Reedy Creek and Solar Energy

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Retired and living 2 miles from The Castle.
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Apr 29, 2004
So, this really isn't related to the podcast but several threads on the boards have discussed the new solar facilities and conventional electrical generation on WDW property. Energy geeks may want to review Reedy Creek's 2018 Annual Report which can be downloaded from their web site, along with several other documents. https://www.rcid.org/documents/

Of note, the new 50 MW solar farm that came on line in late 2018, is widely referred to in various news stories as being able to provide 25-50% of WDW's electric needs. More info in the report (Section 3-6) indicates an expected annual generation of 120,000 MWh annually. By comparison, Reedy Creek's peak electric demand in 2018 was 181 MW. Their total electric consumption was 1,135,868 MWh as shown on Table 2-1 of the report.

By my calculation:
MW = 50/181 = 27%
MWh = 120,000/1,135,868 = 10.6%

Draw whatever conclusions you like....
 
I read the definitions but still struggle to comprehend the relationship or differences between megawatts and megawatt hours (or kilowatts and kilowatt hours). I thought one is flow and the other volume. :teacher: But why would the MW percentage be so different that the MWh percentage? I have to have things like this explained to me like I have two degrees in music. :duck::listen:
 
I read the definitions but still struggle to comprehend the relationship or differences between megawatts and megawatt hours (or kilowatts and kilowatt hours). I thought one is flow and the other volume. :teacher: But why would the MW percentage be so different that the MWh percentage? I have to have things like this explained to me like I have two degrees in music. :duck::listen:

MW is a measure of power. MWh is a measure of energy (i.e. how many MW of power can be extracted in 1 hour).
 
@jcb think of it simply the difference between an instantaneous measure and that over time. For example, a 100 watt light bulb is just that, 100 watts. But if you leave it on for an hour, you consume 100 watt hours.
 
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MW is peak demand for a certain time period, whereas the MWh is the consumption over the year (or whatever measurement period they used). So if the 50MW farm had energy storage (in MWh) that percentage would be vastly different. Just by adding another 120,000 MWh of energy storage would equate to nearly 20% utilization of the PV farm. Now you can see that adding batteries/energy storage to a PV field really can optimize the efficiency.

As far as I know the WDW solar farm does not have energy storage at this time. But, FPL is building a massive solar farm with storage containers full of batteries to harvest the energy from PV and use it on demand (not just when the sun is shining). I foresee that WDW will either add containers in the future or if they create new PV farms it will be included.

http://newsroom.fpl.com/2019-03-28-...elerated-retirement-of-fossil-fuel-generation
 
But why would the MW percentage be so different that the MWh percentage?
Forgot to answer this part of your question. The MW percentage is the capability of the array to the total requirement. But it ignores the simple fact that while the array is capable of producing 50 MW under optimum conditions, those conditions don't happen 24/7.
 
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MW is peak demand for a certain time period, whereas the MWh is the consumption over the year (or whatever measurement period they used). So if the 50MW farm had energy storage (in MWh) that percentage would be vastly different. Just by adding another 120,000 MWh of energy storage would equate to nearly 20% utilization of the PV farm.
But that assumes that there is excess capacity of the farm during part of the day that can be used to charge those batteries.
 


@jcb think of it simply the difference between an instantaneous measure and that over time. For example, a 100 watt light bulb is just that, 100 watts. But if you leave it on for an hour, you consume 100 watt hours.

It sure doesn't help that LED bulbs still say they are 100 watt equivalent bulbs but no longer consume 100 watts of electricity. But I digress.

MW is a measure of power. MWh is a measure of energy (i.e. how many MW of power can be extracted in 1 hour).

So, it's the difference between He-Man and Hercule Poirot's "little gray cells"?

I can explain almost any legal principle but amps, volts, and watts give me fits.
 
Last edited:
So, this really isn't related to the podcast but several threads on the boards have discussed the new solar facilities and conventional electrical generation on WDW property. Energy geeks may want to review Reedy Creek's 2018 Annual Report which can be downloaded from their web site, along with several other documents. https://www.rcid.org/documents/

Of note, the new 50 MW solar farm that came on line in late 2018, is widely referred to in various news stories as being able to provide 25-50% of WDW's electric needs. More info in the report (Section 3-6) indicates an expected annual generation of 120,000 MWh annually. By comparison, Reedy Creek's peak electric demand in 2018 was 181 MW. Their total electric consumption was 1,135,868 MWh as shown on Table 2-1 of the report.

