2011 Summary

[ChrisOlson]

I tallied up all my power logs, starting from 4-4-2011 when we installed our new power system with new inverters, battery bank and went from 12V to 24V.  We generated 5,496.9 kWh in 272 days with four wind turbines, and ~ 2 kW of solar.  Although we didn't install the second kW of solar until the first part of September.

From January 1 to 4-3-2011 we generated 1,224.4 kWh with our 12 volt system.  Although both the solar and turbines were running on 24 volt and we still had 12 volt inverters with a dual voltage bus that I designed to let the generating equipment run at 24V while the inverters each ran off half the bank at 12 volts.  That system was a nightmare to keep balanced.  When our daughter graduated from college we decided it was time to splurge and buy new inverters with what used to be her college money   

We put 454.7 hours on the standby gen for the year, although I don't have a good way to log power from that thing when it runs.  However, I do know that almost half of them generator hours were put on before April.  With the new inverters automatically controlling the generator, it has cut the gen run time considerably.  When the gen was on manual start we used to leave it running too long and forget it then go, "Oh yeah - forgot to shut the gen off."  After it had been floating the bank for two hours.  The new system don't start it unless the bank voltage drops below 24 for more than two hours, and it shuts it off when the absorb stage is done.  Besides taking good care of the batteries, it's also a fuel saver having that auto-start gen.  And after having it, I would never be without it.

My goal for 2012 is to cut that gen run time at least in half   
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Chris

[vawtwindy]

you can Chris, you will do it.

[bj]

   Pretty impressive Chris.

[ChrisOlson]

It pays to keep records.  5,670.1 of our kWh came from wind, which is 84.7%.  The turbines generated 15.53 kWh/day, or 3.88 kWh each.  The average output of each turbine was 161.8 watts for the year.

The solar generated 1,024.2 kWh, which is 15.3%.  The solar generated 2.81 kWh/day, for an average output of 117.1 watts for the year.  Looking at the data from September, when we installed an extra kW of solar power, it looks like the average output of the solar increased to 2.92 kWh/day, but the days are shorter until the Winter Solstice on Dec 21, and we don't get many sunny days during winter.  That should increase drastically as the days become longer.  I've never really had a chance to see what the solar can do yet because the extra capacity was installed during a period of the year when solar power at our latitude starts to drop off rapidly to the Winter Solstice.  We have gotten basically nothing from solar for the entire month of December.

The output from the turbines from September to Dec 31 increased to 19.04 kWh/day, and during the month of December to 29.96 kWh/day.  They're at their worst power production during the "dog days" of summer in July and August.  They're at their best during the winter months when we get our strong norwester winds.

Our highest power consumption is during the winter time - roughly 30 kWh/day - and our standby gen ran for 17.9 hours during the month of December.

We have enough installed wind capacity.  With the extra kW of solar that we installed in September, that should "do the trick" in reducing the gen run time thruout the year, especially during the "dog days" when the wind turbines don't perform well.  It should also help during the coldest months of the year in January-March, as the days become longer and those are our highest power consumption months of the entire year.

So I don't believe we really need to make any changes - installing the extra solar capacity back in September should do it.  If I multiply the 17.9 hours that the gen ran in December x 12 I come up with 214 hours for the year.  So I think we're on the right track to cut the gen time to ~200 hours for 2012.
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Chris

[DamonHD]

The solar on our roof (~5.2kWp) generated a fraction short of 4MWh in 2011; my MotorWind turbine here in a suburban 'leafy' dip may have made me a few 100Wh in the same time, if lucky!  PV output varies from about 1--2kWh/day in mid-winter to 20--35kWh/day in mid-summer.  See my avatar for output over the last few years as I've piled more PV on the roof.  (I hope to add a little combined solar thermal and PV this year if possible.)

Our gross electricity consumption was about 1.5MWh, so even with our mains gas heating (DWH and space heating) we're slightly carbon-negative.  At such time as I switch us to a heat-pump for water and space I hope to be a slight exporter of electricity still and carbon negative; more so in fact.

