Living Car Free - Anyone using Solar?

Looking to add photovoltaic panels to the house.
Anyone out there actually off the grid?
What are your experiences and opinions?

I'm going to do my first tour in early september and wanted to be completly self-sufficiant so i'm going to use solar for my electrical stuff (PSP, ipod, cell, etc..). I've tried out solar panels for small electronics a number of year ago and was dissapointed but it looks like the newer panels and battery or much more efficient now.

I'm assuming a house version would simply be a scaled-up version of what I plan on using..panel --> volatage regulator--> storage battery.

Looking to add photovoltaic panels to the house.
Anyone out there actually off the grid?
What are your experiences and opinions?

I'm neither car-free nor off the grid, but I'll comment anyway, as I have several friends who have been off the grid, or put solar on their houses.

Financially speaking, it's pretty hard to come out in the black without government subsidies. Especially with electricity generation. You might consider starting with solar water panels, depending on your climate. You may not be concerned about 'breaking even' -- it's probably not too hard to come close. Or you can mix solar with a small wind-turbine if possible in your area.

From a use standpoint, to be completely off the grid, you may have to curtail your use, and you will likely have to plan your electrical consumption more than you do now, taking into account the current state of the batteries, etc. You live car-free (?), so you know how to plan things, though. If you don't run a TV and such a lot, it might not be too bad. The refrigerator, then, is the most important continuous load. Running AC, if you use it, might not be too bad, since the demand corresponds to bright sun, more or less.

If you're already connected to the grid, then you can often sell your excess back to the power company. ('running the meter backwards') This allows you to be use-neutral and save on the installation of batteries and such, and would be a great way to experiment. You'll have to check with your local utility on what's required.

Obviously, there are plenty of web-sites out there about this, and I'm giving second-hand reports, so dig around. All in all, though, if you can manage it, it sounds like a fun thing to try.

Just food for thought - I've looked in to the "carbon footprint" of solar electricity: what is the comparison between lifetime kWh production of a solar panel compared to the kWh of fossil fuel energy used to produce the panel?

If you live in a place that is ill-suited to solar power, it could be 1 to 1: the solar panel will produce the same amount of energy over its lifetime as was used to produce it.

More typically 2 to 4 kWh of solar electricity represent one kWh of fossil fuel energy used in solar panel production.... the solar panel's lifetime output is two to four times the energy used in producing it.

Looking to add photovoltaic panels to the house.
Anyone out there actually off the grid?
What are your experiences and opinions?
Direct solar heat like cooking and hot water works well. I stayed in a place off the grid in Mexico. I was surprised at how little of the roof was used for photovoltaic panels. Some of the neighbors added those little sailboat type wind turbines to supplement the photovoltaic panels. We had electricity for lights, refrigerator, fans and some electric appliances like microwave and blender. I use a solar cooker sometimes, it works best in low humidity when the sky is dark blue. In hazy weather it takes longer.

For now I've just gone with a solar hot water heater. It nearly _boils_ water and in the beginning after we lost some tree cover to a storm actually had a few steam incidents where the relief valve opened and it poured 100 gallons of steaming hot water out.
We had a propane hot water heater but when they went to refil it one day we had a "leak" according to them. To fix it we'd need to replace the tank, the underground pipe and since we had an old house it was out of code so they'd need to replace all that stuff too $$$. Second opinion was much the same so off to find another option. Comparing a new gas to a new solar made solare a bit less $$ and it turned out we got a tax credit making it even better. Sure we could have gotten a big electric tank inside but we wanted to recover the space. If we didn't have the propane issue it probably would take longer to catch up dollar wise but solar hot water has a quicker payback then solar electric.

Financially speaking, it's pretty hard to come out in the black without government subsidies. Especially with electricity generation. You might consider starting with solar water panels, depending on your climate. You may not be concerned about 'breaking even' -- it's probably not too hard to come close. Or you can mix solar with a small wind-turbine if possible in your area.

Breaking even or coming close is what we are looking for.
Wind generation is not real feasible for the area. We used to have a windmill to pump water and it could not keep up with demand. A modern windmill may be different though.



From a use standpoint, to be completely off the grid, you may have to curtail your use, and you will likely have to plan your electrical consumption more than you do now, taking into account the current state of the batteries, etc. You live car-free (?), so you know how to plan things, though. If you don't run a TV and such a lot, it might not be too bad. The refrigerator, then, is the most important continuous load. Running AC, if you use it, might not be too bad, since the demand corresponds to bright sun, more or less.

