Slashdot Log In
Solar Power Becoming More Affordable
Posted by
Zonk
on Fri Nov 10, 2006 11:41 AM
from the juice-from-spaaaaace dept.
from the juice-from-spaaaaace dept.
prostoalex writes "With both startups and large companies such as Boeing working on solar power, the technology is becoming more affordable, MIT Technology Review says. Solar power concentrators are all in rage now: 'The thinking behind concentrated solar power is simple. Because energy from the sun, although abundant, is diffuse, generating one gigawatt of power (the size of a typical utility-scale plant) using traditional photovoltaics requires a four-square-mile area of silicon, says Jerry Olson, a research scientist at the National Renewable Energy Laboratory, in Golden, CO. A concentrator system, he says, would replace most of the silicon with plastic or glass lenses or metal reflectors, requiring only as much semiconductor material as it would take to cover an area the size of a typical backyard. And because decreasing the amount of semiconductor needed makes it affordable to use much more efficient types of solar cells, the total footprint of the plant, including the reflectors or lenses, would be only two to two-and-a-half square miles.'"
This discussion has been archived.
No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Full
Abbreviated
Hidden
Loading... please wait.
The Forever Headline (Score:5, Insightful)
This headline can be recycled and reused into perpetuity. Chances are with continuing advancements it will always become more affordable than it was last week, month, year, decade, or century.
But when will it become truly affordable for the masses? That's what most of us want to know. Wake me when it's time to disconnect from the petroleum/nuclear fired grid.
Re:The Forever Headline (Score:5, Informative)
It's already happening in California. This deal is huge. It's between 300 and 900 Megawatts. [signonsandiego.com] And what's even more remarkable is that there is no federal or state funding for this project - not even a subsidy or tax break!
The solar electricity is simply profitable. Watch this closely.
Another interesting run is the Solar Tower project in Australia [enviromission.com.au]. I'm really excited by this one! Once built, the operating costs drop to near ZERO.
What few people realize is how much the price of electricity varies. So go get your utility bill. Call the nearest solar energy installation guys. You may find that it's profitable RIGHT NOW to put solar cells on your roof!
Parent
Re:The Forever Headline (Score:4, Interesting)
Not without tax breaks, it's not, at least for older tech. The Stirling generators that are intended for the SDG&E project (and which are also planned for a 500MW facility near Victorville) may change that, but we'll have to see how they handle the weather conditions here (as opposed to New Mexico) over the long term. And while the deal may be huge in terms of solar, it's really not that large when put in perspective with other plants, where 500MW-600MW plant construction is not terribly uncommon.
The solar tower is interesting, but it's been years since they announced it, and they don't even have all of the permits yet. I question the efficiency of land use as well -- 9400 acres for 200MW, compared to 4500 acres for 500MW for the Victor Valley project I mentioned above and between 2500 and 1600 acres for 1000MW for the setup in TFA. They claim a construction cost of less than US$200M, but I would not be at all surprised if they miss their mark significantly.
Parent
Re:The Forever Headline (Score:4, Insightful)
That's cool.
So, maybe now that we have a Democratic congress, we can shift those gargantuan tax breaks the oil and gas industries got over to the solar industry?
Don't we spend about that much per day in Iraq? I think we can spare a bit to remove our reason for being there.
Parent
Re: (Score:3, Informative)
There
Re:The Forever Headline (Score:5, Informative)
Just a nitpick, really. I'm also quite excited about that project.
=Smidge=
Parent
Re:The Forever Headline (Score:5, Informative)
The R&D was federally financed. I've done some work on it myself.
One of the advantages of this technology is that it is not solar. It's thermal. An external "combustion" engine is used to drive the generating turbine, thus any source of heat may be used.
One of the problems with solar power is that it is unreliable; innately. Some sort of storage/backuup system must be available to go online at all times. By using a heat engine to turn a generator instead of direct conversion to electricity, when the sun goes down you can just throw some buffalo chips (or whatever) in the firebox. There's no need for a completely redundant infrastructure.
KFG
Parent
Re: (Score:3, Funny)
Solar power is reliable as hell. What's not reliable is our atmosphere!
Dyson spheres, anyone?
Re:The Forever Headline (Score:5, Funny)
Dude, the whole impetus for developing an electric power infrastructure in the first place was the desire for lighting when it's dark out.
