04-22-2017, 10:01 AM
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#31 (permalink)
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Volvo-driving MachYeen
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electric blackouts are not very common, maybe 0,5-2 hours a year.
at least in my area. There is a hydroelectric plant about 8kms from our house.
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04-22-2017, 11:50 AM
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#32 (permalink)
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AKA - Jason
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Quote:
Originally Posted by freebeard
Do these calculations take into account people willfully choosing to invest in new and re-roofing that is more durable and incidentally will charge a car locally without any interaction with a/the grid?
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Not the one's I've seen. They just look at the current installed electrical capacity and the additional power required to charge a fleet of EVs.
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04-22-2017, 02:11 PM
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#33 (permalink)
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Master EcoModder
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Quote:
Originally Posted by oil pan 4
So the power grid is too big to fail?
Ha!
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The interconnected grid is complex and a PITA to control. Much of the cost (almost as much as the generation costs) of our power (Canada) is put into controlling which plants are online and which are not, ramping up standby capacity to deal with peak demand, etc etc. There is much discussion about regulation where wind and solar are available. And how fast the information about what output is available from solar and wind get to the control center.
Another large chunk is maintenance/upgrade of the transmission lines and substation gear. The transformers are hardware and they have a design life. The switches have a life rated in cycles. And stuff just generally wears out.
Our power company (SaskPower) has been upsizing and replacing local distribution stations for about 10 years. The gear replaced was 60+ years old and had a design life of 50 years. So it did well, on average. Not to say that they were not replacing stuff before that .. but since the hardware was past design life, the rate of upgrades increased noticeably. Like maybe 5X - 10X the upgrades.
When overloads and lightning happen, the power meters and relays on our grid act automatically to island (trip and isolate the problem) or re-close (maybe it was a tree across cables and we can close on the fault and 'cook' it clear) or whatever the control scheme is. People get involved starting up replacement stuff, dispatching crews for maintenance, and generally cleaning stuff up or having power generation spinning and ready to take over the loads when trips happen.
There is a reason that the power company gives you so little for excess generation onto the grid, besides the fact that they are *EVIL* ... the power generation is only part of the cost. And it is not even the largest cost.
My power at home trips for a few seconds at a time several times per year. 4 years ago it tripped during a rainstorm and I got a flooded basement. So now I have a standby generator (natural gas) and no insurance on flooding.
At the cabin, summer power loss is normal. Maybe 20 times in 6 months. Usually a few seconds at a time. So far, never over 5 minutes during the heating season.
The more I learn about our local grid, and the grid in general, the more I want my own standby system.
But that's only my opinion!
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04-23-2017, 12:59 PM
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#34 (permalink)
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PaulH
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I was told by someone who went to a university talk about the grid that there's a theoretical limit to the percent of grid power that can be from solar grid ties. If it was over some percent, the grid would become unstable, and in practice, it was actually less than the theoretical percent. But the talk was about how the speaker had invented a way to build some inertia into the software, so it wouldn't have the same stability issues. I don't think it's used in general right now.
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04-23-2017, 01:49 PM
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#35 (permalink)
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AKA - Jason
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Quote:
Originally Posted by MPaulHolmes
I was told by someone who went to a university talk about the grid that there's a theoretical limit to the percent of grid power that can be from solar grid ties. If it was over some percent, the grid would become unstable, and in practice, it was actually less than the theoretical percent. But the talk was about how the speaker had invented a way to build some inertia into the software, so it wouldn't have the same stability issues. I don't think it's used in general right now.
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The theoretical limit is 100% solar.
The issue with solar or wind energy feeding into our current electric grid is that the power generation is not consistent. Clouds shade panels and the wind doesn't blow at a constant speed. That compares to a gas plant where generation can be ramped up or down at will to meet the demand. The current grid doesn't have a way to store extra energy and feed it back when needed. There are ways to do this but right now we don't.
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04-23-2017, 02:24 PM
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#36 (permalink)
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Master EcoModder
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Quote:
Originally Posted by JSH
The theoretical limit is 100% solar.
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I think there must be a limit, according to some theory or another, for the grid stability portion
Quote:
The issue with solar or wind energy feeding into our current electric grid is that the power generation is not consistent. Clouds shade panels and the wind doesn't blow at a constant speed. That compares to a gas plant where generation can be ramped up or down at will to meet the demand. The current grid doesn't have a way to store extra energy and feed it back when needed. There are ways to do this but right now we don't.
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Agreed.
- Pumped hydro is one method that is relatively simple to do, but you already need a hydro dam. In low demand periods, you pump the water back up the grade and into the reservoir (using cheap baseload electricity from coal plants that don't ramp up or down quickly, or excess wind, excess solar)
- grid-storage. Flow batteries, rotating mass storage, etc to store the extra energy until it is needed. The battery or mass storage also doubles as power factor correction and makes the local grid more stable and energy efficient.
Those are the ones I read about. I'm sure there are others.
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04-23-2017, 06:59 PM
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#37 (permalink)
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It's all about Diesel
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Quote:
Originally Posted by MPaulHolmes
I was told by someone who went to a university talk about the grid that there's a theoretical limit to the percent of grid power that can be from solar grid ties. If it was over some percent, the grid would become unstable, and in practice, it was actually less than the theoretical percent.
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Be it solar, wind, coal, heavy crude oil, gas, biomass or even hydro, relying on a single source of energy for power generation is always somewhat risky. Hydro is cheaper an therefore more widely used here in Brazil and in Paraguay, but thermal generation usually fed by coal and more recently Natural Gas became more common as a backup.
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04-23-2017, 07:07 PM
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#38 (permalink)
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Master EcoModder
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A technology demonstrated to be more efficient than pumped hydro is steel wheels on rails.
https://www.google.com/search?q=elec...orage+railroad
http://www.aresnorthamerica.com/
Their demonstrator uses miles of existing track with typical grades in Nevada. I think a better solution would be a cog or rack railway.
For a home installation, a stack of barbell weights that traverses a flagpole on cables and pulleys.
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04-24-2017, 09:41 AM
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#39 (permalink)
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Volvo-driving MachYeen
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Our hydro plant is @ a dam, so at lower demands the water bypasses the turbines and gets directly into the river, and at high demands the bypass is closed. There is always a tiny flow, intended for fish.
if apocalypse broke out, i'd fort myself a base in there.
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Last edited by Fingie; 04-24-2017 at 09:43 AM..
Reason: hulagaba
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04-24-2017, 03:22 PM
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#40 (permalink)
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Master EcoModder
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