Grid-tied solar

[TnAndy]

One of the reasons I'm leaning to enphase micro inverters is because they are scalable... in that you can add to the system without having to size a large inverter.

Yep. Just try to have in mind what you plan to expand to eventually.

You can put 17-M215's on a single circuit....so if you planed to start, say, with 5 or 8/etc panels, but were pretty certain you were gonna expand before too long, I'd go ahead and buy the cable for the other 12 "drops" (as they call them), and just plug in the covers they make on the unused portions of the cable for now. That way, when you do expand, it really IS plug and play. And you won't have multiple cables ( and capping the far ends) to deal with. Just a suggestion.....

 

[aczlan]

My guess ( and it's purely a guess ) is grid tied inverters could be 'fooled' by something like you suggest.

Again, you would need a battery bank as a buffer, because if you loaded up on use, and a cloud goes over, you're gonna have a brown out, and maybe kill some equipment....then you get into charge controllers to maintain batteries, and such....so it's not a simple connect A to B kinda thing. If you want off grid capacity, you ought to get it the right way from the start, not try backing into it later....IMHO.....

My own system is a combination of 5kw of grid tie only inverters (Enphase micro inverters), and 6kw of Outback, battery based inverters. My thinking is SHOULD the grid go down for a long time, I could simply connect the output of the Enphase inverters to the off grid output side of my Outback inverters (which puts out cleaner power than the power company), and the Enphase inverters would probably recognize that as "grid" power...and fire up. I haven't done it, and I don't know if it will work, but in theory, it ought to. I wouldn't bother unless the grid looked like it was gonna be down for a LONG time, and I had 5kw of solar panels/inverters sitting there doing nothing anyway.....yeah, I'd be tempted to give it a shot.

My thought with a inverter generator is that it would be running loads within its capacity (ie: lights, circ pumps for HW heat, fridge at times, etc) but that the panels would let the generator "loaf along" vs running full out and as long as the total load was within the generators output rating, it should be fine.


Aaron Z

 

[TnAndy]

One way to find out.........

 

[Redneck in training]

Yep. Just try to have in mind what you plan to expand to eventually.

You can put 17-M215's on a single circuit....so if you planed to start, say, with 5 or 8/etc panels, but were pretty certain you were gonna expand before too long, I'd go ahead and buy the cable for the other 12 "drops" (as they call them), and just plug in the covers they make on the unused portions of the cable for now. That way, when you do expand, it really IS plug and play. And you won't have multiple cables ( and capping the far ends) to deal with. Just a suggestion.....

There is a limit on number of microinverters you can put on single cable. But I agree with buying cable with maximum number of connectors. To be safe you might need a sink with voltage regulator that will sink exces power to keep the voltage below the inverter trip level.

 

[buickanddeere]

I spoke with someone from the company and I do not believe there is any battery(s) involved.

It produces limited real time power from available sunlight and that is it.

The person I spoke with said the intent was to provide an option... such as a small refrigerator, electronics or even charge battery packs.

I'm intrigued because this is the only combination I have found off the shelf that promises grid tied power AND the possibility of limit daylight power with the grid down.

I'm hoping this is just the first step in that direction... otherwise, I like the enphase micro inverters...

I've talked to a number of solar people this year... everyone from the kiosks at Home Depot to licensed Solar electricians/installers... only one even knew of the Sunnyboy option...

Just goes to show you need to do your own research!

Ultra

The company is telling people what they want to hear in order to make some sales. A battery bank buffer is required or the system is just going to cycling and slamming relays.

 

[JPRambo]

I have been considering a solar array for my property in N. Georgia. I am not there but a few scattered weeks a year. I will need it for a well pump and power my camper. What needs to be done when I will not be using the power? I know it will need batteries to power the camper at night. But, is there a system that can be turned off when not needed for a couple, few months a ta time?

 

[buickanddeere]

Why turn it off? The batteries last longer if floated at the proper voltage.

 

[dave1949]

I have been considering a solar array for my property in N. Georgia. I am not there but a few scattered weeks a year. I will need it for a well pump and power my camper. What needs to be done when I will not be using the power? I know it will need batteries to power the camper at night. But, is there a system that can be turned off when not needed for a couple, few months a ta time?

I don't see that as a good use situation of solar power--mainly because you are not there enough to make it worth while. Theft would be a concern too.

I would recommend a good gas generator sized to your well pump draw. There are variable voltage and/or soft-start well pumps that could be run from a fairly small, quiet running and easy to transport generator that you could also use elsewhere.

