On Grid, Off Grid Project Results

Solar PowerHouse. the modules in the background are gridtied and some can be switched to DC

Battery wiring is a temporary set up to be upgraded

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Back on June 20th, I posted about a fairly simple yet sophisticated solar battery system. I finally got the last of the wiring done last week. In the top picture is the "PowerHouse" which I designed and had local Mennonites make as a prototype two years ago. The idea was to build finished solar systems either gridtied or offgrid battery. The slope of the roof is 38 degrees which is the latitude of southern West Virginia. It fits 6) 230 watt modules, although today you can get 250 watters at less price.
The next picture is inside the PowerHouse showing the batteries, charge controller, combiner and inverter. For a full description and a link for the schematic drawing go to my June 20th post "Sensible Solar Battery System".

Two of the three series relays. Note Enphase microinverter behind timber

On July 5th I posted a schematic of a method of switching gridtied modules to DC so additional power can be collected for the battery system. I was a bit concerned the points in the relays might get damaged by under-load switching. I saw no visible arcing switching back and forth, so I suppose it will work for a long time.
The relay and it's socket are under the middle of the PV module and well protected, None the less, I used silicon dielectric grease on the wires, blade slots, and around the base edge of the relay since it didn't look like it was hermetically sealed. Then on top of that, I sprayed an anti-corrosive into the wire sockets and clamp screws. Ought to last for a while. Please note: I used "touch safe" sockets for added safety.
Basically, I doubled my collection power from 1380 watts to 2760 watts. Theoretically, I could charge the battery pack in 4 sunny hours. So yea, now I'm thinking of another set of 4) 220 A/hr batteries for winter conditions. Cha Ching..but that's the nature of the beast and human nature.

Close up of DPDT relay, socket and wiring

Different way to have battery backup on gridtie

This idea came directly from my previous post on a practical PV backup system. I have some grid tied modules nearby my battery backup shed and wanted to employ the grid tied modules to help out when the power was down. I decided to switch 6 modules into a 2 x 3 panel series string to feed the charge controller. The above diagram represents one string. It will deliver >100 VDC @ ~8A. My charge controller, an Outback FM80, can take in up to 150 VDC.
By using 120 VAC for the relay coils, it will automatically switch to DC mode if the grid goes down or you turn off the supply switch. Care should be taken switching in full sun/load conditions. It could shorten the life of the contacts in the relays. Disconnect the AC and DC sides of the system when practical.  You could install 4 RC snubbers on each relay or buy solid state relays. Either is kinda expensive. There may be no problem at all.
I'll be installing this over the next few days and I'll let you know how it works, or not...

Sensible Solar Battery System

It's been awhile since I last posted on this blog. We have been quite busy with our PV and electronics businesses, not to mention all the chores.
Anyhow, now that we are fully gridtied with more than our annual electric needs, I decided to develop a DIY kit for either grid backup or totally offgrid use. I knew it had to be kept simple, conservative, yet as a high performance system with quality parts. It is a 1500 watt PV rating, 48 volt 10KWh battery pak, and a 120VAC 2400 watt continuous inverter. We supply the solar specific parts, you supply the muscle and commonly available wire, gear, and hardware. It will provide about 5KWh per day on an annualized basis here in West Virginia. That may sound not like much, but if you are in survival mode or never had grid power, you'll manage. I have installed a six circuit transfer switch to run critical loads. For us, that's preserving food, a few lights, and satellite tv. Others may have different priorities. But how about water with only having 120VAC? In our case we have a spring fed cistern just below grade. This allows use of a 120 RV-type pump hooked in parallel to our regular 240 pump. If you have a deep well or city supply, you too could bury a cistern or two and fill 'em up when things are rosy. When things go down, use a similar parallel pump system. If you have a site that allows the tank to be planted up hill, you could rely on gravity to return the pumped water. Think of it as a hydraulic battery system.
This kit allows you to get involved in some fun stuff and you may be amazed how easy you could make such a useful infrastructure. We intend on using some fraction of the power every day to keep our batteries exercised and in good shape. We'll also reduce our power demand to boot. If you are interested in learning more go to diy-solar-kit  We also will provide technical resources to help you through the project or to evaluate if this deal is for you.