I am not car free, quite dependent actually. However I'm very conscientious when I use a vehicle.
I'm in a rural area, the only public transport I know of in the county would be the school buses (and I guess prisoner transport out to the jail).
I use a bicycle for most all of my daily duties, and carry one when I travel. I try to use a car only when the distance is too great for bike travel (usually always work related), inclimite weather (heavy rain, 101ºF+ temps, I like cold weather) or transporting loads that are unsuitable for bikes (elderly parents, elderly and large pets,).
The other instances where I use a motor vehicle would be the tractor (live on a small farm) and I'm an avid private pilot, but I fly sailplanes.


If you're already connected to the grid, then you can often sell your excess back to the power company. ('running the meter backwards') This allows you to be use-neutral and save on the installation of batteries and such, and would be a great way to experiment. You'll have to check with your local utility on what's required.

In Georgia the utilities are required to buy back any energy you produce. Using the grid to bank our energy would most likely be the route we take.



Thanks guys.

Just food for thought - I've looked in to the "carbon footprint" of solar electricity: what is the comparison between lifetime kWh production of a solar panel compared to the kWh of fossil fuel energy used to produce the panel?

If you live in a place that is ill-suited to solar power, it could be 1 to 1: the solar panel will produce the same amount of energy over its lifetime as was used to produce it.

More typically 2 to 4 kWh of solar electricity represent one kWh of fossil fuel energy used in solar panel production.... the solar panel's lifetime output is two to four times the energy used in producing it.

I don't believe that's accurate. The most recent issue of Physics Today includes an article on home solar power systems, which states that, contrary to popular myth, a typical solar panel will generate the amount of energy used in its production in 3-4 years. As production techniques improve, the energy payback period is actually dropping.

This same article estimated the financial payback period at 40 years for a small system designed and built by the author (a physics professor in San Diego), assuming $0.15/kWh electricity, and noted that the motivation for installing a system must be other than economics.

AllenG, I would recommend taking steps to conserve electricity first--a detailed study of where your electrical power is going, and then eliminating phantom loads, shifting to more energy-efficient appliances as appropriate, and so on. You will need the information anyway when designing your solar system, and for the most part using less energy will be less expensive than putting up more solar panels.

AllenG, I would recommend taking steps to conserve electricity first--a detailed study of where your electrical power is going, and then eliminating phantom loads, shifting to more energy-efficient appliances as appropriate, and so on. You will need the information anyway when designing your solar system, and for the most part using less energy will be less expensive than putting up more solar panels.

I already live sans dryer, AC, TV, the oven/stove is 45 years old but most other appliances are modern, and all the lights are either compact fluorescents or LEDs and the house is well insulated.

The next step is generating our own power.

Our Costa Rica house will be off the grid, but we have decided to go with a micro-hydro system rather then solar. With the climate down there, we won't have a need for A/C or heat, so our electricity demands will be rather low. Mostly due to low cost, 24hr operation and longevity of the system. Obviously this is only a solution if you have running water year round...

Keep us updated on what you go with, I find solar and alternative energy quite interesting.

I'll never understand these arguments against solar/wind energy... the ones that make the argument that so many gallons of fossil fuels were needed to make the panels. Some people use this argument about bicycles too, that it takes energy to make bikes and to ship them. But once the bikes and turbines and panels are built and delivered, that's it. They don't need to be refilled with gas or oil. It's a useless argument.

I use a small solar charger to charge up my cell phone and iPod. Got it at solarstyle.com.

I'd like to rig up a pedal powered system that could power my laptop while I work from home. THAT would be cool.

I'm not, haven't ever been.
I am planning on moving to Arizona and may mess with a DIY off-grid-type setup (where I use the power directly for whatever).
I'm in IL now and solar setups aren't really economical here--not much sun (year-round) and (therefore) not much rebates.


...In Georgia the utilities are required to buy back any energy you produce. Using the grid to bank our energy would most likely be the route we take....
The practice of the power company crediting you for power you produce is called "net metering", and the type of system you need to do it is called a "grid-tie inverter" setup.

Many utilities will only credit you for the amount of electricity you consume, so in that case you are limited in how much cost you can recover every month by your own usage. You may still have to pay the monthly line maintenance fees and natural gas charge (if present).
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The economic viability of a net-metered solar-electric system very much depends on your local climate, what the electricity buyback rates and terms that you'll get are, and what kinds of rebates you can get from your state government to offset the cost if installing the system. Look for solar-power installers in your region (to qualify for rebates you usually need to have the system installed by a licensed solar installer). If there aren't many (or none) that should tell you something significant.

