Hobbyist Renewable Energy? 607
vossman77 writes "I was looking into renewable energy from a hobbyist perspective, maybe generating a few watts of solar or wind power, just to reduce my electric bill. But upon further review, I found out that I need a special grid-tied AC inverter that shuts off when the grid turns off (for worker safety reasons) and makes the current in-phase with the grid. These two additional features, over the cheap inverters sold at department store, make the cost upwards of $2000, but support more watts than I need. While this is fine for large-scale projects, it is out of range for a small scale hobbyist. A Google search came with some home-brew hacks at best. So, are there any Slashdotters out there doing small-scale renewable energy projects with grid-tied systems? What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?"
Renewable energy comer in many forms (Score:5, Funny)
Breed Whales, burn the oil.
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Use a 'fan center' to isolate when grid power down (Score:5, Informative)
I can probably fabricate a circuit with an oscillator that syncs up to the 60Hz of power. After that, it's a matter of how to convert from DC to AC. It doesn't seem hard to me.
Re:Use a 'fan center' to isolate when grid power d (Score:3, Informative)
Re:Use a 'fan center' to isolate when grid power d (Score:5, Interesting)
But first I would like to make a quick point which is that this is a major political obstacle to alternative energy. It's not a technical obstacle, it's a political issue because we've "deregulated" utilities by letting them regulate themselves and this is insanity. At least it is one way to ensure that we remain bound to fossil fuel solutions.
So, on the topic of a DIY grid-tie inverter here are a few posts from a thread started by a guy looking to outsource the design.
Some dude makes the snarky remark about why don't you just pay the price and this is the response of a user named MarkM
(I've reformatted a couple of his posts into a single thread for readability.)
"Why don't you just buy one"
BECAUSE THEY ARE WAY OVER PRICED. That was yelled a the top of my lungs.
Solar panels cost about $4-5/Watt, inverters cost $1-2/watt. This is crazy. These grid tie inverters are no more complicated than a computer power supply which will cost you about $0.08/watt. The inherint nature of the grid tie inverters is to track the sinusoidal input and drive it to a higher voltage, thus selling the solar power on it. The IEEE 1547 require all kinds of hoops to jump thru and the inverter companies use this as an excuse to charge what they do. Again the hoops are simply jumped by a programed algorithum that monitors frequency and voltage levels. WOOOOO. I see this mans drive to find/build an inexpensive alternativ and do the gorella thing.
The way the grid tie inverters work per the regulatory hurdles is it syncs in on the line power voltage level and sine wave siganture. If power goes down it shuts off, no harm can come to the line man. This type of statement from you or utility companies is old school old day problems stemming from someone hooking a rotatry generator or non-monitoring piece of equipmnet to the line. And if a lineman is doing as he is suposed to he grounds live wires to ground before working on a "dead line". (that's a rule)
Utility companies have this power thing locked up and are going to be very reluctant to let small producers get in the game. Utility companies should not fear small producers they should embrace them and buy their excess power and resell it at a profit without any over head. The largest source of funds to build the power supply sytem is in the pockets of consumers: let consumers build it.
And as far as the regulatory cost as a part of the inverter cost that to is a pile. When the cost of regulation of a certain product is spread over the number of units sold it is small. Again we have a situation of free market and what the buyer will pay. In verter builders are maximizing there profits because competition is nill. I am all for free market but too I am for some of the Chinese or Indian products to slap the US, German and Australan made manufactures into a stop gouging mode.
The original thread is here.
http://cr4.globalspec.com/thread/4482 [globalspec.com]
On the general topic of grid-tie inverters you may find the following Wikipedia posts of interest. You will find the following components mentioned in the documentation for many grid-tie inverters.
http://en.wikipedia.org/wiki/SEPIC_converter [wikipedia.org]
http://en.wikipedia.org/wiki/Mppt [wikipedia.org]
Re:Use a 'fan center' to isolate when grid power d (Score:4, Informative)
You realize that a grid tie inverter is the opposite of a computer power supply don't you? They don't even have to consider phase, their output doesn't HAVE a phase.
