We’re On Our Way
I just got an e-mail back from the installer. He’ll be picking up the check on Monday, and will pull the permits right away!
How It Will Work
First, I’m off to mail the check in a few minutes. After the installer receives it, he’ll be applying for the permits.
For our system, there will be 36 185-watt panels on the roof. Each panel produces a rated 24VDC. The panels will be connected in strings of 6, for a total voltage on any string of 144VDC. Our inverter wants a range of 110 – 350VDC as input, so we’re in the range. (The voltage can get as high as 36VDC per panel in ideal conditions.)
The 6 DC wire pairs will come down from the roof in a PVC conduit and enter the house near the electric meter. In the basement will be a DC disconnect switch that allows us to cut off power from the panels to the inverter if required. Then, each string will be connected to the inverters (3 strings per inverter).
The inverter converts the DC power from the panels into 120VAC 60Hz power frequency-synchronized with utility power. At night, the inverter is essentially asleep (much like the Mars Rovers). Once enough power is received early in the morning, the inverters will wake up and start providing power to the house/utility.
The inverters are connected to a new electrical sub-panel via AC wiring. There are 3 wires – two AC legs and ground. Each inverter’s connection goes through a 240VAC 20A dual breaker in the panel. There will be two of those in the panel.
The panel output runs outside of the house to an external AC disconnect switch. This switch allows the utility to disconnect our solar system from the utility and the house if required. From the switch, the power connection runs back into the house and into our main electrical panel (the one with the existing circuit breakers in it).
The solar output is connected to our main panel by a 240VAC 40A dual breaker. At this point (conceptually) the power mixes with utility power.
From there, we have the existing connection to the utility. Our existing meter will apparently be replaced by a new meter that handles net metering. If the solar system is producing more power than the house needs (likely if the A/C isn’t on during the day in spring and fall), the meter will “spin backwards” and we’ll be credited for the power. If the house needs more power than the solar system is providing (or at night), the meter spins forward and we’re buying power from the utility.
There are security features that cause the inverters to shut down if utility power is lost. That would case a condition knows as “islanding”, where our power would be energizing power lines that the utility assumes are dead (not to mention trying to power our whole neighborhood!). There are also features in the inverters that shut down or reduce output for high temperatures (not likely – they’re going to be mounted in the basement and they handle up to 105F) or for other failures.
All of the electrical equipment is going to be mounted in the basement near the existing electrical panel, except for the panels, conduit, and external disconnect switch. The whole system is grounded through the electrical connections all the way from our existing main panel to the inverters.
A Word on Paybacks
This system is expected to generate about 500-550 kWh per month on average. That will end up being about 2/3 of our electric bill.
That makes the payback for the system about 15-20 years, depending on how quickly electric rates increase during those years.
However, some studies that my installer provided (and that I’ve seen online) state that solar electricity systems have a payback in property values of 100%. The only other home improvement project that has a 100% payback is a kitchen remodel (pools are about 60%, decks about 40%).
You really have to have a motive other than cost savings to put this stuff in – otherwise it’s too expensive. In my case, it’s to increase the ability to generate electricity in a clean manner. For every watt of electricity that I generate, I’m most likely saving generation of a watt through some polluting method – natural gas, oil, coal, etc. There’s some pollution involved in making the solar cells in the first place, but that’s some smallish percentage of the pollution avoided in their use.
And the annual savings don’t hurt either. We estimate that this system will produce negative electric bills for the months of April – June, with a positive bill for the rest of the year. Overall you can’t exceed the usage of your house – the rebate program prohibits you from being a net producer of electricity (as opposed to a net consumer) on an annual basis.
The NJ Process
In a nutshell, here’s the NJ process as I understand it. I’ll make notes of what we’ve done already.
1. Find an installer, get a quote.
Done in Mid-December 2003
2. Apply for the NJCEP rebate. You should get a response in 7-10 days.
My installer filled out most of the application for me – I just needed to fill in a few missing pieces and sign it. I mailed it about 12/22/2003, and received a response on 1/17/2004 dated 1/14/2004. Apparently, the delay was caused by the fact that the office was closed part of the holidays and got a flurry of new applications in a short time.
3. Sign the installer’s proposal, send in the first 50% of the net cost.
We’re doing this tonight to be mailed tomorrow. In our case, we signed the rebate over to the installer, so we’re just sending in 50% of the net cost.
4. Apply for and receive the appropriate permits.
My installer will be doing that for us, and we’ll pay him back at the end for the fees.
5. Fill out and file the PSE&G interconnection agreement (another $100 fee)
6. Install the system.
The plan is for this to be early to mid March, 2004.
7. The township inspector inspects and approves the system. I’ll get an approval sticker on something.
8. PSE&G inspects and approves the system. They will place a sticker on something. Apparently, they’ll also change the meter to an electronic one.
