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Forum Index : Solar : Solar Farm Practicallity
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| Warpspeed Guru  Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Almost noise free dc to ac conversion is best accomplished with a multi step sinewave, definitely not high frequency PWM. Its not too difficult, and at very high power levels, a larger number of steps would produce very little waveform distortion or high frequency noise, with little or no post filtering required. I once built myself a fairly simple experimental 26 step sinewave inverter,(a three transformer design) and I should still have it around here somewhere, it worked amazingly well. Cheers, Tony. |
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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Is that based on the Trace Inverters? There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All I know I will be shouted down by the techno purists using Modern switching converters, but I have a soft spot for old tech that is nearly indestructible. In the old power plant I dismantled there was a rated 100KW rotary converter basically it was a DC 110 volt motor driving a 3 phase 100 KW generator also there was another one at 40 KW which I still have, I know everyone will say they are inefficient and that's true around 80% whereas a good electronic unit will do 90% but I would put my money on a mechanical one for reliability and longevity, I hooked the 100 KW unit to a diesel engine and it worked perfectly and could be still doing so. All the best Bob Foolin Around |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Bob I have not read this entire epic thread, so forgive me if I'm asking and already-asked question, but are there any commercially-available 12-volt to 110 VAC motor generators available anywhere these days? Back in the day (Viet Nam) several of our planes had motor-generator sets, but they were for obscure voltages, made to run obscure navigation gadgets. Also, how are the tomato(?)seeds I sent along back in the day doing? . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
On that note about 110VDC, does anyone know of a comercial 24Vdc or 48VDC to 110VDC converter available on the market. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Bob, You started this thread noting that at 4c/Kwhr it would not be viable to build a solar farm. OK did you take into your figures the LGC which trades on the market and is currently $32.30/Mwhr. That is a wee over 3.2 cents/Kwhr. Now the multiple used to determine how much a day a 1 Kw panel will output each day. The multiple for say your area, Cairns etc is around 5. My areas multiple is actually 7, Real life with mono panels the last 2 years data,(received data yesterday) actually gave that multiple a little under 8, but for our case try 7 average for year. If you calculate again you`ll find we are over the line better then bank interest, but not replacing capital as well as interest in 25 years (life of panels)also no maintenance, breakdowns, insurance factored in. But we are getting there now to find that customer who will pay 15 cents/Kwhr and we are well and truly there. Next snag is that utility that really doesn`t want to know us, will he connect this all up for us and agree to pay us the base tariff (now 4 cents/Kwhr)should our customer go bust. Then we should wait and see what transpires in the Senate in July. But you see where I`m coming from, it can be done without government assistance, without dealing with those time and money sapping bureacrazies. We`ll have to have to deal with the local Council, building approval, we`ll have to be just a wee politically correct. Green tape should be just a formality you would think. Red tape well that could be a bit of drama. But couldn`t they all just let us do our thing, we are doing our bit, and they are making the noises of doing the right thing. Couldn`t we sway (read blackmail) them with this argument. And then how about those Companies making a killing installing IWT`s, will we get up there noses. Without Government assistance how dare they!! We come from the land downunder. Vic |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mack We had a manufacturer called Davey that specialized in 32 volt setups but they no longer make any transverters as I suppose there is little demand for them now with the UG electronic Inverters. I have done a quick search on Google but nothing so far. The weather here has been anti tomato for the last two years the first lot got waterlogged in the floods the second lot produced some fruit and then got cooked in the heat wave, this year the last of the seed is in a planter tray and I am going to pot them out next week when the current heat wave is done, the hydro experiment didnt go to good as when I went to hospital the wife let it all dry out, so when I got home all was lost. Hope the next lot do better. Nice to see your progress on the ranch a lot of work ahead of you though. All the best Bob Foolin Around |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Phill Cant find any in the commercial market at the moment, I had a lot of 32 volt ones but they have gone to other homes over the years, all old stuff salvaged from the scrap when the farm power went through Victoria in the sixties. I have made a couple out of 48 volt fork lift motors belt coupled to a 5 KW 240 volt alternator, they work OK but speed regulation if a bit variable. All the best Bob Foolin Around |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Vic I was just calculating the costs with a ten year depreciation cycle of major components Inverters panels and associated components. the insurance cover was for storm damage only. Output figures was for fixed panels, with adjustment in one plane