Meanwhile, the non grid-tie inverters often output stepped voltage rather than a sinewave (and so harmonics). It's cheaper by far and good enough for many applications, but not for feeding into a big iron core transformer. They don't care about phase either. They just need to be somewhere close (ish) to 60 Hz.
They may still be overpriced, but not by 25 times as you suggest.
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Re:Use a 'fan center' to isolate when grid power d (Score:5, Interesting)
Obviously it can be done, but it seems Very Complicated, and may be something where you want to have a commercial concern do the engineering so that if something goes wrong, you're not the one responsible. Because, let's be clear here: we're talking about generating lethal amounts of power and driving it into wiring that goes into other people's houses and into systems that other people are maintaining.
As for alternators, basically, an alternator is a variable three-phase AC generator. A voltage regulator controls the power flowing through field winding in the alternator, based on the feedback it gets from the charging system as a whole. If you replace the voltage regulator with a simple AC input line (stepped down so as to not arc over) you can get AC out that's related to the AC in, and use that to get phase matching. It's not pretty (given that alternators want to output three-phase) but it looks possible. I don't think it's a great idea, just tempting because junk alternators are cheap.
Don't do it (Score:5, Insightful)
> amounts of power and driving it into wiring that goes into other
> people's houses and into systems that other people are maintaining.
This is the key part. I'm as Libertarian as they come but a power grid implies a need for some sort of standards and real enforcement of same. Forget the legal implications for a minute, do YOU want to kill your lineman? Then don't conduct unannounced experiments on the production power network. Ya got three choices here:
1. Man up and buy the commerical, TESTED AND CERTIFIED product for that key interconnection point.
2. Build a test grid, do your R&D and produce a TESTED AND CERTIFIED product of your own.
3. Restrict your alternative power experiments to those that do not require an interconnect to the grid.
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In addition to not wanting to kill someone, many utilities and state lawws require such a certified unit. Assurances of a homebrew designer won't satisfy that no matter how good the tech actually is.
One potentially interesting idea would be to modufy a UPS to accept additional charging current from the solar rig. The desired behaviour would be to run on battery as long as the battery charge is greater than x% capacity (charging only from solar), run from the grid if available (still charge only from solar
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One teeny problem... (Score:5, Insightful)
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Think of things in your house that you really don't need to run on grid power -- nonessential items. Perhaps, since this is just for
Re:Renewable energy comer in many forms (Score:4, Funny)
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Renewable fuel (Score:3, Insightful)
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Yes indeed; further, it seems the trick is to first identify what is to be powered by this project since some whole-system project is off the table. If not a cell phone, then what? Without answering that first this seems like a search for a solution in search of a problem.
I think, by reading the original post, that the poster would like to leverage renewable energy to power his home. Or at least supplement the power provided to him by his local power company. I'm very interested in doing the same but in my investigation, it's going to cost upwards of $30,000 to do any serious power generation. In the summertime, I get ~$450 power bills which I'd love to offset using solar power since I've got tons of exposure at my house. The problem is, the costs before installation ar
Re:Renewable fuel (Score:5, Informative)
I cut my power to 1/4 doing this. THEN went solar. Your 30K cost is now 7K.
The OP doesbn't need a grid tie invertor. That's for selling excess power back to the power company.
I run a sat receiver by having it plugged into a ups with a ubiquitous 7Ah SLA battery, fully charged, with two 30W solar panels hooked up directly to the battery. It just sits there and works.
I have lots of solar panels, i just hook them up in lotrs of little autonomous systems than do one thing. Free, and forver (or until some part beaks or the sun stop shining).
I've got a bunch of these setups for various things with various batteries and inverters.
I can't for the life of my see how "small scale" and "grid tie" relate at all.
If you had an 18Kw hydro plant I could see it but...
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Maybe someone (other than me) will run the numbers on charging a 12v cordless drill vs
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Re:Renewable fuel (Score:4, Interesting)
The OP doesbn't need a grid tie invertor. That's for selling excess power back to the power company.