Filling Out Our New Solar Economy

Since we have completed our PV expansion a few weeks ago, we have been piling up the KWh credits on our grid meter. According to our predictions, we could generate a surplus of 5 MWh (5000KWh) over the course of a year. This was no accident but a strategy to replace conventional fuels with solar power.
The main appliance we obtained was a high efficiency heat pump made by Mitsubishi. It's purpose is to replace fall and spring heating that we normally use propane. (We use wood in the deepest months of winter)
The unit we bought has incredible efficiencies in both heating and air conditioning. Heatpumps work by taking heat out of cool outside air and "compressing" it to a much higher temperature. This is called coefficient of performance or COP. When it is 47F ouside the COP is 4.11. This means if you put one KW in, you get 4.11 KW of equivalent heat. In this way, you leverage your precious solar energy to a much higher level. Then it gets even better compared to conventional heatpumps. At 17F outside temp, the COP is an amazing 2.77. Still leveraging your power at a strong rate. The COP finally becomes 1.00 at 5F, no better than straight electric heat.
All this is due to an advanced design of a variable speed rotary compressor, fan, and onboard brains to tweek the last bit out of the unit.
And yes, we have used the A/C part. Although we didn't have A/C before, there is a conflict of using it as it would expand our energy footprint, not shrink it. However, on the extremely hot days, we will run it for a few hours. I measured the amperage draw on a 90F day and was amazed to see only 500 watts being consumed. About 3 of our PV modules (out of 41) could run this thing during a sunny day. We will monitor our consumption and make sure we have plenty of power stored once cooler weather arrives.
Another device we added to our solar economy is a cordless cultivator made by Black & Decker. It has a lithium battery and claims to weed 300 sq ft per charge. Don't expect to tear up two foot tall weeds, but it will keep small weeds from gaining root around your garden plants. If you want one, get the lithium model not the NiCad battery unit. You can find them at Amazon.com for just over a hundred bucks. I hope this thing will put to rest the desire to get a mantis tiller. (which uses gasoline)
An unfortunate incident turned out to be rather fortuitous recently. Our 5 year old fridge fried the compressor. Of course, it was on the July 4th weekend, so we were obliged to go to Lowe's for an immediate replacement. To our pleasant surprise, they had a 15% discount on EnergyStar appliances that weekend.
It's hard to pick your favorite from so many units on display. But, I knew our old fridge was just too big. Food got lost in the deep recesses for unknown lengths of time. So we knew we wanted something around 18 cubic feet. We finally zeroed in on an EnergyStar Tier 3 model, the most efficient rating. It's a top mount freezer type with auto defrost. The energy sticker claimed a mere 335 KWh per year. Our old fridge consumed around 450 KWh/year. That's at least a 25% energy savings. We are also eligible for a $100 West Virginia rebate, however, they have run out of rebate money and we are on a wait list if it gets funded again.
The story above is mostly about conservation and living with a smaller impact on the planet. If you have a choice of efficiencies when deciding on a device or appliance, go for the best you can afford. You will get payback eventually and your purchase will be your voice, to the suppliers and manufacturers, that efficiency matters.

Alternative Solar Mounting; POWERHOUSE

Many sites we visit to make a PV assessment have the house roof either facing the wrong way or is too shallow of a roof pitch. When the roof of the house or outbuilding is out of the running, ground mounting is a common solution. It can be a top of pole mount or a linear structure. In any event, factory made ground mounts are always much more expensive than roof mounting.
We recently made a prototype composed of some 230 watt panels and is specially designed garden/storage shed. The shed was built by Yoder Buildings a couple miles up the road. They are Mennonites who started their business a few years ago and do quality construction.
We took their basic saltbox design and made the back roof longer and steeper to accommodate the PV modules at a good compromise angle. The unit shown is the smallest at 12ft x 12ft and has a PV rating of 1380 watts STC. We have several other sizes up to 36 feet long and rated at 4140 watts STC. These are gridtie ready with only the final connection to be made at the customer's site. The building themselves are of good value and high quality and cost just a bit more than a good ground mounting system. The benefit is that you get a great building to use for other purposes.
The Solar Powerhouse can also be configured as an offgrid structure for camps or rural locations. The extra gear such as charge controller, batteries and inverter will run the price up though.

