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The $600 Solution

Generally speaking, with solar power you can get a useful amount of power or an inexpensive system, but rarely both. Full-blown home photovoltaic systems typically run in the tens of thousands of dollars, while the much more affordable portable solar panels, backpacks and such are, for the most part, capable of charging your mobile phone or iPod but not much else. Where, you may well be asking, is the balance? Why can't we get a solar setup that puts out enough power to be useful, but won't require a second mortgage to acquire?

According to the Off-Grid weblog, you can.

Six hundred dollars -- not pocket change, but not hugely expensive for most folks in the West -- is enough to put together a solar photovoltaic system able to run a variety of useful appliances and electric/electronic devices for a usable amount of time on a week's worth of sunlight. The system encompasses a 32 watt photovoltaic panel, a couple of sealed gel batteries, and a few components to make sure that the pv and the batteries get along with whatever you're plugging in:

...the usable power stored in the two batteries is roughly equal to a week’s output from the single 32-watt PV module, so each week you’ll have around one kilowatt-hour of stored sunlight at your disposal. What can you do with it? One kWh will run a 20-inch tv for 20 hours, a portable stereo for 100 hours, a laptop computer for 40 hours, or a 12-watt compact-fluorescent light bulb for 80 hours.

The 800-watt inverter (with a 2,000-watt surge capacity) will run a small vacuum cleaner, a drill or a small drill press, a sander, a jigsaw or small band saw, but not a large circular saw. It will handle many toasters and coffee makers, but not all. A blender would be child’s play for this inverter, a microwave an impossibility. A hair dryer on low, yes; on high, forget it.

$600 isn't enough to convert one's entire life to off-grid solar living, but it's a functional start. Moreover, it makes an interesting moving target: as organic photovoltaics and other forms of plastic solar come on the market, and as more money goes into making this technology more approachable for non-technical folks, we should start to see what's possible with $600 worth of gear improve in short order. And it's not just improvements in photovoltaic technologies that will make a difference here -- better batteries, cheaper high-capacity inverters, even more efficient "wall warts" would help (after all, many power supplies for consumer electronics only pass along 20-40% of the electricity they draw to the devices they power!).

Let's make this an unofficial metric, then: how much usable renewable power generation can one get for $500 (with some wiggle room on price)? With some smart shopping, it might be possible to get a better system than the one listed in Off-Grid; how much better can we do now? What are the best candidates for improving on that metric over the next year?


Listed below are links to weblogs that reference The $600 Solution:

» Solar power: real or mirage? from SciGuy
As a kid growing up during the energy crunch in the 1970s, I often wondered why we didn't harvest all that heat from the sun and use it to cool our homes. As an adult, I sometimes wonder the same... [Read More]

» Inexpensive DIY Solar Power - The $600 Kit from Treehugger
We all know that outfitting a house with solar panels is not cheap right now. Harnessing enough sun to be able to live completely off-grid costs many thousands of dollars, up to many tens of thousands depending on how much... [Read More]

Comments (18)

the $600 solar pv has come at the right time for eCARE (e-Commerce and renewable energy), a new 3-year UNEP project to be launched in Ghana this fall. if this is not just another pv hype, then it looks like we could revise the cost per system dramatically downwards; and the number of rural beneficiaries dramatically upwards! :)

Stefan Jones:

Another use: Grid backup.

If such a system, or one just a little more expensive, could keep these items going:

* Refrigerator
* Radio / TV
* Hot plate
* Three or four lights

(Bonus, if applicable:

* Pump for well water)

. . . then a power outage due to natural disaster or (sigh) pandemic-caused utility trouble will go from a wretched, miserable situation to a tolerable nuisance.

Imagine if developers offered such a backup system as a feature in new homes! An entire neighborhood that doesn't need ice, food, and water during a disaster . . .

Interesting post. I know when my dad priced out a full system for his new home, it ran like 24k -- so it would have paid for itself after 20 years.

But there is a fallacy in assuming we "need" to run everything at the level we are now.

Me, I'll be happy with a micro beer cooler, a laptop with an efficient processor, and a candle. To top it off, I'll be living in a well designed building which does solar passively.

Building walls three times as thick as usual is way cheaper than the full techno-solar spread.

Anybody around here actually off the grid?

Solar cooler here, intended for vaccines in off-grid communities in the developing world, but hey, it'll keep your beer cool too...


One suggestion: Use PV to power things that you want to use when the sun is at full strength. One example: attic fans, to exhaust hot air from the house. Another: several solar-water-heater manufacturers use a small PV array to power the circulator pump of the water heater. We use PV to power small irrigation pump - we need the water when the sun's been at work for a while.

You can also deploy PV panels above and outside windows to make shade while you make power.


Maybe this is worth a monthly-updated feature? 'Spending Sustainably' could pick a couple of pricepoints - $100, $500, $1000 maybe - and hilight some good sustainable buys. At the low end are individual gadgets - replay radio and the like. Mid to high end would be things like this, or like this but scaled up a bit more. I'd love such a feature :)

Maybe also a caution that, depending where you are, a $600 investment in conservation might have faster payback than a $600 investment in production.

... everybody break out the Kill-a-Watts ;-)

(The Off-Grid folks probably already have all of the efficient appliances and usage habits, but the average reader may not!)


The flaw there is many of the more eff models cost a hell of alot more to buy. You can get a low eff fridge for 200 and get a high eff one for 1600... If you dont have 1600 you dont have the choice.

