TED – The Energy Detective

Having a photovoltaic solar system that can run your whole house is awesome. Not having a way to monitor it while you are away sucks. This is where my good friend Ted comes in. Ted is not really my friend in the human sense but in the TED-5000 (The Energy Detective http://www.theenergydetective.com/ted-5002-g ) sense.

TED can measure AC voltage directly and AC current via inductive coupling current clamps. These signals are fed into an MTU (Monitoring and Transmitting Unit) which digitizes them and sends them over the power line in bursts each time the A/C voltage crosses zero. At that point, (for what seems like thousands of micro-seconds to TED), there is effectively no current flowing on the line and a data is sent on a 132KHz channel from the MTU to TED. TED then uses his built in Internet gateway and relays this information to the Internet where I can log into Google power meter and monitor my home energy usage. TED also has an optional $80 handheld unit that receives info from TED via a Zigbee wireless signal. I opted not to get one of these displays when I already have an Apple itouch because, well, there’s an app for that.

I actually bought TED’s schizophrenic brother, TED 5002G, which contains two MTU units. One set of voltage leads and current clamps can monitor the total power coming from and going to the grid while the other set monitors just the inverter’s production. Using the provided software, I can see exactly how much power my house is consuming during any point in time (within 2 seconds).

This also provides a way to monitor actual usage (within 1 watt) of all appliances in the house, including ones that run on 240 volts and/or are hard-wired (like the dish-washer).

To the shock and surprise of my 7-year old son and 9 year old daughter, I requested they turn on every light in the house. We also turned on all four burners on the electric range, the oven, the toaster oven, the microwave oven, the waffle iron, the electric griddle and Kitchen Aid mixer. Last but not least, I turned on some work lights, the table saw, shop-vac and drill press. Ahh. TED reports back that we are currently using 22,300 watts. A quick math calculation reveals we are drawing almost 93 amps at 240 volts. Wow! That’s a lot of power. That is approaching Clark Griswold levels of power consumption.
In the movie Christmas Vacation, Clark Griswold (Chevy Chase) used 25,000 Italian imported lights (assuming 7 watt bulbs). That works out to be 175,000 watts.

Here is an EKG of my electric Oven. What you are seeing here is the preheat cycle followed by the oven coming up to temperature (flat line) and then re-heating caused by a batch of cold cookie sheets with dough being placed in the oven. Awesome! Snort, snort.

You might think that my wife is not too fond of me knowing exactly when lights get left on and when she is baking bread or otherwise using copious amounts of electricity. Actually, she is quite pleased that I got TED because now she doesn't have to run outside into the garage to read the display on the inverter every time I call her on the phone from work.

Watch my meter spin backwards for the first time

The next morning I didn't have to go to work because it was my Friday off. I love working 4-10’s! I got up before sunrise and high-tailed it out to the garage to watch my SunnyBoy inverter turn on for the 2nd time ever.

Standing barefoot on the cold cement floor of my garage, staring at the display on my inverter, I watched in anticipation as the voltage of the solar array climbed slowly until it reached the threshold of the inverter's power-on circuit.  CLICK....  The inverter switched on and started to blink.  A few minutes later, CLICK....  HUM..... and the inverter started feeding power to the grid. 

Here is my account as recorded on Facebook as it happened: 
November 12 8:01am:
Cloudy sunrise: watching my inverter start to convert power to run my house. 34watts.... 57watts..... 64watts... 87watts... 94watts..... 106watts. I'm just geeking out here!!!!! 117 watts and rising.

November 12 at 8:12am
‎195 watts... The clouds are starting to break. 218 watts... 225 watts.... 251 watts. Now running at 1/20th of capacity. I can see the round shape of the sun in the clouds. 566 watts.... 620 watts.

November 12 at 8:19am
1768 watts.... 2087watts and rising fast. Sun has cleared the clouds. 2802 watts..... 2845 watts... Not bad for such a low sun angle... 2859 watts. Anyone need to borrow a cup of electricity?

November 12 at 8:27am
My power meter is going backwards.

November 12 at 8:45am
Just made it's first kilowatt-hr.
I'm 10cents richer. 3283 watts... 3307 watts....

November 12 at 8:47am
4121 watts. Awesome!!! But I see some ugly clouds rolling in.
Uh Oh 1821 watts.... 1773 watts... 1476 watts....

November 12 at 8:56am
With the sun behind ugly clouds, it's averaging about 800-1000 watts. My house power meter is still rolling backwards even with washer/drier running. Turning on the microwave oven causes it to roll forward briefly.

November 12 at ‎10:24am
clouds break. 5062 watts.

