Plans2Reality

Efficiency Doesn't Matter

Not for mass-market solar panels, anyway.

The goal of mass-market solar, otherwise known as grid-tied PV, is to generate electricity for the grid, so we don't have to burn as much coal, oil, etc. It's a fine idea.

But anyone in the fild will tell you that PV electricity is still a lot more expensive than coal-fired electricity, even when the sun is shining - never mind darkness. (And even if you factor in a pretty high carbon tax. Coal is cheap.)

Therefore, the goal is to get the cost of PV electricity down as far as possible - ideally as cheap as coal, even cheaper if possible.

Now, electricty is sold in units of kilowatt-hours (kWh). So we need to get the cost of PV, in terms of dollars per kWh, as low as possible. It doesn't matter how EFFICIENT a PV panel is, only how much it costs. Sunlight (unlike coal) is free, so it really doesn't matter if a panel is 10%, 15%, or 20% efficient - not if such efficiency comes at a cost.

There's nothing _wrong_ with efficiency, per se. And I am sure the boffins will find ways to improve it. But anyone who asks what a panel's efficiency is doens't understand the problem. The only meaningful question is, what's the cost per kilowatt-hour?

Kindle DX

I was blessed with the gift of a Kindle DX recently. Hats off to Amazon; I think they have clearly set the benchmarok for e-book readers. The unit is thin and light. The screen is _amazingly_ sharp and easy to read. It holds about a gazillion books (see Amazon site for details) and book download is automatic, via cell-phone technology. No charge for airtime, either.

The interface is intuitive, but it comes with a built-in manual anyway. Also comes with a dictionary.

I find it as easy to read as a book, and nearly as handy to carry. It won't fit in some places where a paperback would fit, but overall it is thin and light enough - even easier to carry than a netbook.

Font size is adjustable - great for older readers or bad light. You can rotate the Kindle and it shifts the display, too.

It charges via standard USB, so you can share charging bits with iPhones and many other devices.

No doubt someday someone will develop a better e-book reader - it may be Amazon, or not - but the Kindle DX is the benchmark today. Why, it's even better than an iPhone!

Solar Panels: Why Quote the Wrong Spec?

Here at Plans2Reality World Headquarters, we have been looking at solar panels for electricity. This has provided an interesting and instructive lesson in marketing along the way. I shall christen it:

Bragging About the Wrong Thing

Solar panel makers love to brag about two things: their watt-peak (Wp) rating and their efficiency. Oddly enough, neither one matters. Nope, not a bit. Not one d*mn bit at all. 

(Let me interject here that _all_ panel makers are equally involved. In private conversation, many have told me they agree with the analysis I am about to present.)

First, Wp. The peak-watt rating is a measurement of instantaneous power output from the panel, taken under an incident light intensity of 1000 watts per square meter, and at a cell temperature of 25C.

So what's wrong with this? The panel will never actually see these conditions in the real world, and there is poor correlation between these "STC" ratings and real-world performance.

1000W/m2 does approximate the noon-day sun, but most of the time it isn't noon. Furthermore, most solar panels are NOT installed in sun-tracking mounting systems, so at best the panel "sees" full sun only at noon. The oblique angle the rest of the day reduces incident light. (Actually, most smaller arrays are installed so the panels aren't at the optimum angle even at noon - residential rooftops are usually not at the correct angle, but it's easier, and nicer-looking, to mount them flat against the roof.)

So your panel will never generate its Wp rating, due to sun angle. But wait, there's more!

PV panels are quite temperature-sensitive - some more than others, but all are to a fair degree. And when you place an object in the sun, it gets warm - warmer than 25C most of the time.

How much warmer? Well, That Depends.

The exact amount of heat gain depends on the specific PV material. Some panels will get warmer than others. In addition, the degree to which the panel cools off, that is, sheds heat via conduction and convection to the environment, varies substantially among panels. There have been attempts to quanity this (NOCT, PTC) but these are at best compromises.

