Are Hybrid Solar/Grid Houses Practical?

Controlio asks: "With the continuing power crisis and the announcement of major power rate hikes, I figure now is an excellent time to pose this question. Instead of pay these inflated prices for power, I'd like to sink my money into a long-term solution. Cutting myself off from the power grid isn't practical, as I use too much power periodically to be 'solar-only'. But how practical is adding solar for either power redundancy (in case of a blackout) or as supplemental power? Redundancy would be nice, but being supplemental would involve using solar power as my primary power when it's available (and I hear tell that you CAN have negative electric bills if you produce more than you use). Do the costs/advantages for either provide enough incentive to be worth investing in? How would one go about creating a hybrid house? And finally, of course, which is cheaper? Investing in expensive solar paneling, or paying the outrageous charges the power company wants?"

Comments

Re:Sort of...

[Anonymous Coward]

> Drilling for Alaskan oil won't create one watt of power for California since California doesn't have any commerical power plants that use Petrol as a power source.

I suppose that the drillers ignore the natural gas that is pumped out of the well that also pumps oil.

Conservation is not the solution. The population is growing faster than any savings from conservation.

They do ignore the natural gas

[Anonymous Coward]

I worked on an oil platform off the coast of South Africa when I was going through the "what shall I do with my life" phase. The natural gas was piped to a long arm sticking out the side of the platform, and burned as waste. The noise from that thing was amazing. We had to wear ear protection, even indoors, all the time. When you stood outside on that side of the platform, you could become dizzy and sick after a while from the sound exposure. I don't know much about your Alaska oil problems, 'cept for what I read in your Doonesbury political cartoon, but I do recognize a bullshit argument when see one. You claim that people can't restrain themselves because there are so many of them. One person can show restraint as easily as a million people. I thought the original oil crisis in America lowered your speed limit on highways as a conservation method. I know your oil consumption went down during Reagan's terms, and went up again after the speed limit was raised. I think you Americans need to buy some smaller cars, too. That'd be a good first step. The second step is to think, and not take every word your leaders say as gospel truths. Blind faith leaves you in the dark.

Solar Panels or Solar Furnace?

[morbid]

Solar panels are still relatively inefficient. IIRC they only convert about 5-10% of the light hitting them to electricity.
Another way to reduce power bills would be to use solar power to "preheat" water by a few degrees and then heating it up conventionally to the required temperature.
If it's electricity you're after, a "solar furnace" might be better. You get a nice parabolic mirror and pass cold water across the focus. The focused light heats up the water and makes steam which can be used to drive a turbine, driving a generator. You can also use the heat directly to melt metals. (Sunlight is at a temperature of 6500K)

Re:Solar Panels or Solar Furnace?

[shandrew]

Solar panels are still relatively inefficient. IIRC they only convert about 5-10% of the light hitting them to electricity.

That conversion rate is actually quite impressive. The sun sends lots of energy our way (peak about 1.1 kW/m^2), and converting 10% of that into electricity is quite impressive.

The real efficiency problem is one of cost--look at the $/W numbers of solar photovoltaic panels and solar/battery (batteries are extremely expensive) systems, and see how they compare to conventional sources or wind. The places where photovoltaics are efficient are remote places where electricity is unavailable. They're much cheaper than stringing new electric lines to the middle of nowhere.

A solar-powered turbine can be cheaper, but requires much more maintenance and is not something that scales down to individual household use cheaply.

If you're after reliable power, get a generator and UPS. If you want to help the environment, stick to cheaper energy sources (wind, water?) and donate the money you would have spent on solar on organizations which fund research on environmental issues and alternative power.

Re:Solar shingles

[maken]

Heres a company that makes solar roofing systems
http://www.ovonic.com/unitedsolar/roof.html
so you can subtract the cost of reroofing your
house from the total cost of solar. That and here
in california the state will pay 50% to install a solar system!

Sunslates (with link)

[raygundan]

The company that makes these is Atlantis Energy, and you can check it out here:

HTTP://WWW.ATLANTISENERGY.COM/ATL/default.asp

The actual cost of all energy sources

[raygundan]

Is much higher than you would think. Solar is often singled out by skeptics like this because the panels DO require a large amount of energy to make. However, more common energy sources suffer from similar problems. It takes a good deal of energy to search, drill, ship, refine, ship again, and distribute gasoline, for example. Do you think driving all of those trucks around the country loaded down with tons and tons of oil, running refineries, searching out new drilling locations, setting up drilling equipment, and cutting through the rock is energy efficient?

According to this article, the actual cost of gasoline once the tax breaks the oil companies are given are added back in is around $15.14 per gallon. Ouch.

Nearly every source of energy suffers loss in production like this. If you're going to apply that standard to solar, apply it to other sources as well.

Re:The actual cost of all energy sources

[Rogerborg]

• Nearly every source of energy suffers loss in production like this. If you're going to apply that standard to solar, apply it to other sources as well

Fossil mining powers itself and produces a surplus. PV doesn't - if you built a PV production plant powered by PV arrays, it couldn't even sustain itself, let alone produce arrays for me and thee to use. I can see a clear distinction there.

Unfortunately, that's bad news. Fossil is strictly limited, and all sustainable sources suck badly in the cost/production department, and also need a lot of space. I just hope we get enough nuke plants built before the oil dries up.

Keep the location in mind

[ChrisWong]

You are citing Japanese material. The cost structure and energy costs there are rather different from wherever the original poster is residing. Without real data, it is not possible to extrapolate to other locations.

Re:Keep the location in mind

[Anguirel]

The original question didn't include a location, but I was trying to show that the costs are down and efficiency is going up comparatively. Also wanted to encourage more source citing.

