OK So my average monthly useage is 1800 KW a month

Re: OK So my average monthly useage is 1800 KW a month

20 kWH per day is about and average of 833 Watt continuous load... If you have a couple servers, that added to your normal home usage, it is very easy to see that happening. If you have UPS systems for your servers--that also adds more losses (can be upwards of another 20% of your computers' power usage) and heat to your home.

Add hot summer weather and servers--You are spending a lot of money to move that ~1kW worth of electric "heat" out with your A/C systems.

If you can get a Kill-a-Watt meter (or similar) or a larger monitor for your whole home--You can track down where your power is being used.

Another issue that may hit you--In some areas, over 10kW of solar array may have to be installed/billed under a different set of rules/tariffs. So there may be other requirements/restrictions that you need to understand before you commit any money.

If your billing does include Power Factor (or KVA) measurements/penalties, you could look for servers/computers with PFC power supplies (Power Factor Corrected). That would also add savings too.

-Bill

Re: OK So my average monthly useage is 1800 KW a month

I just was not quite sure what to say... PFC definitely does not mean "...the PSU will adapt to any power or Freq down to 80 Volts".

There are features of (power supplies with active) PFC that can mean that the power supply will accept from ~90 volts to ~264 volts (including the 135 to 180 volt range that non-PFC power supplies typically do not support), from 50Hz to 400Hz plus OR DC (DC, in theory, upwards of 370 VDC).

But, what PFC was designed for and why it is required on larger power supplies is because it makes the input of the Power Supply look "resistive" instead of a series of Peak Voltage pulsed current wave forms--Which have very poor power factor (0.67 or even less) because of the Diode Bridge in front of a high voltage capacitor (bank).

If you have a commercial meter which measures Power Factor and adjusts your billing--then PFC power supplies can be very much worth the extra costs. Power Factor Correcting Capacitors only work on "linear" sinusoidal current waveforms. The non-linear (non-sinusoidal) wave forms for rectified/capacitor based power supplies cannot be corrected with capacitors.

Also a PFC power supply will allow you to pull upwards of 1/0.67 (1.49x) more power from a 15 amp (for example) service than you can with a non-PFC power supply.

If you have a residential meter/billing program that does not charge for PF (or KVAR) based measurements), then there is no real power or $$$/kWH savings with PFC power supplies. The only advantage is that a PFC power supply will pull less RMS current than a non-PFC power supply.

Regarding your roofing shingle question--None of us Moderators work at NAWS--So we cannot (and should not) answer any business/product related questions for them. Windsun and Rick both are the Admins, and work at NAWS. But, your best bet is to call NAWS directly as they do not monitor the forum for questions directed towards them.

Personally, I do not like flexible solar panels. I don't think they last as long, don't cool as well on roofs, and usually they are thin-film products which require about 2x the square footage for equivalent power capture from the sun.

If you have restrictions from local covenants/architectural boards, and/or have issues with flying debris, then thin film/roof tile panels may offer some advantages. Again, this is all in my humble uniformed opinion--There are others here that know much more about those products than I.

-Bill

Re: OK So my average monthly useage is 1800 KW a month

Polaraco wrote: »

All I know is we have done nothing other but put that cap bank on. Actually I got it in the hopes it would round off the square wave in my generac.

Not to beat a dead horse, but placing capacitor(s) on square wave/low resistance/and some inductance circuits is not going to do anything except cause ringing (an LC Oscillator/Tank Circuit).

There is no "good" way of killing the sharp edges on a square wave (or modified square wave) unless you "dissipate" the high frequency components (see Fourier Series) either by shunting the energy away or turning it into heat.

One way of turning that "high frequency energy" into heat is with a ferro-resonant transformer. But they are heavy, expensive, and wasteful of power.

Back to your question... What is it you want to do? Grid Tied? Off-Grid (no grid or emergency power)? Hybrid (UPS like system)? Save Money? Go Green? etc... And how much power do you want to offset?

And, if grid tied--As Solar_Dave says--Your utility's policys will have a big impact. Many smaller utilities will not support GT systems. Some will only pay you wholesale cost of excess power generated (usually ~50% of retail).... Others will put you on a Time of Use plan and you can generate power at $0.30 a watt afternoons, and buy it back at night for $0.09 per watt...

-Bill

Re: OK So my average monthly useage is 1800 KW a month

For the sake of discussion, lets guess you are around NY/New Jersey--Pick NYC, grid tied (to save money), using PV Watts and 1kW of solar panels (defaults):

"Station Identification"
"City:","New_York_Ciy"
"State:","New_York"
"Lat (deg N):", 40.78
"Long (deg W):", 73.97
"Elev (m): ", 57
"PV System Specifications"
"DC Rating:"," 1.0 kW"
"DC to AC Derate Factor:"," 0.770"
"AC Rating:"," 0.8 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 40.8"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:","14.5 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 3.17, 79, 11.46
2, 4.17, 93, 13.48
3, 4.57, 108, 15.66
4, 5.25, 116, 16.82
5, 5.30, 118, 17.11
6, 5.78, 121, 17.55
7, 5.64, 120, 17.40
8, 5.52, 119, 17.25
9, 5.06, 108, 15.66
10, 4.48, 102, 14.79
11, 2.90, 66, 9.57
12, 2.85, 69, 10.01
"Year", 4.56, 1218, 176.61

So, 1,800 kWH per month or 21,600 kWH per year:

• 21,600 kWH per year / 1,218 kWH per 1kW of panels per year = 17.7 kW of solar panels

So, that is the size of purely solar array that would, on average, zero out your power usage over 1 year.

Assuming you live in one of the progressive states (like California) that have tiered power rates (the more you use, the more you pay), then you don't need to have a 100% solar array to get good cost savings.

For example, in California we can pay ~$0.40 to $0.50 for power >1,000 kWH per month. And pay ~$0.13 for less than 300 kWH per month. Also, if you have Net Metering, you can get paid $0.40+ per kWH during summer peak and pay $0.09 for off peak power the rest of the time (nights, winter, etc.).

If you are planning on paying an installer--I would call a couple of locals and have them give you some options. They know the local utility and AHJ and their requirements--and should be able to give you better information than I. At least you have some basic numbers and questions to ask so that you will be prepared to look past their sales pitch (we have a next door neighbor that is well shaded much of the day, especially during winter--Does not slow down the sales pitch a bit).

Other issues to think about--If you are not going to live there for somewhere around 10 years or more--It may not be worth placing panels on your roof. Not all buyers think that solar on the roof is a good thing--Plus I do not believe it adds "that much" to the value of the home (for most buyers).

Do you have a roof that is fairly new? You don't want to pull of the panels after 10 years to install a new roof.

And--how do you have 4 wind turbines and not much room for solar (on lot?). In many areas, you have to have a good amount of property to legally install wind turbines.

-Bill

Re: OK So my average monthly useage is 1800 KW a month

Are you going to end up shading the roof so much with the turbine that you will not be able to use solar panels?

-Bill