No, you need one if you want your entire house rigged for solar power. Being able to sell excess power back to the power company is just a side-effect. I started with a battery/inverter based system, and I hated it, so I went whole-house. You simply need a grid-tie inverter for that, if you aren't making enough power on your own to run your entire house.
I've never even come close to having an excess of power to sell back to the power company. That wasn't the goal of the project.
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You need to keep going. You guys can get (if you're a farmer or remote business) Federal grants and Federal financing for a 15 Kw wind turbine.
Here in Canada we can get sales tax refunded. Woopee.
Re:Renewable fuel (Score:4, Insightful)
It would also take a very special kind of buyer to pay any significantly higher price because of it. You'd be severely limiting your potential buyer base.
But, if the price of the home was basically on par with others in the area, you'd probably have an advantage.
It's like swimming pools. They don't necessarily add any value to the home, and they attract only people that WANT a pool. A lot of people don't want a pool, as I suspect a lot of people wouldn't want all that extra complexity that a supplemental power generation system could introduce.
Only spend the money if you KNOW you will stay there long enough for this to pay for itself for YOU.
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Now, if his neighbor has gone out and purchase the latest GE Solar System, I might consider it.
Re:Renewable fuel (Score:5, Insightful)
For a lot of hobbyists, the plan goes something like this:
go 12 volt (Score:5, Insightful)
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All LEDs need DC, AFAIK.
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Re:go 12 volt (Score:5, Interesting)
And if yoiu do 4 you can run then off a car battery. Pretty much forever.
Plus, don't give up on dead car batteries. I have a 10 year old Optima (gel cel spiral wound deep cycle) that I killed this February starting my diesel. Although it was $180 new, 10 years is unprecedented for a battery, especially in a diesel,. But ow it's dead. It puts out a steady 9V nop matter how much you charge it. So it's useless for cars or anything 12V.
But it'll run 1000 hi pwer LED's for about a week, and I can charge it from the sun in under half a day. And it would have got thrown out.
Ask around golf coursds around this time of year. TGypically they may renew their golf cart bartteries and if you ask they may give you the old ones as they just dump them - thwy pay to recycle them actually.
There's a fella near here that got 6 free, a small generator and hge lives off grid for $50/mo in electricy fro a generator he runs once a week.
You think Tesla waited for a fucking tax rebate?
Get to work...
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Re:go 12 volt (Score:5, Informative)
This is a common mistake and is only good for very low power stuff. In picking a wire size people often think going from 120 volts to 12 volts only involves the math of supplying a wire 10X larger to handle the current without overheating. In a 120 volt application, you are permitted a 5% voltage drop. This isn't much as 5% of 120 volts is only about 6 volts. No big deal when running a 1200 watt portable hair dryer. If you simply size the wire to now do the same thing on 12 volts, you no longer have a 5% voltage drop. At the same current you still have a 6 volt drop with the 10X larger wire but you now lost 50% of your power in the wire. Take a hint from the pro.. Use an inverter. The 10% the inverter lost is made up by the 45% not lost in the wire. Do the math. Engineer the project.
Either your high draw items (Microwave, toaster, blender, etc) are either within 20 inches of the battery, or you will want an inverter. With an inverter you can use standard appliances. Look for energy effecient ones.
Another item is to ditch the grid tie for small systems. It goes down with the grid providing no security. Put the critical load on an Outback inverter. It was made just for this application. Small solar, battery maitenance, load transfer to and from solar and battery, etc. You don't have a surplus to sell to the utility, so don't connect that way. Use it to supplimant your load and reduce your total load. As a bonus, you don't have to enter a grid tie agreement with the utility where they buy your power whosale and sell it back to you retail.