KFG
Parent
Re: (Score:3, Insightful)
Yeah but now that we have clocks and almanacs and things, we know exactly WHEN it will be dark out. The sun rises every day. That's pretty reliable. Not the sun's fault this hulk of a planet gets in the way for half the day.
Obvious to me... (Score:5, Interesting)
Solar panels are the way to put power generation into the hands of the people. When I look out at all the rooftops in the area - houses, office buildings, Super S-Marts and their enormous un-covered parking lots, all I can think of is if every one of those surfaces had a single solar panel our energy demands from centralized (corporate
Have we learned nothing from decentralized computing?
Durability (Score:4, Interesting)
Also, there's the fact that solar power is not a viable solution everywhere in the world. Sure, in Arizona, California, etc, it is a wonderful "free energy" thing.
In Pacific Northwest, the northern Midwest, etc, especially during the winter months, solar power is a complete non-option.
Parent
Re:This is why Solar isn't taking off! (Score:4, Interesting)
Then again, they could just reorganize and move into the manufacturing and maintenance side of things. Someone will have to fix and maintain the solar homepower systems ultimately. The one major advantage of having a power distribution grid, though, is the ability to redistribute power. If Sunville, AZ is having a month of sun with no clouds, and it has been cloudy for a month in Bad Ass, MS, the energy can be redistributed so that all of the Badassian's batteries don't run down.
-b.
Parent
Re:This is why Solar isn't taking off! (Score:5, Insightful)
The problem with all these "The Big Bad Industry doesn't want X to succeed!" is the absolutely staggering number of X's that have nonetheless succeeded. Who cares what my power company "wants"? If I could buy cost-effective solar, I would. I can't. (And given that I live in cloudy Michigan it's going to be even longer for me than for some of you, but that's just a detail.)
Good luck to any power company foolish enough to stand in the way of something with the PR power of solar power. Can you imagine the media bloodbath that would ensue if any power company executive even mumbled something about getting solar outlawed?
Seriously, less emotion, more brain. It's the Universe making solar power hard, not a conspiracy of apparently-omnipotent "evil executives".
Parent
Re: (Score:3, Insightful)
Take hydrogen. The day someone figures out how to easily produce hydrogen the days of energy monopolies are over - anyone with access to water (or whatever the raw material turns out to be) can do it.
Making hydrogen isn't the problem. Storing it, transporting it, and keeping it from leaking out of every valve, seam, and fitting along the way, are the problems.
Re: (Score:3, Funny)
I'm sick and tired of you naysayers and skeptics bringing up conservation laws. Didn't the conservatives just get thrown out of congress? Now those pesky conservation laws can get repealed once and for all!
And maybe they'll do the laws of Thermodynamics while they are at it.
Same old song on efficiency... (Score:3, Insightful)
>No one is going to be able to figure out a system that uses less engerdy to split the molecules
>than you get in return by burning the hydrogen or using it in fuel cells.
Man, there are a shit-load of things we buy and use every day that consumed more energy in their making than I get out of it in the end product.
My reply to this is a big fat "so what"!
Let's say it takes 100 times as much energy to make a volum
Solar Energy - Been looking into this the past few (Score:4, Interesting)
Talk About Global Warming... (Score:4, Funny)
Let's see, four square miles of sunlight focused onto my back yard. Conversion efficiency ~30%. Melting point of silicon 1414 deg C.
Unless I've got a backyard the size of Bill Gates, lifetime of new solar plant = one sunrise.
Re:Talk About Global Warming... (Score:4, Informative)
-you increase the overall efficiency of the system (up to 80-90%) by getting both electricity and heat
-you heat water while cooling down cells, which improve their efficiency too (you can get as much as 30% with germanium)
http://www.solartecag.de/sites/innovation.htm [solartecag.de]
Parent
Here Comes the Sun (Score:5, Funny)
Passive solar heating... (Score:3, Interesting)
What about in summer? The windows can be opened and replaced by screens or shaded.
-b.
Re:Passive solar heating... (Score:4, Informative)
Parent
Re: (Score:3, Insightful)
Re:Passive solar heating... (Score:4, Insightful)
1 - they are "ugly" to most people that want the cookie cutter that looks like the other 15 homes in the new subdivision.
2 - They require more land than the typical suburbian/urban lot offers.
3 - Actually paying for low-e glass + correct design + insulation is expensive! They would rather have cherry cabinets, stone fireplaces with a plasma TV above it than energy efficiency.