9. Go live!
10. File the remaining paperwork for the rebate, including approval documents.
11. Pay the remaining fees and 50% of price.
A Little About Us
In case you’re wondering why we might be interested in making our own electricity.
Me: a 35-year-old computer systems analyst for the direct to consumer division of a major consumer durable goods company (home decor stuff)
My Wife: About my age (I think I dodged that bullet), a mechanical engineer with her Professional Engineering license and PMP (Project Management Professional) certification, working for a major multi-national corporation in the turbomachinery division (what engineer in power generation can resist generating her OWN power?) With the PE license, she might end up certifying some of the work on our project to save some money.
We have no kids, but we have 2 cats.
The System We Chose
Rick Brooke of Jersey Solar came to my house in mid-December, 2003 and did a site survey and discussion of our options.
Our house is a 2200-square-foot colonial home built in 1995. Unfortunately for us (our fault – we bought it new and chose the lot), the front of the house faces east, making the roof ridge line almost exactly north-south. That puts a natural limit on the amount of solar energy that we can generate, since we won’t be in full sun all day on either side of the roof. However, we should have sufficient sun to generate at least some power most of the day – sunset being the exception.
After a review of the site, Rick recommended putting the panels on the front of the roof – facing east. This was primarily for three reasons:
1. The back side of the roof has things sticking up out of it (plumbing vents, exhaust fan heads).
2. We have planted trees in the back yard intended to shade the back of the house from the summer sun in the afternoon – prime air-conditioning time. Those trees should eventually cause shadows on the back of the roof. We have no such trees in front – just a small fruit tree that shouldn’t get tall enough to block the sun.
3. The back of the house is close to other houses and a large several-hundred-year-old tree, which will block the sun. The front has the front yard, the street, and the neighbor’s front yard before an obstacle to sunlight.
We originally considered a grid-connected system with battery backup from AstroPower. We decided against it because that system would provide 5.76 kW of power and have a net cost to us (including the batteries) of $24,500. As you’ll see below, that is a $10,000 increase over the system we chose just to add battery backup. We decided that we could buy a gas generator and transfer switch for much less than that installed, should we ever want the backup capability. Besides, we haven’t had a power failure over 1 hour in the 8 years that we’ve lived there (and that only once or twice). PSE&G provides rock-steady power in our area.
We chose a Sharp system instead that will provide 6.66 kWdc of power for a net cost to us of about $15,500.
The system will include:
36 Sharp 185 watt NT-S5E1U solar photovoltaic (PV) modules
2 Sharp JH 3500 DC to AC inverters with digital display (each with a capacity of 3.5 kW)
Mounting Hardware
One exterior PVC conduit from the roof to base of the foundation for the PV module connections
One exterior cutoff switch (required by the utility)
A new electrical subpanel for the output of the inverters
Some other miscellaneous electric switches, conduit, wiring, etc.
The gross cost of the system is about $51,500, with the state rebate program paying the difference between gross and net to us. We’ll also have to pay out as much as $500 in fees for permits and PSE&G interconnection.
We have a 25-year warranty on the PV panel modules and a 5-year warranty on the inverters. The installation is warranted for 5 years as well.
Research
I started my research on the net, as always.
I found a few interesting things:
1. New Jersey has an amazing rebate program for small PV systems (under 10KW). You can find their site at NJCEP. The bottom line is that they’ll pay for up to 70% of your system as long as it is grid-connected and you use net metering with the utility (You buy from the utility when needed – like at night, and you sell to the utility when you have excess power – during spring daytime mostly. Your meter runs backwards some of the time!)
2. These systems cost about $50,000 total, but the rebate (above) reduces that to a reasonable level.
3. There is almost no maintenance required for a PV system.
I ended up choosing Jersey Solar of Lambertville, NJ. Rick Brooke is the President of that company. This company was featured in all of the residential case studies listed at the NJCEP website (above) and the PSE&G solar energy page http://www.pseg.com/customer/home/save/rebate1.html. More in the next entry on what we’re buying.
Welcome to the blog – how I got started
Hello, world.
This blog is intended to log my journey purchasing and installing roof-top solar cells for my house in Hamilton, NJ.
I’ve been intrigued by solar electricity for a long time, but it’s always been too expensive. However, right now New Jersey has some amazing state rebates that reduce the cost to reasonable levels. Also, it’s just really cool to be able to generate your own electricity.
This summer, the Northeast and parts of Ohio suffered a major blackout. That pointed out to me how frail the electric infrastructure is, and pushed me to look at alternatives (generator, fuel cell, etc). As you’ll see below, we didn’t choose anything that backs up the utility system, but this is what pushed me in this direction.
Web Stuff
