Best Solar Power Solution?

Heat water... see my diy job...dirt cheap and it works.

Del

You have efficiency and cost directly linked. The higher efficiencies are more expensive. Higets is NASA stuff as just under 30%. Some labs have 36-37% prototypes and there is hope for multi.layer types eaching 45% or so in 5 years.

The silicon is the cost factor on that type. There is a shortage of the very pure stuff needed for 18-20% or so. That is the cells. The panel consumes area and cute efficiency. Most commercial affordable ones are 14% or so, if kept clean and aimed automatically.

Lens concentrator types allow for higher % efficiency silicon cells to be used, but they need 1-2 degree pointing accuracy for the insolant hours. The concentrators run the cells at a 6 or more to one focussed concentrations and can give 20% or more. They use fall off NASA cells from lines that can make the 27% ones NASA wants if run perfect at all times. Still quite good.

Then there are the cheap amorphous cells. 5%-6% efficiency but very cheap. Ovonics makes them.

http://www.ovonic.com/ there are others. You can google all the above

Hi Not, How's your wind? Check out a wind map of your state at http://www.eere.energy.gov/windandhydro/windpoweringamerica/wind_maps.asp. This gives a very general idea of the wind conditions in your area but you can get a more detailed profile off a local weather station via http://www.met.utah.edu/mesowest/. A wind turbine may be a much cheaper option for you. WindGenMan

http://freepages.genealogy.rootsweb.ancestry.com/~chtank/homepower.html

I used to work for Bill Kemp. He built his own house, off grid, and I've been in it. almost everything you ever wanted to know.. in a concise and practical book.

http://books.google.ca/books?id=lZ_gKlO9BS0C&dq=bill+kemp+energy+handbook&pg=PP1&ots=2--f-raiBY&sig=UQoKKhwjkamhQ3kzYhdN_g8pUl0&hl=en&prev=http://www.google.ca/search?hl=en&q=bill+kemp+energy+handbook&sa=X&oi=print&ct=title&cad=one-book-with-thumbnail

The problem with books like this, the information is already outdated by the time it gets to press. This book was published in 2005 and giving a year to write it and two years to gather the information for the book, it is likely that schema is over five years old. I suggest that one needs to stay in touch with the Department of Energy (DOE-USA) and the Environmental Protection Agency (EPA-USA). Also, one needs to keep up with all the developments within the world's academic community. Things are moving very, very fast these days, yesterdays news is old news.

Generally, I agree with you, and people investigating this material should do their homework.. however, as far as this book goes, it is still valid, very timely and very well thought out, and practical. It is based upon his experience building his own off-grid house, and upon the decades of experience as an electrical designer and manufacturer.

His house still works, his wind turbine works, the solar cells work, the inverter works, the battery bank works, his low power appliances work,... and the guidance contained in this particular book is all still very valid, regardless of technological innovation. wisdom and pragmatic thinking are timeless. His energy systems produce an excess of power, which he could sell back to the power companies, if they wanted to build a line... It cost less to put this system together in the first place than to build a power line to his house. and it has continued to work and save energy costs and annoyances with power outages for 5 years. that is a testament to the design philosophy and quality of construction, not a criticism of it. This house and the book are still far above any typical new housing start in terms of its energy consumption.

However, I am sure that Bill has kept up with the latest information, as he is a designer and manufacturer of power systems, and would answer questions to serious builders. He is also a consultant to the industry and government.

Everything you need to know about solar can be found through this website.