I know Japan has high energy costs, but most regions also have frequent cloud-cover. If you live in Sunny Southern Cal, there's a good chance that solar panels would be in almost constant use. I didn't say my data was flawless, but at least I made mention of where my numbers came from. If you live in Seattle or the Bay Area it probably doesn't make sense to use Solar Panels. But hopefully the questioner already realizes this...

~Anguirel (lit. Living Star-Iron)
"Veni; Vidi; Vi C++"

AC/DC

[ChrisWong]

Just a simple issue: photovoltaics generate DC. Grid electricity provide AC and most appliances use AC. Seems like there is a certain cost involved in converting DC to AC. What are the costs and efficiencies involved?

Small Lesson in Market Economics/Energy

[scotpurl]

It's a waste byproduct if you can't sell it. Or get it to market.

That's the short version. The longer version is that natural gas in North America comes primarily from Canada, and from the United states. Very little of it is ever shipped by boat from one country to another. Natural gas is expensive to ship, it requires cryogenic/high pressure storage, special ships, and on and on (but they're trying to increase safety and lower expense all the time). The cost of shipping natural gas is quite low by pipeline, and higher for petroleum and oil because you must heat the oil so that it's thin enough to be pumpable. The lowest grade crude oil is thicker than peanut butter.

If all of the Alaska Wildlife Refuge were tapped and drilled, it would produce a maximum of something like 600,000 barrels of oil per day, starting in about 8-10 years. The current global oil production is around 75,000,000 barrels per day, with the U.S. sucking about 15-20,000,000 of that down. For a good reference to read on this topic, see here. Overall, because the U.S. hasn't modernized at the same pace as Europe, we consume roughly 25% more energy to perform the same tasks (both at home and in industry). If we had modernized over the past years at the same rate Europe did, we would currently have a 10-20% energy surplus, compared to what we consume right now. And we wouldn't have to build a single power line, power plant, or drill a single well to get it. Energy companies would have to invest no new money in risky exploration and development. They would earn more, and their stockholders would achieve higher returns. There is no long term downside to conservation. In the short term, energy sales goes down. Lower sales drives process efficiences, and the companies learn to make more money on less effort.

Back to natural gas. Because of the specialized equipment required in shipping natural gas, and the expense of moving it long distances, almost no one will buy it who's not living on that continent. That means that NG in Saudi Arabia doesn't get sold to the U.S. If there is no market, it is not transported. If it is not transported or sold, then there is no reason to store it locally, as that is another expense. Thus it is burned onsite as a waste product.

It's a fact of doing any task. What you consider waste product might not be considered waste if someone else had a use for it. Very few people these days have use for the bones and hides of the animals they consume (or even see the bones and hides).

The short truth is that it will take years, even at a frantic war-time pace, to develop the oil that's under the Alaska's wildlife refuges. There's the surveying, getting equipment there, infrastructure, finding laborers, moving the prodcut -- it all takes time.

Conservation, on the other hand, can have an effect right now. Rolling blackouts are a form of forced conservation. Much less drastic measures are tax breaks/incentives, and new taxes on consumption to affect behaviour. While that sounds evil, it's already done quite a bit. Taxes on cigarettes, alcohol, gasoline, furs and diamonds, expensive cars, SUV's (low miles-per-gallon tax), airport gate taxes.... The list goes on. If President Bush had made an impassioned plea to the people of California to conserve, and to set their air conditioning three degrees warmer, and so on, there would have been an overnight change. America conserved all it could during World War II, because it needed to. It needs to again, and the enemy is ourselves.

Re:Small Lesson in Market Economics/Energy

[shandrew]

The short truth is that it will take years, even at a frantic war-time pace, to develop the oil that's under the Alaska's wildlife refuges. There's the surveying, getting equipment there, infrastructure, finding laborers, moving the prodcut -- it all takes time.

Furthermore, there are no plans for the new drilling in Alaska to supply natural gas--the cost of a pipeline for it would be prohibitively expensive for the amount it might supply. California does not use oil to make electricity; it's primarily a natural gas state. Therefore, new oil drilling in Alaska does nothing to help with California's electricity woes--oil is much more valuable to be refined and sold as oil than converted to electricity.

Re:Small Lesson in Market Economics/Energy

[f_ckthisaddy]

First let me say I don't know, so this is mostly a question, but I was under the impression california(or anywhere) could buy electricity off of the grid from other states(Ca could buy from TN) so if the drilling in Alaska produced more electricity anywhere, couldn't CA buy some of it? I know that isn't the same as CA producing it, but same net(although more expensive). BTW, I'm not supporting the Alaska drilling, just an observation. Also I blame CA for their problems, they didn't want nuclear power plants so, they don't have power...They have several nuclear plants that aren't operational(state gov't/ca voters) shut them down...so its their own fault. I also remember reading an article years ago in Popular machanics(or science) about "growing" an island and I kind of remember them saying they were going to channel ocean currents through an enclosed area and that would produce electricity(hydo principles)...is that an option for costal areas where lakes are going dry(OR)? An offshore hydro-electric plant? Just braingstorming....

Sort of...

[scotpurl]

If it's a new house, meaning you haven't broken ground yet and you're still talking to the architect, then you can make the energy savings work. If it's an existing house, then there's quickly diminishing returns.

The Canadians experimented years ago with super-insulated houses located up on Hudson Bay. When I say superinsulated, I mean four-foot thick insulated walls with foot-thick panels that closed over windows at night. It wound up being that the body heat from the occupants almost heated the house. If you cooked, even in the dead of winter, you had to open a window. Some of the solar heating panels were disconnected because it actually overheated the house. If you insulated a Florida or Arizona house that much, you could keep it nice and cold inside. (Insulation doesn't just keep heat in.)