November 12 at 10:25am
Noticing that even though the meter is moving backwards, the numbers are not decrementing. I figured as much. I need to wait for the city to swap out the meter head with one that can. In the mean time, I am cleaning the oven using sun-power. Anyone want some free energy? For the next 4-hrs I'm just giving it back to the city for free.

November 12 at 5:37pm
Panels and inverter generated 20 kilowatt-hours of energy today. Not bad for a partly cloudy day in mid-November.

To celebrate the first day my solar array back-fed power to the electric grid, Cheryl made a solar array cake.
It was baked with 100% solar electricity. Mmmm taste that solar goodness..

Wiring up the Solar Panels to the Inverter

11:55PM. I could not sleep. The racking was done and twenty-six 240 watt Phono-Solar panels were securely mounted on my roof.

All I needed to do now was bend and install the last bit of conduit from the ceiling of my attic down to the Sunny Boy inverter mounted on the back wall of my 3-car garage and pull a few lengths of 10AWG high voltage wiring through to it. I thought to myself, “It’s better to do it now and lose 2 more hours of sleep than toss and turn all night and not sleep at all.
Well, I finished at 5:15AM, just in time to get ready for my real job.

I didn't dare connect the 500 Volt DC wires to the inverter yet. I measured the voltage of the solar array (before sun-rise) and both strings read wildly differing values. One was 45mV and the other was 85mV. True it was dark outside with only a few street lights on but I was worried that I may have wired something incorrectly. I didn't want to be 20 miles away at work when the sun came up and things started turning on. A daylight reading should be closer to 400 Volts and each identical string’s voltage shouldn't vary from the next by more than a few percent.
After fighting my way through a 10 hour day of staff meetings and paper work in my cubicle, with no sleep, I made it back home an hour before sunset. I tore open the inverter and measured the voltage on the wires. 442 Volts on both strings. “Yes!” Not only did I wire my panels correctly but they were both generating a voltage within the allowable range of the inverter. I still had time! Carefully using pliers and leather gloves, I made the final connection from the solar panels to the inverter. No sparks! So far so good. I flipped DC disconnect switch to the energized position. LED lights starting blinking as the inverter ran its self-diagnostic test.
I flipped on the A/C disconnect feeding the inverter to the grid. After a few minutes, the Sunny Boy grid-tie inverter clicked on and started generating power. 84 watts…. 78 watts…. 67 watts. It was almost sunset now but it was making real, usable power. Awesome!

Building permits and Installing my Solar System

I have learned by experience whenever you are getting a building permit or having a building inspector come to check out your wiring, never disagree with what they have to say. And never, ever reveal that you are an Electrical Engineer and that you know more than they do about electricity. Just out of spite, they will make it that much more difficult for you to pass your inspection.

Just smile, say, “Thank you very much and have a nice day”.

I was the first in Kaysville to have a grid-tie system that would generate enough power to require a NET meter (a power meter that will roll forwards and backwards) to be installed. The city officials gave me a lot of extra requirements because they had a lot of questions too. Most of them were answered by http://www.utahsolar.com/. After all, the good folks at Utah solar have been doing this for 20 years and know a thing or too about solar energy.

There was one question they asked me which was mine alone to answer. Why?
Why are you installing solar panels? Nobody else in Northern Utah does this. Why are you doing it? To which I answered, “Why climb a mountain?”.

I have pondered that question a lot lately. Why am I doing this?
Long-term cost savings, self sufficiency, I want to be a good steward of this Earth on which God has placed me, and reduce my personal impact to the environment. If for nothing else, solar power is super awesome!! Dude.

HOA
The HOA which rules over my neighborhood was kind of nervous about me installing a bunch of trashy looking panels on my roof. Can you blame them? Half of the solar panel videos on You-tube are of some backwoods tree hugger leaning his panels up against a rusted out 57 Chevy with weeds growing out of the engine compartment.

"If I am going to do this, I want the install to look clean, sleek and aesthetically pleasing."
I also went to great lengths to run the high voltage wiring and conduit through my attic instead of around the exterior of my house to the garage where the inverter is located. The most beautiful home theaters don’t reveal any wires. The same goes for solar panels.

RackingIt’s amazing to me that the best solution tends to be the most simple one. Even Leonardo da Vinci said, “Simplicity is the ultimate sophistication”. I was wondering how the solar panels were going to mount on to my roof. When I opened up the mounting rails and L-brackets, it was all clear to me. Using a simple lag screws and L-bracket, an extruded aluminum mounting rail can be fixed solidly to the roof. The panels then clamp to the mounting rails (or racking as they call it). It is a very strong, easy and fast way to install panels on the roof. It also looks very beautiful to have them mounted flush to the roof.
With just me (and my young kids helping at times), I was able to install all the racking in 1 ½ days. The solar panels all went up in a few hours. I averaged (6 minutes/panel). To my neighbors horror, By myself, I carried all 26 of the 50 lb solar panels (almost 1300 lbs in all) up the ladder and onto the roof.
The solar panel’s aluminum frame has a lip on the back side that makes it a cinch to grab hold with one hand over your shoulder and carry the panel resting slightly on your back. Just don’t try it with more than a 2 mph wind.