Two sites:
http://www.solarpowerforum.net/forumVB/ (though it has been offline last day or so)
http://www.fieldlines.com/ (click on the "solar" subheading)

Generally speaking--for most of the US, it is very difficult to install a photovoltaic system for cheaper than what utility power would cost you over the same term. Technically it's a neat idea but for most areas it simply doesn't pay. It can even be quite a lot more expensive.

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Solar heating is a good idea to explore, if you can benefit from it.

Solar direct-heating water and air setups often don't qualify for rebate programs, but then, they cost far less to construct than photovoltaic systems, they are simple enough that you can do them DIY with basic woodworking and plumbing skills, and solar heating setups can have much shorter payoff periods than photovoltaic systems.
~

Our Costa Rica house will be off the grid, but we have decided to go with a micro-hydro system rather then solar. With the climate down there, we won't have a need for A/C or heat, so our electricity demands will be rather low. Mostly due to low cost, 24hr operation and longevity of the system. Obviously this is only a solution if you have running water year round...

Keep us updated on what you go with, I find solar and alternative energy quite interesting.
I have water on my property but not enough elevation change to make a hydro system practicable.

Hot water panels will be going up, and I believe I can use a completely passive system as well.

I was looking and researching about photovoltaic for the last 3 years to power my house and heating/cooling system.
But so far the break even was in about 20 years. Too long. When the price hits 1$/1W I'm going to be all over it.
I need a 4kW system to sufficiently power my house and the price is around 20k for such a system at the current price. Once it hits 1$/1W it drops below 10k and becomes affordable.

Also the federal tax credit of 30% for the price of a system with a 2000$ cap has expired Dec. 31st 2007.
So unless your state has a grant or tax credit for your installation, you're on your own.

I have always wondered about these lengthy break-even periods. Does the large setup costs indicate there has been a large amount of energy involved in their manufacture? Just a thought...

Around here, particularly in the rural areas, folks are looking at geothermal as a means of heating and cooling their homes. I figure heating costs should provide the biggest bang for the buck. If you were able to drastically reduce heating costs, your carbon footprint would lighten up more than if you cut back on appliances and lighting. As well, in a crunch, you could probably dispense with the electric or gas dryer and perhaps even the refrigerator. But it would be difficult to cut out heat in the winter.

One problem that I see with geothermal though is that installers insist on running the lines through the water table. I'm not sure why this is, but I know that they often have to drill below 200 feet to hit it.

So once again, you have to wonder if the capital costs outweigh the benefit.

I have always wondered about these lengthy break-even periods. Does the large setup costs indicate there has been a large amount of energy involved in their manufacture? Just a thought...

Around here, particularly in the rural areas, folks are looking at geothermal as a means of heating and cooling their homes. I figure heating costs should provide the biggest bang for the buck. If you were able to drastically reduce heating costs, your carbon footprint would lighten up more than if you cut back on appliances and lighting. As well, in a crunch, you could probably dispense with the electric or gas dryer and perhaps even the refrigerator. But it would be difficult to cut out heat in the winter.

One problem that I see with geothermal though is that installers insist on running the lines through the water table. I'm not sure why this is, but I know that they often have to drill below 200 feet to hit it.

So once again, you have to wonder if the capital costs outweigh the benefit.

I think it has to do with economy of scale. Solar panels and components are still a niche market with only a very few players. We had solar hot water panels for years. The controller died, we were unable to source a new one. Ended up taking the old one apart and building a new control board for it ourselves. Many companies start making solar stuff only to go out of business a few years later due to a variety of reasons. Also there is no set standard in the market, you pretty much have to buy from single source on a lot of the components to get a system set up...adding to the cost.

FWIW I haven't gone solar yet, but am definitely looking into it. I live a state and a half north of AllenG...on a small farm (imagine that!) and we are definitely in solar country. Wind is a hit or miss proposition around here. Kyrocera used to make (might still for all I know) a self contained well pump kit that included a solar panel, battery and pump. It was intended for remote locations where power was not readily available. Unlike AllenG we do have a fairly decent water flow on one branch that I am checking the head and flow rate to see if we can get a small hydro plant to work. The military has some generators that can be anchored out in the middle of a running stream of water to generate electricity, from what I can tell they are fairly small only 5k watts or so, but interesting none the less. I also checked into the possibility of selling excess power back to the power company, but they don't make it easy. If I were designing a solarvoltics system from the ground up I would design a house with DC power to make the conversion as easy as possible. Using LED's and CFL's is a good start. Take a look at what is available for the RV market for lighting. By eliminating/minimizing the inverters/converters you can increase the efficiency of the system. And as was pointed out conservation is a key component. And like everything else electric the batteries for storage and nighttime use are the weak link.

