Post by Maria on Apr 29, 2010 22:47:04 GMT -8
Jennifer wrote to me this morning and asked me about my home, which is, of course, off-grid since we are in the middle of the jungle. As I did a little research to answer her questions, I realized that this information might be useful to the writers here at the forum who are considering Hom being run on solar energy as supplied to on-world primary solar towers and then distributed to the population.
Here is what I found:
Get your sun hours from this chart (U.S. only chart):
Then go here:
www.affordable-solar.com/gt-estimator.htm
If your goal is to end your electric bill forever, you will need to know what your monthly electrical use is in one average month. This should show as the kWH (kilowatts per hour) on your bills. Average this. If you do not have a bill, you can safely assume that your usage is 1250 kWH for every 1000 square feet of your house if you run a high average. It will also ask for your monthly bill amount just as a reference.
Type those two facts in plus your peak sun hours (for the Washington Olympic Peninsula, for instance, the average peak sun hours are three). Then click Calculate to see what type of system you will need.
As an example, Jennifer's house would need a solar system that produces 60 kW per hour to cover the energy usage. It would save her $7200 in electric bills every year, add $150,000 to the value of her house, and eliminate more than a million pounds of C02 which is the equivalent to planting 2000 trees.
On average, photovoltaics solar panels will produce 9 watts per square foot of solar panel. For example, a roof area of 20 feet by 10 feet is 200 square-feet. This would produce 9 watts per sq ft, or 200 sq ft x 9 watts/sq ft = 1,800 watts (1.8 kW) of electric power .
But how much power to run, say, a laptop prior to the movement for green-energy and powersaver machines? There amperage in '90s was about 3.47A. This multiplied by 120 will tell you the watts. Divide that number by 1000 and you'll have the kilowatts used by the machine in one hour. Jennifer has a steampunk laptop. It uses 0.41 kilowatts per hour. If she wanted to convert the shed in her forest to a writing studio where she would go to write two hours every day, using her steampunk laptop, the shed would have to be retrofit with a .42 DC kW system or better so she would require less than 40 square feet of solar panels.
Now, how much does all of this cost per foot of solar panels or per kW created? Well, to covert Jennifer's home, it would cost about $8000 if she wanted to own the system. However, if she wanted to lease the system and pay the owning company, there are deals in the U.S. that allow for free installation and under $50 per month for the lease.
I also loved this find by off-grid pioneer Rex Ewing. How to make your own small solar system (such as I described for a studio) with just $600:
"Got 600 bucks hiding in an old book somewhere? Maybe it’s time to bring electricity into that little homestead you’ve got tucked away in the woods. But wait a minute, you say, with justifiable hesitancy. Solar-electric systems all cost thousands, don’t they? No, just the expensive ones.
"Would you like to run a few lights, maybe a TV/DVD combo or a small notebook computer? How about some moderately-sized machine tools? An investment of $600 will get you there with all new components, as long as you don't crank your expectations up too high. How? Read on.
"First off, for the sake of simplicity we'll assume the system is for either a generator-run workshop, or a weekend cabin, since that's really where a $600 solar system belongs. In this way the PV module can spend more time collecting energy than you'll spend using it, so you can invest less money in energy production (PV modules) and more money in backup power (batteries).
"But what components do you need to buy, and how much are they going to set you back? Fifteen minutes of surfing on the Internet turned up the following items. I’m sure a more thorough search would produce even more favorable results:
One Uni-Solar 32-watt amorphous-silicon PV module, 12 volts: $180.00
One Morningstar 6-amp charge controller, 12 volts: $40.00
Two Deka 92 amp-hour sealed batteries, 12 volts: ($130.00 each) $260.00
(Or five pairs of six-volt golf cart batteries $46 apiece).
One Aims 800-watt modified sine wave inverter, 12 volts: $65.00
TOTAL: $545.00
"This leaves you with $55 for wire, battery cables, mounting hardware, fuses between components, and the miscellaneous odds and ends that are always needed for any project of moderate complexity. What can you expect from this bargain-basement system? First I’ll explain the components, then we’ll take it out for a theoretical test drive.
"Summing-up the parts... First, the 32-watt amorphous silicon PV module. I chose amorphous silicon, as opposed to crystalline silicon, for its superior performance in low light conditions, since you’ll want to capture every ray of sunlight you can. It’s nominally rated at 32 watts, but for reasons too complicated to explain here, the most power you’ll ever see it produce with a standard charge controller is around 25 watts. This peak production will be for the two or three hours that straddle midday, when the sun is highest in the sky. Though output varies with the seasons, this small module will produce between 0.15 and 0.20 kWh of power each sunny day; considerably less during cloudy periods. So, in a reasonably sunny climate, you should be able to count on about one kWh of energy per week, give or take. What can you do with that much-or that little-energy? Keep reading.