only, tracked and optimized the power output goes up 25% but the cost and extra maintenance left it slightly negative on the fixed panels allowing extra panels to make up the deficit.All work was on a self management basis with contract to do the the initial installation and ongoing electrical licence requirement work. No subsidy or government assistance was included in the costing, and no legal costs incurred in fighting for the right to do it where included. Local council is no problem and ground mounted panel racking didn't require planning approval if lower than 3 meters, and 30 meters from the property boundary. Panel output was checked against a new 250 watt panel fixed at 23 degrees for an average output of 200 watts for average six hours a day at 300 days a year. Panel cost at $1 per rated watt, this is variable on bulk buying, and was used as a worst case cost. All in all the return would have to be 12 cents KW to give a 10% return on investment over the ten years, if the reliability and durability of all components prove to be better than calculated and Murphy stays away the figures may upgrade a bit, but with my luck worst case is more realistic. Your area would have a higher input so that would help, but you have more cyclones up there, we have hail storms here so all part of Murphy's Law. The biggest stumbling block is dealing with the negative authorities and power retailers, we will see what the future brings with the senate hearing, but I fear it will be just more gobbledygook to placate the unwashed masses and direct the profits to existing Quango's and reseller companies. All the best Bob Foolin Around |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mack Those transverters you mentioned where 24 volt to 180 volt and 300 volt to work the radios and some used 400 cycle ac power, a very interesting bit of gear, I used a few of the 24 volt ones to power amplifiers out in the bush as they worked well on 32 volts, very stable and regulated with carbon pile regulators. All the best Bob Foolin Around |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
The LGC`s like the RECs are not government subsidies they are simply a trading unit the non-renewable generators have to purchase from the renewable lot so as they can keep burning coal etc. Depreciation is a wee problem with the solar cells having warranties to 20-25 years still putting out 90% of rating, a problem for the standard business model. That is something when taken into consideration ups the ROI substantially. Yeah we get them liquid sunshine rocks here, but cyclones are not known to be a problem here(Insurance Co class us in cyclone zone however) The old cyclone uses up a lot of HP getting over the great divide, eg Top wind gust from Yasi here was 60.1 km/hr. We`re 50 ks from top of great divide. Anyhow with the solar multiple being 7 rather then 5 in our area has made a solid contribution. Gotta agree dealing with officialdom is a drama. I think you will find your Councils like mine view proposals for solar farms a wee different then backyard solar. Unfortunately they want their piece of cake. As do of all things Health & Safety too, tis a quagmire for sure. We come from the land downunder. Vic |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Vic I didn't put any allowance for REC's or other concessions as they are to variable to be counted on in a long term model, the warranty on panels is a bit of an issue over 25 years, I have some 20 year old Australian made cells and they only give 30% of ratings, the Chinese ones only give 60 percent after 4 years some German ones my mate had are around 50% after ten years, with one set replaced under warranty after 2 years. They are a return to factory for warranty and me thinks that all the factories will not be there in 20 years and me too for that matter. Storm gusts are an issue here I have seen 160 Klm on occasion, it bent the mast on my mill and ripped the weather station pole off the shed roof, Hail isn't such a problem as I am just off the storm track where hail is the worst, but it happens occasionally, my shed roof looks like it is hammered and it has the skylights replaced with sheet because they got smashed out so when it comes it can do damage. One of the big problems with series mounting of the panels is the string can only conduct the amps of the weakest cell on my test set the panels are rated at 5.4 amps while the best full sun ideal position is doing just over 3 amps a 40 % loss. By parallel string the the loss is negated as all panels do the best they can, then into a inverter to bring the volts up to the GTI with a loss of 10% but more complication. I have shelved my idea as my health is not ideal for long term projects and if I kick the bucket the wife has no concept of the set up, so it would be useless in the longer term. There isn't enough fat in the plan to employ professional help for field maintenance and ongoing upgrading of the system. It would be nice if we could help solve the pollution crisis world wide but that is a pipe dream so it must work as a business at a reasonable rate of return to be a viable option. Now if I was 40 years younger it would be a different kettle of sardines, but alas such is not the case. All the best Bob Foolin Around |
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mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
