Submissions     Contact     Advertise     Donate     BlogRoll     Subscribe                         

Sunday, February 1, 2009

A photon saved is a photon earned.

We're in the segment of the year when our house energy balance is always very, very tight.

I was just getting ready to do an "energy/building/planning" post when I got ambushed by Crunchy, who wants to claim that unplugging your fridge will cost more energy than it saves...

Such a silly head. :-)

The discussions there are well worth reading- and actually, I don't think La Crunch and I disagree, in the end- it's more a matter of I was talking generalities, as in "for most families in the First World..." and she was talking "in MY household..." Yes, by golly, if your Kitchen Boss is also Obsessive/Compulsive, you can use a refrigerator in a useful, non-wasteful fashion. Many homes are not so lucky, however, and quite few refrigerators have operators on the other end of the "careful" scale.

Sure, Crunch, you do very well with your fridge- though I still want to see your ACTUAL energy consumption numbers- measured by a Kill-a-Watt or something, like Sharon uses. I can just SEE you, standing in front of the open door of your EnergyStar fridge- and planning stuff- 8 times a day, for minutes at a time... :-p And how many times a day do the kids and hubby open the door? Hm? What the maker promises, and what you actually use, are not the same thing atall atall.

And, incidentally, the Inspector General of the EPA has just (Dec. 17) issued a report: industry scam on the Energy Star program. Guess what? It ain't all they say it is. One clue- it's a program run by- the appliance industry (largely started so they could avoid real government regulation by showing "voluntary industry compliance" - but don't say that out loud).

In any case, fridges are not the only piece of the energy equation, by a long shot. While I hope to do a "fridgeless" update in the near future, at the moment I want to concentrate on some aspects of being off the grid.

Winter changes what is going on with your solar panels- unless you live on the equator.

The usual situation at higher latitudes is; you get weaker sunlight, because it has to filter through more atmosphere at lower angles; you get fewer hours per day; many winter months tend to be more cloudy (though not all locations are the same). At the same time, however, the panels themselves put out 1% more power for ever 3°C colder- which can mean a LOT on a -20° sunny day, like 20% more current than rated for (boiled my batteries, first year).

Over all; you have less power available in the winter; though it's not as bad as most expect.
And you have to include the effect on your system batteries; we've got only 4 lead-acid golf cart batteries, quite a small bank. One of the management requirements for lead-acid batteries is they need to be "topped up" regularly; once a week at least, you need to push them to full charge. It's really hard to do that using panels alone in the winter. So- if you're like most off-gridders, you do have a backup generator. We have TWO! Just so you know. Ok, 5; but 3 of them are broken. The broken ones are older, the working ones are state-of-the-art, and carefully maintained.

Your goal, as an obsessive/compulsive home electric system manager, is to have to buy as little gasoline (house) or diesel (greenhouse) as possible. So you really do want to get every last photon captured that you possibly can. Every photon makes a difference.

At this point, in the Little House, we're missing a lot of winter photons; partly due to design compromises discussed previously here, and partly due to the passage of time, with some unanticipated consequences.

If you'll look closely at the photo above (and I hope to heck that you can click on it and get a bigger view- sometimes Blogger does that, and sometimes not, and I haven't figured out why, and they're not telling) you'll see that the panels are shaded by tree branches (the trees are 200' away, but the sun is low) and, the panels are covered with frost, greatly reducing the input.

The frost comes from- the chimney. The "smoke" you see there isn't smoke at all; it's steam. When we have temperatures below 0°F day after day, the woodstove is actually burning very hot and clean most of the time. But water is the other product of combustion, along with CO2; and under the right conditions, it will form frost on anything in what is normally the smoke path. This was one of those days; and it was so cold the frost didn't melt off until almost noon, costing us a big chunk of the daily photon budget.

Frost on the panels from the chimney is a compromise I knew about at the start- the position of the panels on the roof was determined by many things, including access for maintenance. It ain't perfect. I was also worried we might get smoke deposits on the glass panels; but in reality it's never been a problem; a good rainstorm every once in a while works fine. I actually went up there and cleaned the panels with Windex every month for the first year- at which point I decided it wasn't worth while. Biggest bang I got was in the spring, during oak pollination. Some days, the oak pollen blocks more sun than the frost ever does.

Frost like this is a minor problem; usually happens only 6-10 days a year; and most times melts off quickly. The reason I was tracking things so closely was:

An unexpected, and unbudgeted electric load for the system to carry. This is a "nebulizer", which the doctor prescribed for Smidgen in the middle of our fight with upper respiratory bugaboos. Doc examined her and said she was on the edge of bronchitis and or pneumonia; the medication inhaled from this thingy opens up the air passages, and helps stave all that off. It seems to be working.

It has a powerful little air compressor that drives the mist-making device; Smiden has to sit in this delight for a half hour, four times a day. And it's noisy. You can't eat, drink, draw, read, or play with it on; so we've bent one of our rules and allow her to watch DVD's on one of the computers while she sits (that's her "mesmerized by Disney" look). More energy consumption not in the budget.

Of course (BIG MAJOR ADVICE ALERT!!!) when you were doing your original budget for the power out/power in/power storage calculations- you DID include a substantial chunk of the budget for "unanticipated needs" - didn't you? :-) Of course you did. Good for you.

I did, in fact. But that was 25 years ago, and the world has changed; that margin has long been used up; so the extra load now has pushed us over our normal winter brink. Instead of running the backup generator once a week in winter, we're now having to run it about every other day. If we don't- the first thing that happens is the DSL modem drops out. Horrors!

The other loss of power, stemming from the shadows of tree branches; is fairly new. Those trees only grew that tall in the last 3 years, and I hadn't really expected them to, ever. Silly me.

I was basing my tree height expectations on what my farmer neighbors told me, and the observable heights of trees in farm-forests around here. Surprise- if you manage the forest for the trees- not the cows- the trees get quite a lot taller, in 30 years.

Now, in December/January, because of tree growth, the solar array is actually charging the batteries for only about 3 hours a day; drastically less than the usual 5-6 hours. Thankfully, it will only be a few more weeks before the sun rises high enough in the sky so it is above the trees much earlier. Meanwhile; more gasoline. We're sighing in relief over the current drop in gas prices; but for the future, this is all a problem; the basic equations for electricity for this house are now out of balance; and unbalanceable without some serious changes in the array. No easy answers in sight.


On a different but highly related note; the Little House has been approached by Nick Rosen; author of How to Live Off-Grid , for us to be one of the families he'll cover in his new book on going off-grid in the USA (first book is UK). You can find out more about him, and find lots of off-grid discussion at his website:

Part of his new book, though, is that he's trying to pair up the families he covers; he wants one "old-timer", and one "newbie" for each region; so he can match up expectations and realities. Sounds good to me.

The upshot being; we're looking for newby not too far away from The Little House; someone who has just recently gone off-grid. Is it you? :-)

For those who don't know; The Little House is in SE Minnesota; if you're within 100 miles or so, I think that's likely close enough for a match; certainly our insolation and climates will be pretty similar.

If you're interested - email Nick at; or you can send me a note here by making a comment.

And hurry up about it- he's about to arrive in Florida and start driving; or may have started already.


No comments:

Post a Comment