Solar is Growing in West Virginia

Most people think solar won't work well in West Virginia. The fact of the matter is that WV has better solar irradiance than the Great Lakes states, New England, and even Germany which is the most PV developed country in the world.
If you go to the National Renewable Energy Lab (NREL) and look at their OpenPV site, you can click on any state and see the statistics gathered over many years. If you click on West Virginia, you'll see the counties that are beginning to grow in PV. There is a concentration in the eastern panhandle (DC burbs) and the Greenbrier County area.
The mountains of WV do produce more clouds, but at the same time, a higher elevation provides somewhat higher energy due to the fact that there is less atmosphere above you. Southeastern WV can provide about 5.5 peak sun-hours in the summer and 2.7 in the winter. The annual average is around 4.3 sun-hours. A sun-hour is a standard measurement of power and includes all the cloudy days and seasonal sun angle for a particular site.
You can also access cost per watt installed by selecting a state and county and viewing the cost statistics in the surrounding graphs. Greenbrier County averages $6.01/watt compared to over $7 for the state and national installations. That dollar can make a big difference on the bottom line of your installation.

PV Upgrade Finally Done

A few months ago, I posted about our plans to add on to our home PV system. This spring has been the most rainy one I've seen in a while. Needless to say, progress was slow on construction. Add to that a couple customer PV installs, and I'm amazed it is done at all.
Anyway, we added over 4kw to our existing 3.6kw. The design of the mount was a prototype of a less expensive ground mounting. It is a linear array of 21 modules on a post and rail system of treated wood. The frames were fabricated in our shop from stock aluminum shapes. Every three modules are an assembly and can be tilted to winter and summer angles.
While the design was decidedly cheaper than factory racking, it took up the savings by taking a long time to install. This is an excellent design for a handy person who doesn't pay himself.
This system should produce 10 or 11 MWh/year (10,000-11,000 KWh/year) That is more than we normally use, but have plans on using the net meter surplus to use less propane and acquire electric tools to replace gasoline burners.

Another Dust Bowl Starting?

Exceptional drought in the southern midwest is spurring some to predict the beginning of another dust bowl. It's not just global warming but climate change that describes the effects of CO2 release. Think of all the recent severe weather and floods around the world.
We must do all we can as individuals to stem our carbon output.

WV need a Renewable Portfolio Standard

West Virginians with solar installations may sell their solar renewable energy credits (SRECs) to the District of Columbia, Pennsylvania, and, Ohio. This monetary reward, up to 34 cents per kilowatt hour, helps to pay off the upfront costs of installing your own net metering PV system. It is essential to have this benefit to increase West Virginia's renewable energy content.
Since WV has no Renewable Portfolio Standard (RPS), we are at the mercy of other states to toss us a bone. The inclination of eligible SREC state markets is to prefer in-state installations first, then turn to outside sources to meet their needs. This puts WV installations as second rate and yields less value for your investment.
The answer to providing continued benefits for WV PV, is to have our own RPS legislation. I'm not sure how to promote that exactly. Do we pressure the WV Public Service Commission, our local representatives, or some entity in Charleston? (maybe all, or yet more?)
Please respond to this plea by offering methods (via comment) to make WV step up and get in line with this important legislation for our future.

