What's the Point of Hybrid Cars If These Are Still Running?

[TomBrend]

My theory on solar is that everyone who lives in a relatively sunny should have solar panels on their roof if they can afford it. It will not ever supply all of your power, but it'll supply some. In climates that will allow it, solar water heating is an excellent way to reduce bills.

I don't think solar is a good way to generate the entire world's power. I think to get away from coal/oil/gas power plants, we should switch to mostly nuclear, while continuing to build more wind generators, developing solar technology a bit more, and doing more geothermal, though I'm not sure how developed geothermal is.

[Telaril]

There's also always the question of how much it costs (energy and materials-wise) to produce and maintain solar panels. There's actually been a bit of talk about some of the most popular and efficient solar panel manufacturing materials being in short supply, and the need to develop different varieties of solar panels.

[TomBrend]

Yeah, which is one of the nice things about solar water heating- the equipment is damn cheap, and pretty efficient.

[Telaril]

My mom keeps looking into getting solar panels for our house. We're in a non-ideal climate (New England), but not the worst possible one.

Here's one of the other problems: Solar panels just keep getting better. To oversimplify, solar panels bought five years ago will almost certainly never pay for themselves - they'll become inoperable or need expensive repairs before they produce enough energy to pay off their cost. Ones made nowadays will just about break even in ten years, used in an ideal climate (like So-Cal or New Mexico) but probably won't quite break even in a less ideal place (even taking into account government write-offs you get for having them in a lot of blue states). In five years, who knows? We might be producing panels that can consistently earn return on investment practically anywhere, or it may take another ten years to get there.

I'm not saying that cost should be the sole motivator for getting solar panels, but it's somewhat reasonable from a financial standpoint to wait for five years and spend the cash on, say, weatherproofing and organic food for now.

[TomBrend]

I recently have been interested in home wind turbines. If your family has the money, pretty much all of New England has enough wind.

This is the only guy who does small installs in New England as far as I can tell: http://www.rhodeislandwindpower.com/

[jtaylor]

In the latest Business Week which I only picked up and glanced at for a few minutes there is an article on building eco-friendly ships and one of the interesting things was creating bubbles along the hull of the ship to reduce friction between the ship and the water.

[Metcarfre]

I used to work for a guy that had the low-tech version of using solar energy. Basically black garden hose on a rack on his roof, the hot water heated up like forty tons of sand, upon which he built a small unit that he rented to a student. The heat in the sand preheated water for his hot water tank, heated the spare house, and partially the main house. He said it cost him around $600 (without building the other house, which included putting in all the sand). Not bad. Wish I could do it, but you can't fiddle with apartments as much.

[Dutch guy]

...

Think about it for a minute. Try to recall any thermodynamics lessons you've had.

You absorb a portion of the sunlight. That energy gets used to create electricity, which is then used to power machines. Those machines produce two things: work and heat. The energy you absorbed is thus re-released as friction and thermal exhaust.

You just tie up the energy for a time. What significant adverse affect can come of not heating up an empty region of blasted desert wasteland quite as much as normal? The energy you divert will simply be released elsewhere, from light bulbs, from computers, from vehicles, from all sorts of machines.

It might screw with convection and air currents, I'll admit. But honestly, how much of the energy in weather systems comes from hot sand slowly radiating the heat it gained from absorbing light? Air is an excellent insulator, most of the heat absorbed by the sand radiates downward into the crust, not upward into the air.

~Alja~

Ehhhhhh. You are very VERY wrong on that last bit. ALL heat absorbed by the sand gets transfered into the air, then transported away by thermal/convection motions. I fly gliders (sailplanes, whatever you call em) as a hobby, and thus I often rely on thermals to get me higher up. Sand dunes and sandy areas are excellent thermal generators. Sand is an even better thermal insulator than air. Have you ever been to a beach in the baking sun? The top layer gets very very hot, but as soon as you dig down maybe 10 centimeters the ground is still cold. Air is only a good insulator when it isn't moving. Once convection (Aka moving air) comes into play it can transfer quite a lot of heat.

Taking away the massive low pressure belt over the sahara by removing the heat convection there would screw up earth's weather systems beyond belief. (I'm talking complete collapse of all established weather patterns)

[TomBrend]

Which is why INSTEAD we should harness the results of those weather patterns, stealing a fraction of a percent of the wind.

[Sable]

Hi!

I've actually built a few hybrid wind/solar/generator systems, so for the purposes of this new wall of text, let's pretend I have some idea of what I'm talking about.

