drewk79
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The 20 watt per sq meter effective solar number. Is that what solar cells can produce? Or is that the total energy the sun puts out? thanks?
vanesch said:Very simple: multiply energy prices by, say, 50. You'll see an effect. Maybe not the effect hoped for.
drewk79 said:The 20 watt per sq meter effective solar number. Is that what solar cells can produce? Or is that the total energy the sun puts out? thanks?
There are two major reasons that [much of] Europe uses less energy per capita than the US, besides living standard:vanesch said:The "250 KWhr/day per person" in the US is divided by 2, simply because his argument is based upon the UK, and there, energy consumption is about half of it, 125 KWhr/day per person, and he has all his numbers ready for this quantity.
Now, living standards are higher in the US than in Europe, but one is nevertheless left with the sentiment that there must be more potential for simple economies of energy in the US without affecting lifestyle, as energy-saving measures which are already in place since long in Europe are not so much applied in the US as far as I understand. Now, as living standards in the US are higher, it will probably not be possible to bring US consumption down to Europe's consumption (halving), but some diminishing must surely be feasible.
Astronuc said:So if PV's are 10% efficient and the flux is 1000 W/m2, then a PV would produce 100 W/m2 of useful electrical energy. There maybe further losses depending on resistance (dependent on distance between supply and load) and other conversion losses.
drewk79 said:The 20 watt per sq meter effective solar number. Is that what solar cells can produce? Or is that the total energy the sun puts out? thanks?
Hey, page by page online references now. Great way to access a book.vanesch said:signerror already gave the answer. Of course, this is dependent on the region and so on. It is what MacKay quotes for photovoltaic
http://www.inference.phy.cam.ac.uk/withouthotair/c6/page_39.shtml
in the UK, and also what he quotes for thermal solar in the North-African desert:
http://www.inference.phy.cam.ac.uk/withouthotair/c25/page_182.shtml
These are ballpark numbers of course.
OmCheeto said:...
Kind of refreshing to hear from a professor of physics rather than Geraldo.
...
http://www.inference.phy.cam.ac.uk/withouthotair/c20/page_127.shtml
I’ve looked up the performance figures for lots of electric vehicles –
they’re listed in this chapter’s end-notes – and they seem to be consistent
with this summary: electric vehicles can deliver transport at an energy cost
of roughly 15 kWh per 100 km. That’s five times better than our baseline
fossil-car, and significantly better than any hybrid cars. Hurray! To achieve
economical transport, we don’t have to huddle together in public transport
– we can still hurtle around, enjoying all the pleasures and freedoms of solo
travel, thanks to electric vehicles.
http://www.inference.phy.cam.ac.uk/withouthotair/c20/page_126.shtml
Regenerative systems using flywheels and hydraulics seem to work a
little better than battery-based systems, salvaging at least 70% of the brak-
ing energy.
I actually did something like that when my serpentine belt tensioner broke off one day. I was too cheap to have the car towed home so I installed the 3 panels to replace the alternator for the 15 mile drive home. Worked fine.http://www.inference.phy.cam.ac.uk/withouthotair/c20/page_131.shtml
Q: I live in a hot place. How could I drive an electric car? I demand
power-hungry air-conditioning!
A: There’s an elegant fix for this demand: fit 4 m2 of photovoltaic panels
in the upward-facing surfaces of the electric car. If the air-conditioning is
needed, the sun must surely be shining. 20%-efficient panels will generate
up to 800 W, which is enough to power a car’s air-conditioning. The
panels might even make a useful contribution to charging the car when
it’s parked, too. Solar-powered vehicle cooling was included in a Mazda
in 1993; the solar cells were embedded in the glass sunroof.
OmCheeto said:2. Sometimes it's difficult to tell when he's being sarcastic. Which would he prefer: Trams, bicycles, or electric cars?