Solar Powered IRAs

We just sold our first two SRECs (Solar Renewable Energy Credits) which are 1 Megawatt/hr blocks of energy from our PV array. The buyer actually does not buy the power itself, but the right to call it their renewable energy. We used all that power at home already for free, so its like getting paid twice at 2 to 3 times the going rate. The lucky buyer was Washington, DC for $250 each. We can also sell to PA and soon Ohio who has the best prices (~$300+)
Now that it has actually happened, after waiting 6 months, it gives me a renewed interest in adding capacity to our system. Our plan is to add a 6.9kw linear array across the pond dam. (see array further away in image) The two pedestal mounts by the willow tree are what we have right now and are rated at 3.6kw for both pedestals combined. Our total will become about 10kw capable of producing about 13 SRECs a year. The plan is to stuff that money away in our 2 IRAs for as long as the party lasts. We also get a 30% tax credit from the Feds and $2000 tax credit from the state of WV.
The capital for this installation comes from an online joint trading account we have maintained for years. Now that the market is up, we intend on liquidating part of our portfolio that has yielded good gains. One of those holdings is a domestic oil/gas field salvage company called Linn Energy. (LINE, stock symbol) It is both ironic and symbolic that we are taking the profits from petroleum and investing in solar. The whole country should be doing so by raising fuel taxes, enacting a carbon tax, and stopping subsidies to big oil and apply those funds into furthering incentives for alternative energy. According to my calculations, we can expect 8% to 25% (at much less risk than the stock market) return on our money depending on installation costs and future SREC and electricity prices. Any capital gains or dividend taxes are offset by the tax credits for PV and IRA investments.
But it doesn't stop there. We will have twice the generating capacity of what we currently use. The plan is to install a heatpump to replace our propane heat supplement. (we also burn wood) No more propane except the cook stove. Yea!
With all the incentives and the fact that electricity and propane prices will rise steeply over the coming years, this system makes sense to us. As we get older, we will appreciate the free energy (system payback in a few years) and yearly contributions into our IRAs. PV isn't instant grats, you must look out 5, 10 or 20 years. These modules should still be puttin' out in 50 years, although I most likely won't. Then there's my grandkids..........hmmmm

Power Bill

This is our power bill for December 2010 showing that we finally bought some net grid power from Allegheny Power (264KWh) Ever since the PV net meter system went online back in June, our bills have been virtually zip. Its hard to tell what we used per month last winter and spring because of the over-estimates the power company used. They are now required to read the meter every month and the net metering data is hand calculated.
This kind of bill is only possible with a 3600 watt array if you also have your usage under control. Its not hard to do, just upgrade lights, appliances and behavior. It took two years to trim our use so PV made sense.

New West Virginia Energy Source

Research produced by Southern Methodist University's Geothermal Laboratory, funded by a grant from Google.org, suggests that the temperature of the Earth beneath the state of West Virginia is significantly higher than previously thought and capable of supporting commercial geothermal electricity production. As seen in the above maps, which shows temperatures from 4.5 to 7.5 kilometers deep, a large area is at least 200 degrees C. (392 degrees F) This is plenty hot enough to run steam turbine generators. Previous maps showed the orange areas as green, not hot enough. This WV source could be the largest geothermal field east of the Mississippi, ready to distribute power to highly populated areas in the east.
If only 2% of this renewable energy were utilized, it could be in excess of all of WV's generating capacity from coal. (about 16,000 Megawatts) However drilling this deep with existing technology would be very expensive. Research is in high gear to develop a new type of drilling called hydrothermal spallation along with a technique called Enhanced Geothermal Systems which helps to extract heat from the hot dry rocks in the form of steam or hot water. This technology should be available in a matter of years, not decades.
Once again, WV will have another resource from underground. This time it can be clean, green, and infinitely renewable. (At least in the matters of the human race) Did you know that WV has an Official State Rock? (really) It's coal...maybe it could be changed to Hot Rocks instead?

Power Production Update

At the end of November we had a surprising 400-some KWh in credits on our meter. After 28 days of snow and clouds, I suspected we would have burned that up by far. When I checked the meter 12/28, I saw we had finally bought 122 net KWh from the grid. I never thought we could get this far into winter before dipping into the grid. The gridtie system has performed beyond expectations here in the West Virginia hills and hollers. Can't wait to see when we get back into credit territory.

Return of the Sun, Eclipse of the Moon.

Ever since near the end of November to present, our weather has been unusually cold, snowy, and cloudy. It's the kind of weather you would more expect in January. Needless to say, it really knocked a hole in our PV production. Our predicted harvest was for 216 KWh, the lowest month of the year. So far, we have only captured 96 KWh and it is the 20th already. This is where the climate averages play in. Even though this month is bad, last month was well above average. That's why you can't get freaked out over unusual circumstances with solar, it all works out in the long run.
One thing to celebrate is the Winter Solstice on the 21st. It is symbolic mostly, however it does mean that the sun will be rising ever higher and the days become longer. That's about all we can reinforce ourselves with as we enter January and the bottom of winter. By March, we are predicted to produce 435 KWh, twice as much as December. I think that's plenty to look forward to.
As an interesting note, around 3am tomorrow morning, there will be a total lunar eclipse. It will be the first one to fall on the Solstice in over 400 years and we can all witness it as long as it's not... CLOUDY.