If it's solar power you want, well, that kinda works. You can live off it, but it takes a lifestyle change, and some rewiring. No distributed.net cracking for you, and you'll need to get rid of all those appliances (microwave, stove, VCR) that use power when they're not on (those little clocks and indicator lights add up). The Chicago Tribune ran an article a few months ago about apartment dwellers, in urban Chicago, who had gone solar. It can be done, it costs money, and a lifestyle change is mandatory. No blow-drying your hair, no clothes dryer, no electric oven.

Wind works pretty well, depending upon where you live, and depending upon zoning laws (neighbors may not want one looming over everything). There's some concern that wind power kills birds, but since they tend to place those flailing blades in prime bird habitat (open grassy fields), then it may not be a causal relationship. All the old windmills and wind-powered water pumps don't kill birds, so someone needs to get a big grant and do more research. It might be habitat/proximity, and it might be blade design. Maybe noisier blades would help.

What alternative energy for an existing home does do is cut down peak use, and perhaps spin your meter backwards sometimes. There's tax breaks for alternative energy sources, but basically be prepared to write the whole expense of installation off, and consider it paying off Mom Nature's bills. Figure $10-20k to get anything significant going. You'll need a big bank of batteries to store that peak power to consume during off times (like nighttime), or just spin the meter backwards and sell it to the local utility.

If you're lucky enough to have a running stream nearby, there are companies that sell mini-hydro devices. It's not a small dam, but just a small turbine that a head of water spins.

Try http://www.homepower.com as a great starting point.

Contrary to Bush's pathetic energy plan, the real solution is (in order), Lifestyle change, convervation, and consumption limiters (insulation, efficiency changes [better appliances]). Drilling for Alaskan oil won't create one watt of power for California since California doesn't have any commerical power plants that use Petrol as a power source. They may augment power generation with these things, but it's not really what you build a power plant from.

Re:Sort of...

[babbage]

Conservation is not the solution

<sarcasm> Right. If it's not a 100% solution, it's not a solution at all, is it? Better to do nothing than to do too little. Republican logic is so much more creative than regular human logic... </sarcasm>

Seriously, if you have a population of $num people, and each person is consuming $quan amount of energy, then the total consumption is of course going to be $num * $quan. If each individual can reduce their consumption, even marginally, then the net result -- $num * ($quan - $conserv) -- can be pretty significant on the aggregate. Certainly cheaper than producing lots more power plants.

I'm willing to accept that we may need more plants, but it would be a lot less expensive for everybosdy if, say, everyone stopped driving those stupid Suburban Ussault Vehicles. The reality is that any solution is going to be a big, expensive project for the country to undertake, and anything that helps control the size & burden of that project would be much welcomed.

Re:Sort of...

[kachuik]

The result of that test was the R2000 program that tries to eliminate air leaks. It works so well that there has to be a forced air exchanger to keep people from passing out.

The cost of solar drops if you eliminate the storage batteries and use the electricity to reduce the size of the utility bill. If this $ savings is less than the interest you could get by leaving the money in the bank, leave it in the bank. Generally, it is less. Since the cost of solar keep slowly dropping, and utility costs keep going up, waiting may make good sence.

Here is someone who's done it

[Raetsel]

There is data on the size of the house (2900 sq. ft.) and the costs involved. The difference here (assuming you refer to a pre-existing structure), is that this house was conceived as solar home from the design stages. It was built knowing they were doing this from the start. It makes a major difference in the design and placement of a structure.

This place has been featured on the History Channel and HGTV. Okay, it's in Maine. Maine is a long way from California. In this case, heating via solar is a goal (but not exclusively), just perhaps more so than in a California home application.

• www.solarhouse.com is the site.

Yes, in some cases, he gets a check from the power company instead of a bill. It's do-able. He's also installed an inverter and battery system for power in the event of grid blackout.

I'd wonder, carefully considering de-regulation, if you can choose which power company to sell your surplus to...? It might be something to consider, as I have seen advertising for power generators in California with different goals (environmentally friendly & socially conscious vs. low cost & raping the land, etc...)

He speaks directly to California residents in several places, and has a point that I envy.

• Notice to Californians: You have a 50% state subsidized rebate program for solar PV installations.

  (No such luck in my home state, dammit.)

(Final "grain-of-salt" note -- I don't agree with some of the cost numbers he quotes for non-solar houses. $400 worth of heating oil used in just 28 days??? They must have been heating all of southern Maine! Perhaps they had a 500 gallon tank topped off, but I can easily make that much heating oil last for 6 months... and that includes hot water, too. Yes, my place is smaller, but I have horribly leaky windows, and not-that-great insulation... I still don't use that much oil.)

Re:Here is someone who's done it

[Mr. Slippery]

I don't agree with some of the cost numbers he quotes for non-solar houses. $400 worth of heating oil used in just 28 days???

Doesn't seem unreasonable to me...I can go through $200 worth of oil a month during the coldest months in Baltimore. (50 year old, three bedroom house, maybe 1800 square feet, moderate insulation (and that's upgraded...it was piss poor when I moved in, but some new windows and some foam blown into the walls have helped a lot.))

I could imagine that between regional price differences and a colder climate, a larger house in Maine could pay twice that much.