Solar panels certainly do keep getting better, but they aren't advancing in a Moore's Law-esque way. Solar panels purchased five years ago will almost certainly pay for themselves, provided the homeowner lives in that house for quite a long time. A panel from the 1970s might be expected to produce around 80% of its rated wattage if you're lucky enough to get them surplus. The panels from that era won't produce as much power per square meter as modern panels (largely due to advances in semiconductor production and panel production in general) but compared to their rated capacity, they are still quite good.

Now, about the homeowner living in that house for quite a long time. Yes, it takes a long time to recover the costs of solar panels, because the initial outlay can be enormous.

Let us take, for example, a system similar to the ones I've actually built, with my own hands. You will need:

1.) An area that has a usable amount of sunlight! This is actually a quite wide range of places, my solar systems were in Alaska, on top of mountains, and periodically produced enough power to weld with.

2.) Solar panels! This is probably the easiest part on paper, but one of the most difficult in practice. Good solar panels can cost anywhere from 5-10 US dollars per watt of output (This includes mounting equipment, shipping, and any necessary labour). Not bad, until you realise the average house uses between 8-24 kWh per day. Rather a lot more if you live in a poorly-insulated house (like I do now), and are in an area where you need to use air conditioning or heating systems regularly.

3.) Batteries! You see, the systems I built over-generated during the day (by design) and stored this energy in large battery banks so that the installations could keep running overnight. This is a (relatively) cheap way to continue your off-the-grid existence into the hours of darkness. Really the batteries are just an energy-storage medium, if you prefer, you can store it as steam, vats of molten salts, or whatever else strikes your fancy. Using some back of an envelope calculations, you're going to want around 5-15kWh worth of batteries (depending on your house) so that you can have a buffer against to draw on poor generation days, and a little extra capacity on over-generation days. Remember, this is what you will be drawing on when none of your other generation systems are working, and before you start drawing on the grid. Also, you never completely discharge a battery bank unless you feel like replacing it, so your actual usable capacity will be somewhat less. This is the reason a Prius never discharges its battery pack below 60%.

4.) Electrical management equipment! What, you thought you just hooked your panels to an outlet and went to the races? Solar and wind systems need to be attached to equipment that can deal with the fluctuating output of these systems, so that (in this case) you don't fry your batteries or do something else expensive. For this example, we'll go with just battery chargers - these are not like automotive battery chargers or something, and can be quite expensive. Their basic operation is that they take the output of your solar panels, whatever it may be, and converts it to your battery pack charging voltage, so that there is a moderator between the raw unfiltered power from the panels. This is really important.

5.) Grid-tie equipment! This is another very important part. This equipment is responsible for managing your house's load against the battery charge level, and connect it to the grid if the batteries are getting flat. These are often combined with the battery charging equipment (or in communication with them, Outback Power products are great for this) to not only decide when to switch your house to the electrical grid, but when to sell over-generation back to the grid. For example, if you're having a really nice day and you aren't using much power, you might fill up your batteries but still have the sun out. In this case, the grid-tie equipment will start to sell energy back to the grid instead of letting it go to waste.

Another option for over-generation is to use a load-dump system to heat your house's hot water, assuming you are not using solar heating already.

6.) Contractors. Unless you are a contractor yourself, you should never ever ever try to do this stuff yourself. Rooftop solar in particular can damage your roof if improperly installed (leading to leaks at best and raccoons in your ceilings at worst) and grid-tie equipment can electrocute you. The charge controllers and batteries are very straightforward if you have even a basic understanding of how electricity works, but still should be treated with some care; the batteries I used in my installations were so large, and could produce such a powerful dead-short, that if you dropped a wrench across the 24v bus you'd have quite a fireworks display.

Does this mean that you shouldn't have solar systems? No, that's not what it means at all. What it does mean is that decentralised solar power generation (e.g. rooftop solar in neighborhoods) is fantastically expensive. Sure, it's a nice idea for "everyone to have solar if they can afford it," but the pool of people who can is very small indeed. The system above would cost roughly 40,000-50,000 dollars for an average home with 1500-2000w worth of solar panels on the roof (This is also assuming you have that much roof available) once all the costs are taken into account.

Considering the resources involved, and how our power systems are already heavily centralised, it is far, far more reasonable (to me) that our energy providers be the ones to lay out costs for solar or wind systems. They are not trivial, and can become incredibly significant on the scale we are talking about, but compared to the capital these entities have or could acquire (through bank loans, stock options, or the myriad ways a large corporation makes money) they are much closer to being within reach.

Now, home wind generation is something that is much closer to being reasonable. Wind turbine costs are generally around one dollar per watt of generation for the turbine, and masts are not terribly expensive. Provided you have some experience with these things (Or know someone who does), you can raise a wind turbine on a 30-meter guy-stabilised mast in an afternoon without using a crane. You still need charge controllers, batteries, and grid-tie equipment (the last of which will still require an electrical contractor), but the overall installation costs would likely be much lower.

