Our little solar array charges batteries that run our interior lights, most of the time. However, we want to be more self-sustainable. So, we met with a solar contractor to inquire about adding a significant solar array to our roof. Such a system would be grid-tied (net-metered) turning our utility meter backwards when/if excess is produced. After state & federal incentives, a 3kW solar array which would cover ~33% our our electrical demand, would take 40 years to pay it back and cost $17,000!! upfront, not what we have in mind or wallet.
Again, I looked into wind, we get 8.3-10.4mph average winds (depending upon who's data you uses) at 10 meters height. This is "not enough wind for a turbine." So I researched and researched. I found some very nice wind turbines that were more of a sculpture than a wind mill,... However, none of these VAWTs (Vertical Axis Wind Turbines) currently qualify for state & federal incentives and the one we really liked, only produced about 8% of our consumption. Without the incentives we would be looking at a 151 year payback!! >;-(
For the heck of it I looked at the turbines that are on the qualified list. I've always liked these turbines, they are true heavy metal, solid, tested machines. After looking at all of the manufacturers and models, I selected four competing units, of different sizes (Skystream 1.8kW, Bergey 10kW, Gaia 11kW, and Jacobs 15-20kW). I started a spread sheet to actually compare the various units, to really look at the numbers. Some interesting things started to jump out. You actually get more incentives for the larger units because the incentives are based on rated and produced kilowatts. So the upfront cost differences are reduced.
The initial investment is only part of the picture. The smallest turbine would be the easiest to install but "only" supply about 33% of our utilities (we are 100% electric, no gas etc.). The larger turbines would cost slightly more upfront and be more complicated to install but would produce 90-250% of our demand. Although the larger turbines are more expensive they should pay for themselves in a similar time frame as the smaller/cheaper turbine, about 13years. After this time we would never have a utility bill again. Additionally, any excess production would go to charge a future electric car (which would cut the payback time in half) and any further excess would go to support those in need utility assistance. So, the big turbines are where I focused my efforts.
The 11kW two blade turbine, really caught my interest because it operates at a very slow 45RPM and its rated wind speed is only 21mph so its power curve is shifted to the left, which is a good thing, more power in slower winds. It actually would produce more power in our winds than the 20kW turbine because it performs better in our lesser winds.
I forged ahead, trying to line up all the details. I contacted our permitting/planning department, had the electric company on site to estimate what would be required from them, been in extensive conversations with the Energy Trust of Oregon (ETO) and the various turbine manufacturers. The major concern is the tower height. I want to install it at, 80 feet. As you go higher the wind speed increase and thus there is more energy, wind energy is based on the cube of the wind speed. For example if the wind is 5mph (cubed 5x5x5=125units) if the wind is 10mph (cubed 10x10x10=1000units), so the energy is not twice as much but eight times! Of course tower height causes issues; installing, planning/permitting, public concerns, birds/bats, expense, etc, etc.
80 feet is the height that Audubon says is the highest tower height that is "safe" for migratory and soaring birds. They have weighed in on the heated birds vs. turbines issue and have stated that, even though it is a fact that birds are killed by turbines they feel that wind turbines are a sound way to produce electricity. Far more birds are killed by domestic cats, cars, collisions with buildings, pesticides and pollution, but these numbers are not well documented because they are not a point source.
We have also discovered that wind turbines are typically white because the first countries that seriously produced turbines felt that white was the color that best blended naturally with their environment. Countries are now beginning to look into other color options to blend in their unique environments. I could watch a moving bright orange turbine all day but I don't think our neighbors would approve. In Vermont, USA, a grayish color is required for all turbines, as this color blends most closely with their skies. We think this alternate standard gray color will work well for us also.
so we purchased a helium balloon.
would be a good tower location.
Uh-oh the winds are blowing the balloon,...
into a little tree,...
and we weren't able to get a picture with surrounding
ground based landmarks to get a feel of the actual height.
We will have to head out early in the morning to try again.
So the balloon came inside.
At sun rise the next morning I got up
and ready to head out with the balloon.
Uschi had been warming-up for hours on his wheel.
Vladi had been on and off the bed tens of times
to be sure I was up. Tanji had worn himself out running
in and out of the kennel checking conditions.
The brothers are "ready."
Even at 6am the winds still pushed the balloon but
this is about 80' high at about 400' away, pretty tall.
Additionally, I just discovered Solarcity, a company that leases their solar systems. More investigations will be required but this program sounds promising. We get the electricity produced and pay a small monthly lease fee. So we would have a reduction in utility bills because of the solar arrays production the result, including the lease fees, should be about a $17/month total savings. This is not huge but it is instant savings and SIGNIFICANTLY better than a 40 year payback on a solar system we would own and have to maintain. Solarcity currently doesn't operate in our area, of course, but I have contacted them and they seemed very interested in expanding into our region.
I'll keep you posted on all of these adventures.