Anyone considering solar or other alternate power for their shop?

  • Advertise with us

« back to Focus on the Workspace forum

Forum topic by crank49 posted 02-01-2015 06:45 PM 1471 views 0 times favorited 21 replies Add to Favorites Watch
View crank49's profile


4030 posts in 2966 days

02-01-2015 06:45 PM

Been working on cost benefit calculations and it is surprising how affordable solar power is becoming.
I’m not looking at going off grid yet, but behind the meter works and has some possibilities, even here in Tennessee where I have to deal with TVA fighting me every step of the way.
If I lived in an area where net metering was a possibility I wouldn’t even think twice about it.

By the way, I’m making my living, my day job in other words, by designing and installing solar power for light industrial and commercial users. But my company does not normally install residential systems so I’m not trying to sell anything here. Just wanted to be up front with that. And wanted to point out that there are some possibilities here for anyone with DIY skills, and that is most wood workers, to save some money and help the environment. Not to mention the thrill giving the power company the one finger salute.

21 replies so far

View Mark Davisson's profile

Mark Davisson

597 posts in 3312 days

#1 posted 02-01-2015 07:00 PM

Crank, what do you calculate the cost per kwh to be over the life of the “behind the meter” equipment you would install? How quickly would you achieve payback?

-- I'm selfless because it feels so good!

View patcollins's profile


1685 posts in 2860 days

#2 posted 02-01-2015 07:04 PM

Interesting, in Maryland you are not allowed to be “off the grid” we haven’t had a hurricane that knocked out power for a week or so since that law went through but it means if you are tied to the grid your solar doesn’t work when the lines are down…..

View crank49's profile


4030 posts in 2966 days

#3 posted 02-01-2015 08:50 PM

Installed solar cost varies with the size. Bigger systems are less per watt than smaller and every case is different for the install, roof mount, ground mount, length of power cable runs etc.
But a basic rule of thumb right now is $2.75 to $4.00 per watt. Life expectacy is 25 years.
Just the basic PV panels can be had for $0.75 per watt.

The systems my company installs are all USA made and usually have a payback less than 7 years, but would be more like 4 to 5 years if we could use net metering like the rest of the country.

Most folks need to have a study done by a reputable installer that will involve location, hours of peak production possible per day, electric bill, electric rate, etc. Some companies even offer financing and leasing options with no up front money required.

Off grid “not allowed” ? Is this still the USA we are living in? How the hell can a government entity tell you that you can’t be off grid? Well, after obamacare I guess anything is possible, but I’d wind up in court over that one.

Behind the meter systems use grid interactive inverters. They sync up with the grid voltage and hertz and just back feed the power panel through a breaker. They are designed to shut down in 0.16 seconds should the hertz be above 60.5 hz or below 57 hz. This is a code safety requirement to prevent backfeeding the grid and endangering line workers during a power outage. But automatic transfer switches can disconnect the grid and allow the solar system to continue operating.

This is very new technology, but battery systems can also make them function at any time. Kinda like a UPS for your computer, except for the whole house.

I just did a remote hunting cabin for an industrial customer and he was entirely off grid. He has 7.2 KW of PV panels on the roof (14 ft x 29 ft), an 8 KW inverter with an 11 KW standby generator. The PV panels or the generator will charge a big 1200 amp hour 48 volt battery. He has a gas stove, tankless gas water heater and everything else is electric, including his wood shop. This kind of complete system is just over $24k.

I’m designing a small 3 KW system for my own house and it will run less than $7500. There is an Investment Tax Credit available that will pay back 30% this year. The other $5250 will be payed back by a reduction in my electric bill over the next 5 years. But I’m doing all the work myself.

View Mark Davisson's profile

Mark Davisson

597 posts in 3312 days

#4 posted 02-01-2015 10:26 PM

Thanks, Crank. Would you say installation costs are roughly equal to the cost of the hardware, itself? Less than that? More than that?

-- I'm selfless because it feels so good!

View patcollins's profile


1685 posts in 2860 days

#5 posted 02-02-2015 02:14 AM

Crank49 there was a story about an old man who had a lien placed on his house over an unpaid sewage bill. The kicker is he never connected to the sewage system but was required to pay for it some how. The water/sewage here is nothing short of a cartel, in 8 years my bill has more than doubled.

I think around my neighborhood I have seen 10-12 houses with solar panels on the roofs, one of them has the panels on the north side…. there are also a lot of trees here so I can’t see it being cost effective.

My personal misgivings are about some somewhat trained installers drilling holes in my roof.

View Crank50's profile


173 posts in 1571 days

#6 posted 02-02-2015 06:53 AM

Mark, in very round numbers you could say installation costs are about equal to the hardware. In my case the panels are about $2500, the inverter is about $1500 and the battery is about $3000 and the charge controller, required electric switch gear and misc. will run about $500 to $1000.
If I weren’t in the TVA electric service area I wouldn’t need the big battery. I can’t backfeed my surplus power onto their grid without having to give to them for free, so to see a payback I have to store the surplus energy from the day time and use it at night.