Net-net of all this: the Wp rating of the panel represents a power output you will never see in real life. Couldn't be much more meaningless than that, huh?

So what specification SHOULD we be talking about? 

We should be talking about kilowatt-hours per dollar. Why? The answer is quite simple: Solar panels are installed to generate electrical energy. Electrical energy is measured - and sold - in units of kilowatt-hours. So why not measure our PV installation the same way the electric utility measures the electricity it sells us?

It's just that simple. Really.  I am putting up PV panels so I don't have to buy kilowatt-hours from the utility. Great. So tell me how much the kilowatt-hours from the PV panels will cost.

Nothing else matters, folks. Nothing.

Next installment: Efficiency doesn't matter either.  ;-)

Eli's Almost Here

The Kingdom of Simplicity, a new novel by Holly Payne, is set for release on June 6th. Her third; it is an excellent book, and IMHO her best yet. I've had the privilege of proof-reading the galleys, and I love the story.

Eli Yoder is an Amish boy trying to come to terms with tragedy and forgiveness. The story is, in once sense, fiction, but it is true in another - it's based on true events, both in the Amish community and in the author's own life.

Find out more at: Kingdom of Simplicity. And soon on Eli's own blog. Stay tuned....

Spring

The season and the mechanical device. I can't quite beleive I haven't posted since February. After a slow winter, business activity has increased. It seems as though there was a sort of pause last fall, waiting for the other shoe (or bank) to drop. Now, while we are by no means out of the woods, business activity is increasing again.

So, here at Plans2Reality we are springing forward as well. We've expanded our offices and our service offerings. There's increased emphasis on what I call 'Driving the Design Win Process' as we help our clients close the technology design wins they need to drive sales.

Got Design Wins?

Eli's Coming......

Yes, Eli is coming. Stay tuned for details.

Writing for PDF

Most technical documents today are distributed as PDF, not as hard copy. This leads to a question: are you writing for PDF?

Writing for PDF means taking advantage of the assumption that the user will either view on-line or print on a laser printer. Many of the conventions of bookbinding make little sense when documents are laser-printed - the idea of different right and left pages, for example.

You can take it a step further, of course - PDF allows you to embed hot links to other places in the document, and to web locations.

You can also embed video and audio files. This is of particular use if your product has video or audio capabilities. As the old writer's maxim puts it: show, don't tell.

Think about your audience's intended use of your document - then write for PDF.

Snipping Tool - My favorite bonus from Vista

As a software product manager and now as a consultant providing Technical Communications, I've been using screen captures for a long time. 

Initially, in the 80's I used <Print Screen> capabilities from the keyboard, with any necessary additional edits done in Paint. It had its limitations because the file was saved as .bmp which didn't allow size adjustment without distortion.  But, it was a great tool at the time.  In the 90's when I needed to do a number of captures that were saved to files, I purchased SnagIt.  It was and is a fine program that made saving to files much easier than the multisteps required when saving from a <Print Screen>.  But as is the case with many such speciality products, it had lots of features I never used or needed, but I loved it anyway because it filled a definite need.

Now with Vista, there is a great new application built-in called the Snipping Tool.  I just used it to create documentation that included some Web screens.  It is a really nice tool that lets you capture what you need, be it:  a free-form shape, rectangular subset of a screen, a window, or a full screen.  It lets you immediately save the file to any one of a number of formats: .png, .jpeg, .gif, or .html.  It has enough features to do what you need done, without the overhead of features you don't understand.  It's a great and useful addition that I already love!

Thanks, Veterans! And Those On Duty Now

The title says it all.

You are remembered, and appreciated. As you always will be, so long as there is liberty in the world.

Welcome to Plans2Reality!

Welcome to the blog site for Plans2Reality, a company which specializes in technology communications. We've created this blog as a place to discuss technology and the art of explaining it, along with a wee bit on tech in general, Max OS X, Vista, and perhaps an occasional book mention.

Thanks for stopping by!