http://www.solarbuzz.com/index.asp

Overall, the two first things to consider are how much do you pay for utilities and how long do you expect to live where you are--my own experience leeds me to a conclusion that it is best to go all-electric, then self generate either through solar or/and wind. Things to consider are space [do you have room in yard or on roof for solar modules], neighbors [who usually moan when they see a wind tower going up]. As fas as concerns the So. CA market, the rate has been between $9 to $10 per watt generated, turnkey installed, before applicable rebates--last I heard statewide residential rebate was $2.50/watt and has probably dropped. Generally you need to be paying about 0.25/kWh average for a solar PV system to payoff in a resonable [10 years or less] amount of time. As to space, keep in mind that it requires about 100 sf of module to generate 1kW--the best way to calculate what size system you need to REPLACE your billed electricity, take twelve contiguous months of billing, work out what your average daily use is in kWh, [example: 25000 kWh/year = 68.5 kWh/day]--figure that you will average six hours/day of useful sunlight [this is a year-round average]--divide 68.5 by six hours/day = 11.416 kW--11.5 kW is the size of the system you would need to REPLACE your billed usage [again, this is based on the kWh usage, not billing $--this is also based on a grid-tied system and "net zero" billing scheme, where your meter spins backwards as you pump electricity into the grid and runs forward when you draw power. As an ideal circumstance, you first have your building performace tested to find and fix leaks, inadequate insulation, under-performing equipment, etc. Then you replace any gas-fired appliances with electric [range/oven, tankless hot water, clothes dryer, etc.] Both Solar and Wind have the drawback that their sources do not "supply" 24/7 [wind doesn't always blow, it gets dark at night] -- as for doing it yourself, unless you are very handy I would not recommend it, but pallparks figures for modules at retail level are $3.80 to $4.00/watt output [150 watt rated module = $570 to $600 generally] Inverters range $3000 to $7500 depending on output [sometimes it's better to go with one large output, other times two smaller ones.] Using the example above 11500 watts = $103000 before rebates

more info check www.aerosunelectric.com

"What is the best solar power solution for a homeowner wanting to lower utility expenses."

Since your aim is to lower expenses, not to be self sufficent, the photovoltaics is the way to go. You can reduce your daytime utility buy by the amount of electric ity they provide, you will not need to buy storage (goal was reduce, not completely replace) and if you can get paid for feeding grid, with any surplus, so much the better.

Frankly, running photovoltaics to a plugin rechargeable electric vehicle would be the best payback.

My work is estimating cost of this for parking for employee vehicles as a true "green" solution. When the plug in Electrics are available, a few of us plan on making the switch...

milo

Photovolaic powered heat pump that provided hot water and a cold fridge is an interesting idea (sharpens pencils) ;-)

Mark Addinall. Cairns, Australia.

Good answer. Excellent link. Thanks for the tip!

This is very much ON TOPIC because heating with photovoltaic solar is not reasonable.

To use a phrase so overworked it's become cliche' -- "It ain't easy being green!" -- Yes, it would be a great use for solar PV to charge a plug-in EV or Hybrid -- again, the greatest problem, from my perspective, is that utilities generally do not have to pay for your excess generation, which is why I lean toward a system that replace ALL the billed electricity and spins that meter backwards as far ans as fast as practical [Practical is the watchwword]. However, if one is simply looking for the most cost effective application, it would have to be replacing the hot-water system. Domestic hot water is probably the largest year-round energy expense, so a solar heat-exchanger of some type would probably be the best compromise between expense and return-on-investment

Interesting. Need to sleep now though.

The factors have been spelled out clearly; you have to look at your greatest expenses, then consider your regulatory environment.

Heating water is usually high on the list, heating your environment second depending on your locale (mine swap since I live at altitude and propane my only delivered option), then you need to determine your utility environment.

My house was built in the '70s and there is no insulation in the roof and it has aluminum frame windows. I live at 7,000 ft and even summer can be cool. The basic construction is adobe, yet it is not designed for passive solar and there are a lot of us, so I purchased 4,000 sq ft of house.

My power is electric at .15 cents per watthour and my heat is trucked propane at 2.65 per US gallon. So far.

I am running the calculations of needed therms to heat this rockpile through the winter since total costs last winter were: 2400 gallons of propane, 3 cords of wood, roughly 1500 watthours per month. Given a 4 to 6 month heating cycle my budget was devastated and many renovation projects reprioritized.

My regulatory environment is quite friendly though. I can generate onsite and when the meter spins back to under zero the utility gets to either buy from me monthly at .10 cents per, or annually cut me a check, or roll my generated credits until I sell the house. (Largely depends on the capability of the utility as we have a patchwork of providers) The state and federal government are also offering multiple overlapping incentives for effiency upgrades.