Tom Swiss | the infamous tms | http://www.infamous.net/

I would like to do this

[macdaddy]

I'd like to do this to the house my parents are wanting to build soon. It will be a clean start out in the country. Ok, when I say country I really mean country--not that you live in the subarbs with a gas station up the road a mile and 10 trees on your property. I mean hedge trees, cattle, deer, creek, lake, ponds, dirt roads, shotguns and coon huntin'. That's real country. They will have 2 or 3 large out buildings. Heating those could be accomplished with with solar water heating panels on the roof and piping laid in the concrete floor. That would work well. A friend of the family did it with a large wood stove heating pipes that get run to a storage tank (a small oil tank, 200-400 gal) incased in concrete block walls with sand packed in around it. The fluid was pumped through piping in the floors that heated the building. The fluid used is old motor oil. It heats easily and retains that heat well too. Fire up the stove once a week or so, heat the oil in the tank, and heat your building for a week. That would work well for heating a building or heating water for hot water usage. What I'm more interested in is electrical usage. I don't want it to be their primary source or power or really even a secondary or backup source. Supplemental power is what I'm after. There will be a large number of landscaping items that will consume power. Acent and border lighting, pump-driven water fall/creek, etc... If we could use the power for that, it would be a big step. They already make small independent acent lighting units that are solar powered. They charge up during the day and kick on at night. I would rather use cheaper low voltage units and power/control them as a group instead.

One of my questions is about solar panel maintenance. Here in Kansas we get hail storms. They happen every year. Sometimes it misses an area or two and sometimes it totals vehicles and crops. Will that kill solar panels. Is there a way to protect them? Maybe a hard screen or wire screen 3-4 inches above the panels would work. Another question is about winter. Will hard freezes affect the panels at all? Would motor oil be better used in a case like that or water with anti-freeze (since it will be thinner than cold oil). What about battery life and maintenance? Will that be a big hassle? I'd love to find a good resource that can set some of these concerns to rest. It would be a really viable source energy-savings I think. A windmill isn't out of the question either. Any thought or past experience anyone care share is greatly appreciated.

--

Re:I would like to do this

[arete]

The Oil/Hazmat issue is definitely a big one.
Water holds heat much more densely (more J/degree)than most anything else, including oil. When you put a sufficient quantity of antifreeze in it this effect is diminished, but still present. Water and Water/Glycol therefore make excellent heating/cooling fluids.

If you want a really massive amount of heat-transfer, the phase-change to steam is the common way to go.

The first action is proper sealing of buildings to be extremely non-leaky. Then some people recommend a small purposeful leak on the top level. Canadians usually recommend making sure you have underpressure in your house, or else your respiration moisture will rot your insulation - no joke! The second action is increased insulation.

I definitely, absolutely, and without a doubt think that a good geothermal heat-pump system goes much farther towards your goals than any particular generation. This essentially involves some welldigging. I suppose that's the third action.

The fourth is water preheating - essentially a thinnish flat tank of water out in the sun - like on your roof. This tank reduces (pretty dramatically) the amount of power you have to put into your water to make it warm. As a bonus, it absorbs heat during the day and keeps a lot of it around at night (as long as it doesn't freeze and burst) Along this vein are other natural ways to trap heat - I once saw an indoor pool coupled with many double-pane skylights.

Only after all of these is power generation seriously likely to make a big difference, unless you're particularly lucky about wind or water where you are. Both are wonderful in some places.

Re:I would like to do this

[Spamalamadingdong]

A few comments on your concept:

1. Stay away from used motor oil in your system. Stay away from oil, period. If you have a leak or a line rupture, you could have a hazmat/groundwater pollution problem that's worth more to clean up than your house and land combined. Stick with water and ethylene or propylene glycol; they are easy to handle, easy to pump and biodegradable.
2. Before you think about solar heating systems, think about insulation. Every watt of heat you can keep from leaking out of the house is a watt that does not have to be generated or captured.
3. Many solar panels are laminated onto plate glass. I don't know how much hail these are able to stand. This panel is rated for one-inch hail, but I wouldn't expect it to handle two-inch. The only way to protect a panel against hail is probably to put it on a tracking stand and turn it vertical (edge-on to the hail) when your conditions were bad. Making a hail-detector that can trigger the stowing process soon enough is probably a problem with no off-the-shelf solution. If you are talking about a solar-thermal panel for heating water, it's likely to have its cover glass busted in a hailstorm. You might be able to deal with this using a plastic top layer, but I have no idea who makes such things. Try doing a little research.
4. Solar (photovoltaic) panels love the cold. The cell voltage improves as the temperature goes down.
5. If you have strong winds in the winter, definitely think about a wind generator. You can probably heat your house with the power generated during winter gales; a 10 KW machine is good for better than 30,000 BTU/hr if you dump the output to heating elements, and several times that much if it runs a heat pump.

Surf over to Home Power and check out their advertisers.
--
Having 50 karma is an itchy feeling; I know I'll get

Re:I would like to do this

[LeeMcK]

Here in Half Moon Bay California, the weekly paper profiled local houses with solar electricity. Roughly speaking, the installed cost was $9 per watt. Or 21,000 to 30,000 dollars for a pretty large installation. No mention of batteries, but some of the users provide some net power to the grid. My house has a 1985 vintage solar water heater on the roof... and it has reached the age where it has 2 small leaks and the roof underneath is nearly worn out. This goes to the hail problem (no freezing or hail here) ... solar power systems have to be carefully worked out to last long enough to pay for themselves. The roof or supporting material has to be equally long lasting. I'd say the time is arriving when we need to build houses with 100 year roofs. Then put 100 year solar power systems on the 100 year roof.

Thanks

[macdaddy]

Hey thanks for the input. It's greatly appreciated. I'm going to have to do a lot of research and trial & error to make this a really viable and efficient solution for them. I may do some of it myself when I get a house (instead of an over priced apartment).

The reason that guy used motor oil was because of its thermal capabilities. It holds heat really well and he had plenty of it to spare. Freezing isn't a worry either, although you can't let it get too cold or your circulation pump will hate you. :) Water and anti-freeze would work too but I would think that your pipes would eventually gum up.