Aaron:)

I asked someone at our state government about it, wondering about any available tax credits and such. I forget the details but the general idea of what he said was that to make solar panels for electricity work well you have to have enough sun (obviously, but I think the idea was southern exposure and full sun all day, compared to my shady yard). He also said that if I was interested mainly in saving money, the biggest results would come from conservation, compared to trying to generate some of my electricity from the sun and not bothering to cut my use.

So what that says to me is that conservation is the first place to start no matter what. If you are just trying save money, conservation will make the biggest difference. If you are trying to get off the grid, you won't be able to do it unless you cut your use in addition to adding the solar panels, so you will have to do the conservation in that case also.

... Unlike AllenG we do have a fairly decent water flow on one branch that I am checking the head and flow rate to see if we can get a small hydro plant to work. ...
Warning--you may need to secure water rights before you can legally do this. There are stories online of people "learning the hard way"...

... If I were designing a solarvoltics system from the ground up I would design a house with DC power to make the conversion as easy as possible. ...
People on the fieldlines board have discussed the fact that (in the US) there is no code standard for DC home wiring, or DC-only receptacles... So home-DC power can be easy, difficult or impossible, depending on your local inspector's feelings on the matter.

... By eliminating/minimizing the inverters/converters you can increase the efficiency of the system. ...
I think that this is a big part of the reason that home PV systems are slow to be adopted--because there's no easy way to fully utilize the power output of a solar panel. Large-wattage inverters and battery banks work but they are rather expensive, they can easily double the cost if an installation. Small 12V inverters are cheap but cannot run the biggest appliances used round-the-clock--the central air and refrigerator.

Ideally you would want a device that-
1) could run straight off the daily DC power swing that a panel puts out,
2) you would normally run every day,
3) does something useful even though it will only run during daylight hours, and finally-
4) that is reflected in reducing your utility bill.

So far, the only thing I can think of that would do all this would be an air heating/cooling unit, and this would only be so for people who live in a climate where they normally need heating or cooling all the time. This device could be nichrome radiant heating (if you needed heat all the time) or a Peltier-based heating/cooling unit if you needed cooling all or part of the time. This would provide additional heating/cooling for your house and since the central air unit is thermostat-controlled anyway,,,, the solar contribution would allow your regular central air unit to operate less, so it would be reflected in your utility bill.

Peltiers have a few problems of their own, but I may end up playing with making an air-cooling unit anyway.
~

Solar panels suck. Look into steam powered generators using a Fresnel lens to heat the water. You can also power a Stirling engine this way to generate electricity......You can also power a Stirling engine with a parabolic reflector which works really well. Granted in order for the investment to be small you'll have to start small. You can add more as time progresses. You will still need batteries and all the other stuff you'll need to store and convert the power you make to useable current but you can DIY for cheap if your crafty and you know where to look. Here is a good place to start: Neat stuff!

http://www.youtube.com/watch?v=fUrB7KRvxUk

Our Costa Rica house will be off the grid, but we have decided to go with a micro-hydro system rather then solar. With the climate down there, we won't have a need for A/C or heat, so our electricity demands will be rather low. Mostly due to low cost, 24hr operation and longevity of the system. Obviously this is only a solution if you have running water year round...

Keep us updated on what you go with, I find solar and alternative energy quite interesting.

Joe,
Have you guys ever looked at underground houses?

Solar panels suck. Look into steam powered generators using a Fresnel lens to heat the water. You can also power a Stirling engine this way to generate electricity....
Solar panels are expensive and don't put out a huge amount of power, but then again, solar panels are quiet and for the most part maintenance-free. The same cannot be said for any other method.
~

Unlike AllenG we do have a fairly decent water flow on one branch that I am checking the head and flow rate to see if we can get a small hydro plant to work. The military has some generators that can be anchored out in the middle of a running stream of water to generate electricity, from what I can tell they are fairly small only 5k watts or so, but interesting none the less.
Aaron:)

Aaron,
I ran across this (http://www.realgoods.com/product/id/1007926.do) while looking through Real Good's products. They don't have much info though.

Just food for thought - I've looked in to the "carbon footprint" of solar electricity: what is the comparison between lifetime kWh production of a solar panel compared to the kWh of fossil fuel energy used to produce the panel?Compared (http://jupiter.clarion.edu/~jpearce/Papers/netenergy.pdf) to fossil fuel based energy it emits ~1/6th to ~1/30th of the Carbon emissions.

Aaron,
I ran across this (http://www.realgoods.com/product/id/1007926.do) while looking through Real Good's products. They don't have much info though.