Given that heated space and water are my biggest expenses and my state will subsidize the purchase of a multi-use (heating and storage) water heater, and the house is already ducted, I will probably run water lines through the ducts to radiators and keep jacking solar panels onto the roof until the gas heater never comes on at all.

This takes into account that the house needs $10,000 of window upgrades, and I am investigating both how to insulate my adobe walls as well as insulate my flat roof.

Just my estimation of the best way to offset my expenses, cooking and lights just don't cost me that much.

This site will let you check your incentives, if you are in the US.

http://www.dsireusa.org/

There are so many sites depending on which way you decide to go that I couldn't list even the best, but the web is a dandy resource (the advice on this site being one of the best).

I should have looked at your location before I started typing, but that and your highest expenses are good places to look for your best savings. Also do not disregard used or defective equipment, one of my local supply houses does a booming business in less than optimal solar arrays aaasolar.com.

But keep feeding the group specifics and I am sure they will help you arrive at the best approach.

And also I would point out that renewables are as much a patriotic and political statement as environmental. Heard on the radio that oil may actually go to $200US per barrel before the end of summer resulting in gas prices as high as $7.00 per gallon and Mexican production is decreasing daily.

Way too chatty this morning - sorry

Emmett

I think you are looking at the issue correctly. Have it make ECONOMIC sense, then environmental.

For my money, insulate your place, more than the experts say it 'needs'. If you use AC in the summer, plant trees or make an artifical 'tree' to shade your house in the summer against the sun, especially afternoon. Go ahead and convert to flourescent or LEDs. Reduce your 'paracitic' uses of electricity. Check out ALL the ways you use electricity and reduce/eliminate what you can. Now you can get a baseline on what you need to generate (and this is MUCH cheaper than building power generation!)

I did have and use a passive solar 'pre-heat' system years ago and it did well in Houston TX. Partly paid for by the Jimmy Carter era solar energy investment tax credits (not deductions). It was basically a couple of black painted/anodized stainless steel tanks, in double walled boxes with glazing on top directed to the south and west (best for our location). They were plumbed directly (yes, we had cutoff and bypass valves put in) to the house potable water, through the tanks serially, then to the input of the hot water heater. From there the hot water went as before. This kept the ease of installation reasonable. This is a good installation for the folks below the Mason/Dixon line, others might use different techniques.

This also meant that the regular hot water heater works only if the pre-heat can't keep up, or it has sat there to long. If you are building, putting the solar pre-heat before a tankless water heater might be a good thing too.

If you could get a couple of tanks they make hot water heaters with, paint them with high temp flat black paint, and put them in some well insulated and glazed boxes, you could do the same thing much cheaper than we had it done back 'in the day'. Active solar water heat schemes are OK, but complexity and cost go up quickly. Batch heating works, but I like the continuous.

To heat your garage, do some solar space heating. A guy builds and sells them at http://www.iedu.com/DeSoto/solar.html ... He is working on other things too, but his solar heating panels look pretty good. (Not a customer or user, just an admirer)

Unless you really need to be off grid, net metering is good. Reduces your equipment needs (no batteries or battery maintenance) and you should be able to add new capacity as time goes on. But your grid tie inverter (special inverter to put power safely onto the grid and not cause possible harm to others or you in case the grid fails (which does happen from time to time)) needs to be sized and capable. Check this out with your vendor before purchase.

Here in TVA territory they do not do net metering, but they have a similar program. Currently it pays back abut 15 cents/kwh and they charge about 10.x per kwh. Their current implementation is a dual metering program. If you are commercial and of the right size they will pay 20cents/kwh according to what I read.

Now to supply the grid tie inverter, pick your poison on power supplying techniques: PV, windmills, methane from your septic tank driving a generator, solar powered sterling engines, mini-hydroelectric, etc. Personally I like the idea of a MIX of powering techniques. PV is probably the easiest, but review your $/KWH installed on whatever method(s) you choose.