4 - building from real materials is also insane expensive. I live in a all brick and Stone home now that is from the 1950's It's beautiful and would cost nearly $1,000,000 to build today. The stonework is real the brickwork is real my walls are 2X6 and then have the stonework on the outside giving me 10-12 inch thick walls, new mansions dont have real stone anymore, they have the faux or created stuff that is in reality only an inch or two thick even for their fireplace stonework (I have real marble and limestone) so building the home to have real thermal capabilities is not possible except for the rich.
5 - efficient materials like adobe is illegal most places, an adobe home is incredibly efficient.
6 - efficient designs are hard to get approved by the association... Any home that looks different is considered ugly. Domes are the absolutely most efficient. I had one that during some winters was self heating due to the sliders and skylights to the south. Paying $85.00 a year for propane for heat is really stinking nice(1999-2002)
The common person cant have an efficient home, they cant afford it. Jsut like solar and alternative energy. No average joe can float $5000-8000 for a basic solar install that will pay back in 10 years saving few dollars here and there.
Parent
Re: (Score:3, Interesting)
Not necessarily. Besides, the suburban houses that are being barfed up by builders there days are cheaply built and ugly. Yay for particleboard (not the good kind!) roof beams. How they get some of that stuff past the inspectors I can only guess.
2 - They require more land than the typical suburbian/urban lot offers.
Incorrect. We had a 1200 sq ft beach house on a *tiny* (read
Nitpick (Score:5, Insightful)
thermovoltaics (Score:3, Interesting)
Re: (Score:3, Insightful)
Your idea about the computers and brake shoes would work -- in theory. However, with car and train braking, there's a better way to extract energy from braking - just use an electric motor running as a generator to slow the car. It's done in hybrid cars and the NYC subway.
As far as the condensers in fridges and A/C units, it won't work, since you'll need more energy to run the t
Computers created and killed Solar Power. (Score:3)
But the demand for silicon in the creation of computers, has kept the price high. It is an ironic, catch 22 situation.
But there is hope. If we ever switch to non-silicon based computers, the price of pure silicon is expected to drop to a level low enough to make cheap solar panels a reality.
Solar Energy not just Photovoltaics (Score:4, Insightful)
You can get higher efficiencies by going to other chemistries, like GaAs, and by layering different chemistries on top of one another. These are not cost effective, and won't ever be able to get above, say, 50% efficiency.
But solar energy is not limited solely to photovoltaics. Probably the best way to use solar energy is solar thermal - capture all that 1000 W/m^2 of incident sunlight as heat. It can be used to heat a fluid up to fantastic temperatures, which can drive turbines, etc. This is the principle behind Solar One, Two, and Tres [wikipedia.org] and the Nevada Solar One [wikipedia.org] plants. These are, however, demonstration plants, not utility scale.
The other major kind of solar energy is biomass. Photosynthesis is a pretty good way to capture sunlight and make it do something useful. Plants have had a looong time to get good at making use of sunlight, which we use to our benefit in many ways. When cellulosic ethanol comes around, you'll probably make better use of sunlight by planting crops and building a solar power station.
Demonstration plants? (Score:3, Informative)
We still need better inverters (Score:3, Interesting)
We still need better inverters. These are the devices that convert DC into AC for use by common appliances and to power your home. The ones designed for home operation are wimpy, apparently intended for a home where people trim back on using energy in electrical form, already. The ones designed specifically for the wide range of voltage change from photovoltaic arrays/strings are big expensive commercial units intended for selling power to utilities, or for the utilities to buy for themselves (they shut down and night and can't run from batteries very well).
I want to reduce my carbon footprint with emphasis on reducing use of fossil fuels in particular. I'm less concerned about burning wood than I am about burning gas (natural gas or liquified propane). So I'd like to run my kitchen from solar and wind generated electricity. That means I need on the order of 12 kW of power just for potential peak cooking. Add another 2 kW for microwave. Add some more watts for the blender, coffee maker, refrigerator, etc. It adds up.
One of the big makers of home inverters for general DC conversion (e.g. batteries charged from various sources) is Xantrex. But their largest unit in this market segment is only 5500 watts. Two of the North American 120 volt units can be "stacked" to get 120/240 volts, but that's still only 11 kW. Some other companies offer as much as 6000 watts in a single unit, and do not even appear to be "stackable". What we need is a line of inverters, each specifically designed for the various world power systems so people can use their common domestic appliances, but with a variety of power levels in many steps all the way up to 100 kW or more.
