I would start studying the situation on the demand side, such as hourly loads for each time zone and season. In addition figures for different latitudes should be analyzed.
A good quality grid also helps using renewable sources effectively, but there is the pylon problem or going to expensive HVDC ground cabling.
The US/Canada is so large that a good grid will reduce "night" time significantly. Hydroelectric plants running at nights only, also help a lot.
The problem with greenies is that if some technology works in one place, they assume that the same applies to everywhere :-). This causes problems to those of us, who implement renewable system all over the world. You really have to do the analysis place by place and country by country, methods that work in one place, doesn't necessary work in an other place.
Actually there is a developing technology of hot solar. There high temperat ure is used to stimulate photon emission from an emitter and directed at a more or less conventional PV material to produce electric energy. The wavel ength of the emitted photons is optimized for unheard of solar conversion e fficiencies. The drawback is we're talking temps in the 1000oC range. The i dea is to use solar thermal to collect heat energy that's stored until nigh t when this process kicks in. They have to do something intermediate to mak e this 1000oC process practical, or look to invent a whole new class of ins ulating materials.
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It's latent heat and sensible heat. Specific heat is material constant http ://hyperphysics.phy-astr.gsu.edu/hbase/thermo/spht.html
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
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I'm looking for work... see my website.
Thinking outside the box...producing elegant & economic solutions.
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| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I'm looking for work... see my website.
Thinking outside the box...producing elegant & economic solutions.
Until it gets submerged by sea-level rise. Florida is remarkably porous, so the Dutch solution of building dikes around the coast probably wouldn't work.
A global 10 m tsunami tomorrow at 12:00 UTC would be a significant disaster. However, the possible sea level rise would take thousands of years and considering that the economical life time for buildings and other infrastructure is in the order of 100 years, so all it takes is to build new structures about 1 m higher than the top water level at design time. What extra costs would be of building 1 m higher up ? Divide that with the economical life time (say 100 years) the cost of slow level increase would be insignificant.
What do you mean by "wrong way" ?
If you are referring that the peak demand is in the afternoon, then pointing the panels to the south would be a conflict. Pointing roof-top panels to the south would require houses built solely in east-west orientation and putting panels on the south side of the roof.
However, houses are built in random orientations, so populating the west or south west side of the roof would better match the demand.
Realistically, the installed solar capacity should be as much the day/night consumption difference. For roof-top installations the installed capacity that just handles the own peak air condition load should be sufficient. No need for mains connected panels.
People who prefer roof-top panels usually also support "small is beautiful" and no heavy infrastructure is needed. However high pressure areas can be 1000-2000 km wide, in which no wind is blowing, making wind power useless in that area. Low pressure areas with rain can be as large, making solar production impossible.
Thus, to supply electricity to areas that are temporarily without renewable sources, you need to be able to transfer electricity from outside to this area. This means building many new HV lines with high pylons, which will frightens some people.
In reality 20-30 % should be the maximum to handle the day/night difference, after that, there are going to be all sorts of storage issues. Handle the night time consumption with wind, hydro and nuclear.
Even 10 m sea level rise in 1000 years is not desperately urgent (see my previous point about building economical lifetime).
One alternative is to use huge continental wide east west power lines between time zones.
In the UK 100 miles is a long way. In the US 100 years is a long time. Sounds like that is also true in the antipodes.
My mother remembers someone that had a significant positive influence on her when she was young. That person was born somewhere around 1835, the same time my mother's house was built.
all the oil we are burning is merely stored solar energy, so we are alread y relying on stored solar energy.
dug up makes burning oil a strictly short term solution, even if you are si lly enough to think that it's a good idea to keep on dumping more CO2 in th e atmosphere.
to satisfy our current demand for power, but we could do it. We'd also have to invest in storage schemes of one sort or another - thermal solar towers capturing heat in molten salts at 500C can store thermal energy for days i s just one of the options.
al investment involved with dealing with 10 metres of sea level would be at least as substantial.
The problem is that the sea level rise won't be spread over thousands of ye ars. The geological record from the end of the current interglacial and previous interglacials shows that ice sheets don't melt in place, but eventually sl ide off into the sea. The sea level rise will take place over a century or so, not over a thousand years.
ou've just produced an example their kind of misleading output.
ying
the
There's an optimal orientation for solar panels, and rooftops aren't built to offer that orientation.
If there is a south, or south-west fancing slope in the roof. This isn't gu aranteed.