He's serious here. The drama is in keeping with his frustrated search for answers where the figures on the physics actually work out, and EVs are one place where they do.McKay said:I’ve looked up the performance figures for lots of electric vehicles –
they’re listed in this chapter’s end-notes – and they seem to be consistent
with this summary: electric vehicles can deliver transport at an energy cost
of roughly 15 kWh per 100 km. That’s five times better than our baseline
fossil-car, and significantly better than any hybrid cars. Hurray! To achieve
economical transport, we don’t have to huddle together in public transport
– we can still hurtle around, enjoying all the pleasures and freedoms of solo
travel, thanks to electric vehicles.
Wow. That's a big difference. We pay $0.118/kWh peak and $0.037/kWh off peak. Though I'm not on metered service. But I would cut my bill at least in half if I were. At least 90% of my electric bill in devoted to heating. But I guess this is where Jevons paradox jumps in. Why get more efficient with your usage if you can get what you need for a third of the price by working the system. Up here in the northern latitudes, there are maybe 5 days a years when cooling your house is necessary.drewk79 said:I was searching my Electric bill yesterday and found they off Real Time Pricing for electricity.
I found a few articles on the subject and they say a 10% drop in peak consumption is common when this is implemented.
I looked back at some of the past high cost days and during the day prices would get to .20kWh but that night they would drop to just about $.02 kWh.
I've seen that on TV before. It does make sense.I have a large chest freezer maybe 30 cubic ft. We don't use it currently. I am thinking I could fill it full of water jugs and freeze the water at night then open it during the day to keep the house cool. Maybe install a fan.
I know there are systems that I can buy to do this but I have these parts what do you think?
If the utilities around here had a 10 to 1 difference between peak and non-peak and everyone were to utilize it, I think they'd go broke. I just don't see any logical reason to leave the heat on in my house when I'm not there. I suppose some people might want to come home after a long day at work to a cozy house. But watching that electric meter spin makes me go through all manner of hoops to get it to stop. A 6 m2 solar thermal collector is first on my list of projects. I built a prototype 2 weeks ago out of 3 garden hoses, one solar panel, one 12vdc 500 gph bilge pump, and a 32 gallon rubbermaid trash can. It generated around 750 watts of thermal power with the pump consuming about 20 watts of power. The garden hoses were simply tossed onto a sunny spot on the roof. Away from the street of course. I don't want the neighbors thinking I'm some kind of mad scientist.Also being able to adjust our energy usage to low cost times of day is an immediate way to reduce peak demand immediately.
In my area it is $2.50 a month to be in the program they are using the old grid and they just change out your meter for free.( i guess that's what the $2.50 is for)
I am a home builder in the area and I live in a town with 700 people. I don't know anyone else in town using this and I talk to a lot of people. I guess the power company should get some credit for making it available but they get an F for putting it into effect.
Too late, that horse has left the barn I expect.OmCheeto said:... I don't want the neighbors thinking I'm some kind of mad scientist.
mheslep said:Too late, that horse has left the barn I expect.
Re your solar panels, may I ask: who's the manufacturer, when did you buy them, and how much?
Sizewell is 1.1GW(e). Replace w/ 1.5MW turbines at 35% capacity factor, yep. And they'd still have to address storage / base load.If you don't like nuclear, for every Sizewell you want to get rid of you need an extra 2000 wind turbines
The purchase price of a battery exchange capable EV with a chassis comparable to either a Prius or Civic should be substantially less. The Prius commands a premium because of its battery and hybrid drive train; the high mpg Euro Civic also does because of the more expensive diesel engine (Edit: and the Civic is smaller than Better Place's Renault)russ_watters said:My only quibble with your calcs is with this one. We're a long way from electric vehicles being a total replacement for cars, so for right now and for the next several decades, the only people who would buy them are those who are highly conscious of fuel efficiency. And those are the people who today would buy a Prius at 40mpg or a Civic at 35...
Electric Truck
2 kilowatt hours of energy units per mile
Operation cost: 20 cents per mile
...
