4”-20 nuts, bolts and washers (say 12 each)
- $10: Plastic parts
Guess. This would be in volume
- $2: 12” 14”-20 threaded rod (2)
- $6: In-line ball joints (2)
- $3: Phenolitic balls with 14"-20 threaded inserts (2)
I think I got these for 50 cents each, but using this for now
- $35: Mirror, 1 square meter, Ikea
Controversial. I'm sure true 'solar mirrors' have coatings for strength and UV resistance, etc, so this may give too cheap a perspective. But, these are also retail. ESolar is working with Google to figure out how to make cheaper solar mirrors. Here's a general link on the topic.
- $4: Wire
Guess -- .20/foot x 20 feet average per stat
- $5: Arduino
Maybe it's cheating, but I'm assuming one arduino runs at least 6 stats
- $3: Motor control electronics
Again, maybe cheating, but in any mature situation, these would be custom made for cheap.
In general, these are retail prices but without taxes or shipping. There are no costs for installation and profit. It's not meant to be perfect. In earlier calculations I've gotten into the $80 per square meter range and I still think that's possible.
My vision is something like an in-lawn sprinkler system. Central control is in the garage, 10-20 mirrors would be a typical residential installation. A home owner could do it themselves, or hire someone local who could install it all in a day or two and make $500 or so. 10-20 square meters of mirror isn't enough to power your house but if the ROI was 5%-10% it would attract some interest. A mid-tier application might be 100 heliostats generating about 10kW at peak, making the owner about $2K/year for a capital investment of $15K-$20K, so 10%+ return. A larger application would be an open source 'power tower' type configuration with thermal storage and power generation from steam turbines.
Note: For the figures above, the value of generated power assumes available solar energy of 1000 watts per square meter, with the conversion to electricity operating at 10% efficiency (100 watts per square meter). It assumes 5 hours a day of sun, 300 days a year, so this really only works for the US Southwest and similar climates. Power is considered to be worth .12/kW-hour -- whether used or sold back to the utility.