"Next in line is the 6-amp charge controller. The positive and negative leads from the PV module go into it, and the + and – leads to the battery come out of it. A simple, inexpensive charge controller like this one does exactly two things: it charges the batteries without overcharging them, and it prevents electrical current from running backwards from the batteries into the PV module during the evening hours. While the latter function could be easily performed by an inexpensive blocking diode, if you want to be able to leave your system for days or weeks at a time, you’ll absolutely need the charge conditioning capabilities of a charge controller.
"Now for the batteries. You’ll want sealed gel-type batteries, even though they’re pricier than flooded lead-acid batteries. Why? Two reasons: first, you won’t have to build a sealed box to keep them in; a box which would have to be vented to the outside to prevent the buildup of flammable hydrogen gas. secondly, you won’t have to worry about all your water cooking out if you have to leave the system alone for a few months while you’re off exploring the headwaters of the Amazon.
"With a rating of 92 amp hours each, the two batteries wired in parallel (+ to +, and – to -) will store a total 184 amp hours, or 2.2 kWh of power (12 volts x 184 AH = 2,208 watt-hours, or 2.2 kWh). You’ll never be able to use all that power, however. In fact, the most you’ll want to discharge the batteries on a regular basis will be about 50 percent, though if you occasionally have to dip a little deeper into the wattage reserves it certainly won’t hurt anything. To be certain, you should test the batteries from time to time with an inexpensive multi-tester. If they’re below 12.25 volts after sitting idle for a few minutes with no load, they’ll need rest and recharging before being asked to do much more work.
"That leaves the inverter. If you only wanted to run a few lights and a TV, or a laptop computer with a car adapter, or even an RV-type water pump, you could get by without the inverter, but the extra cost for DC lights or a 12-volt DC television would probably pay for the inverter, anyway. Besides, you’ll inevitably want to run something that needs 120-volt AC (especially if the system is going in a workshop), so bite the bullet now and buy the thing.
"A $65, 800-watt inverter lacks many features common on more expensive inverters, such as battery charging capabilities, so you won’t be able to plug a gas generator into the inverter to give your batteries a little pick-me-up. Also, the modified sine wave it produces is but a crude approximation of the graceful, undulating waveform the power company (or a fancier inverter) sends through the lines, and some sensitive electronic devices may not work well, at all. But for most of the things most of us use electricity for, the modified sine-wave inverter will be perfectly satisfactory."
There are commercial systems that produce energy for RVs and small cabins for between $400 and $700 but the less expensive kits require four or more sun hours.
The best idea for my studio example would be here:
www.spheralsolar.com/products.php?product=60%252dWatt-Charging-Solar-Power-Kit#
This kit includes everything needed to install and set up the relay and produces power even on cloudy days using four amorphous solar panels all for $450.
I hope this example of solar power being used in our world today is helpful to the Mardi Gras 3000 writers when considering solar power being used to most of Hom.
Maria
Here is what I found:
Get your sun hours from this chart (U.S. only chart):
Then go here:
www.affordable-solar.com/gt-estimator.htm
If your goal is to end your electric bill forever, you will need to know what your monthly electrical use is in one average month. This should show as the kWH (kilowatts per hour) on your bills. Average this. If you do not have a bill, you can safely assume that your usage is 1250 kWH for every 1000 square feet of your house if you run a high average. It will also ask for your monthly bill amount just as a reference.
Type those two facts in plus your peak sun hours (for the Washington Olympic Peninsula, for instance, the average peak sun hours are three). Then click Calculate to see what type of system you will need.
As an example, Jennifer's house would need a solar system that produces 60 kW per hour to cover the energy usage. It would save her $7200 in electric bills every year, add $150,000 to the value of her house, and eliminate more than a million pounds of C02 which is the equivalent to planting 2000 trees.
On average, photovoltaics solar panels will produce 9 watts per square foot of solar panel. For example, a roof area of 20 feet by 10 feet is 200 square-feet. This would produce 9 watts per sq ft, or 200 sq ft x 9 watts/sq ft = 1,800 watts (1.8 kW) of electric power .
But how much power to run, say, a laptop prior to the movement for green-energy and powersaver machines? There amperage in '90s was about 3.47A. This multiplied by 120 will tell you the watts. Divide that number by 1000 and you'll have the kilowatts used by the machine in one hour. Jennifer has a steampunk laptop. It uses 0.41 kilowatts per hour. If she wanted to convert the shed in her forest to a writing studio where she would go to write two hours every day, using her steampunk laptop, the shed would have to be retrofit with a .42 DC kW system or better so she would require less than 40 square feet of solar panels.
Now, how much does all of this cost per foot of solar panels or per kW created? Well, to covert Jennifer's home, it would cost about $8000 if she wanted to own the system. However, if she wanted to lease the system and pay the owning company, there are deals in the U.S. that allow for free installation and under $50 per month for the lease.
I also loved this find by off-grid pioneer Rex Ewing. How to make your own small solar system (such as I described for a studio) with just $600:
"Got 600 bucks hiding in an old book somewhere? Maybe it’s time to bring electricity into that little homestead you’ve got tucked away in the woods. But wait a minute, you say, with justifiable hesitancy. Solar-electric systems all cost thousands, don’t they? No, just the expensive ones.
"Would you like to run a few lights, maybe a TV/DVD combo or a small notebook computer? How about some moderately-sized machine tools? An investment of $600 will get you there with all new components, as long as you don't crank your expectations up too high. How? Read on.
"First off, for the sake of simplicity we'll assume the system is for either a generator-run workshop, or a weekend cabin, since that's really where a $600 solar system belongs. In this way the PV module can spend more time collecting energy than you'll spend using it, so you can invest less money in energy production (PV modules) and more money in backup power (batteries).
"But what components do you need to buy, and how much are they going to set you back? Fifteen minutes of surfing on the Internet turned up the following items. I’m sure a more thorough search would produce even more favorable results:
One Uni-Solar 32-watt amorphous-silicon PV module, 12 volts: $180.00
One Morningstar 6-amp charge controller, 12 volts: $40.00
Two Deka 92 amp-hour sealed batteries, 12 volts: ($130.00 each) $260.00
(Or five pairs of six-volt golf cart batteries $46 apiece).
One Aims 800-watt modified sine wave inverter, 12 volts: $65.00
TOTAL: $545.00
"This leaves you with $55 for wire, battery cables, mounting hardware, fuses between components, and the miscellaneous odds and ends that are always needed for any project of moderate complexity. What can you expect from this bargain-basement system? First I’ll explain the components, then we’ll take it out for a theoretical test drive.
"Summing-up the parts... First, the 32-watt amorphous silicon PV module. I chose amorphous silicon, as opposed to crystalline silicon, for its superior performance in low light conditions, since you’ll want to capture every ray of sunlight you can. It’s nominally rated at 32 watts, but for reasons too complicated to explain here, the most power you’ll ever see it produce with a standard charge controller is around 25 watts. This peak production will be for the two or three hours that straddle midday, when the sun is highest in the sky. Though output varies with the seasons, this small module will produce between 0.15 and 0.20 kWh of power each sunny day; considerably less during cloudy periods. So, in a reasonably sunny climate, you should be able to count on about one kWh of energy per week, give or take. What can you do with that much-or that little-energy? Keep reading.
"Next in line is the 6-amp charge controller. The positive and negative leads from the PV module go into it, and the + and – leads to the battery come out of it. A simple, inexpensive charge controller like this one does exactly two things: it charges the batteries without overcharging them, and it prevents electrical current from running backwards from the batteries into the PV module during the evening hours. While the latter function could be easily performed by an inexpensive blocking diode, if you want to be able to leave your system for days or weeks at a time, you’ll absolutely need the charge conditioning capabilities of a charge controller.
"Now for the batteries. You’ll want sealed gel-type batteries, even though they’re pricier than flooded lead-acid batteries. Why? Two reasons: first, you won’t have to build a sealed box to keep them in; a box which would have to be vented to the outside to prevent the buildup of flammable hydrogen gas. secondly, you won’t have to worry about all your water cooking out if you have to leave the system alone for a few months while you’re off exploring the headwaters of the Amazon.
"With a rating of 92 amp hours each, the two batteries wired in parallel (+ to +, and – to -) will store a total 184 amp hours, or 2.2 kWh of power (12 volts x 184 AH = 2,208 watt-hours, or 2.2 kWh). You’ll never be able to use all that power, however. In fact, the most you’ll want to discharge the batteries on a regular basis will be about 50 percent, though if you occasionally have to dip a little deeper into the wattage reserves it certainly won’t hurt anything. To be certain, you should test the batteries from time to time with an inexpensive multi-tester. If they’re below 12.25 volts after sitting idle for a few minutes with no load, they’ll need rest and recharging before being asked to do much more work.
"That leaves the inverter. If you only wanted to run a few lights and a TV, or a laptop computer with a car adapter, or even an RV-type water pump, you could get by without the inverter, but the extra cost for DC lights or a 12-volt DC television would probably pay for the inverter, anyway. Besides, you’ll inevitably want to run something that needs 120-volt AC (especially if the system is going in a workshop), so bite the bullet now and buy the thing.
"A $65, 800-watt inverter lacks many features common on more expensive inverters, such as battery charging capabilities, so you won’t be able to plug a gas generator into the inverter to give your batteries a little pick-me-up. Also, the modified sine wave it produces is but a crude approximation of the graceful, undulating waveform the power company (or a fancier inverter) sends through the lines, and some sensitive electronic devices may not work well, at all. But for most of the things most of us use electricity for, the modified sine-wave inverter will be perfectly satisfactory."
There are commercial systems that produce energy for RVs and small cabins for between $400 and $700 but the less expensive kits require four or more sun hours.
The best idea for my studio example would be here:
www.spheralsolar.com/products.php?product=60%252dWatt-Charging-Solar-Power-Kit#
This kit includes everything needed to install and set up the relay and produces power even on cloudy days using four amorphous solar panels all for $450.
I hope this example of solar power being used in our world today is helpful to the Mardi Gras 3000 writers when considering solar power being used to most of Hom.
Maria
