The best-known of these tools is probably the hand-held window squeegee, used to remove the cleaning fluid or water from a glass surface. A soapy solution acts as a lubricant and breaks up the dirt, then the squeegee is used to draw the now water-borne dirt off the glass leaving a perfectly clean surface.
Another way of estimating the cost of electricity would be the cost of an ordinary solar system, or $21,000 as shown in the example above. So the cost of a Tesla retrofit system would be in the range of $33,000 to $37,500.
The Model S 90D, which has the highest range of any Tesla at 294 miles, costs $90,700, and the more powerful P90D tops the six-figure mark with its starting price of $110,700. Tesla says that all of these revisions go into production immediately at the companyâs factory in Fremont, California.