There is one technical issue with inverters, and this is not something that is easy to solve. It also exists to some extent with small generators. That issue is that under short circuit conditions, they produce only barely (about 15%) more current than their design rating. To many this might seem like a good thing. But it actually is a hazard. The reason is because short circuits will fail to trip home branch circuit breakers. A common circuit breaker rated for say 15 amps generally won't trip for a while under a 20 amp load, until its thermal element gets quite warm. For an instantaneous trip using its magnetic element, the current has to be significantly higher, like 150 amps or more. Utility power through a transformer can easily deliver several hundred amps under a short circuit condition. With hefty power lines and transformers these days, if you are close to the transformer, you could even get several thousand amps real close to the breaker panel. This is why if you have ever shorted out a power circuit, you get a nasty *POP*. That's some big amps followed by the breaker cutting the circuit off.
I've found some inverters that have circuit breakers on the output AC side that are rated at a higher amperage than the maximum they could deliver under a short circuit condition. In other words, short out the AC right after the circuit breaker and you can't even get enough juice to cause the breaker to kick off. The inverter itself may very well detect the overload and soon shut off.
Many appliances may not even work under this low fault current condition. Big motors can have trouble getting started if they can't pull 3 to 5 times the normal amperage for part or all of a second. And even some electronics wants that much power or more when you turn them on to charge up the power supply capacitors. One relative has found that his big screen TV, although using way less than the 5000 watts his generator can produce, just won't even turn on under the generator. When he turns it on with utility power, all the lights in the house dim significantly for just an instant as the monster sucks a huge number of amps.
Ultimately, if you want to power you whole home with AC power through an inverter that converts the DC stored in your batteries charged up from your solar and/or wind power sources, you'll need some hefty
Hallelujah! (Score:3, Funny)
Simple modular lenses (Score:3, Informative)
These concentrating lenses do not need to be very complex at all. In fact they don't even need spherical curvature at all. What they need are angles. That effectively makes a crude, but adequate, Fresnel lens. With flat surfaces, they are also cheaper to make.
The original Fresnel lens design for lighthouses needed to work with a very small focal point, the light source, and beam that light very straight. Thus it needed that spherical curvature. Even in its varies steps or layers, that sperical curvature still exists. Solar cells, however, do not need this.
Suppose you have a small solar cell module that measures 10cm x 10cm. Place it at the center of the back of a larger 50cm x 50cm box with the front aimed directly at the sun. Over the front of the box place a 5x5 grid of 25 openings, each the size of the solar cell. In the center, only a flat piece of plastic is needed. Outward from the center, a piece of plastic that is angled like a thin prism would be placed to bend the light at the necessary angle to hit the solar cell at the back. You'll have to figure out the right angle based on how deep the box is. But you will only need to have just a few different kinds of angles to complete the construction and concentrate almost 25 times the light onto the solar cell. Solar cells even operate more efficiently on concentrated light levels.
The box will need to track the sun to keep the various angled beams focused on the solar cell.
An alternative design is a box that is wider in one dimension and has open sides in the other. Stack multiple boxes with the wider dimension vertical so their open sides mate with each other. Tilt the stack to the angle of the sun's path and aim it for about the noon sun position. Then the morning and afternoon sun will be at an angle that lens light from one of these narrow boxes go through the mated openings and hit the solar cells of the adjacent box. You only lose what would be at the ends but you don't have to set up a steering mechanism.
Variations of these designs use mirrors instead of lenses to concentrate light. I personally favor the mirror designs using non-imaging reflective topologies. The same methods are also used for water heating.
Also consider using a water heat collector behind the solar cells. They do get hot (they aren't 100% efficient, so the energy is wasted somewhere).
Solar Power still Useless (Score:3, Interesting)
Solar power isn't a solution. Its a distraction. It lets politicians and others pretend that they are doing something about serious energy questions instead of making unpopular, real-world choices.
Re: (Score:3, Informative)
Power grids supply a mixture of peak and base load. During the day in the summer here in Australia a lot of the peak load goes to supply commercial aircon systems which do scale the same way as solar power systems.