 

[JPRambo]

The reason I am thinking of solar for this is:
I do not have power on the property.(I need to get easements from neighbors and $4000 to install.)
I also need to have a well drilled (another $4000 - $4500) and I thought since there is no power available, I would go with a solar set up for the well and the camper when we are there. I have a 12' x 16' shed where I would mount the solar on the roof and store the batteries.

 

[TnAndy]

I don't see that as a good use situation of solar power--mainly because you are not there enough to make it worth while. Theft would be a concern too.

I would recommend a good gas generator sized to your well pump draw. There are variable voltage and/or soft-start well pumps that could be run from a fairly small, quiet running and easy to transport generator that you could also use elsewhere.

I'm a solar fanatic, but in this instance, I'd have to agree with Dave. A decent generator could be bought for under 2k, and to set up a solar power system to equal it would run you 2-4 times that. (or more) If you planned to be there more like several months out of a year, it would make more sense....otherwise, go with the generator.

As far as having to 'turn it off', you don't. An off grid system takes care of the battery bank first, and if there is no other use for the power, it simply doesn't generate.

 

[dave1949]

The reason I am thinking of solar for this is:
I do not have power on the property.(I need to get easements from neighbors and $4000 to install.)
I also need to have a well drilled (another $4000 - $4500) and I thought since there is no power available, I would go with a solar set up for the well and the camper when we are there. I have a 12' x 16' shed where I would mount the solar on the roof and store the batteries.

I think you are a good candidate for an off-grid system sometime in the future if you plan to live or spend more time there. Even if you had an off-grid system in the future you would still want and likely need a generator. Let's say you have a component failure in your solar system; you would still need something to run your well pump/frig/etc. while diagnosing the problem and waiting for parts. A portable generator is a good fit for that purpose now and later. It's money you would spend anyways with or without a solar system--just change the order of what and when.

If you are planning on a future off-grid system then select the well pump model with that in mind, plus any other appliances you buy. It is a lot cheaper to conserve electricity through good choices than to buy solar generating power.

As recently as five years ago off-grid homes typically off-loaded a lot of power requirements to propane and wood. Propane refrigerators, ovens, cooktops, clothes dryers, water heaters, etc. With current solar pv prices and the energy efficiency improvements in standard appliances that is no longer necessary with the possible exception of ovens and cooktops; I think propane still makes sense there. Even heating and cooling a properly insulated home is within solar pv's reach using high efficiency mini split units or other heat pump technology.

Just food for thought.

 

[JPRambo]

I have a 5500 watt generator I bought after hurricane Charlie went through town in 2004 (I run it every couple of months). But I usually borrow a 3500 watt from work (it fits into the camper door for travel) both will run the camper(mostly propane).
The wife likes to cook with gas and the W/H was propane 'til it went on a holiday weekend and I could not get one installed quickly. I put in an electric one I got from the big orange box store. The dryer is electric but the house is plumbed for gas if it should it go out. I would like to be off the grid or grid tied solar in my retirement years if possible. I have 7 acres to retire to and plan to heat with wood in a smaller well insulated home.

 

[dave1949]

I have a 5500 watt generator I bought after hurricane Charlie went through town in 2004 (I run it every couple of months). But I usually borrow a 3500 watt from work (it fits into the camper door for travel) both will run the camper(mostly propane).
The wife likes to cook with gas and the W/H was propane 'til it went on a holiday weekend and I could not get one installed quickly. I put in an electric one I got from the big orange box store. The dryer is electric but the house is plumbed for gas if it should it go out. I would like to be off the grid or grid tied solar in my retirement years if possible. I have 7 acres to retire to and plan to heat with wood in a smaller well insulated home.

If retirement is five or more years away, it's possible that by waiting until you retire before building a solar system you would really benefit from some of the panel and battery research in the pipeline now. In five years solar systems won't be any more expensive than now, they have a good chance of being less expensive later. Wish I had a crystal ball.

Two things are holding back solar power (for people living in areas with good solar potential):
Gas and oil well fracking is changing the energy landscape. It will take some years to get past that but it won't be half as long as the 100 years the marketing cheerleaders say. As of now it is giving utilities the ability to make cheap power while flying under the environmental radar. I don't think that will last more than another decade.

The current revenue structure of electric utilities and power grid operators is not set up to be compatible with grid-tied systems. They would go broke if solar power saturated their market areas. We know they won't be going broke, so as solar installations increase, utility pricing strategies will change--they have already begun that process. They will have to position their pricing below off-grid costs, low enough to keep grid-tied customers, or they will go the way of phone land lines; many people will just cut the cord.

