WetEV
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Re: Economics of Renewable Power, simplified.

Mon Jul 18, 2016 5:38 am

RegGuheert wrote:But the fact of the matter is that a couple of days' worth of storage does not get you to: "the diesel engine plant will only operate in exceptional/emergency case," especially during the half of the year when there is insufficient wind to power the island. Half the year is not "exceptional" in anybody's book. It happens every year for half the year. In those months when there is less than 1/7 that amount available, two days of storage hardly makes any difference. How would you use it?


Two days storage should let the renewable fraction be near 100% for perhaps half of the year, and for that half of the year the diesel engine plant would operate rarely. From a controls and systems perspective, that is very interesting. System stability, automatic integration of weather forecasts into storage planning, and so on. Expect to learn something.

Too bad they are not talking about what they are learning.
WetEV
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RegGuheert
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Re: Economics of Renewable Power, simplified.

Wed Aug 10, 2016 12:30 pm

Roger Andrews reports that the El Hierro hybrid wind-hydro electricity system achieved a record renewable fraction in July at 65.9%.

It appears that on July 13 they increased the cap on wind production from 7 MW to 7.5 MW.
RegGuheert
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GRA
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Re: Economics of Renewable Power, simplified.

Wed Aug 10, 2016 5:09 pm

Reg, glad you're keeping an eye on this. I check the site when I remember, but there's so many others I monitor regularly that this one falls into the 'infrequent' category.
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Re: Economics of Renewable Power, simplified.

Tue Nov 29, 2016 7:28 pm

El Hierro October performance: http://euanmearns.com/el-hierro-october ... ce-update/

19.8% renewables for the month, versus 58.2% for August, for a total of 38.8% total since start up. Be sure to read the article translated from German linked in the comments, which talks about some of the other EU-subsidized idiotic projects that have been built on El Hierro. It also mentions that depending on who's doing the calcs, the storage would have to be 5, 20 or even 200 times larger to supply 100% from renewables, which is what many of us have been saying for a couple of years now.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

WetEV
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Re: Economics of Renewable Power, simplified.

Wed Nov 30, 2016 6:09 am

GRA wrote:El Hierro October performance: http://euanmearns.com/el-hierro-october ... ce-update/

19.8% renewables for the month, versus 58.2% for August, for a total of 38.8% total since start up. Be sure to read the article translated from German linked in the comments, which talks about some of the other EU-subsidized idiotic projects that have been built on El Hierro. It also mentions that depending on who's doing the calcs, the storage would have to be 5, 20 or even 200 times larger to supply 100% from renewables, which is what many of us have been saying for a couple of years now.


El Hierro has roughly two day's worth of storage. I don't think any reasonable design would need 400 days of storage.

To need 400 days of storage, you would need to be bridging gaps in production of over a year. Wind just isn't that variable.
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GRA
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Re: Economics of Renewable Power, simplified.

Wed Nov 30, 2016 6:05 pm

WetEV wrote:
GRA wrote:El Hierro October performance: http://euanmearns.com/el-hierro-october ... ce-update/

19.8% renewables for the month, versus 58.2% for August, for a total of 38.8% total since start up. Be sure to read the article translated from German linked in the comments, which talks about some of the other EU-subsidized idiotic projects that have been built on El Hierro. It also mentions that depending on who's doing the calcs, the storage would have to be 5, 20 or even 200 times larger to supply 100% from renewables, which is what many of us have been saying for a couple of years now.


El Hierro has roughly two day's worth of storage. I don't think any reasonable design would need 400 days of storage.

To need 400 days of storage, you would need to be bridging gaps in production of over a year. Wind just isn't that variable.

Depends on what you mean by 'two days storage,' as that's highly dependent on how they use the reservoir. I agree that 200 times seems too high to me, but as we don't have the details of the calcs that went into that or the other (5 and 20x) estimates, it's impossible to say for sure. Still, given their less than optimum use of the reservoir, there may be situations that require 200x. What is clear is that the storage is wholly inadequate to approach let alone achieve 100% renewables, as many of us were saying early on once we had details of the design. It seems pretty clear that this system should have been designed as a PV/wind hybrid, given the large seasonal swings in wind availability and the inadequate storage.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

WetEV
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Re: Economics of Renewable Power, simplified.

Wed Nov 30, 2016 8:52 pm

GRA wrote:
WetEV wrote:El Hierro has roughly two day's worth of storage. I don't think any reasonable design would need 400 days of storage.

To need 400 days of storage, you would need to be bridging gaps in production of over a year. Wind just isn't that variable.

Depends on what you mean by 'two days storage,' as that's highly dependent on how they use the reservoir.


Currently, they mostly seem to not be using the reservoir as pumped storage. However, if they pumped empty the lower reservoir into the larger upper reservoir, then used the water to generate electric power as it refilled the lower reservoir, the hydro power generated alone could provide enough for average load for about two days.
WetEV
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GRA
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Re: Economics of Renewable Power, simplified.

Tue Feb 28, 2017 8:42 pm

http://euanmearns.com/an-independent-evaluation-of-the-el-hierro-wind-pumped-hydro-system/
Generally agrees with what many of us have been saying about the undersizing of the storage and the fact that the system had no hope whatsoever of achieving 100% wind even if it had worked as designed, but goes into far more detail about how much it's undersized, (possibly) why, and why it's been operated in the way it has been.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.

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RegGuheert
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Re: Economics of Renewable Power, simplified.

Thu May 18, 2017 5:24 pm

Judith Curry has an excellent guest post looking at the feasibility of a 100% renewable electricity grid in Texas. Texas is a good choice for evaluation since it uses 10% of all the electricity in the U.S., has excellent renewable resources, and has lots of available land area available for generation.

The article is encouraging about the technical possibility for achieving this goal. It will investigate costs in a second post.

One item which was particularly interesting to me was the mention of a new approach to long-term energy storage based on solid-oxide fuel cells which utilize CO2 and methane and can achieve a 70% round-trip efficiency. That's the kind of performance we need to achieve to make long-term storage a viable possibility.
RegGuheert
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SageBrush
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Re: Economics of Renewable Power, simplified.

Fri May 19, 2017 9:26 am

GRA wrote:http://euanmearns.com/an-independent-evaluation-of-the-el-hierro-wind-pumped-hydro-system/
Generally agrees with what many of us have been saying about the undersizing of the storage and the fact that the system had no hope whatsoever of achieving 100% wind even if it had worked as designed, but goes into far more detail about how much it's undersized, (possibly) why, and why it's been operated in the way it has been.

I went back to 2014 articles and found assessments of ~ 65% renewable generation. Still double the two year average output. I'd love to see a break-down of generation:

Wind power to grid
Wind power diverted to pump
Pumped water efficiency

It was interesting to note that the nameplate capacity of the wind-farm is about the same as the fossil fuel plant. That sounds way optimistic from the get go. Perhaps adding more wind capacity in the form of more windmills or a refit to bigger blades will help.

Addendum:
http://euanmearns.com/an-independent-ev ... ro-system/

Does a good job of explaining the problems(s):
1. Inadequate storage (the upper storage turned out to be geologically unstable)
2. Very high seasonal variability

Their choice really does seem to be building excess wind for part of the year.
I wonder if the desalination could be a power sink.
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