Thursday, September 17, 2009

Hmmm... Interesting...

I wonder if this design will scale up well....

As it is, it's a bit small; though it seems a much better solution for a small multi-turbine array than most other small systems. Certainly much more efficient.

The list price for the "system" is $6k, but that includes interconnect, panel, inverter, wiring etc... which I wouldn't be using in my installation. All that would be handled at the central powerhouse, to match the solar, and backup generators into the battery bank, and grid tie.

According to Popular Mechanics, the turbine and mounting hardware only price, is $4500. That's something less than half what I was looking at for considerably larger conventional turbines of a similar capacity; and I'm guessing from the construction that they'll handle overspeed wind a lot better (no gear train to damage). Also, most conventional turbines have a startup speed of 6-9mph, and a cut off around 20-25mph of wind, this one has a 2mph startup, and cuts off at 42mph.

That's a hell of a lot more useful capacity on the average day. I just wish it was a bit higher capacity overall. In a class four wind region, more than 60% of the average day is spent at between 6 and 14mph windspeed; at which these turbines generate between 40 and 250 watts.

Even at 250 watts, that's only about 5% of our peak hour load (and a lot less than peak instantaneous, which may reach as high as 14kw when multiple AC units and refrigerators are kicking on). Of course we DO live in Arizona, in a poorly insulated house.

Long term, we're looking at living in a class 4 wind region (possibly a class 5 depending on the exact home site), and building towers above the treeline. Under those conditions, a turbine like that one would only realistically generate something like 2000-3000kwh per year; or an average of 160-240kwh per month (Honeywell says that in a class 3 zone it can do 2000kwh per year mounted on a house roof - about 75% less output than a class 4 above the treeline installation - so I figure my estimate is pretty realistic).

Although, we are looking at living in a net metering sellback region with a 100% tax credit after the federal 30% credit (capped at $20,000 total after federal). With that incentive program we could buy seven of them and the things could pay for themselves immediately; but it really would take something like seven of them, or more, to meet our power needs.

The average household in the U.S. currently consumes something like 12,000kwh per year; but about half that is the utilization of air conditioning in the sun belt states, or electric heat in the cold states. Outside the hot zone, and for households with gas or oil heat, the national average is more like 6000kwh.

Right now, living in Arizona, we use about three times the national average (or about six times the average someone in say, New Hampshire would use). We run from around 1500kwh in January to 5500kwh in August; and total around 35,000kwh per year, for which we pay almost $4000.

We once used 6500kwh in a single month (for which we were charged over $800), but that was with our pre-replacement 30 year old primary AC unit, plus a messed up air handler and heat exchanger, and running two large supplemental AC units 24x7 that entire month (not coincidentally, the month before the old unit died horribly).

We have what they call a "smart meter", which lets us see our spot utilization day by day, and hour by hour. Just for fun, we looked up how much power the house was using when we weren't even in it, for our vacation this past few weeks.

With us out of the house, the AC and all the lights and computers off, we used about 30kwh per day, just keeping the fridges and freezers cold etc...

Uhhh... that's almost the national average for people who are actually, you know, using their houses and AC and heat and computers and TVs etc... WTF?

For a little more masochistic fun with the smart meter, we averaged 50kwh per day in January, one of only two months this year when we didn't run the AC at all.

So... even on our best day, we're using about 1.5 times the national average juice, and about 3 times the average for a cold state; however, we are only using 20kwh more per day to run all our stuff than the house is using all by itself...

Ok that's screwed up right there.

Anyway, back to the cool stuff.

When we move, since we're planning on moving to a colder state, and not using electric heat; we expect to cut that excessive "3 times average" utilization down a lot, because of the dramatically reduced AC requirement. That still gives us a baseline of something like 12,000kwh per year however.

Any savings we make using hyperinsulation, and efficient lighting and appliances, we expect to more than offset with greater use of tools and power equipment (welders alone... oy).

Ideally, I'd like something that could generate more like 3 times that 2000-3000kwh per year, per turbine; and build an array of say, four of them, for total spot capacity, and for redundancy.

...But even as it is, with seven of them paid for entirely by tax credits (not including installation, and the towers of course) we could likely generate 14,000-21,000kwh per year...

That's pretty decent. Even when you account for losses in the storage battery system and inverters, that's probably most of the household power requirements at any given time (not include surge power when the welders are running, or the AC and fridges start up at the same time of course).

That would of course be in addition to solar, and micro-hydro if the property is capable of it; and back up diesel or propane generation for full capacity. Then of course there's all the storage batteries.... ooooh boy those are gonna cost.

Anyway, at that cost per turbine, if you've got enough land to set up six or seven of them (and we will) it's viable. Importantly, it's a LOT cheaper than an equivalent solar setup.

A solar system in the same region, with the same capacity, would cost about $120k. Of course you'd still get the 30% federal credit plus $20k from the state, for a $64k total cost to us, vs. a near zero cost to us (again, not including installation costs, just to keep it apples to apples).

Of course, as I said, we plan on having wind, solar, and generators (and would really love a property with micro-hydro capability) anyway. Ideally, we want to have a diversity of power sources, AND enough power even on cloudy days, or wind free days, to run whatever we need (again, short of the welders at full duty cycle etc...).

The great thing about combining wind and solar, is that when solar tends to be performing poorly, wind tends to be performing well; and vice verse.

Now if they would just get those cheap, relatively efficient, printable solar panels to market, we could do BOTH relatively cheaply.