Pat, I’m sure Maryland is a beautiful place to live but I’d have a big problem to live there myself. It’s bad enough to have to get creative to deal with the electric utility here in Tennessee, but having a lien placed on my house for service I didn’t use would be a bridge too far.
There are quality installers and there are shade tree installers. Be sure anybody you deal with is certified and insured. There are online sources for the calculators too tell whether your site is feasable.

View Mark Davisson's profile

Mark Davisson

597 posts in 3312 days

#7 posted 02-02-2015 11:37 AM

Thanks, again, Crank.

Here in Indiana we have net metering (customer is credited at full retail) and 100% property tax credits, so that’s good. But the payback would need to be shorter for me to invest.

-- I'm selfless because it feels so good!

View Buckethead's profile


3194 posts in 1863 days

#8 posted 02-02-2015 12:35 PM

Solar/alt is a no brainer. It’s sad that your state fights you on it, as our utility companies enjoy monopoly status, and are supposed to be benefactors to the general public. (Lol)

I don’t know the ins and outs, but definitely want to get solar when I build my dream home on some acreage, in the land of the free. Say… Anyone know how to get there?

I’m actually running out the door, but I’ll read up fully later. Hope this thread gets lots of attention.

-- Support woodworking hand models. Buy me a sawstop.

View TheFridge's profile


9444 posts in 1481 days

#9 posted 02-02-2015 01:16 PM

It’s getting to the point where it doesn’t take 25 years to pay itself off.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View Davesram's profile


1 post in 1620 days

#10 posted 02-02-2015 02:33 PM

Does anyone know if solar can be used in Maine? Moving there soon and I would like to run everything on solar if I could, but especially my shop!

View JesseTutt's profile


854 posts in 2105 days

#11 posted 02-02-2015 03:08 PM

I have considered solar (dreamed about it). So far I don’t have enough knowledge to feel comfortable moving forward with it.

would you post links to reputable online calculators?

Here in Missouri, I asked the local electric provider (Ameren of Missouri) and they said they would put a bi-directional meter on my house for free. I asked about rates and was told that the amount they would pay me for electricity was “much less” than the rate they charged me for it. I was also told that most of the funding for subsidizing solar installs had ran out of funding.

There was a news story about a family that installed a 22kw solar system. American Family Insurance dropped them saying that 20kw or larger was only allowed in a business. So check your insurance company before installing.

-- Jesse, Saint Louis, Missouri

View jmartel's profile


7882 posts in 2145 days

#12 posted 02-02-2015 04:03 PM

It s getting to the point where it doesn t take 25 years to pay itself off.

- TheFridge

Depending on your location, it’s already well past that point. Even here in Seattle, the payback point is under 10 years. And we get less sun and have cheaper electricity than most areas of the country.

-- The quality of one's woodworking is directly related to the amount of flannel worn.

View RobS888's profile


2411 posts in 1840 days

#13 posted 02-03-2015 12:26 AM

I lease solar in MD and we have automatic disconnect to prevent backfeeding BGE’s lines. Only get about 1/3 from solar, so no going off the grid and we have never had a situation where we have sun, but no power, so I’m ok with the auto disconnect, especially if it reduces the chances of a utility worker getting hurt.

We have net metering, so that is really nice. My budget billing has been reduced twice now by electricity supplier.

I pay 33 dollars a month for a 3 KWH system, as long as it generates 220 KW a month, I’m happy. BGE rate and distribution equals about 15 or 16 cents per KW.

The panels look nice and are insured, and I don’t have to do anything to them. The generation is guaranteed if it falls below 90% of original new system output.

Pat lives in Southern MD and that is a different world In many ways, so there may be different rules.

We had prices locked in for several years to allow competition (none really showed up) but our rates were frozen at 1996 levels or somewhere around there. When it ended the rates jumped 73%. BIG issue let me tell you. The final outcome was everyone had to pay to help phase in the rate increase over a year or two. So for 10 years everyone has to pay 4 dollars/month rate stabilization fee, it is a finance charge for phasing in the increase. To assist with loses due to the new competition BGE was allowed to collect higher transmission rates. They collected and banked 500 million dollars That made me want to leave BGE.

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

View crank49's profile


4030 posts in 2966 days

#14 posted 02-03-2015 12:51 AM
This is a popular calculator provided by NREL (National Renewable Energy Lab)
Just enter your address to get started.
This is a link to a solar map published by NREL.
It shows how many equivalent hours of peak solar production you can expect in a day.
I can expect 4.7 hours in Tennessee.
In central to northern Maine you might expect 4.2 hours.

If I install 4 KW worth of PV panels they will produce 4KW X 4.7 hours = 18.8 kwh a day, on average.
Here in Tennessee that would be worth 18.8 x .11 per KWH = $2.07

View patcollins's profile


1685 posts in 2860 days

#15 posted 02-03-2015 01:56 AM

Hey Rob, funny story about BG&E, they keep calling me and telling me they are going to shut off my electric and they don’t even service down here. I have told them over and over where I live but they insist that I live up there and my name is Mark.

showing 1 through 15 of 21 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics