Alternate Energy 101 -- The Heart of the System (with improved links)greenspun.com : LUSENET : TimeBomb 2000 (Y2000) Preparation Forum : One Thread
OK, corrected the one bad link closure, didn't find the problem with the other links, so I just provide the URL as well. If the link doesn't work, use the URL>
In the beginning, man created public power companies. These provided electricity, silently, and surely to our abodes.
Now, we may be faced with -- quickly and inexpensively -- creating our own electricity. This thread is intended to provide the very basics of alternate energy.
The first thing most people think of when the think of alternate energy is generators. As well see, generators are good, but theyre not the way to go in order to begin to become self-reliant. Well cover generators in other threads.
AC or DC?
Household electricity is Alternating Current (AC). Generators put out AC. There is not feasible way of storing AC electricity. That means we use all the power that comes in from the electric utility, or is generated out back in a generator. This is bad......sometimes we want to use electricity when the utility isnt providing it or when our generator isnt on. Households operate on 120 volts AC (vac) --which usually is about 117 volts.
We can store Direct Current (DC), using a battery. Thats good, because its about the only form of electrical storage we have that makes sense.
If youre going to provide any sort of alternate electrical system youll need batteries to store the energy you generate in excess amounts in order to be able to use it when you want it.
Batteries store from 2 to about 12 volts -- not nearly as much as we need to light a lamp. The typical batteries youll use for alternate energy systems are 6 volt batteries.
Batteries for alternate energy systems are made differently than car batteries. Car batteries are designed to put out a lot of current in order to start the car, but are never discharged very much. Discharging batteries is harmful to them; discharging car batteries will kill them in a hurry. Generally one of several types of deep discharge batteries is used for power storage. The least expensive (at least initially) is made especially to be discharged to about 30 to 50% of capacity. Examples are the Trojan T-105 golf cart battery and (further upscale) the Trojan L-16 battery. Specifications for these can be obtained at :
http://www.windsun.com -- Wind Sun,
http://www.jademountain.com -- Jade Mountain, or
http://www.mrsolar.com -- Mr. Solar.
Both of these batteries are 6 volt units: we need them in multiples of 2 or 4 in order to get either 12 or 24 volts in order to drive a device called an inverter.
In order to get stored power from the battery to the house, we need an in-between device, called an inverter. Actually, we need some special fuses and heavy duty wiring, as well.
Inverters come in various sizes, from 50 watts to 4800 watts. Some put out better alternating current (sine waves) than you get from the electric company, others put out a semi-dirty modified sine wave. If you want to listen to Beethoven and Bach on hi-fi, youll need a full sine wave unit; a modified sine wave unit will do for most household applications. Modified sine wave units are less expensive, sine wave units do a better job -- draw less current, cause less heating -- for microwaves and some motors.
Inverters that you buy for use in the U.S. come only in 120 volts output. If you need to power a deep well pump or any other heavy duty stuff, you may need to generate 240 volts. In that case youll need to stack two 120 volt inverters that have been designed for that purpose.
Example: Trace Engineering DR series inverters can be stacked to get 240 volt outputs. See: http://www.traceengineering.com -- Trace Engineering. This is a good site to browse.
Cheap inverters are off-the shelf at Walmart. These are fairly dirty modified sine wave units and are low power. Unless youre really going to do a very cheap installation, do yourself a favor and get a good inverter. Trace is good. Browse the other sites listed above for other inverters if you wish. Advantages of the good inverters are that they will automatically detect loss of input (utility) power and switch over, plus, when input power is available, the inverter acts as a battery charger.
The Minimum System
You can work for a couple days with no utility power, no generator, no solar system, and no wind power system. Simply start with fully charged batteries. This shouldnt be a problem if youre using an inverter with charger and automatic switchover.
When the power goes out, the batteries will act to power those things you absolutely need. If power comes back on, the system will switch and let you charge the batteries. If you have a brownout condition, where the utility voltage goes low, the system will shut off the utility and run off batteries.
This is really good for short outages (less than 2 days), and for rotating blackouts (where you get power for 4 hours a day and dont have it for the next 20) -- use those 4 hours to charge the batteries to provide some power the other 20 hours.
Hooking it Up
First, decide what it is that you absolutely have to have. Ill provide sizing information in another thread.
Install a small subpanel with breakers on the output lines. As an example you might want to provide power from the batteries, through the inverter, to 4 of the lines in your house. You might decide to wire up the following:
a. Fluorescent lamps in one room
c. Fan for a heater or pump for a boiler system and/or small Fan for a fireplace insert.
d. Shallow well pump for pumping water from a cistern and pressurizing the household system.
You would wire from the inverter AC output to the subpanel, and from there to each circuit.
The batteries would be wired in series (minus of one battery to plus of the second battery, leaving one plus and one minus terminal (6 volts plus 6 volts = 12 volts) to run to the inverter. Added current capacity can be obtained by adding other pairs of batteries, wired identically, across the first pair, wiring plus to plus, and minus to minus. Some inverters are 24 volt units (more efficient), so that you would need 4 6-volt batteries, stacked in series, minus to plus, again leaving one plus and one minus terminal.
If you have problems visualizing this and really need help, go to Trace Engineering. Download any of the inverter manuals (theyre in .pdf format) and you can see wiring diagrams. They take a while to download, so if youre only casually browsing, it probably isnt worth your effort. If you want to know what youre going to need to order, its well worth it.
In order to protect things, you need to install a fuse between the batteries and the inverter. This is code, and it just makes good sense. You dont need to start a fire in the cables, and ruin the batteries because you goofed and laid a screwdriver across the inverter input terminals. While youre at Trace, look up their 250 amp fused disconnect (DC250). Thats what you need. It allows you to manually disconnect the inverter in order to work on the system and provides a good fuse on the input line.
The End Result
You havent bought a generator, nor solar panels, nor a wind generator, but you now have a system that will provide light and heat for a couple of days. Moreover, it will switch back and forth automatically. Great thing to have if you have short power outages for any reason. And, its all set up so that you can add solar or a generator or wind later. The approximate cost of this system is:
1. Qty 9, Trojan T-105 batteries, @ $80 ---------------$ 720 2. Qty 1, Trace DR2412 or DR2424 inverter--------- $1000 3. Qty 1, Trace DC250 Fused disconnect-------------- $ 250 4. Miscellaneous Wiring---------------------------------- $ 150 5. Subpanel---------------------------------------------------$ 60 Total----------------------------------------------------------- $2180
Not cheap, but it lets you cook, boil water, have some lights on, and stay warm. And, yes, you can get things cheaper and smaller. You pay the price when you do this, however.
Tip -- replace all the normal lights with fluorescent units. You can run about 4 times the lights.
Next Thread will be -- Sizing the system: how do you know how much power youll need. Well practice by sizing the system we outlined here that will do the heater pumps/fans, some lights, microwave, and a small shallow well pump.
We will if theres any interest. Let me know.
-- de (email@example.com), July 08, 1999
-- Wind Sun,
-- Jade Mountain, or
-- Mr. Solar.
Hi De! Check your e-mail. :-)
-- Gayla (firstname.lastname@example.org), July 08, 1999.
Hey De...nice work! I know how long this type of write up w/ research takes...so please don't be offended if I add a couple of things? 1- there are inverters larger than 4800 watts 2- and to run a 240 VAC pump, you can often use a Trace T240 step-up tranformer to boost the inverter output from 120 to 240 VAC and avoid the expense of buying 2 inverters. Generally, this works OK with the larger 3600 watt or larger inverters and with pumps up to 3/4 and even 1HP in size. Again...nice job and I'm looking forward to part 2! Roy Four Winds
-- Roy Butler (Roy@Four-winds-energy.com), July 08, 1999.
Thanks, Roy. Yes, there are inverters larger than 4800 watts.....but I believe 4800 is about the upper limit for systems that have a reasonable number of buyers.
As far as the transformer, in my mind it make better sense to use stacked smaller inverters than to use a larger (more expensive) inverter and go to a transformer. Reason: redundancy. If one inverter fails I have a reduced performance system, but I have a system. The costs are roughly equivalent [two DR1512's versus a 3612 + transformer, for instance]but I like that backup.
-- de (delewis@Xinetone.net), July 08, 1999.
Good thread ... and I think folks need help understanding that generators are not generally the solution to running continuously if electricity down (fuel, breakdowns, etc) unless you are very generator-savvy.
Personally, we have opted for non-electric (100%) and 8KW diesel (luxury as desired), but many folks think that a gennie will keep them humming 24 hours a day indefinitely.
OTOH, inverters and batteries ain't cheap ....
-- BigDog (BigDog@duffer.com), July 08, 1999.
We've got a starter solar system from Roy and are very happy with it (and Roy!). It's not cheap, true, but once it gets going you've got free electricity. We got started for just over $2000 plus batteries (about another $200), which will keep us warm (via the waterbed heaters), provide light to read by, run the non-solar battery chargers (for all sorts of small appliances), and run a fan.
We'll be adding two more panels and another battery soon. We'll just keep expanding as we can afford it.
A nice plus: our state permits a 40% tac credit for any solar equpment, including sunfilm and solar battery chargers, as well as the big stuff! (Providing their systems are operating. . .)
-- Old Git (email@example.com), July 09, 1999.
Thank you so much for pulling this information together. You have jumpstarted me to continue with my own mental activity on this topic, and I made a lot of progress on it tonight, I think. I have started a new thread asking for feedback on my proposed design. I didn't include it here because the questions I have at this point don't yet speak to the system sizing issues on which you are focusing.
-- Y2K, ` la Carte by Dancr near Monterey, California (firstname.lastname@example.org), July 12, 1999.