Diesel Truck with 5 miles-per-gallon*
Operation cost: 80 cents to 90 cents per mile
* The above energy consumption and energy cost comparisons are based on a 100% duty cycle, which diminishes in the diesel truck when the truck is idling. A common 50/50 duty cycle in a diesel truck, reflecting 50 percent idling time, would increase the diesel truck’s cost per kilowatt hour from .90 to $1.80
Well this part is disappointing:OmCheeto said:Did anyone read the article in the latest SciAm today regarding grassoline?
http://www.scientificamerican.com/article.cfm?id=grassoline-biofuels-beyond-corn"
I've not had a chance, and am running quite late.
C'mon Sci American. That the explains the lack of any mention of the recent Science paper showing the biofuels are better used to produce electricity than gasoline....[the author] is the founder of Anellotech, a biofuel startup
mheslep said:Port of LA now using some electric trucks for its short haul work around the port. Full size 18 wheelers, 60000lb load, 40-60mi range. They went lead acid with the first ones, lithium on the next go round.
Mfn Fact Sheet
http://www.portoflosangeles.org/DOC/Electric_Truck_Fact_Sheet.pdf
Video
https://www.youtube.com/watch?v=<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/0f1AlrG8gVU&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowScriptAccess" value="always"></param><embed src="http://www.youtube.com/v/0f1AlrG8gVU&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" allowScriptAccess="always" width="425" height="344"></embed></object>
Lead acid has two drawbacks here RonL, weight is one but the other is limited deep cycle lifetime. So its fine to build a few of these trucks with lead acid to see how they work out, but the batteries will quickly give it up. Even that's ok for the experiment - replace them, but it can't fly economically. A real working E-truck requires something else like Li-ion and thousands of deep cycles, which the Port of LA is doing as the sources above show.RonL said:When I suggested this type of truck, someone said it was an asinine idea, Oh well not everyone thinks alike.
I'm still working on the lead acid batteries that last a lifetime. Even if energy density is compromised at 50% to 75%, would it be worthwhile?
I think so.![]()
mheslep said:Well this part is disappointing:
C'mon Sci American. That the explains the lack of any mention of the recent Science paper showing the biofuels are better used to produce electricity than gasoline.
No.mohd_adam said:For nuclear power plant 1000 MWe, it needs 24 tones of enriched uranium 3- 5%.
To get 24 tones of enriched uranium 3- 5% , we need 200 tones of uranium oxide 'yellow cake'. ( i hope correct of numbers are wrong )
in 2006 the world produce 39100 tones. If the world started depend on nuclear power, when uranium will run out !?
--------
http://web.mit.edu/nuclearpower/pdf/nuclearpower-summary.pdfClosed fuel cycles extend fuel supplies. The viability of the once-through
alternative in a global growth scenario depends upon the amount of uranium
resource that is available at economically attractive prices. We believe that the
world-wide supply of uranium ore is sufficient to fuel the deployment of 1000
reactors over the next half century and to maintain this level of deployment
over a 40 year lifetime of this fleet.
mohd_adam said:For nuclear power plant 1000 MWe, it needs 24 tones of enriched uranium 3- 5%.
To get 24 tones of enriched uranium 3- 5% , we need 200 tones of uranium oxide 'yellow cake'. ( i hope correct of numbers are wrong )
in 2006 the world produce 39100 tones. If the world started depend on nuclear power, when uranium will run out !?
--------
Well I don't know of any civilian reactor examples where reactor waste heat is used, so I think that must be ~15,000 one GW(e) reactors.signerror said:The world uses about http://www.iea.org/Textbase/stats/balancetable.asp?COUNTRY_CODE=29 of thermal energy (1 ton oil equivalent = 42 GJ); one 1 GWe nuclear reactor produces about 3 GW of heat. So as an order-of-magnitude estimate, we would need about 5,000 one-gigawatt reactors.
Plus another 1.5 million tons of Th worldwide...
conventional reserves - 5 years
conventional reserves in FRs - 500 years
phosphate reserves - 30 years
phosphate reserves in FRs - 3,000 years
seawater reserves - 5,000 years
seawater reserves in FRs - 500,000 years
Hope this is helpful.
mheslep said:Well I don't know of any civilian reactor examples where reactor waste heat is used, so I think that must be ~15,000 one GW(e) reactors.
Plus another 1.5 million tons of Th worldwide