Thanks Allen I added RealGoods to my bookmarks. That unit appears to max out at around 1500 watts and that is with a substantial water flow. We are having an engineer come in and look at our situation. We have planned on a dam for a couple of years and it is time to get it moving. They will do a preliminary survey, then if we like the looks of the results they will come in with a full design and recommendation for the dam. We are figuring on using the resulting pond for irrigation and fire control. My seat of the pants estimate is that we should be able to get around 6 acres in water if all goes properly.

Aaron:)

Our pond is about three acres. We use it for some minor irrigation.
Sadly it is on one of the lowest spots on the property.


I haven't found any solar trough generators in less than industrial sizes, shame.
I have found a few DIYs for solar steam generators that resemble large satellite dishes that use flat mirrors. And one who used a large satellite dish as the armature for one.

Our pond is about three acres. We use it for some minor irrigation.
Sadly it is on one of the lowest spots on the property.
Does it make sense to use micro hydro generation with a solar system that pumps water into a higher level artificial pond? I'd imagine there's a much higher capital cost and some conversion inefficiency, but at least it would eliminate the battery from a fully off grid system. Plus, you could easily add solar and wind capacity increments.

Solar PV is very popular here in Calif due to state rebates (about $3.50/watt installed) as well as electricity rates that are tiered and also time-of-use. Tiered rates mean a heavy user pays a lot more for their electricity, as much as .25-.30 per KWh, so PV pays back really quick if you lop off your more expensive usage, even if you don't cover all your use.

With time-of use metering, the electric utility (PG&E out here) pays more if you generate it from 2pm to 7pm or so in the summer, when they have massive loads from all the AC in use. With all the individual users pumping power into the grid it helps defer the very expensive "peaker" units they have to employ for peak power generation, and saves them a fortune as that is also very expensive power to generate. You make 32 cents per KWh selling during the afternoon and and buy in the morning or at night for 12 cents.

Everyone wins, and solar PV generally pays back in 5-7 years out here if you have a good solar orientation without shading. Most units here are now serial high voltage with higher efficiency grid-connected inverters. Very little loss compared to off-the grid systems and of course you can sell your generation.

Does it make sense to use micro hydro generation with a solar system that pumps water into a higher level artificial pond? I'd imagine there's a much higher capital cost and some conversion inefficiency, but at least it would eliminate the battery from a fully off grid system. Plus, you could easily add solar and wind capacity increments.

You run into (I think) the first law of thermodynamics. The amount of power to pump the water up hill would be more than the water coming back down hill would generate.

Rather than moving water, one would be better off to use that power directly.

You run into (I think) the first law of thermodynamics. The amount of power to pump the water up hill would be more than the water coming back down hill would generate.

Rather than moving water, one would be better off to use that power directly.
Second Law, the first is about conservation, the second is about dissipation. We know what you're getting at... But what platy is saying is use the pumped storage rather than a battery, you have losses from using a battery too.

Joe,
Have you guys ever looked at underground houses?

Yes, but not for long. I don't see any obvious advantages to an underground house in the Costa Rican climate.

Thanks for the link to Real Goods, just bought a microhydro book for more research.

Second Law, the first is about conservation, the second is about dissipation. We know what you're getting at... But what platy is saying is use the pumped storage rather than a battery, you have losses from using a battery too.

Gotcha.

Gotcha.
I did a little more research. People have considered pumped storage with solar. Bottom line is the pumped storage costs at least 5 times as much as batteries, even allowing for battery replacement every few years. So that's yet another beautiful alternate energy idea slain by an ugly fact.

I did a little more research. People have considered pumped storage with solar. Bottom line is the pumped storage costs at least 5 times as much as batteries, even allowing for battery replacement every few years. So that's yet another beautiful alternate energy idea slain by an ugly fact.


This is almost always true, but not 100% always. Back a few years ago when power got so expensive, BC Hydro was making a KILLING by selling power during the day, then pumping water back behind their dams at night, and effectively reselling "the same" power the next day by running it back through the dams again. Peak hour rates were so high, and off peak (in relative terms) so low, that this was quite profitable for them.

Another thing to take a look at if you have running water is a hydraulic ram system (http://www.lehmans.com/shopping/product/detailmain.jsp?itemID=274&itemType=PRODUCT&iMainCat=878&iSubCat=883&iProductID=274) for moving water up hill, it isn't free. But pretty efficient once you have it set up. My grand parents had one on their farm. They used the fall from the spring collection tank on the hill to the basement in the house to provide water pressure to the house. Before that was installed you had to hand pump water from the tank in the basement to the storage tank in the attic...

Aaron:)