Of course, this is not necessarily viable in many parts of the country, especially ones where you live in Suburbia, an apartment building, condo, etc. Homeowner's Associations (God I hate those) will almost never be happy with you putting up a hundred-meter steel pole in your backyard. For that matter, a number of them get their knickers in a twist over rooftop solar as well.

What does this mean? Again, wind power probably should be centralised on the existing electrical grid for the largest number of people to get the benefit of wind generation.

Will electric companies actually move away from coal and oil to things like wind, solar, geothermal and (possibly) nuclear? That all depends, and nobody can say for sure. There are new wind farms coming online all over this country (Eastern Oregon and Washington have built a lot of new wind turbines in the past couple of years, Hawaii is on track to be 20% on renewable by 2020, and Texas - yes Texas - is the largest producer of wind energy in the country), and it's a good step in the right direction.

Ultimately no single resource for "alternative power" - wind, solar, hydro, geothermal, whatever - is the answer to the problem. Decentralisation, unless it comes down in price to an hilarious degree, is almost certainly not going to be a big part of that answer.

Does that mean you shouldn't do rooftop solar if you can afford it, or do your own wind turbine if you're in an area where people won't get ticked off at you? Absolutely not. If you're affluent enough to put solar systems on your house, by all means, "do your part" and do it. If you're in a windy area with no neighbors to complain, put up a wind turbine. There are people I drive by every day here in Arizona that not only have solar panels, they have solar trackers that move the panels so that they always receive the maximum amount of light for that part of the day. One guy has solar trackers and his own 2000-watt wind turbine, and I think he's fuckin' rad.

Again, what this means is that distributed generation is difficult and enormously expensive, and outside the reach of most people. Not that it shouldn't be done, but that it should not be relied on as a big part of "the solution."


References:

Kyocera 205-watt panel (This is the new version of panels I've used)

Bergey XL.1 1300-watt wind turbine

Outback Power FLEXMax solar battery charger

Outback Power FX-series Battery charger/inverter/AC source switcher

An assortment of 2v high-capacity batteries suitable for storage on this scale

Twelve of these batteries would give you 8.6kWh of total capacity

Twelve of these would give you rather more than 14kWh of total capacity

[Dubious_wolf]

Hi!
-snip-
and Texas - yes Texas - is the largest producer of wind energy in the country), and it's a good step in the right direction.
-snip-

DAMN STRAIGHT SKIPPY!
See we aren't unreasonable down here we have massive wind farms here, after all we have to have something to replace the oil

[Metcarfre]

Man, if I knew a renewable energy thread would get Sable to come back, I'd have one up every week!

And it should be said that I am using solar power a bit in my apartment - to grow vegetables, bitches!

[Wraith]

My grand father a few months back asked me if I knew about the 15 most polluting ships in the world. I said no and I decided to get round to look them up. These 15 ships produce more pollution than all 750m cars. Why are people pushing us all to drive hybrids when these 15 ships wipe all that out in one go?

http://www.treehugger.com/files/2009/04 ... n-cars.php

I'm not following your logic. You're saying "why reduce the impact of one problem when there are much bigger problems out there?" That's like asking why they want to stop muggers when there are murderers out there.

[TomBrend]

Sable, thanks for the insight into solar. I think a lot of us (me included) didn't understand just how much labor / expense can be involved in a solar install.

One thing I've seen recently is the roofline wind generators, which use a vertical-axis turbine (such as the Windspire http://windspireenergy.com or the Enviro Energies http://www.enviro-energies.com/products.htm ), and thus don't need to be mounted on towers. Most of them don't generate enough power to run a whole house, but they're certainly a step in the right direction.

[Sable]

I would type more here but I'm tired:

- The Windspire turbines are very good, my company back in Alaska had one under test. Their primary limitation for us is that while they have a very low wind start-up speed, they also have a very low wind destruction speed. In other words, while they (and all vertical axis wind turbines) produce usable power at lower speeds than horizontal axis wind turbines (HAWT), they fly apart into bits at speeds that HAWTs just auto-furl at.

Note: One of our Bergey XL.1 HAWTs exploded last week. The rotor and generator assembly tore out of the nacelle and is currently missing. Bergey estimates this took a sustained wind of 160 miles an hour.

- The Windspire turbines are still about 10 meters tall on their own - you won't be seeing these in suburbia anytime soon. The Enviro Energies turbines are more likely to see suburban appeal, but at 10 foot wide and five foot tall they are still not inconspicuous. You would also need a very unobstructed wind (no trees, neighbors, etc.) to get anything like the rated capacity. "Producing power at 4MPH" does not mean "producing 2.5kW at 4MPH," you'd be lucky to run a digital watch.

