solar power

[sodamo]

Does anybody have feedback on the actual vs rated performance of the solar systems are. In essence, how much power do they actually produce on average in kwhr per day?

I know the depends on a number of factors, primarily:

Tracking or not,
Location Latitude,
Location Cloud cover.

I am looking at several different systems for a remote site, and would like some feedback from actual installations(not factory reps).

Thanks
Chris

Chris, Here is 2 years data of my system:
4.5 Kw fixed array located zipcode 96773

 

[houstonscott]

If you can connect to grid and sell back, don't go batteries and don't use tracking. Your better off spending that money on more panels and selling during good hours and buying power at night.

HS

 

[grsthegreat]

well I'm all for solar and wind energy IF i could install it in a cost efficient way.

So far, Ive never been able to crunch the numbers and find a cost savings for anyone that lives next to utility power lines. they have only worked for the rural guy living a few miles from power where the utility company wants HIM to foot the entire bill.

For me, i would NEVER save enuf money to pay for the system. Never.

Now, if they would come up with a better system and get the price into a reasonable ballpark, thats different. A few years ago, there was a company here in Idaho that was looking for electrical contractors to install the new revolutionary roof mount wind turbine that produced line voltage power (110/220v) to supplement your house power costs. the unit was the size of an oil drum. had nice pics and nice brochure. I signed up for more info....never heard anything back. Not sure what happened to them, or if was just some sort of hoax. I thought...finally an affordable wind system.

my elect bills vary from $50 - $120 per month depending on how lazy I'm at in stocking the wood fireplace, or running the a/c. Now if i could rely on a solar system to pump the power to me and pay for itself over a few years, id do it. but these systems constantly need new batteries, inverter problems,maintenance, etc. so its not just a one time cost.

That being said, if a direct a/c input system comes around that i can use to augment my current system, id jump at it ... unless it costs $50,000 which it probably will. My ultimate wish list system would provide for power with both sun and wind (snows here in idaho), and provide line voltage.... also would need cheap battery storage and inverters....like that will ever happen

 

[catfishdaddyengineering]

GRS,
The problem with line power for wind is that an AC generator requires lots of torque (wind) to excite the field before it starts generating power. Just think of inrush current on a motor. Most require at least 15mph winds to start generating. The system in your 4th paragraph was probably a VAWT (Vertical Axis Wind Turbine). They look kind of like a squirrel cage fan, do not have to track the wind, and start generating in as little as 5mph wind. These are awesome, and you can build them yourself for less than $500.

Right now there is no line power system for solar, because the way the cells work is virtually the same as a battery. Not to get too technical, but the sun excites the top layer and electrons flow through the substrate to the bottom. The top and bottom are connected just like a battery with anode and cathode; therefore, it makes a loop. This makes it DC. Our body's energy works the same way.

If you plan to grid-tie, it is also better to have DC-to-AC inverter, because the inverter does all the work of regulating voltage. It can synchronize to the grid much faster and easier. In other words, cheaper than a synchronizer system for AC generator.

 

[grsthegreat]

GRS,
The problem with line power for wind is that an AC generator requires lots of torque (wind) to excite the field before it starts generating power. Just think of inrush current on a motor. Most require at least 15mph winds to start generating. The system in your 4th paragraph was probably a VAWT (Vertical Axis Wind Turbine). They look kind of like a squirrel cage fan, do not have to track the wind, and start generating in as little as 5mph wind. These are awesome, and you can build them yourself for less than $500.

Right now there is no line power system for solar, because the way the cells work is virtually the same as a battery. Not to get too technical, but the sun excites the top layer and electrons flow through the substrate to the bottom. The top and bottom are connected just like a battery with anode and cathode; therefore, it makes a loop. This makes it DC. Our body's energy works the same way.

If you plan to grid-tie, it is also better to have DC-to-AC inverter, because the inverter does all the work of regulating voltage. It can synchronize to the grid much faster and easier. In other words, cheaper than a synchronizer system for AC generator.

cool, thanks for the input.:laughing: :thumbsup:

im going to look up some info on the VAWT systems, cause they really intrigued me at the time

 

[IXLR8]

cool, thanks for the input.:laughing: :thumbsup:

im going to look up some info on the VAWT systems, cause they really intrigued me at the time

VAWT systems are very intriguing, but usually not worth the paper the brochures they are printed on. They don't need much wind to start them generating power, but to get any real amount of power out of them, you need a good wind. You don't get good wind close to the ground, I would hate to see one spinning at the top of a 60 ft tower. Advancements are being made all the time but from all the research I did 2 years ago, VAWT systems have a long way to go. Having said that.. I hope they can find a way to make it work.
Solar PV, the new grid tied systems are affordable, especially if the gov't is willing to pay for 30% of the installation. Without the batteries, their cost of purchase/maintenance, the system I looked at produced the power I need for .07/Kwh, less then half of what I am paying now. It will take 8-10 years to payback, but the panels are rated for a 30 year life cycle and I figure if the inverters last the 5 years they are warranted for, they should last as long as the panels. So that is 20 years of free power. If I ever get my garage finished... this is what I am going to do.

 

[kenacp]

Unless you need to get power when dark (i.e. off grid), I'd go grid tie so you don't need batteries. Why the focus on off grid (just curious :

Pete

Looking for off grid because my place is set back off the road and the power co. wants to charge me pretty good to run power.
Still have to crunch some numbers. Thanks for all the great info!

 

[dynasim]

Sodamo

Thanks! That was exactly what I was looking for. It will help in number crunching.

Chris

 

[eepete]

Does anybody have feedback on the actual vs rated performance of the solar systems are. In essence, how much power do they actually produce on average in kwhr per day?

I know the depends on a number of factors, primarily:

Tracking or not, - Non tracking, 7.7 KW DC array
Location Latitude, - 36 05.365N, 79 09.695W
Note: Use on line maps for sun coverage estimates
Location Cloud cover. Part of a cloudy day, then a full sunny day shown.

So with 7.7 KW DC rating, on a cloudy day I might get as low as 10 KWH. Mixed day, 20, and full sun 50 KWH. Grid tie. If you charge batteries, you won't get the power out that you put in, don't have an exact loss percentage, would guestimate 25% loss? Hope the battery crowd can chime in here too, I'd love to know what the total system efficiency is.

I've been on line about 6 months, made about 7 MHW for a daily average of about 38 KHW/day (with 7.7 panel capacity). That translates to about:

5 KWH per 1 KW panel capacity per day.

Realize that some days have been as low as 600 watts per 1 KW panel capacity per day. The weather was very cloudy with rain.

People with off grid can chime in, but I'll bet anyone who is off grid has a generator as part of their system.

Pete

 

[dmccarty]

This thread made me do more pondering regarding PV. :laughing: Apparently I was pondering last Aug/Sept because I bought that issue of Home Power magazine. That issue just happened to have quite a few reports on solar projects that might work for us.

So if you can find that issue online, at the library or buy it, that would be a good resource.

Any who, the story about grid tied systems mentions an installed cost of $7-9 per watt.

They were using a total SYSTEM efficiency of 66%. There is a side bar conversation regarding how the calculated the 66% number.

Later,
Dan