I think a wire screen could protect a solar panel. Let's say 3/4" by 3/4" screen primed and painted black, stretched over the surface of the panel about 4" away from the glass and supported with a square tubing framework. I think that would protect it from most hail. Baseball or softball sized hail might still break through. Any hail smaller than that probably won't hurt the panel. It's an interesting thought. I think it's doable. I'm going to have to dig around for details on how to convert and store the electricty those cells pump out. I should have finished that dual computer/electrical engineering major. That would have helped. :)

The winds depend on the season and the year. I remember one winter way back in HS when we had a bit of a dust bowl. The ground was super dry. We had just had about 16" of snow and everything but the snow was a dry as dirt. The snow/dirt off of the fields started blowing. Visibility was null. It sucked. In late May, towards the last day of school with 90 degree weather there was still snow in the deepest ditches. The dirt insulated the snow so well that it didn't melt. If you cut a core out of it with a knife, you'd find dirty snow under the top layer of dirt. How much wind do we have to have a productive windmill?

Thanks again for the reply.

--

Real Goods is an excellent source of knowledge

[mmarcos]

Check out http://www.realgoods.com/. They have a strong collection of books on alternative energy and construction materials. They are also a good source to purchase solar, hydro and other forms of alternative energy source equipment from.

They also host educational sessions but I have no firsthand experience with them.

Re:The short answer is...

[Mr. Slippery]

Unfortunately, photovoltaics take more energy to produce than they will produce in their lifetime.

No, they don't. They pay back the energy required for manufacture in about two years.

PV's don't last forever, either, they break when things drop on them, they corrode, they get dirty.

Modern PV panels are rated for about a twenty year useful lifespan.

If your home is extremely isolated, then PVs start making more sense, because it can be very expensive to run power out to the middle of nowhere.

Doesn't even have to be in the middle of nowhere...the break-even point between running copper and a modest PV setup is, IIRC, on the order of 100 feet.

Tom Swiss | the infamous tms | http://www.infamous.net/

Re:Small observation

[Mr. Slippery]

You might also consider a tankless water heater. Gas ones have been around for a long time and are, I understand, common in Europe; electric ones have recently come on the market.

There's a larger upfront cost, but they last a very long time and are quite efficient. (These guys claim a 50% energy savings.)

With a tankless heater, you can only draw n gallons per minute, but for as long as you desire; whereas a tank heater lets you draw pretty much unlimted hot water per minute - until you run out. I'm seriously considering junking my tank heater for a tankless one just so I never have to wait for hot water after someone else takes a shower.

Tom Swiss | the infamous tms | http://www.infamous.net/

Re:The Independant Home

[RenaissanceBug]

There's a great book on doing all of this stuff called _The Independant Home_. Unfortunately, it seems to be out of print, as I can't find it at any of the major book outlets online.

Well, I did an Amazon search on "independent home" (with "ent", not "ant") and did turn up a couple of books that looked correct. Try the search that way--is the book you're talking about in there?

Re:The short answer is...

[Anguirel]

To stick in a few 'facts,' with appropriate citations...

Energy Payback Time on PV cells is well within the lifetime of the cell. Amorphous Silicon Cells payback in about a year, Normal high-temperature crstal melted cells take 4 years. The high-yield single crystal cells might not be able to pay themselves back, I'm not entirely sure. I'm not exactly a PV engineer or anything...

The current high-yield, ultra-expensive cells get 23% conversion, other cheaper ones get between 12% and 18%

And the citation...

http://www.atip.or.jp/ATIP/public/atip.reports.97/ atip97.030r.html

Section 3 in there has most of the info I paraphrased here.


~Anguirel (lit. Living Star-Iron)
"Veni; Vidi; Vi C++"

Re:The short answer is...

[GooseKirk]

if the power grid is available, PVs will never beat the grid.

Yeah, that's right, because as we all know R&D nevers pays off and technology never gets any better, so PVs will never beat good old-fashioned grid power, so just forget about it, OK? Just go back to sleep, America, everything's fine... those fruity renewable power enthusiasts won't make any progress here if we have anything to say about it...

The short answer is...

[Matt_Bennett]

No. Unfortunately, photovoltaics take more energy to produce than they will produce in their lifetime. Melting down all that silicon takes a lot of Joules, and they're relatively inefficient- a very, very good PV is about 20%, typically near 10%. I remember an estimate of about 1200W/sq-m for sunlight, so you could get maybe 120W/sq-m- In a sunny area, I think you get the equivalen of about 6 hours of sunlight/day- which is about .7 KW/hr per day, per sq. meter of PV. PV's don't last forever, either, they break when things drop on them, they corrode, they get dirty.

From an economic standpoint, if the power grid is available, PVs will never beat the grid. If your home is extremely isolated, then PVs start making more sense, because it can be very expensive to run power out to the middle of nowhere.

Re:The short answer is...

[Matt_Bennett]

The info I was originally citing was a bit dated, but the payback time varies greatly- this study: http://www.siemenssolar.com/Paybackstudy.pdf has a wide range, but this look: http://www.archrecord.com/CONTEDUC/ARTICLES/01_01_ 1.asp has estimates ranging up to 40 years for payback on an installation in New York.

But even in Hawaii, which traditionally has some of the highest electricy rates in the US, this report http://www.hawaii.gov/dbedt/ert/pv_hi.html states advantages and disadvantages- notably:

1. Photovoltaic-produced electricity is presently more expensive than power supplied by utilities.

...

4. Batteries need periodic maintenance and replacement.

5. Some of the materials used in the manufacturing of PV panels are toxic.


Most of the references I found when googling the topic were positive when they were trying to sell you PVs, and neutral otherwise- look at the sources of the articles- Siemens has a great interest in you buying their PVs. Really, it gets into the classic case of shifting the pollution to a lower-rent district- not really providing a global solution.