By my calculation:
MW = 50/181 = 27%
MWh = 120,000/1,135,868 = 10.6%

Draw whatever conclusions you like....
Where did you get the 50% figure from? This is the article I remember reading and it says 25% under peak conditions:
At any moment, more than 500,000 panels that came online in December produce enough electricity to run two theme parks. Under pristine sunny conditions, up to 25 percent of Walt Disney World Resort runs on solar power, company officials said. It comes as the company seeks to reduce emissions by 50% in 2020 compared to its 2012 levels.
https://www.orlandosentinel.com/business/os-bz-disney-solar-farm-20190418-story.html

25% peak from solar that takes 1/2 the day off. Add in cloudy and non-optimal conditions and 10.6% sounds about right.
 
Where did you get the 50% figure from? This is the article I remember reading and it says 25% under peak conditions:
Some folks have taken the statement that the array makes enough to power 2 theme parks as being 50% since there are 4 theme parks. Not my position, just what some have said.
 
widely referred to in various news stories as being able to provide 25-50% of WDW's electric needs.
Some folks have taken the statement that the array makes enough to power 2 theme parks as being 50% since there are 4 theme parks. Not my position, just what some have said.
What a ridiculous interpretation of that statement. Those people have somehow forgotten that there is far more to WDW than the 4 theme parks. What about the more than 25 hotels and resorts? Disney Springs? Two water parks? Obviously, Disney's energy usage is far greater than just what the 4 parks consume.
 
But that assumes that there is excess capacity of the farm during part of the day that can be used to charge those batteries.

Not if the farm is designed to charge the battery banks prior to deploying the remaining capacity to the micro-grid.

It makes no sense for the expensive battery containers to not be fully charged and staged for deployment. Some micro-grids partition the battery bank so there is always a capacity reserve to buffer outages while still using the other partition to feed overnight requirements. Once the battery bank has reached it's targeted SOC, then it requires very little amps to maintain it.

This is part of the reason why the 50MW PV farm at WDW off of 429 irks me each time I drive by it. It consumes many acres that offers zero contribution to the grid overnight (assuming that there is no storage). So while WDW gets major accolades for this farm, it lacks optimization based on the figures above. Of course, the $/Wh or $/W plays into the equation.
 
So, it's the difference between He-Man and Hercule Poirot's "little gray cells"?

I can explain almost any legal principle but amps, volts, and watts give me fits.

That's a good analogy, but I do think He-Man would still have more stamina/energy than Poirot.

I spent over a decade working directly with leading Ph.D battery cell designers (Energizer/General Electric). So by osmosis, I had to learn amps, volts and watts.
 
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Of course, the $/Wh or $/W plays into the equation.
Indeed. I'm not familiar with how the grid works in FL, nor am I familiar with the typical WDW load curve, but if they are buying/selling hourly then it may make more sense to have batteries that get charged when the price is low and used when the price is high.
 
Indeed. I'm not familiar with how the grid works in FL, nor am I familiar with the typical WDW load curve, but if they are buying/selling hourly then it may make more sense to have batteries that get charged when the price is low and used when the price is high.

Yes. There are monetary benefits for fast responding resources in both charge and discharge in the wholesale market (grid). For example, FERC order 755 rewarded solutions that offer the highest amount of MW mileage without having resources merely add costly capacity.

I'm very confident the WDW solar farm is helping flatten their duck curve. But as you pointed out with the MW ratio at about 27% on a singular peak demand, the contribution over, say, a year would be less.

Since our company was essentially, and discretely, in WDW's own backyard we had to research Florida grid operations and ISO/RTO's.

If you're interested, I can PM you one of my presentations I made at FPL (Florida Power and Light) for our battery/grid benefits.
 
Yes. There are monetary benefits for fast responding resources in both charge and discharge in the wholesale market (grid). For example, FERC order 755 rewarded solutions that offer the highest amount of MW mileage without having resources merely add costly capacity.

I'm very confident the WDW solar farm is helping flatten their duck curve. But as you pointed out with the MW ratio at about 27% on a singular peak demand, the contribution over, say, a year would be less.

Since our company was essentially, and discretely, in WDW's own backyard we had to research Florida grid operations and ISO/RTO's.

If you're interested, I can PM you one of my presentations I made at FPL (Florida Power and Light) for our battery/grid benefits.
I would like that. I'm a retired utility guy from New England and did a lot of work in the energy and transmission area.
 
Were you part of the NE-ISO? Did you work on regulation A and D signals?
I worked for one of the T&D companies in ISO-NE. I was a bean counter, so was dealing with annual revenue requirements and the impact of Transmission investments.
 

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