Time Is Energy

Savings available with V-shaped solar panel design

I'm planning to attend the Solar2008 conference and exhibit in May in San Diego, CA. I registered for a booth at the exhibit figuring that will be an effective way to get my designs in front of thousands of people interested in solar who are likely to attend. I will show off my V-solar design which I’ve posted about on this site before and possibly other designs. The link has "pretty pictures".

I put together a handy spreadsheet to back up the savings that I project are possible with these designs. Unfortunately I am unable to post a spreadsheet to the blog. I’ve tried posting rows & columns of numbers before and the results are illegible.

So let me attempt to present the info in paragraph form. To begin with I make a few simple assumptions: 1) one square meter = 10 square feet and intercepts 1000 W of sunlight. 2) Solar panels “cost” $3.50 per W (producer wholesale price) and half this cost is due to solar cells ($1.75/W). 3) Mirrors cost $2.50 per square foot. I assume the mirrors reflect 100% of the light for simplicity, but then provide a $/W figure for a 90% reflective mirror in []. Except for the perfect mirror assumption, I believe these are conservative estimates.

So on a square foot basis, 100 W of sunlight hit a solar panel. I then look at two cases: case 1) solar cells are 10% efficient meaning the panel produces 10W per sq. ft.; case 2) solar cells are 20% efficient meaning the panel produces 20W per sq. ft.

In case 1) the cost of a square foot of standard design panel is $17.50 (10W x $1.75/W). With my cell & mirror design, I use 0.7 sq. ft. of solar cell ($17.5 x 0.7 = 12.25) and 0.7 sq. ft. of mirror ($2.5 x 0.7 = 1.75) per sq. ft. of panel. So my design costs $14 to produce the same 10W per sq. ft. which comes to $1.4/W…a 20% savings!
[For a 90% reflective mirror the cost is $1.47W, a 16% savings]

In case 2) the cost of a square foot of standard design panel is $35 (20W x $1.75/W). With my cell & mirror design, I use 0.7 sq. ft. of solar cell ($35 x 0.7 = 24.50) and 0.7 sq. ft. of mirror ($2.5 x 0.7 = 1.75) per sq. ft. of panel. So my design costs $26.25 to produce 20W per sq. ft. which comes to $1.31/W…a 25% savings!
[For a 90% reflective mirror the cost is $1.38W, a 21% savings]

I have performed a similar analysis for other designs that can lower the cost of solar even more.
Besides reducing the $ cost of solar, these designs use less silicon which should lead to a shorter EROI (the time it takes for the panel to generate as much energy as was used to produce it) since it takes a lot less energy to produce a mirror than a solar cell.

If no additional savings can be achieved (I believe additional savings exist) in the “balance of panel” costs, then total panel savings of 10%+ are easily achievable using this design (i.e. half the bolded savings, since solar cells are assumed to make up half the price of the solar panel).

I hope to post a similar analysis in the coming weeks/months for other panel designs. This design discussed in this post is patent pending.

posted by Daniel @ 1:21 PM