Shadow Study

One thing you can do on snowy days is to explore the capabilities of your computer. I regularly use Google Earth to study PV site for potential customers. This time I decided to model our proposed shop PV array using Google SketchUp (free, google it) The sketchup program can use Google Earth data for shadows and geophysical features. There's a control where you can set anytime of the day, any day of the year, to see how the sun's shadows affect your array. Even nearby mountains will cast their shadows accurately.
I wanted to confirm my row spacing for maximum module density without interference. It takes awhile to get a handle on modeling in sketchup, but its time well spent. I will use this tool to prove the design is good for a grant we are pursuing and see how roof angles and protrusions may influence some future complex new install.

Winding Down

After finishing the job described on the previous post, I thought there would be a quiet period while winter ramped up. To our surprise we started a job on a new home site by setting poles for a top of pole PV installation. We'll try to get all the conduit laid while the builder is there with excavation equipment. At some point he'll have to shut down during any severe weather. We'll pick it up again when the weather returns to bearable.
It's been unusually cold and cloudy for the past week and we're using our last couple hundred KWh's in credit on our meter. To our further surprise it looks promising for another PV job where the owner wants to spend the money this year for tax purposes. We'll work on that one as the weather opportunities arise.
In the photos above you can see the pole fabrication in progress. I want to thank Lola Alderman for helping and doing a fine job on finishing. By the way, that's my new forklift I got to unload trucks delivering pallets of PV modules. In fact, its only new to me, it has some hours on it and I had to rebuild some linkages and fit chains to the tires. We couldn't afford a forklift that didn't need fiddling, so I'm happy to do it. It runs well and we might even paint it.
The pic of the PV array is the one at our house after days of snow showers. The deep blue sky is a wonderful sight. I didn't brush off the snow so I could see how it melts and slips off with a little sunshine. It took 4 hours to clear itself that sunny morning.

Final Day On the Roof

Due to the fact a recent customer decided to get a new roof before we install, and waiting on back-ordered parts, we are finally here on November 22nd for the panel installation. Ominous weather forecasts and Thanksgiving pushed us to work on the weekend and Monday to get off the roof part of the installation. As you can see the weather was perfect that day. Now, all thats left is the homerun wiring and disconnect that aren't so weather critical.
This is a grid tie net metering system with 24 modules rated at 220 watts for 5280 watts STC total. The inverters are Enphase D380's that connect to two modules each. This made wiring simple and less expensive than traditional systems. After inspection, our power company must follow through with their end of the deal. They have been rather slow about getting the new meters installed lately, and we hope sometime in December our customer will be enjoying the benefits of solar power. That will be the weakest solar month of the year for production but they can look forwards to really gaining output as the season progresses. This system should harvest 6 MWh/year given his exposure and some trees in the way in the morning and evenings. His SRECs should yield $1800 a year not including the "free" electricity.
Speaking of weather, I looked at our meter today and was surprised to see we had 460 KWh in credits. I can only attribute that the ongoing drought has produced more than usual sunny days and we have not used as much electricity. Next week is December and I suspect we will use those credits up if the cloudy days come. None the less, I am delighted we went this far without using net grid power.

Getting Better

The image is from the Open PV Project of the National Renewable Energy Laboratory. It shows the national average cost of an installed PV system at $7.15/ watt. Our last few installs worked out to be about $5.50 to 6.00/ watt. These were projects that were pretty straight forward roof mount, grid tie systems. Special mounting options or offgrid installations are more expensive.
Our selection of the latest technology and reduced panel prices have contributed to making solar more affordable. Being able to take advantage of the tax credits reduces the cost even more.
Let's hope America continues to promote all types of renewable energy for far into the future. We need it.
Alterra Renewable Energy