You may need to bring your peak load generators (gas powered, usually) on at night but there is still a net ga
Re: (Score:3, Informative)
The first thing to remember is that people usually go down when the sun does (give or take). During the day, when solar power is producing the most, people are up and running, working in their power hungry manufacturing plants and cubicle farms. That's when we need the most energy, so when it comes time to decide whether to build a new coal-fired plant, and it's only ne
Re:Solar Power still Useless (Score:5, Informative)
Power storage for solar can come in many forms. For a solar-thermal system (i.e. a stirling engine generator) you can simply store the heat using one of many mediums. For a photovoltaic system you can store the power using batteries, capacitors, hydrogen, heat, or even gravity by pumping water uphill. While the last three require a hybrid power system to access the stored energy (PV->H2/heat/gravity->electricity) they are not new technologies. In most areas you won't want a single power generation system so you'd have multiple plants anyway. The solar-thermal systems are particularly compatible with stored power as they work under direct solar energy, stored heat, or any combustible fuel (coal, wood, ethanol, petroleum, etc). And a solar/hydrogen power plant would double as a power source for hydrogen vehicles.
While it is true that areas closer to the equator see more power generation capacity from solar, even areas farther away still benefit from solar's ability to mitigate peak demand in summer and winter.
The cost of solar (PV or thermal) eliminates the almost incalculable secondary costs of conventional fuels (impacts on asthmatics from particulates, acid rain, ecological damage from mining coal or spilling oil, etc).
Parent
Re:I've heard they're fast (Score:4, Funny)
They are, only problem is that you can't know both what their position is on an issue, and how fast they want to implement it.
Also, I think they have a dead cat, or something....
Parent
Re: (Score:3, Funny)
Re:Interesting use of the word ONLY (Score:4, Insightful)
Let's just say that it costs a super cheap 20$ a square foot. The cost of the mirrors alone would be $1,115,136,000.
Wow. I can make up numbers too. Let's assume it was a "super cheap" $2 a square foot. That's only
$115 million. Oh wait, let's assume it's only
Rather than pulling numbers out of your ass, maybe you should have real estimates of what it costs to make a plastic mirror. Considering you can make wood flooring for
Parent
Re: (Score:3, Insightful)
Ok I'm going to add around another billion to pay for cleaning equipment, staff, etc.
Let me pull some numbers out of my butt.
I'm also not a physicist so forgive me if I've made a basic mistake in my following assumption: For your $2B investment you get 1 gigawatt production. What is this - 1 watt = 1 Joule per second, if I remember. So 1 GW = per second. After 3600 seconds you are getting 1GW/hour. Dunno how much a KW/hr costs in your locale, but here it
Re: (Score:3, Informative)
I know that in the roofing industry you can put down a membrane that complies with CRRC requirements and within a month it won't. Granted, we're talking about relatively flat horizontal surfaces but anything left outside almost immediately begins losing measurable reflectivity from dust and dirt.
A little google search turned up $5/sq. foot (Score:3, Informative)
Re:What's a 'libratarian'? (Score:4, Funny)
(Stop that snickering, you in the back!)
Parent
Re:The Days of 100% ... exactly how? (Score:4, Informative)
Actually, a heat pump is a bad example, since you're putting energy in to move heat, not moving heat and getting energy out. With an engine, the amount of heat moved always has to be greater than energy out. Same with a heat pump - you actually can move more heat energy than you put power in. Hence coefficients of performance greater than 1.
-b.
Parent
Re: (Score:3, Informative)
I once heard a mechanic say "You can just think of an engine as a glorified air pump" (a really dirty one)
The point is you just have to change how your looking at it. To see a heat pump as a generator, look at hot air on one side as fuel being burned (with colder air being the exhaust output) and hot air on the other side as the output energy.
Actually it has 2 fuels... the electricity comming in too. So it burns electricity and hot air, and makes hot air on the other s
Re:The Days of 100% ... exactly how? (Score:5, Informative)
In solar cells, the point is that photons excite valence electrons across a barrier, giving them enough energy to create a current. There isn't really a classical analogy for this effect.
There's a limited discussion of solar cell efficiencies here, although it doesn't talk much about the underlying physics:
http://www.lbl.gov/Science-Articles/Archive/MSD-f
The upshot is, cells of a single type of material can only get up to about 30% efficiency, but we can stick several materials together to get past that barrier.
Parent
Re: (Score:3, Funny)
What? You've never heard of the were-car?