With PVs, not every place is the same- KWh/year of sunlight at installation location, PV conversion efficiency, energy costs, area available all have an effect on the final cost. No payback time estimate is valid unless this data is included. I'll maintain my original proposition- PVs don't make sense if you're trying to save money on energy for the average home.

Re:The short answer is...

[chrysrobyn]

What I've read disagrees with what you state. What I've read is that solar panels (given realistic sunny weather in the SW US) pay for themselves in 1-2 years, and inside of 7 years produce as much power as takes to make them. So, if you have them for 10 years, you're netting a benefit for the environment and saving your pocketbook. These numbers assume no battery backup-- just reverse metering for peak and forward metering for night time. If you use batteries, the payback time goes up to 5 years or so, by which time you may need to re-buy batteries. Sorry I have no link handy, but I wanted to get my disagreement in quickly.

Re:The short answer is...

[Fian]

I've read a few comments now that use the argument that storing the electricity generated in batteries is inefficient, high maintenance and environmentally unfriendly. In rebuttal - how does the collection, transport and use of hydrocarbon fuels stack up (most internal combustion engines are reasonably high maintenance)? Would you say nuclear is envirofriendly? Don't just dismiss a solution because it has disadvantages, weigh up the pros and cons and compare to other solutions. Now for some constructive discussion...how about storing the electricity generated in some other form? Compressed air, heating liquids, spinning up flywheels (BIG flywheels), electrolysis of water (ie splitting it into hydrogen and oxygen), pumping water up a gradient (ie into a storage pond for later use to drive a hydroelectric station) are all possible alternatives. I'd be interested in reading other peoples thoughts on the viability of these alternatives.

Re:Small observation

[nublord]

Thanks for the link. I've been planning on checking out the water heater's setting but always seem to forget when I get home. A timer would be even better. Even though my wife is home during the day she doesn't use hot water very often. Maybe once a day for dishes, once a week for laundry, and almost never for showers (the water's so warm to start off with).

Small observation

[nublord]

I don't have much expertise in this area, just a simple observation.

By parents have two solar panels on their house (Phoenix). These panels power their water heater for them. The water heater is not on a schedule - the water is always being heated. Their house is about 2,000 square feet. The entire house has vaulted ceilings.

My house has no solar panels and is about 1,500 square feet. I have only two rooms that are vaulted (living room and master bedroom). I'm also in Phoenix.

Our electricity bills are the exact same.

What they save in heating the water with solar power allows them to cool 500+ more square feet. I estimate that the water heater represents about 1/4 to a 1/3 of my electricity bill.

Re:Small observation

[stilwebm]

Ahh yes, that is the other thing I should have mentioned. Turning the thermostat down to 125 or lower (mine goes down to 100 I think) helps a lot, especially if you do need to leave it on all day.

Re:Small observation

[stilwebm]

While water heaters represent a good portion of your electric bill, if it is 1/4 then it is too high. If your home is unoccupied for a large portion of the day, or you don't need hot water all night, then you might consider turning it of for those periods of time. Timer are also available to help you with this. If your water heater was built before 1990 (maybe it was a little later) you can put a blanket or other insulation over it to help. Also exposed hot water pipes (interior and exterior) can be insulated for about $0.69 per meter, which will help some (may also help with your AC since you're in Phoenix).

There is a really good web page at http://hit.lbl.gov/ with more information about reducing your utility bills.

Re:Cringley has the answer - Batteries

[FSK]

(Like a lot of what Cringley says) This is one of those ideas that only works on paper. Consider the following:

1. The electricity would have to be converted from AC to DC (to be stored in the battery) then converted from DC to AC (since that?s what your appliances use).

2. Batteries (in the quantity needed) aren't cheap.

3. Batteries are amazingly bad for the environment.

Here's what I think.

[TheLink]

It's not necessarily a case of not modernizing.

It's a case of making energy and materials plentiful at low cost.

The more cheap energy you can get to convert to high value stuff, the better your economy is.

Spread the cheap energy around and boom, tons of things come alive that you'll never see anywhere else - lots of silly little toys etc.

It's just like comparing the tropical rainforest, a temperate forest, and the Antartic and Artic. I'm sure polar bears and other Artic creatures are a lot more efficient than some random creature in the tropics. But you sure don't have that many creatures in the Arctic, and it's harsh.

Plentiful energy makes a big difference, even if a lot of it is "wasted" on creatures/businesses which in lower energy situations will just die out quickly.

It's probably why the US economy was and is doing better than the EU.

Someone, somewhere at the top in the US seems to know that, which can explain the US actions regarding the Middle East, global warming and so on.

economy != economical.

Cheerio,
Link.

Good info

[Thu Anon Coward]

I have been planning my house for the last few years and I can tell you that you have not EVEN scratched the surface yet. You can build houses out of straw bale, hebel block, SIF's (structural insulated forms), etc. (http://www.ci.austin.tx.us/greenbuilder yes, I live in Austin,TX :)
For heating and cooling, I didn't see anybody mention geothermal. EXTREMELY efficient! There are all kinds of sources. (www.demarcoenergy.com,www.waterfurnace.com)
The big problem with solar power is that the batteries are so d*mned expensive. They take up about 1/2 the cost of the system. Wind power is great but there are a few more options.
I could go on and on but lack the time. Definitely check out all the options available to you and take your time.

The latest

[Shipwright]

It will cost $10K to $20K to get solar electric providing most or all or your household electricity. RealGoods.com is the best source of practical info. Lately the advancements seem to be in making "plug-and-play" on-the-grid equipment, i.e. you don't have to have an EE degree to set it up or pay a top dollar electrician to figure it out. Most states have net-metering laws which require your electric company to reduce your bill to at-most $0 (at least in Virginia) based on how much electricity you produce. There are links under doe.gov that detail your state's laws.