Here's a link to my solar panel install time lapse video.
http://www.youtube.com/watch?v=0NJovItcdCI

Solar Training

It has been my goal to learn how to do every trade skill that I possibly can. Not only do I want to be self sufficient in all areas but I’m also a cheapskate and figure labor is the highest cost of any remodel or construction project.
I took a 12-hr on-line training course on how to install solar panels. Even though I am an Electrical Engineer by trade who has worked in the home construction business for 10 years before that, I gleaned a whole lot of good information from the solar training.
Sometimes you have to review your basics in order to get a deeper understanding of the technical details.

Good-to-know Tip#1:
Shade on 1/3rd of a single solar panel will take out the entire array, so plan your location wisely. Determine where the shade is going to be during the entire day, every day of the year. Don’t mount your panels in those areas. There are ways to limit the problem by using micro-inverters. 

Good-to-know Tip#2:
Design your solar array layout to handle the maximum wind load ever recorded in your area. In Kaysville, UT it's 120mph. I took it up a notch and designed it for 132mph. Mount lag screws into the studs of your trusses, NOT the decking material.

To Grid-tie or not to Grid-tie

Actually for someone living in a metropolitan area with a fairly reliable power company, it's a no brain-er. Grid tie systems are way cheaper and don't have nearly the maintenance and upkeep costs that going fully off the grid requires.

Let me illustrate:

For off-grid systems, if your panels make a ton of power and you don't use it all that day, it all goes into your batteries. That is until they batteries are all full. At that point, if you don't have another place to store all that extra energy, your panels are essentially not doing you any good anymore. Sure they look pretty but that's about it.

If it was cloudy and your solar panels didn't produce very much energy, you must ensure your battery bank is large enough to sustain you. If it isn't, well... You'll be in the dark.

For grid-tie systems, if you make a ton of extra power, your grid-tie inverter simply stores it on the grid, as if it is an almost infinite capacity battery at your disposal. Only this battery doesn't contain volatile hydrochloric acid and doesn't need to be replaced after 3-7 years. It takes whatever your inverter gives it, spinning your power meter backwards in the process. At night, when your solar panels stop producing electricity and you need power, you simply pull your stored energy back off the grid, rolling your meter forward again.

If I wanted to power my home completely off grid, I would need to have a solar array that was 3 times larger than the one I have now (18.6KW instead of 6.2KW) only because the winter months have so little sunlight.  During the summer months, I would have way more capacity than I needed but a finite battery bank to store it all.  Any excess would be wasted. 

An on-grid solar system allows all the excess solar energy to go back to the grid until the darker, snow-covered months when you can draw it back off again.  

Because all the energy generated by the panels will always be used eventually, they entire system operates way more efficiently.

The only down-side to a grid-tie system is when the power goes out. As a safety measure, when the grid power goes out, the grid tie inverter also shuts off. This prevents the poor lineman sent to repair a downed power line from being killed when he discovers your inverter is still live and well. Also, your inverter might not like it when the entire sub-station is trying to draw power off of it.

Where I live, the power goes off about 3 times a year and rarely for more than a few minutes or hours. I would love to have an emergency source of power derived from my solar panels. Short of re-wiring all my panels, I have not found it yet.

My system uses 26 solar panels wired with two strings of 13 panels in series. Thirteen, thirty-eight volt panels in series equals almost 500 Volts DC running down to my inverter. This allows for less line loss from the solar panels to the inverter.
If you wired all the panels in parallel, in order to overcome the resistive losses of the wiring, you would have to have a huge tree-trunk cable running down to the inverter. 

Buying Panels

As luck would have it, the day before I bought my solar system, the 25% rebate offered by the state of Utah was discontinued. Ah crap! Too late now, I'm committed regardless.

Above is a picture of my order (that http://www.utahsolar.com/ took) before being loaded on the truck in California and to shipped to my house in Utah.

I took out a $22,800 home equity loan for the panels but initially paid using credit cards. If you get 1% cash back on all purchases and pay off the balance before the due date, why not? That knocked off $214.65, more than enough to buy a remote power monitoring hardware/software and Internet gateway package, (TED5000 www.theenergydetective.com/store). Cool! Snort snort.

Here it is being unloaded at my house.

For our anniversary, I told my wife I was buying something beautiful, expensive and that sparkles in the sunlight. For some reason she was not as excited as I was when it arrived on the truck.