Also, can you take it with you if you move? Could you re-capture investment cost in case you must leave it if you move? (probably from current trends) How stable is the power company in allowing/helping you do this? Will you need to get someone else to maintain it or will you? (Do a business plan on this project, include capital and operating costs and income, future cost of money projections, the whole bit. ... If you don't know how, talk to a real accountant or to talk to folks at the SBA or in a local business school. Paying a little consulting money could make a difference in the future.) Check to see if there are some local funding assistance (grants, no/low interest loans, one time 'incentives', etc. ... buy equipment on 'sale' or possibly some 'seconds').

I hope this helps.

http://www.epa.gov/chp/

Having read all of the comments, and many of the suggestions were excellent, I do have another idea to toss in. It all comes down to the economics of producing the heat and electricity. I think that solar generated electric power is great for the daytime, but at night it is not there and that is when you need it most for lights to see with. A battery bank can be expensive.

It would take a fairly large reflector to concentrate the sun's heat on a spiral tube of water and turn it into steam and the reflector would have to follow the sun, but it is possible that you could run a small steam engine to power a generator that way. At sunset the steam/generator would be powered by a fueled boiler using any fuel of choice. A couple of batteries would be needed to turn the reflector back to the east. The used steam could heat the water for the house and heat the house before going back through the condenser. Even the heat from the boiler fire could be used in the same way, thus increasing the efficiency.

The main problem is that the equipment doesn't come ready-made, except for the steam engines and boilers. It would take some engineering and machine shop work to build one. The advantages are reliable power and long operating life with little maintenance. Oh, and steam power is safe, clean and efficient, despite the propaganda of the internal combustion engine makers and the ignorance of most people about steam power.

One approach to 'round the clock power!

Sun tracking parabolics are available, returning approx 650F at a 1.5 to 2 gpm flow. Now run an oil instead of water and store it.

Run water through a heat exchanger and you have steam. I had been contemplating... then you run the steam through a low-temperature heat-engine such as a Stirling...

But you are correct, very little off-the-shelf, and no available turn-key systems.

Emmett

The tracking parabolics are interesting, I haven't seen them available commercially apart from large scale - can you provide details?

Thanks!

One can make their own. The bright, shinny packaging from around many processed dry food packaging is an outstanding sunlight reflector and a wooden frame parabolic shaped support is not too difficult for even a highschool student to build. Also, I do believe a small electric motor can be used to drive a sun following mechanism. Of course, this might require a little work to build your own, but why pay extra for something one can do by him or her self? One can prepare his own meal or one can pay to have someone else do it.

I was thinking of designing a DIY 'Fresnel parabolic' reflector that could be made at home without to much problem.

Would anyone be interested in the design, once/if I do it?

http://www.redrok.com/ sells solar tracker electronics for all kinds of setups. You need to be some of a DIYer to use them.

His stuff will work on one and two axis systems. To make heliostat tracking work it is a bit more complicated (mechanics). It looks like quite a few folks use these inexpensive tracking electronics (in kits or pre-built) for solar panels, parabolic dish tracking, etc.

It also has some safety features built in. There is a lot to read on that web site.

(just an avid reader, not a customer, principal, or user of their stuff... yet!)

I made a low tech solar tracking parabolic dish on equatorial mount. I made it to focus on one spot all the time. I did not make the dish as well as i could have but it did work. There are several problems most of which are caused by the seasons. You need to make a part of a parabolic dish. Not the full dish. You can then mount it like a satalite dish and it rotates round the focal point to adjust for the seasons. But each time you adjust you have to reballance the thing! So you need an easy reset on your ballast. And the focus MUST be on the equatorial axis on which it spins. I think a solar tracking accumulator like what I made is possible commercially (easy commercially actually) but it is too much as a backyard project. I really think you should go heliostat instead because it can stay ballanced and the focal area can readily be moved. I am going to try make 2 or 3 all on equatorial mount and all rotated by one timer. They will all be focused on one solar cooker (hopefully with a little concentrating between the heliostat and the cooker. I am going to try it as low tech as I can go. Brian

I haven't done business with them, but these seemed to offer lots of bang-for-the-buck at a reasonable price...

http://www.i-heat.com/