Find Outback stuff here;
http://www.outbackpower.com/ [outbackpower.com]
Disclaimer, I just use it. I am not otherwise involved with this company. The company has grid-tie stuff if you decide you really want it. I don't recommend it except for larger installations. This company has done a great job meeting the market. Their grid tie units are the first that I know of that operate instead of shutting down in the event of a blackout. They solved the number 1 problem with grid tie stuff.. blackouts.
http://www.partsonsale.com/outbackgridtie.html [partsonsale.com]
Re:go 12 volt (Score:4, Informative)
The purpose of the grid tie isn't to provide security or to support a critical load. The purpose of a grid tie is to prevent the home power system from powering the grid when the grid goes down - if you pump power into the grid when it's down, you risk the health and life of workers trying to restore the grid.
For example - A line went down that supplies my road. Before workers started repairing the line, they isolated it at the substation, rendering it safe. Without a grid tie the line remains powered from the home systems - which can kill.
If you have a critical load, put it on a UPS. Don't skip the grid tie unless your home system is entirely isolated from the grid.
Seriously, there's times to home brew and jury rig and save a few bucks, this isn't one of them. Do it right and don't put lives and property at risk.
Go 12 volt...and burn your house down! (Score:5, Informative)
I'm sure that you can do it safely but you will need far thicker cables than a 240V system and be careful that you have good connections. Plus you will loose 10-20 times more in power transmission than before.
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Common mistake: voltage here is the potential drop over the resistance, which in this case is the wire. Since power is V times I, and this is typically what needs to remain constant for the device, reducing V by a factor of 10 means that you must increase I by a factor of 10. This will also increase the potential drop along the cable by a factor of ten and so you have 10 x 10 = 100 factor increase in the heat. A better formula to use is P=I^2 R in this case.
Or
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Re:go 12 volt (Score:4, Informative)
Really, $2000? (Score:3, Insightful)
Electricity is a dangerous thing, jury rigging solutions is not an option when your safety is at risk. The device is $2000 because it must pass safety, UL, and a whole host of standards so it doesn't you know kill you or blow up the local transformer when somthing goes wrong.
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Burning a house down is the least of his concerns (Score:5, Insightful)
Those transformers on the poles work just as well when operated backwards, stepping the 120V output from your inverter up to the 7-13 kV distribution level. Unless your inverter has enough "smarts" to isolate itself from the grid in the absence of utility power, your system will attempt to power up your part of the utility network, resulting in a severely overloaded inverter (with resultant blown fuses/smoke/fire) at the best, or a serious hazard to lineworkers at the worst.
People HAVE been sued when lineworkers are killed/injured by improperly installed generators or PV systems that resulted in backfeed. Prosecution for criminally negligent homicide is also a possibility, especially if the prosecution can prove that you KNEW of the need for automatic isolation, but failed to provide it in order to save a buck.
In short, use properly designed equipment, installed according to manufacturer's instructions (and get the proper permits/inspections as required), or stick with a completely isolated low voltage DC system.
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Well, Yea, 2000 bucks (Score:2)
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What if the main line supplying your grid-tied juryrigged safe-to-you system goes down for an unrelated reason, in the mi
Hardware switch (Score:2)
Ugly hack (Score:3, Interesting)
- at the moment of switchover, your appliance gets cut off.
- you are always wasting some or all of your power - assuming that both supply and demand vary, and the switching is granular.
To some extent, you can improve on this by using a UPS downstream of your switch.
This isn't exactly an "efficient" solution, but it will work, and it's simple and cheap.
Keep your cheapo gear off my power grid (Score:4, Insightful)
This site should help (Score:2, Informative)
The joys of regulation and insurance (Score:5, Informative)
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Not cheap (Score:5, Insightful)
conventional sources subsidised for generations (Score:3, Informative)
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Fossil fuels are becoming more rare, and their price is going up.
Technology is making advances for other energy sources, so their prices are going down.
Besides, as someone else mentions, there are already tremendous hidden subsidies in place for current sources. The same issue comes up with rail transport, because rail subsidies are explicit while air and road subsidies are hidden.
Keep it simple (Score:2)
To generate 12V DC to charge a car battery, get a 24V or 36V cooling fan for a stationary motor (for something like a large industrial compressor) and mount it on a post. Add a big diode and hook it to the battery. Simple as that.