Getting Started

I've wanted to get solar panels for at least the past 10 years. Every time the idea came up, I was either too busy on other projects or the funds were not available. This year was different. In October of 2010, I was doing my annual "price out a whole house solar array" when I came across a web site at http://www.utahsolar.com/, based out of Victorville, CA. Ha ha.
They had very good prices for solar systems around $3.40/watt. You can barely buy the panels for this price let alone all the roof mounting hardware (racking) and a grid-tie inverter. But there it was, just waiting for me to buy it. Also there were some amazing state and federal rebates and credits totaling 55% of the cost of the whole system.
Just then, a Wells Fargo solicitor called trying to get me to take out a home equity loan. I replied with my usual, "No thanks but I am not interested in a home equity loan," but then I paused. "Wait a minute, that's it! I can take out a loan for the solar panels and when the rebates come in, I can pay it off. "I'll take it!"

Before I bought a solar system large enough to power my whole house, I had to figure out how much electricity I required each year. Being the big nerd that I am, I already knew that and kept a spreadsheet for my monthly usage for the past 4 years.

My average (since we moved into our new house) was 1080 kilo-Watt-hours/month. I should add that I live in a 5000 sqft house that is fancy but fairly energy efficient (R-13 in walls, R-38 in the attic, low-e glass windows). It has a ton of south-facing windows that provide plenty of sunlight in the daytime. To make it more efficient, we also did the following shortly after we moved in:

• Swapped out incandescent lights for CFLs.
• Added curtains to cover windows (so we can reduce direct sunlight during the summer months).
• Added an attic fan (to help vent some of the heat from the attic).
• Added more insulation around the cold condenser pipes running from the central A/C compressor and condenser.
• Added more insulation to the attic as well.

My average electric usage would have been about 35-45% higher had I not done these improvements. In any case, after all these improvements, 1080 KWH/month is my baseline electrical usage.
It's a Good Start But It's Not Enough:
My target 6.42KW solar system will only generate 960 KWH/month of electricity. In order for the solar panels to cover 100% of my house electric needs, I needed to shave over 120KWH off my total usage.
I recently found a really cool website on how to save electricity http://michaelbluejay.com/electricity. It is one of the best ones I've seen about energy conservation and saving money on all your utilities.

The best way to get your house onto solar power is to reduce your use first. Why pay for a super expensive solar system when with a tiny bit of tweaking you can get by just fine on a smaller and cheaper one?

Using my Kill-A-Watt meter http://www.killawattplus.com/ I was able to plug in and measure the energy usage of almost every appliance in my house. Some things like the refrigerator you leave plugged in to the meter for a few days to get the average usage of the appliance.

I made a spreadsheet that shows what every appliance uses and what it is costing me to run.

It's all About duty cycle:

Surprisingly, some appliances use a lot of energy but don't really contribute to your total electric bill that much. Others don't consume a lot of energy but over the whole month it adds up to a lot. For example the glow-in-the dark clock on my microwave oven uses more energy in 24-hrs than the microwave oven does to cook something for 30 seconds.

Each of my two super-energy efficient desktop PCs (Intel i-3 processors with WD green hard drives and 80 plus power supplies) that I keep on 24-7 use more energy than my electric range does to cook a meal 30 minutes each day. Obviously there were things that I could still do to reduce my total energy usage.

My goal in reducing my KWH consumption was to reduce energy usage without sacrificing convenience and luxury.

To make a long story short, in addition to the improvements I did when we moved in, I also did the following:

• Swapped out the electric clothes drier to a gas one, (reduced by 130KWH/month)
• In the daytime (except summer), open curtains and turn off all lights (20-45KWH/month reduction).
• Set the computers to go to sleep after 5-10 minutes of being left idle. (15KWH/month per PC).
• At bedtime, turn off all lights and use LED night lights (3 KWH/month reduction).
• Use only LED Christmas lights, (234 KWH/month reduction in December).
• Added a ceiling fan in the main living space, (estimated 100KWH reduction in the summer months).
• Get the kids to actively turn off the lights when they aren't using them (work in progress). As part of their weekly jobs, one of the jobs is titled the Energy Conservation Advocate.

As you can see, the clothes drier brought me all the way to my goal with the other stuff just being extra.
That was so easy that I want to see how much I can reduce it further. After all, why waste energy and money if you don't have to?

I still want to do the following additional energy reducing enhancements:

• Upgrade my PCs with solid state hard drives (3KWH/month per PC).
• Solar Tube skylight in the dining room and hall way, http://www.solatube.com/
• I am anticipating that having 500 sqft of solar panels on my south-facing roof will reduce the solar load on my home as well.