The low-cost intro to saving money with solar is through hot-water heating or pre-heating. Search the web or try the library - I have found books from the '40's with solar hot-water heating plans!

Also if you are building a house now there are a few simple rules that will drastically effect you heating/cooling bills such as facing the windowed side of your house south instead of towards the $%^&&^&* street.

Good luck.

Cringley has the answer - Batteries

[eean]

Robert Cringley wrote a column the described how to solve the energy crisis. Basically, eveyone would have a battery that would store energy during the night and release energy during the peak times. I don't know if this would provide any benefit now - I believe that energy costs the same no matter what time it is sold.

Check it out:

http://www.pbs.org/cringely/pulpit/pulpit20010510. html

Re:Cringley has the answer - Batteries

[ryochiji]

I know they do something similar in Japan. Some office buildings have huge refrigerated water tanks on top of them, and the water is cooled during the night when electricity is cheaper, and then used for air conditioning during the day. It's economical, but probably not ecological. In fact, it sounds aweful inefficient to me (isn't there a rule in thermal dynamics about how energy is lost every time it's transferred from one medium to another?).

Solar thermal electric and dish/Stirling engines

[Uninvited Guest]

Stirling engines are remarkably efficient at generating electricity. Whisper Tech has developed a system that can generate sufficient power for a home. The US-targed units run on natural gas, but they are not manufactured in sufficient quantities to be cost effective (US$12,500). We have to start somewhere, eh?
Some studies have been done using a parabolic dish or trough to drive a Stirling engine. I have investigated buying an old satellite television dish with tracking motors to track the sun. All I would have to do is paint or cover the dish with some highly reflective substance. That part is fairly cheap. I can't find the Stirling generators used in the article above. None of the Stirling engine producers seem to be selling engines to the open market.
If anyone knows where to buy a commercial solar thermal-electric Stirling system, I would like to see that posted here.

tankless heater

[kriemar]

I saw a home improvement show with Bob Vila (or however you spell his name) where they demonstrated a tankless water heater. Beautiful! I'm a student; my wife and I live in an apartment right now. As soon as we get a house (if we get a house?) I want to put one of those in! No comparison. Tankless heaters are more efficient, take up much less space (the one I saw was just resting on the wall; about the size of a small/medium sized fuse box), and, best of all, as you point out, no running out of hot water!

starting place

[onepoint]

To see some cost go to this page of solarelectric http://www.solarelectric.com/products/level3_162.h tm

otherwise I would advise, that you spend some hours reading about solar power and some of the things you need to take into consideration.

As most of the above posters advised. Insulate your home. That will reduce your load, one that is done then look towards solar power as the alternitive means to power your home.

ONEPOINT

The Independant Home

[wizzy403]

There's a great book on doing all of this stuff called _The Independant Home_. Unfortunately, it seems to be out of print, as I can't find it at any of the major book outlets online. However, Amazon (I know, I hate their politics too, but they have a useful search engine) has a bunch of books on building renewable energy into your house. I don't know how good any of them are, but it's a place to start.

I took a class in renewable energy back in college, which is where I picked up the book I was talking about. At the time ('96) it was still hard to get a lot of "modern conveniences" like TVs bigger than 8", or non-portable stereos that are 12V friendly. And forget about appliances like dishwashers, washing machines, and clothes dryers. Now if you make your battery storage array big enough, and also include wind power for the cloudy days, then with the right inverters you should be able to run a lot of your stuff "off-grid". However as you point out, unless you are willing to make substantial lifestyle changes and invest a buttload of money up front, you are never going to reach self-suffience.

What it really comes down to is how much money and work do you want to invest in this? If you have enough land, and you do a combo system (PhotoVoltaic and Wind let's say) then you can probably generate enough power to not have to worry about rolling blackouts, at least as long as you're smart about it and don't run your oven, 6 microwaves, and clothes dryer while you are off-grid.

If you throw a hotmail.com at the end of my handle, you can drop me an email and I'll buzz you back with the publication info on that book. I have it at home in a bookcase with all my college stuff.

Solar shingles

[Kiff]

I read somewhere (home improvement mag?) about a family that had installed shingles that contain PV cells... this enabled them to supply their power needs for the daytime and then get power from the grid at night (also, no unsightly solar panels to deal with). Some months, their bills were next to nothing or negative. I think the initial expense was a little steep, though...

That's not how it works.

[Spamalamadingdong]

To correct this some units in power stations are run as motors instead of generators, it consumes power but ensures that the power that goes out will run electrical equipment reliably.

Someone misinformed you. Loads which draw reactive power (inductive loads, lagging power factor) are balanced with three things:

1. Generators which create reactive power (over-excited synchronous generators),
2. Loads which create reactive power (over-excited synchronous motors), and
3. Capacitors.

A company might have a synchronous motor running without a load in order to balance their VAR consumption and keep their electric bill down, but they are not going to operate a generator as a load (consuming real power) just to balance VARs.

As for solar hot water systems - surely California is warm enough for them to operate?

That's what makes the complaints of poor San Diegans so funny; they live in one of the sunniest parts of the nation, and some of them have the gall to whine that they can't afford to take hot showers! Geez, you can go to a camping store and buy a black 5-gallon bag that you fill with water and stick in the sun, and have a hot shower for the cost/effort of the water.

Gray Davis is an idiot. If he had a brain in his head, he would have pushed to make solar water heaters mandatory on all rental housing and new construction. Instead he keeps pointing fingers at the utilities. I hope the voters of California are smart enough to boot his mangy bum out of politics (I'm smart enough not to live in California).
--
Having 50 karma is an itchy feeling; I know I'll get

Re:That's not how it works.