The Evolution of Lighting

When I was a kid watching Voyage to the Bottom of the Sea on TV, there was a scene that facinated me so much, it is clear in my head to this day. In the 1965 episode called "The Invaders" Robert Duvall played a being from a 20 million year old race that disappeared from Earth. The scene shows Commander Lee Crane getting acquainted with this advanced entity. The being reached up to a light fixture in the submarine and said:"your lights emit unnecessary heat". Followed by: "you have not learned how to conduct electricity without...wires?"
Somehow, those lines made an impression upon me and how to gauge what the future would be like.
Today, with the availability of compact florescent bulbs with good efficiency and being relatively inexpensive, that was the first improvement over standard incandescents. I knew we were finally on track to becoming an advanced race. I'd been waiting 40 years after all.
CFLs are a step in the right direction, but they are still relatively inefficient, thus giving off a fair amount of heat. I was walking through Lowes the other day and stopped by the LED shelf to see how that technology/cost is coming. I saw that a 40 watt equivalent, 8 watt actual, was available at around 19 bucks. Much better than even a few months ago. I bought one.
When I got home I was anxious to screw it in a lamp socket and perhaps have light without heat. After waiting a while, it got warmer and warmer, but still cooler running than a CFL and vastly superior to a scorching incandescent.
We're not yet in the future as I have been waiting for, but there are substantial improvements in conservation ready to use. LEDs hold the best promise once efficiency is improved. Right now, a LED lamp boasts 50,000 hour lifetime. That would be like burning 5 hours a day for 27 years. Think of how many CFLs (8000 hours) and standard bulbs (1500 hours) would not have to be made and replaced. LEDs do not contain mercury like CFLs and the emissions from a coal fired power plant. More conservation, less emissions, less mercury.
Let's compare the costs of installing a solar electric system to the different types of bulbs discussed. The basis will be 5 hours a day for the bulbs and 5 peak sun hours/day for the PV. The current cost per installed watt of a PV system is running around $5.50/watt.

40 watt incandescent-retail price: $1.50- daily consumption: 200 watt/hrs.
Cost of PV system to run it: 40 x $5.50=$220.00

40 watt equivalent, 11w actual CFL- retail $4.00- daily consumption: 55 watt/hrs.
Cost of a PV system to run it: 11 x $5.50=$60.00

40 watt equivalent, 8 watt actual LED-retail $19.00- daily consumption: 40 watt/hrs
Cost of a PV system to run it: 8 x $5.50=$40.00

Although you really couldn't or even want to install such a small (40 watt) grid tie array, this is just looking at a slice of the consumption/production ratio. Conventional wisdom in PV land is that for every dollar spent on conservation, you would save about 4 or 5 bucks trying to make the power yourself. If you have huge power bills, a substantial PV installation would be a disappointment. If you work down your usage, the PV investment will represent a larger percentage of your consumption and the experience will be satisfying. By the way, I just checked our power meter on Oct 25th and we had 490 kWh in credits. I was totally amazed we were "still in the black" coming up on November. We have not used any net grid power (read: no power bill) since we went online June 8th 2010. This is only possible because we reduced our use over the previous two years. It not hard, it just takes discipline and smart choices.

PV and the State of the Economy

We have two nice PV jobs to get done before the snow flies. Timing is everything in the logistics of pulling the various parts together on the sites. In the past, its been a matter of placing an order with a couple of suppliers and the parts would show up in a reasonable amount of time. As this year marched on, I noticed the cupboard shelves for PV parts getting a bit thin.
The past two weeks I spent an inordinate amount of time emailing and finding alternate sources for the required parts. Some of the parts have a particular spec that affects another part's compatibility. So, it cascades though your parts list, if you change one spec in order to get the job done. All this adds stress to my job and it seems the suppliers have no remorse for the inconvenience.
My theory is that industry and corporations are hoarding cash to hedge any uncertainty in the future economy. They reduce their inventories, cut costs, and production so they don't spend as much money. This means they're not much into hiring either. Those reduced supplies trickle down to the distributors and me, the installer. The banks are the same way, reluctant to lend money while they are sitting on huge cash reserves.
No amount of stimulus will undo this mindset. If our economy is to proceed, big business must boost productivity and hire more personnel. Until that happens, our economy will just flounder along and the consumer will have no confidence to invest in solar or efficiency improvements into their lifestyles. Someone must make the move.
On the benefit side of our lousy economy, PV module prices have dropped dramatically over the past year or so. Last summer module prices were about $3.50 per watt. This year we are selling at $2.50 per watt. Part of this was a glut in supply caused by everyone jumping into the PV manufacturing business, especially the Chinese. On the other hand, the consumer pulled back on actual spending, even though interest in renewable energy is spreading through our country.