Ma'am, with all due respect, the article is good, but seems "bent" more towards selling than impartial review. A few facts I offer are these: All our home PCs utilize a Power Supply, either contained within (like a "desktop"), or separate, integral with a power cord, which plugs into a wall outlet, typical set-up with a laptop computer. My own, in use right here, has a power-cord type supply, which serves two-fold: it charges the PC's internal battery after cordless use, and it also powers the PC when in use, thereby sparing the battery. It's output is 18.5 Volts D.C., 3.5 Amperes. Knowing these things, makes one point obvious: Solar generated electric power is a "natural" for computers, well-suited since solar cells generate Direct Current, which is needed by the PC.
Here are a few drawbacks. First, computer availability will likely be desirable "24/7". The Sun don't shine 24/7 (fortunately for us!). So, the Solar Power generated during daylight must be "saved" or stored for use at such time as solar output is zero. Furthermore, computers are sensitive to input voltage changes; they want "constant voltage". Solar output will vary from near-zero (night-time) to maximum during noon day sunlight, with great variation between those limits of minimum and maximum output. So, the solar power generated is usually "stored" in the form of Chemical Energy instead of Electrical, which does not lend itself to "storage". A class of electrical devices called Capacitors have the capability of "storing" electrical energy directly, that being available for use by electrical connection to the capacitor. To my knowledge, capacitors are not yet being used for practical energy storage, but I am at the same time "behind the times" in current development aspects. This leaves us with the specter of storing our solar power in batteries, which serve as energy sources for the computers. Batteries are heavy and expensive. One "fine-tooth" decision before committing will be whether the desired solar system will be installed in an area which has
some commercial power availability, or
no power available at all.
Cost: For a "grid-tie" system which provides about 800 KWH (Kilowatt-Hours) per month, about $10,000. This from:
http://www.wholesalesolar.com/solar-information/solar-cost
Average lap-top PC power consumption is roughly 100 Watts. This from:
https://secure.www.upenn.edu/computing/resources/category/hardware/article/computer-power-usage
Using worst-case use scenario, assuming our PC will be "On" 24/7, it will require 2.4 KWH per DAY, or, 72 KWH per MONTH. Thus, an 800 KWH solar system would be adequate to run 800/72 PCs, about 11 computers. Thus, running one computer entirely by Solar Energy, using the above mentioned solar source, would require an initial investment of about $900. Many factors here remain unanswerable, however. One is that the system mentioned is designed to supply an Alternating Current load (a home).
A more realistic approach to cost estimating might be to use cost figures for the components themselves, solar cells, hardware, etc., then "lump in" a figure for design and construction cost, adding a profit margin, then go looking for a suitable system some company has already marketed. imp