[Spamalamadingdong]

Suggestion: Learn how to use the

and

tags.

No, I've seen it done with a 120MW unit, three years ago.

Yes? Without looking at the actual phasor for the unit, how would you know what it was doing? Steam turbines have to be kept rotating even when they are not in use, or the shafts acquire a "set" due to gravity; how do you know that the unit was only being powered to keep it ready for operation, as "spinning reserve"? Here's what you said in #41:

To correct this some units in power stations are run as motors instead of generators, it consumes power but ensures that the power that goes out will run electrical equipment reliably.

That statement sounds good to the ignorant, but to anyone who's studied electrical power engineering it is just a nonsensical string of buzzwords.

I'm talking about the power stations, where they don't have to worry about electricity consumption, just fuel, maintainance and capital costs, and consuming a small amount of extra fuel to fix the power factor is how it is done sometimes.

If the utility is doing that, the utility is run by morons. First, generating VARs at the generating stations increases the current carried by the lines and transformers. This consumes their capacity without actually carrying power, so you max out at less than their actual capability. Second, generating VARs at the generating station increases the resistive losses in those same lines and transformers; less of your real power gets to the customer, driving your costs up and forcing you to start your peaking plants sooner than you otherwise would have. It is much cheaper to generate VARs close to the point of consumption, because a VAR requires only a tiny amount of power to generate (the losses in the capacitor plates and dielectric). This lets you devote the entire capacity of your lines and transformers to carrying watts, and keep them from overheating and breaking down (like Aukland did not long ago).

You're talking about enormous capacitors there.

A 1000 uF capacitor across a 120 V RMS 60 Hz line takes a current of 120/(1/2fC) = 750 mA, or about 90 VARs; that's not a very big capacitor, and it's sufficient to offset the inductive load from your typical refrigerator motor. A properly designed network has lots of capacitors sprinkled all over it, to generate VARs wherever they are needed. If you look up a power pole sometime you may see a gray box with two wires going to it. That's a capacitor; you've probably been seeing them all your life and had no idea what they were.

As for extra power generation capacity, the stop-gap measure put in place here (Queensland, Australia) was a few jet engines running on Avgas!

I don't know what your Aussie terminology is, but in the USA "avgas" is aviation gasoline and is completely unsuitable for turbine fuel; it contains tetraethyl lead as an octane enhancer, and the lead products foul turbine blades just as badly as they do spark plugs (you may have a few tens of hours before a mandatory overhaul). The lubricity is all wrong for the typical turbine fuel pump, too. If those machines were running on aviation fuel of any kind, it was all but certainly jet fuel (JP-4), which is essentially kerosene. Diesel fuel and heating oil would be likely substitutes, on the basis of cost and suitability.
--
Having 50 karma is an itchy feeling; I know I'll get

You're welcome

[Spamalamadingdong]

The reason that guy used motor oil was because of its thermal capabilities. It holds heat really well...

That's why you don't want it; you want something that will take heat easily, store a lot of it and give it up on demand, not hold onto it. The specific heat of water is a lot higher than oil (per gram, per unit volume it's even better as water is denser than oil). Your pipes will be just fine if you fill the system with distilled or deionized water; it's a closed system so you only need to do that once, barring leaks. It's mighty hard to get mineral deposits when you use water without minerals.

I think a wire screen could protect a solar panel. Let's say 3/4" by 3/4" screen primed and painted black...

Which would block a fair amount of the incoming light, making your per-watt cost even higher. After a point it makes sense to pay insurance and just replace anything that gets damaged by hail.

I'm going to have to dig around for details on how to convert and store the electricty those cells pump out.

www.homepower.com. You'll find people selling off-grid systems and grid-intertied systems, something for everybody.

How much wind do we have to have a productive windmill?

I think that requires a site study (of your particular site; two spots a quarter-mile apart can be like night and day and a tower can make all the difference in the world). You can find people selling recording anemometers if you look around.
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Having 50 karma is an itchy feeling; I know I'll get

Grid Interactive Inverter System

[grumio]

One of the power distribution businesses here in Melbourne Australia - http://www.citipower.com.au/environment/rooftop.ht m has a scheme running where you can get a heavily subsidised 2-2.5kW solar setup on your roof feeding a grid interactive inverter. These systems feed power into the grid if you are generating more than you use, and will literally spin your meter backwards at these times. At the moment they will pay you the same rate for the power you generate as the power they sell you, but this is only really for simplicity for the pilot scheme, and ultimately will use a more sophisticated meter that would use different rates in each direction. No battery backup, so if the grid goes you only have what you can generate at the time, but this does remove most maintenance problems. Not really economical without significant subsidies

Need this kind of information

[Bourbonium]

I've just purchased a house in California, and since we have to replace the roof anyway, I've been investigating the benefits and drawbacks of adding solar panels during the re-roofing process. Since the energy situation isn't about to get better any time soon, I felt it would be a prudent investment, and would add greatly to the value of the property. I opted to change my power provider the minute it was allowed two years ago during the early stages of the "deregulation" (cough) process, and switched to Green Mountain for their solar/wind combination package. That worked great until Green Mountain pulled out of the California market after PG&E stopped paying them for the power they were sending to the Golden State. I'd still like to stay with renewable energy mechanisms, and am intrigued by the generous rebates offered for those of us who go this way, but I'm not sure I trust the utility (PG&E) or the State (now near broke) to fulfill their end of the bargain. I'll keep studying the options, and keep pricing solar panels and intertie systems for another few weeks. Thanks for posting this discussion!