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You can't tie into the net with non-approved gear. (Score:3, Informative)
The consequence of doing things like that without permits and/or inspection is that on the off chance that there was ever a problem, you'd be financially liable for any consequences.
There are opportunities to do strictly off-grid stuff, or at least you could keep to the low-voltage side of things. If you have a UPS for your computer or phone/router infrastructure, you could put up a solar panel to keep the standby battery charged. To the extent that the system runs off of DC power, you could supplant the power drawn from the grid with a panel, and reduce your electrical footprint that way.
Not necessarily true.... (Score:2)
The conventional wisdom of pubs like HomePowerNews and The Mother Earth News seem to advocate understanding battery technology and inverters, and also where you're consuming juice where those consuming devices can be better used (unplugged when not in use) or replaced with more cost-e
Re:You can't tie into the net with non-approved ge (Score:2)
My partial solar solution in my grid tied house (Score:5, Interesting)
My house is grid tied, but my wall unit Air conditioner (and roof vents, and 2 of the outlets on my porch) are 100% real time solar (with no batteries capacitors), in their own closed circuit, which is not at all grid tied. So, basically I cool my house for free, and it cost less than $1000 for everything (panels, raw materials to do the wiring myself).
My next step is to get an outlet in the kitchen to run my next worse appliance that only needs to run part time: The washing machine, then The Dishwasher.
Like the OP mentioned, this is a hobby thing just as much as a "green" or "money saving" thing, so I found the approach of taking the low hanging fruit (electricity I NEED to use only during the sunny time) was a favorable approach over using batteries, and expensive grid-tied adaptors/regulators/converters.
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I would add that with heating and cooling you could always get two units. If your renewable power can't take up all of the load the grid powered one can help out. i.e. set your grid powered air conditioner thermostat a few degrees higher than your renewable one.
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details? (Score:3)
Details! I'd love to hear more about how you did this, and I'm sure that many others on here would equally appreciate any hints/information/etc you can offer.
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unfortunatly I am a software developer, so I tend to resist all forms of documentation. Here is my rundown (the setup of my house means I didn't even run any wires through the house so this was so freaking simple:
Wall unit AC (was what we used before the conversion) is on the back wall of the house) 115v 10,000 BTU unit I think they retail for ~$400-$500 (but we
Re:My partial solar solution in my grid tied house (Score:5, Informative)
Re:My partial solar solution in my grid tied house (Score:4, Informative)
Wall unit AC (was what we used before the conversion) is on the back wall of the house) 115v 10,000 BTU unit I think they retail for ~$400-$500 (but we already had it)
My solar panels were second hand, so they were cheap, they were operating at ~81% their original capacity, so the company sold them to me for less than 1$/watt I have about 1300 watts, and the AC when it is on (it switches off and on throughout the day) it uses up to 875 watts. I got very lucky on the price for the panels, and the additional wiring and stuff, so maybe my $1000 number was not very "honest" maybe double or triple that if you are buying with urgency instead of waiting for a killer deal like I did. The capacitors I use are a cluster of those 2000 Farad Car stereo ones (I know I know it is not the right thing to do but it is the cheap thing to do, and they are firewalled). They are before the inverter, to feed it continuous power. And seriously that is about it, I mean wiring solar panels is about like wiring batteries (parallel banks of your desired series of voltage), then do the same with the capacitors, then the inverter, which can be bought for cheap from a Truck Supply store (some bigrigs use them, to run things like 1000 watt Routers, jackhammers, etc) From there, my inverter is mounted on my back porch (near the A/C unit) and the A/C is plugged directly into that (it has A/C outlets in it).
The roof vents are just seperate left over panels, with DC fans that run directly wired to the panels.
So basically I bought cheap ass panels, some consumer electronics, and put it all on my roof/porch. Doesn't sound as glorious when I put it that way, but in all I have almost made my money back in energy savings as compared to the bills from last year... and that is significant for me since I really only did it for fun. I think I will be in the black in August of this year, and the gear is still going strong, so hopefully it will be an actual cost savings.