I only have a couple of usable kWh of storage (400Ah@12V) for the off-grid part of my system, that hosts my main internet servers (such as earth.org.uk and hd.org), mail, etc.  The boost from a nominal 3 days' storage to 20 has avoided me having to put it back on-grid at all.

So, not as big a system as yours by any means, but we have a small and sheltered place.

Rgds

Damon

[ChrisOlson]

I wish we had better solar conditions here.  Our solar is pretty much yard decoration for close to 6 months of the year.

Solar Panels (sole-urr pann ulz): n: devices installed in Wisconsin that collect snow at the proper angle to reflect all the sun's heat down to the Bahamas


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Chris

[DamonHD]

We only have had an average of a few days per year with snow-covered panels.  No snow at all so far this winter, though we did today have gales, very dark cloud, and torrential rain!

With the new/planned combined solar PV/thermal I am seriously considering briefly running fluid through them in winter to clear light snow if the energy balance is right.  Shouldn't be too hard to do (just force the circulation pump on stealing some heat from the thermal store) and they would be at the roof edge so snow may be able to slide right off.

Rgds

Damon

[taylorp035]

I once heard that NW PA average less than one sunny day in the month of February.  Definitely a plus to have a good wind/solar mix.  Wind speeds pick up to an average of ~14-15 mph in the winter but drop to 6-8 mph average in the summer.

Its really cool to see some numbers from people are really living off the grid.

[bj]

   Well Chris, I guess you can take solice in all the happy people in the Bahamas.  That wet sticky snow will kill you every time.

[Dave B]

Chris,

  We got hit the past couple days with Winter and I just got in from brooming about a foot off my panels (much more than that on the ground) I was surprized though at how quickly once they start producing a thin layer of snow and ice melts pretty fast. I did 2 things right with these, they are pole mounted and close to the house and that makes things much easier, it's 0 degrees here now and falling. Batteries are fully charged and my turbine is running my office free tonight in 10-15 mph winds. I'm not off grid (yet) but even so I can't imagine not having this additional power.  Dave B. 

I wish we had better solar conditions here.  Our solar is pretty much yard decoration for close to 6 months of the year.

Solar Panels (sole-urr pann ulz): n: devices installed in Wisconsin that collect snow at the proper angle to reflect all the sun's heat down to the Bahamas

(Attachment Link)
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Chris

[ChrisOlson]

I got plowed out of the blizzard yesterday and have kept the snow cleared where I have to lay a tower down to put my new MPPT turbine on it.  I'm hoping to get that done before the banks get too deep.

Cabin Fever hasn't set in yet, but it will start in another couple weeks.   
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Chris

[wpowokal]

From where I sit I say you and yours are in an enviable situation, very few of us have sufficient wind resource to make 85 % of our power requirements, while I don't have the time to read all your posts you do seem to have evolved a quite balanced system.

PS I have never seen snow.

A of J

[ChrisOlson]

From where I sit I say you and yours are in an enviable situation, very few of us have sufficient wind resource to make 85 % of our power requirements, while I don't have the time to read all your posts you do seem to have evolved a quite balanced system.

I don't know how enviable it is, because wind turbines are high-maintenance machines.  A generator is actually less maintenance than a wind turbine for the power it makes.  Over time, I've looked at what causes maintenance issues on my machines and tried to design the maintenance issues out of them.  But no matter how you do it, a wind turbine is still a machine with moving parts and I've got a machine down, on average, once a month doing something to it.

One of the big problems I've had is snow getting into the generator when the stator is hot, melting, re-freezing and then the rotors start to rub on the ice.  If the machines stops it freezes up solid and won't turn.  I got covers on the generators, but in a driving blizzard the front of the machine gets just caked with snow because the machine is warm.  So on the last two machines I've changed the stator support so it shiields the generator to the front from the snow blast.  But then the generator doesn't get enough cooling air.  So I put holes in the stator support to let air in.  Then the snow blows in the holes and builds up on the back side of the front gen rotor and it starts rubbing on the stator support.

With wind turbines it's a never ending battle.
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Chris