An off-grid system at a reasonable cost would completely sidestep the utility issues--for you personally at least. Better and/or cheaper batteries would make a huge market difference today if they were available.

You have generators now, so you are set with that. I just don't see any advantage to you in your situation to do a solar system at your retirement location now.

 

[dave1949]

The nano material engineering is really beginning to take off.

New solar power material converts 90 percent of captured light into heat -- ScienceDaily
A multidisciplinary engineering team at the University of California, San Diego developed a new nanoparticle-based material for concentrating solar power plants designed to absorb and convert to heat more than 90 percent of the sunlight it captures. The new material can also withstand temperatures greater than 700 degrees Celsius and survive many years outdoors in spite of exposure to air and humidity. Their work, funded by the U.S. Department of Energy's SunShot program, was published recently in two separate articles in the journal Nano Energy.
....
Modeled after President Kennedy's moon landing program that inspired widespread interest in science and space exploration, then-Energy Secretary Steven P. Chu launched the Sunshot Initiative in 2010 with the goal of making solar power cost competitive with other means of producing electricity by 2020.


The DOE SunShot web site:
SunShot Initiative | Department of Energy

The SunShot Initiative drives research, manufacturing, and market solutions to make the abundant solar energy resources in the United States more affordable and accessible for Americans.

Since the SunShot Initiative was announced in February 2011, the office has funded more than 350 projects in the following areas:

Photovoltaics (PV)
Concentrating solar power (CSP)
Balance of systems costs (soft costs)
Systems integration
Technology to market.



A nano cavity based solar-thermophotovoltaic (STPV) collector which uses more of the light spectrum and is efficient at wide light angles:
How to make a 'perfect' solar absorber -- ScienceDaily

 

[dave1949]

The October, 2014 results.

Just a bit above the model, about 1/2 of a sunny day for my system in October.

Month--NREL Model (AC kWh)--2012 Actual---2013 Actual---2104 Actual

Jan.----388----------------------NA--------------440-------------360
Feb.----412----------------------NA--------------375-------------446
Mar.----509----------------------NA--------------462-------------577
Apr.----374----------------------NA--------------487-------------525
May----353----------------------NA--------------375-------------361
Jun.----308----------------------NA--------------379-------------390
Jul.-----341----------------------NA--------------377-------------395
Aug.----383----------------------461-------------470------------453
Sep.----394----------------------481-------------476------------489
Oct.----369----------------------378-------------453-------------380
Nov.----283----------------------400-------------414
Dec.----331----------------------297-------------278

 

[300UGUY]

No experience with solar here, but I was watching a interview with a exec of a solar company on CNBC, he said that within 10 years, the cost per Kw for solar would be down to 4c. Cheaper than natural gas or coal! You think it was just BS?

 

[dave1949]

No experience with solar here, but I was watching a interview with a exec of a solar company on CNBC, he said that within 10 years, the cost per Kw for solar would be down to 4c. Cheaper than natural gas or coal! You think it was just BS?

Could happen. A lot depends on if and how quickly some of the new technology makes it to market. Solar is competitive with coal using clean air treatment now. Any reasonable storage/battery advances will turn the market on its head in a short time.

Currently solar pv panels retail for around $1 per watt. At present efficiencies the general ratio of installed wattage to output watt hours is 1:1 over a years time. For example a 5kW system produces about 5kWh in a year--give or take. No magic in the 1:1 ratio, just a coincidence of current technology used under typical conditions.

So, given a useful service life of 20 years, an installed watt produces 20 watts hours over it's lifetime (one watt hour per year). $1/watt divided by 20 watt hours = 5 cents/watt hour average lifetime cost. This does not include supporting hardware such as the inverter or installation charges.

 

[300UGUY]

I think he was talking retail. Right now, my cost is 14c / kw

 

[Redneck in training]

Our DIY built system produces 1kWh for 8.2 cents before taking into acount tax incentives or 5.8 cents after tax incentives. It is actually better because my calculations don't take into account mortgage interest tax deduction and investement gain on tax rebate investment. The construction was financed by a second mortgage with 3.7% interest.

 

[Jim Nelson]

We got our 3kw system installed in late June of this year and are in the net metering system.We used the air conditioning as needed to stay comfortable and quite a bit more than in previous years when our bill would be near $300 per month.Through Sept.the total accumulated bill grew to $63 and change.We didn't use any ac in Oct. and the accumulated bill dropped to $33 and change which seemed like a lot to me.I'm wondering if everyone has this big of swing or maybe there is an accounting error that will be corrected later.