Off the top of my head... (Score:2)
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so you better be N'sync.
or in their own words...
You might've been hurt babe, that ain't no lieeeee...
hot water solar (Score:5, Interesting)
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120v automatic transfer switch (Score:2)
When the UPS dies, the ATS will switch to regular house power.
Separate 12vdc (Score:3, Interesting)
separate circuits in the house (Score:2)
Simply install a small second breaker / fuse box and move a couple of wires. Might want to have an electrician do the work or inspect it to make sure you've covered everything. Do you want to have battery backup for night time
Once your hobby has progressed
Low voltage DC lighting is a good answer (Score:2)
Run these on their own completely separate circuit; you can use regular 12 volt batteries as your energy storage and charge the batteries with solar cells or a automotive alternator driven by some kind of alternate energy (steam? water wheel? windmill?) or any combination thereof. If you h
Run LEDs - they're more efficient (Score:2)
Your average lightbulb converts (AFAIK) about 65% of the energy into heat - which we don't need as the boat already in a hot climate
Calculate load/power (Score:2)
non-grid-tied DC motors, pool pump (Score:3, Informative)
Experience with solar heating (Score:2)
The problem with enthusiast wind generation is that power scales exponentially with the size of the turbine blades. Hence the attractivene
Storage (Score:2)
Don't help this loon. (Score:2)
Also, if you are going to waste bandwidth on the Internet, why not give some damn details about your plan? Make it interesting at least. Right now, your ramblings seem to indicate you want free help for a poss
Here's what I did with my 200watt panel (Score:2)
Forget solar (Score:2)
However, if you want to do some solar stuff for a hobby (which I have done) and cost isn't the primary concern, then don't even tie to the grid; if you have to ask the questions you ask, you aren't even remotely qualified to homebrew a grid-tied inverter!
For a hobby project, consider 12 volt stuff - perhaps use solar to run your computer (you will need to build a computer PSU th
Generator patch panel (Score:2)
I don't see any reason you couldn't plug s
people who "know "it can't be done (Score:2)
http://www.otherpower.com/otherpower_systems.html [otherpower.com] is one page on a site run by a group who develop off-grid and grid-tied systems they might be a fun place to browse, also try their discussion page. Some of the stuff they get working looks like props from a mad max movie but they do work. wood fired steam engine driving a dynamo, anyone?
Seperate Home DC Grid (Score:2)
One of my personal dream projects is to run Power over Ethernet or some other DC-based power grid in the house. There are tons of AC-DC converters in most houses (computers, cell phone chargers, etc.), and it'd be a lot more efficient if we could run just one AC-DC converter with DC-DC converts on the specific devices as needed.
This should go hand in hand with any home generator, since most such projects use large lead-acid batteries to store excess power, so you won't need an inverter at all for most app
do it off the grid (Score:2)
Gorilla Solar in Home Power Magazine (Score:3, Informative)
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You're doing it wrong (Score:3, Interesting)
why not just have separate circuits to power small items like alarm clocks, charging electric toothbrushes, etc....
Are there really people investing in new sources of energy so they can power a toothbrush? Remember the mantra is reduce, reuse, recycle...
Ditch the electric toothbrush and can opener, the constantly charging rechargable tools you use infrequently, the wall warts that are always buzzing, and maybe it won't take as many solar panels you keep your household running.
But for a small scale s
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That's what I did. Butg once I got the laptop and the satellite working off solar the rest became suddenly far less important. Har.
Imagine if everybody in America ran just once
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But for a small scale system, the ability to tie in to the grid is essentially useless.
It is amusing how easy it is to spot people who have never actually thought about the matter by comments like these.
The purpose of grid-tie is to avoid having to futz around with batteries. Batteries need charge-controllers, they need to be serviced, they have a finite life-time and they're either over- or under-speced because no two weeks will ever have the precise same power.
So you used the grid as your battery. It's as simple as that. You over-produce in the afternoon (assuming solar -- maybe in th