We have both a 1600 fridge freezer and a 200 buck freezer.

This needs to go from do it yourself to a finished product, able to be installed in any south facing window sorta kinda like an air conditioner except you have to aim it towards solar south at the proper angle for your latitude. Sell it through Home Depot and Lowes.

Another iteration of the same idea is that of Ross Nizlek (ross.nizlek@uvm.edu), a student at UVM who installed a 20 watt PV system on his dorm room whom I read about on treehugger.com. He documented the process at http://www.uvm.edu/~rnizlek/

One window systems of from 20 to 60 watts should be enough for a reading light and a cell phone and a radio or a computer or a TV. Use it direct to DC for keeping one room going on an everyday basis or to have an emergency back-up. This is one way we will ease into whatever solar future we have left.

wintermane - When I shopped for refrigerators I was surprised to find that the very efficient (sears, energy star) started in the low $400s. The delta is not as broad as you imply. Instead, efficiency models are mixed up with style models all the way up and down the line. When I was at sears, for instance, there was one of those diamond-hatch industrial looking fridges you were supposed to buy for your garage, to hold cold drinks. For some absurd reason it was the same size as my efficiency model, cost $800, and used twice the electricity.

Certainly, the extreme off-the-grid fridges cost $1000+, but again, if we are talking about the average reader, they might have some easy pickin's here. Especially with the coming rebates (more in 2006 from the energy bill?)

Lastly, while the fridge is the first thing, lights are the second thing, and I think you can do the house-full for $600.

BTW, with just the sears fridge, a few fluorescents, and an LCD TV (30"), I dropped my condo electricity bill to $15/mo (when I'm good, and $18/mo when I leave the computer - still a dell tower with a 17" crt - on too much).

Surfing now I don't see a solid number for the southern California average, but it might be something like $80/mo, with fliers ... people who air-condition large houses ... out ath $300/mo.

Again, time to break out the kill-a-watt, and see what's appropriate.


I prefer dim lighting so I always forget about lights. When we shopped for a fridge when we first moved to our new home the only realy eff model was the then brand new `1600 buck one. But then I fergot to mention it is a very large fridge.

While I harrange eff improvements over more poeer arguements we do in fact have alot of eff items in our home. I just dont want us putting all our hope of eff improvements vs getting some extra capacity in power plants.

Dont forget the bottom line in eff is the more capacity the power company has over what it needs the less often it uses its least eff power plants and that can have a mighty big effect. That and it cuts down on interstate power transmission wich also eats energy.

Good comments all around, but I'd like to echo pj's comment about finding a price point (or two) and doing some sort of monthly feature, either on conservation (especially for these coming winter months) and production. I'd say around $100 is a good one, as would be $1000. DIY projects are best, as you get more bang for the buck.

And not to belittle the brilliant folks here at worldchanging, but maybe if we all asked the folks down at Make Magazine nicely, they'd be willing to lend us some expertise on the subject. They're professional DIYers, after all!


Right now if I had 10k extra id get myself a nifty puter and put the rest in the bank for a few years before finaly getting a good home power generation system. Its just a few years before the true storm begins.

Interesting suggestion, "antonymous." Thanks!

Doctor Edge:

I don't want to rain on this parade, but 1kWh is frankly a piss-poor amount of energy for a week's charging - and this will be vulnerable to the vagaries of the weather, of course. Also, getting 50kWh a year for an investment of $600 strikes me as a bad bargain; I pay 8.8p/kWh (about 16¢/kWh) for 100% green power here in the UK, so this system would displace power from the grid worth about $8 each year. For grid-remote applications, fine, but it doesn't sound like a complete solution even then. Don't get me wrong, solar power is a vital part of a sustainable energy future, especially BIPV, but on this evidence, not only is investing in efficiency better, so is investing in large-scale, grid-connected renewables. A better bang-for-buck small-scale solution in the near term is likely to be the new generation of small wind turbines coming through, especially Renewable Devices' Swift (http://www.renewabledevices.com/swift/index.htm). Once in mass production, this 1.5kW turbine could cost as little as £1,500 (under $3,000). And that'll be generating a darn sight more than 50kWh per year.

Jon Foley:

Dumb question, but can anyone point me to a cheap solar PV system for recharging all those dumb devices I seem to have: laptop, cell phone, etc.?

Is there a charger system that can draw from a PV panel when the sun is out, and then use your regular AC/DC charger brick when it's dark?

The biggest cost of these solar systems seems to be the invertor and batteries, so why not stick to DC charging applications for a while? Or, as David suggested earlier, use PVs to things you want to do when the sun is shining?

Jon, the good news is that there are lots of solar chargers for smaller devices. The bad news is the reason for the market segment - people are willing to pay "unreasonable" ammounts for the output provided. Since they are often bought as fashion (or eco) accessories, they don't have to hit the $/watt required for larger scale applications.

So yes you'll find them (google "solar backpack") but don't expect to EVER save enough off your power bill to pay it back. (If you need the "remote" charging ability that is another story.

OTOH, bad "bricks" are a real efficiency problem. The worst are very lossy and draw power (stay warm) even when no device is connected. The EPA was on a push to get them all cleaned up a year or two ago. The problem was/is that too many were made as cheaply as possible, rather than with ANY eye toward efficiency. If they do get warm, unplug them when not in use.

If you have a kill-a-watt (google it) you can check out the actual drains from the things, and perhaps swap bad ones out for general purpose chargers.


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