Peak air conditioning load in winter occurs in the middle of the night.
Which does make an extended high capacity grid useful.
Some people are frightened of their own shadow. A lot of the extra capacity is likely to be in higher voltage lines, so "many" new HV lines is a littl e misleading.
At some point it is going to be worth burying a grid built with high-tempe rature superconductors, which introduces other constraints.
ring to make enough solar cells to supply 100% of what we need is straightf orward, and we'd probably cut the capital cost per kilowatt of capacity by a factor of four in the process of setting up enough manufacturing capacit y to do it.
The storage issues are pretty well defined. We've got solutions that work, but cost capital investment, and only recover about 90% of the stored energ y.
Nobody wants to make the capital investment, so we keep on digigng up fossi l carbon and burning it, devaluing a whole lot of other capital investments we've made.
matter gets desperately urgent.
Except that when it happens it won't happen over a thousand years, but some thing like a hundred or so - when ice sheets start sliding off into the oce an they slide fast.
overnight - they are all bulky and expensive, but perfectly practical and entirely useable.
t one more excuse for not getting on with solving the problem.
Germany did a pretty thorough proposal for building solar farms in the Saha ra and shipping the current north to Germany. It was feasible, if expensive , but did create a lot of crucial infra-structure in places that it wouldn' t be easy for Germany to defend.
However, at least 1/3 of that continental ice is below current sea level, so only 2/3 can melt into the oceans. During previous interclacials the Melankovich cycles provided the extra energy to melt ice. During the next 10 000 years, the extra energy due to
I claim that panels are oriented into more or less random directions.
Do you have statics about house orientation n the US ?
Really ? Some locals have indicated that it occurs between 15:00 and
18:00. Anyway, using water as temperature storage, that would not be a problem even at midnight.
It makes such grid absolutely necessary.
At least in Europe, the grids within a country are strong, but the country to country interconnects are weak (perhaps only 1000 MW).
High voltage AC lines are used due to the lower cost. In order to transfer high power AC in a ground cable, you need compensation station every 30 km to compensate for the capacitive reactance.
For this reason HVDC links are used in under water/ground cables.
The heat ingress into superconductive cables is so great that you should transfer at least 10 GW for every 1000 km to pay for the heat leakage.
The only realistic solutions that I can think of is hydroelectrics and generation of biogas, which EU just tried to shut down.
Please note, I am not very interested in fossile fuels, but I hate all those unrealistic greenies that think that one size fits all.
The last event took 10000 years for a surface rise of 100 m. Thus 1 cm/year.
DESERTEC has been scrapped a long time ago. One was the politicial instability in that region.
There are some subtleties in solar panel orientation. For example, power generated late in the afternoon, is worth more than power generated in the morning. That's why some areas prefer east-west facing panels on both sides of a roof to just everything pointing due south. "if your solar roof is oriented directly east or directly west instead of the optimal south-facing, you will only see a 20% decrease in the amount of electricity you produce."
Lowering the tilt angle to get more power in the late afternoon also helps: See section under "Solar panel orientation in cloudy cities".
We have several local home solar panel installations that face east-west and which work quite nicely. We also have some that have random panels scattered all over the roof pointing in all manner of different directions. Such arrangements work because micro-inverters can be paralleled without losses.
More on this:
A problem in urban areas is that many building have a minimal roof, such as apartment buildings, which is insufficient to produce enough power for the entire building. So, for urban areas, the solar panel farms will probably need to be placed in adjacent rural areas. There is some talk about allowing solar panels in reserved areas (green space).
Personally, I think some effort put into uniformly distributing the demand to reduce peaks will help. On the bottom graph "Yesterdays Net Demand", notice that there are two peaks, at 6AM and at 7:30PM. Those are cooking peaks, for breakfast and dinner. If the dinner peak can somehow be moved to when the sun is shining (before 6:30PM for this time of year), much of the early evening peak demand will be eliminated.
Also, notice that the peak demand is at 6PM, not in the "afternoon" as is so often cited in the news.
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Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
I claim that opinions on the subject are more or less random.
I also claim that as the price of Chinese panels continues to fall, and the panels become a decreasing small part of the cost of a solar power installation, it becomes economical to simply install as many panels as possible, pointing in inefficient directions and locations.
This might be of interest: Google - Project Sunroof
Sorta: This gives the solar potential without details on the orientation: Click on "Methodology" -> "Read more Methodology". The problem is how far off of due south do you consider to be an acceptable orientation? I suggest +/- 45 degrees of due south. I might have access to the necessary data but only for Santa Cruz county.