Plus holy crap you could literally buy like four XL.1 turbines and masts for what the 2.5kW Enviro Energy product costs.

[empath]

...

Think about it for a minute. Try to recall any thermodynamics lessons you've had.

You absorb a portion of the sunlight. That energy gets used to create electricity, which is then used to power machines. Those machines produce two things: work and heat. The energy you absorbed is thus re-released as friction and thermal exhaust.

You just tie up the energy for a time. What significant adverse affect can come of not heating up an empty region of blasted desert wasteland quite as much as normal?

Yeah, but that's what I'm asking.

We DON'T know..yet.

The energy you divert will simply be released elsewhere, from light bulbs, from computers, from vehicles, from all sorts of machines.

It might screw with convection and air currents, I'll admit.

Yeah, in all honesty, that sort of effect would probably short-term (relatively speaking) and it'd adapt and correct itself into a new 'equilibrium'. Of course, what effect those changes will have on US...well, that's what I'm ASKING about.

But honestly, how much of the energy in weather systems comes from hot sand slowly radiating the heat it gained from absorbing light? Air is an excellent insulator, most of the heat absorbed by the sand radiates downward into the crust, not upward into the air.

Also very true, and I imagine the amount of energy absorbed into the crust is small compared to the energy transmitted OUT to the crust from the core, but still, small changes CAN have vast, UNEXPECTED consequences. And some people argue it is IMPOSSIBLE to predict the result on a complex system when you make supposedly trivial changes...

...in short, we DON'T have any anecdotal evidence of what happens, we don't have any sort of accepted speculation on what COULD happen if we do it (and it's possible we CAN'T speculate accurately), so we're never gonna know what'll happen UNTIL we try it.

...and I want to know.

I'm not saying it's a bad idea - I'm saying I (and indeed EVERYONE) not only doesn't know whether it's a bad idea but CANNOT know whether or not.

I'm not even saying "don't do it" because we don't know what the outcome will be, I'm just saying "if you're gonna do it, try to prepare for unrelated consequences".

[TomBrend]

Sable, where I'm from from 11AM-5AM you have 15-20 MPH winds, pretty much all the time. In winter it's all day, 10mph+. The last time I talked to the RI Wind guy he was spinning up (no pun intended) to do a Windspire install on someone's house.

Also a large boarding school in RI got a HAWT a couple years ago, and the town of Portsmouth, RI got one last year. I watched them building the base for one that is not yet operational in Middletown, RI. Hopefully people will learn that wind turbines are a good idea, and learn to appreciate their technical beauty rather than seeing them as eyesores.

[Sable]

Sable, where I'm from from 11AM-5AM you have 15-20 MPH winds, pretty much all the time. In winter it's all day, 10mph+. The last time I talked to the RI Wind guy he was spinning up (no pun intended) to do a Windspire install on someone's house.

Also a large boarding school in RI got a HAWT a couple years ago, and the town of Portsmouth, RI got one last year. I watched them building the base for one that is not yet operational in Middletown, RI. Hopefully people will learn that wind turbines are a good idea, and learn to appreciate their technical beauty rather than seeing them as eyesores.

If you live in a wind zone like that, then household wind is certainly very viable, I never meant to suggest it wasn't. Of course, large-scale commercial wind would be fantastic too...

The biggest thing I've got in my craw about the Enviro Energy turbines is their cost. That sucker is REALLY expensive per watt. I would contend it's actually quite a lot TOO expensive, considering that after the 12000-16000 cost for a 2.5kW turbine and inverter you STILL have to get it installed and possibly have your roof reinforced so it can withstand the forces the turbine will put on it.

[Dutch guy]

But honestly, how much of the energy in weather systems comes from hot sand slowly radiating the heat it gained from absorbing light? Air is an excellent insulator, most of the heat absorbed by the sand radiates downward into the crust, not upward into the air.

Also very true,

NO, WRONG, VERY VERY WRONG!!!


I'm sorry, I get irrked a little when it comes to thermodynamics things like this. Heat transfer from the topsoil to the crust is non existent. Thats why heat-pump installations work. Put a large coil of piping about 15 to 25 feet underground, hook it up to an aircon like cooling system and you've got a perfect source of cool in the summer (As the ground would be cooler than the surrounding air) and a source of heat in the winter (Because then the ground is warmer than the surrounding air). This wouldn't work if heat got transfered to the ground in any way.

All sunlight energy absorbed by the toplayer of the soil get transfered to the air by convection and simple radiation.