There are some army/navy gen sets still available from way back. I have'nt read the entire post, so I may be talking bs and off topic here. Mac46 I'm just a farmer |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Bob, Your experiences with solar cells degrading over years are not in line with mine. I have solarex and BP solar panels all aged more then 20 years two would be near to 30 years all still pumping away every day. They supply my water and whilst I have not meter checked them if they have dropped 10% I`d have noticed it. Have the panels you speak of always been in use? But regarding solar panel manufactures being around for any length of time. The only one I know of is Sharp. I note Suntec, one of the leaders in Chinese Solar is facing bankruptcy. Interesting the founder of Suntec is a OZ(Chinese parents but born & educated in OZ), who was allowed to keep his OZ citizenship whilst living and building Suntec in China. We come from the land downunder. Vic |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
WA is still paying residents 40 cents/kWh; they wanted to reduce that and it caused such a storm that the politicians had to keep the subsidy. I do not know what happens if one applies now, it probably only applies to old systems. Reading German newspapers it looks like the "love" with RE and the huge subsidies there have led to a rethinking of the whole RE debate and as they are still committed to stopping all the nuclear power plants Germany will just build more gas/coal plants. There is also the acknowledgment that due to fracking the US is gaining an advantage over the European industry with its lower power prices. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| anteror Senior Member  Joined: 06/10/2009 Location: FinlandPosts: 189 |
I have Schot Solar Perform 250W solar panels 11 units in my roof. They really perform. When I started this I wanted to have sun-tracking system, but wind conditions here are very rough and 11 units in the roof, mission impossible.(picture) My only option was to mount them on the roof, because the elevation of the terrain. Now they are all at a steep angle, because snow falls from them very easily and late in the autumn and early in the spring, the best angle is deep.. Short time sunlight and sun is shining from very low angle. WE had winter solstice at 22.12-13 and now day is getting longer and sun is getting higher and higher day after day. Now we have temperature -26C that is -14,8 Fahrenheit. There is now snow in my roof (picture is not from this winter) which acts as little mirrors and I get a lot of scattered radiation and also from surrounding terrain which is covered with snow. The atmosphere is also particularly dry and clean, when there is so cold. The amount of light is at maximum and very bright. No wonder there is so called snow blindness among helicopter pilots and hikers in snowy terrain with full sunshine. I have got record high readings from my solar panels. Also panels give their max power readings(and more with with snow blindnes..) without any heat loss, when weather is so cold. Even when the sun is shining just a short time 4-5 hours a day now, I can get my batteries charged. In the summertime I get 85-90 Amps from my panels, now I get 105-135amps, with 24V system. I have got 10-25Kwh daily now, when there is so cold and high pressure, with full sunlight with just few hours. You are so lucky ones 
"Australia is one of the sunniest continents on earth, so producing power from the sun just makes sense." Here it is LITTLE.. different  , but but the more challenges,
the more tricks and solutions ! You have SUCH resource and a treasure trove of opportunities. that you do not undertand it all, now ! Fortunately, my wife and I have a few friends and connections to Australia and there YES ! I would like to live in and move.. Antero |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
My original RAPS system was/is trackable and I found I got about 20% more power by sun tracking. That was fine when panels were at best, poly silicon and expensive. Now mono high efficiency panels are relatively cheap so it is easier to fit an extra 20% of panels and have them fixed. No tracking mechanism to break or electronics to fail (lightning strikes etc.) I guess the snow would act like a reflector. When I first started, I used to prop up a sheet of shiny galvanized steel to reflect the morning light onto the panel before the normal sunshine got that far. It made quite a few amps difference but was just another "wind vane" to try and tie down. Now I have another roof mounted mono system connected as grid connect to my battery inverter "grid" Even on cloudy days my batteries still charge. And if we are lucky enough, the wind blows occasionally and our little OEM 500watt unit kicks in. What more could I want? David M. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Vic My old solarex panels are down to 4.5 amps from 12 amps they where in storage for 5 years the BP panel held up better with minimal loss untill it developed legs and wandered off. The Chinese panels are all over the place with their power out, some above and some below rating a QC issue, I have noted they drop off after 3 or 4 months and then stabilize, time will tell as to how they last out but will outlive me so I may never know. The solarex are still providing water and floating my 12 volt batteries and providing emergency lighting when I get stormed so still useful, but wouldn't be commercially viable. All the best Bob Foolin Around |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mac In Australia the scrap dealers have decimated most of the old and interesting power and gen sets,I have salvaged a few in my time but most have gone on to be a Toyota or Hyundai long ago. How did your VAWT go? I may have been away when you finished it. All the best Bob Foolin Around |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Domwild The high feed in price is one of the problems that has made it difficult for solar farms as it has overvalued the power returned to the grid, it would have been better to set a commercial sustainable rate, my guess is at 50% charge out rate. All the best Bob Foolin Around |
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