One limitation to rooftop solar is the local building code, which demands a 3ft backset on the top and sides of the panels for the fire department to walk on the roof, or to ventilate the roof in case of a structure fire. That has removed huge amounts of potential rooftop solar panel area.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
On the hottest days my utility has asked us to reduce power between 3 and 6 PM. I don't know where the peak is in this range, but obviously this is the range the are finding uneconomical to buy power for.
In their cost plan that is weighted for peak usage, they reduce the off peak rate of power supply from $0.08/kWHr to $0.043/kWHr. But from 3 to 7 PM, October to May the rates are $0.12/kWHr and June to September the rates skyrocket to $0.43/kWHr. This could make electricity generation by solar highly profitable in the late afternoon and early evening. My roof has a high pitch and faces the south-west, a nearly perfect alignment.
I seem to recall that you're on the east coast. There should be an ISO (independent service operator) type intertie organization in your area that has the numbers. For example: More: (See Electric Power Markets sub-menu on the left).
Really stretching my failing memory, I seem to recall that you were in Virginia. My apologies if I'm wrong: (Give this page time to load. It's reallllllly slow).
Map of the various acronyms, abbreviations and zones: (6.4MB)
Yikes. Playing with the real time graph, there were two big expensive peaks today at 1PM and 4:30PM east coast time, where the price of electricity went up to $80/MegaWatt-hr ($0.08/kWhr). Usually, it hangs between $20-$30/MWatt-hr. Kinda looks like someone had to shut down some generating capacity and needed to import some power for an hour or so.
Yep, that's why many fixed arrays point south west. Afternoon electricity is more valuable than morning electricity. So, are you going to rush out and buy into solar power? The official pitch line for why the rates go up during summer is increased use (air conditioners) and decreased availability of cheap hydro. With California getting 12% of its power from large hydro, and 6.2% from small hydro, I'm not sure the official explanation holds water.
Dumb question: Why is there a somewhat linear increase in power consumption starting at about 6:30AM and ending at 6:30PM? I would expect consumption to be flat over the work day. I can see the usual peaks at 6:30AM for breakfast and 7:30PM for dinner on the "Net Demand" graph, but the underlying increasing slope is still there.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
I just see a map and names, no explanations of abbreviations at all. Most of these pages aren't very usable because I don't know the meaning of LMP, PJM, etc. After some minutes digging, I found PJM is the name of the local transmission company (short for Pennsylvania, New Jersey, Maryland but now is much larger).
Interesting. I clicked the "Real Time" button rather than look at forecast data and the peaks turned into *much* higher prices. Looks like the Dominion price pushed past $750/MWHr. That's $0.75/kWHr!!!
There is only two days of info available for the PJM region. I'd like to see the instantaneous data for some of the highest peak days like Jul 22. It doesn't matter so much where the peak is on most days if they aren't really stressing the system. But then economics would indicate load isn't the real issue, rather the time of peak marginal price. Or course the peak price would normally coincide with peak demand unless there are issues with supply.
I don't really care much the "rational". The rates are what I have to live with. But I feel ripped off that they charge so much more than what they are paying under the Time of Use Service schedule. I wonder if they prohibit supplying them with power under that schedule?
Why would use be flat during the day? AC or heat runs a duty cycle depending on the temperature. I see a very similar cycle in my personal usage corresponding to the temperature with a lag of an hour or two or even three.
I'm having the same problem. To many abrevs and acronyms without explanation. I'm sure there's a list somewhere, but I can't find it. The map was the best I could find.
You might find these of interest:
Yep. The highest scale on the above map is >$500 suggesting that such prices are quite real. Since they appear to be rather short term, they probably don't have a big effect on overall prices. If you want more detail or history, you have to have a login on the system:
It seems that you can get historical prices at: but I couldn't figure out how to make it work without a login.
Your usage pattern is probably not the same as the usage pattern for the entire system. For example, as the temperature increases, I would expect most of the A/C over a large area to turned on almost at the same time. Same for turned off when it cools down. The should show up as a step function on top of the normal usage. I've never seen that.
Residential electricity is about 1/3 of the total along with commercial and industrial. I would not expect the overall usage graph to look so neat, smooth, and consistent. It's like that almost every day of the year on many of the interchange web sites. I've been watching the charts for several years wondering if it's for real, or a side effect of load balancing by the power grid.
So, what is really happening?
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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