Saturday, November 1, 2008

Solar By Numbers

A group at the University of New South Wales has announced that they have achieved a record 25% efficiency with a silicon solar cell, improving on their previous 24.7% performance...

...except that it is the SAME CELL as before. It's just that the standards body changed the reference spectrum upon which the PV cell is tested, and their cell happens to take better advantage of the new spectrum.

“Improvements in understanding atmospheric effects upon the colour content of sunlight led to a revision of the standard spectrum in April. The new spectrum has a higher energy content both down the blue end of the spectrum and at the opposite red end with, dare I say it, relatively less green.”

This is (exactly) like having the EPA change their mileage test and then having an automaker trumpet the "improved" performance of their products.

Mish, who is usually rather astute, fell for this nonsense.

NSW does good work, but please...



1 comment:

Michelle L. Jones said...

I have another, sort of alternative energy question. When people talk about how much (industrial) energy is consumed within a country, they are including all industrial sources, from nuclear to oil to coal to solar, etc. But when they say that "country x gets 45 percent of its power from renewables" they are meaning that country x gets 45 percent of its electricity from solar, wind, etc. So I guess I have two questions. 1) Am I reading this correctly, that when they say "power" they mean electricity generation? and 2) Why would that be the case? I understand the definition of power as this: "In physics, the amount of energy put out or produced in a given amount of time. Power is often measured in watts or kilowatts." But I also understand that "Power is nothing more than the rate at which energy is used. The familiar unit, the Watt, is simply Joules per second. A 100 W incandescent light bulb is spewing 100 J of energy per second in the form of light and heat. It does not make sense to talk of Watts per second or Watts per hour." So why would someone talk about electricity in terms of power and oil and gas in terms of energy? Why are they seeming to mix those different measures? Or am I just being silly and missing something completely obvious?