Nuclear + storage - Revision history

Trevor at 08:33, 23 August 2024

2024-08-23T08:33:47Z

Trevor at 08:22, 23 August 2024

2024-08-23T08:22:07Z

Trevor at 11:09, 20 October 2020

2020-10-20T11:09:32Z

Trevor at 11:03, 20 October 2020

2020-10-20T11:03:14Z

Trevor at 10:56, 20 October 2020

2020-10-20T10:56:49Z

Trevor at 10:19, 20 October 2020

2020-10-20T10:19:16Z

Trevor: /* Close-coupled nuclear generation & compressed air energy storage (CCNG-CAES) */

2020-10-20T09:50:48Z

‎Close-coupled nuclear generation & compressed air energy storage (CCNG-CAES)

Trevor at 09:44, 20 October 2020

2020-10-20T09:44:22Z

Trevor at 09:28, 20 October 2020

2020-10-20T09:28:28Z

Trevor: /* Close-coupled nuclear generation & compressed air energy storage (CCNG-CAES) */

2020-10-20T09:14:41Z

‎Close-coupled nuclear generation & compressed air energy storage (CCNG-CAES)

@@ Line 156: / Line 156: @@
 The size and scale of one compressor unit can be gauged from the access ladders in the following illustration:
-https://p3.aprimocdn.net/siemensenergy/f8bf87f9-03a9-484e-9c3d-b00d006a5e5d/GearlessCompressor-SS-Overhung-jpg_Original%20file.jpg
+[[File:GearlessCompressor-SS-Overhung-jpg Original file.png|800px]]
 Recall that the compressor stage is six lines of four compressors - and the expansion stage has 24 air turbine generators and 18 steam turbine generators

@@ Line 156: / Line 156: @@
 The size and scale of one compressor unit can be gauged from the access ladders in the following illustration:
-https://assets.siemens-energy.com/siemens/assets/api/uuid:f3c024e1-a924-44a5-b0f6-b7adf8fe990f/width:640/quality:high/gearlesscompressor-ss-overhung.jpg
+https://p3.aprimocdn.net/siemensenergy/f8bf87f9-03a9-484e-9c3d-b00d006a5e5d/GearlessCompressor-SS-Overhung-jpg_Original%20file.jpg
 Recall that the compressor stage is six lines of four compressors - and the expansion stage has 24 air turbine generators and 18 steam turbine generators

← Older revision		Revision as of 11:09, 20 October 2020
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	The question rather misses the point of the case study - which is to illustrate the sheer scale of the balance of plant required to provide 1.1 GW of discretionary power. Certainly the Coire Glas scheme has twice the storage and a greater output - but it doesn't produce any power in its own right, unlike CCNG-CAES. Many candidate sites for pumped hydroelectric energy storage are in the Scottish highlands and remote from electricity generation and demand; electricity transmission losses will not be trivial. And who knows what the future relationship between Scotland and the rest of the UK might be?		The question rather misses the point of the case study - which is to illustrate the sheer scale of the balance of plant required to provide 1.1 GW of discretionary power. Certainly the Coire Glas scheme has twice the storage and a greater output - but it doesn't produce any power in its own right, unlike CCNG-CAES. Many candidate sites for pumped hydroelectric energy storage are in the Scottish highlands and remote from electricity generation and demand; electricity transmission losses will not be trivial. And who knows what the future relationship between Scotland and the rest of the UK might be?

−	The feasibility of CCNG-CAES is subject both to the availability of suitable void from extractive industries and acceptable location of new nuclear generation build. It has least the potential of closer proximity to a high energy demand heavy industrial conurbation area.	+	The feasibility of CCNG-CAES is subject both to the availability of suitable void from extractive industries and acceptable location of new nuclear generation build. It has, at least '''''the potential''''' of bringing flexible output generation capacity at scale in closer proximity to a high energy demand heavy industrial conurbation area.

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 Each of six lines handles 850 tonnes per hour (850,000 kg) of air with the void pressure cycling between 5 MPa (50 bar) ‘discharged’ and 6 MPa (60 bar) ‘charged’. Density of air at 35°C at the two pressures is 56.85 kg/m³ and 68.21 kg/m³ respectively; difference is 11.37 kg/m³. One line for one hour therefore requires 74,787 cubic metres, multiplying by 6 lines and by 12 hours gives a total requirement of 5,385,000 m³.
-For example the void space at Veolia’s Minosus facility at Middlewich, Cheshire which is used for hazardous waste storage was 23 million cubic metres (2006). Ongoing salt production of 1 million tonnes per year produces new void of about ½ million m³ a year.
+To put this requirement in context, salt mining / extraction creates large volumes of void space and salt mines are favoured locations for compressed air storage. The void space at Veolia’s [https://www.veolia.co.uk/sites/g/files/dvc1681/files/document/2015/04/Minosus_Brochure_PDF.pdf Minosus] facility at Middlewich, Cheshire which is used for hazardous waste storage was an estimated 23 million cubic metres in 2006. Ongoing salt production of 1 million tonnes per year produces new void of about ½ million m³ a year.
 ==Compression stage==

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 So comparing cases, without storage the nuclear power station delivers 16 GW-h electricity continuously over a 24-hour period while the CCNG-CAES generates 13.2 GW-h for 12 hours and nothing for the other 12. The analogy is inexact but the system is in effect a 13.2 GW-h battery with a round trip efficiency of 82.5%
-It is also informative to compare this with SSE’s Coire Glas pumped hydroelectric scheme – 30 GW-h storage with 1.5 GW input/output
+It is also informative to compare this with SSE’s Coire Glas pumped hydroelectric scheme – 30 GW-h storage with 1.5 GW input/output https://www.sserenewables.com/hydro/coire-glas/
 ==Flow diagrams==
@@ Line 162: / Line 162: @@
 ==Is it worth it?==
-The question rather misses the point of the case study - which is to illustrate the sheer scale of the balance of plant required to provide 1.1 GW of discretionary power. Certainly the Coire Glas has twice the storage and a greater output - but it doesn't produce any power in it's own right, unlike CCNG-CAES. Many candidate sites for pumped hydroelectric energy storage are in the Scottish highlands and remote from electricity generation and demand; electricity transmission losses will not be trivial.
+The question rather misses the point of the case study - which is to illustrate the sheer scale of the balance of plant required to provide 1.1 GW of discretionary power. Certainly the Coire Glas scheme has twice the storage and a greater output - but it doesn't produce any power in its own right, unlike CCNG-CAES. Many candidate sites for pumped hydroelectric energy storage are in the Scottish highlands and remote from electricity generation and demand; electricity transmission losses will not be trivial. And who knows what the future relationship between Scotland and the rest of the UK might be?
 The feasibility of CCNG-CAES is subject both to the availability of suitable void from extractive industries and acceptable location of new nuclear generation build. It has least the potential of closer proximity to a high energy demand heavy industrial conurbation area.

@@ Line 15: / Line 15: @@
 It is also informative to compare this with SSE’s Coire Glas pumped hydroelectric scheme – 30 GW-h storage with 1.5 GW input/output
-==Flow diagram==
+==Flow diagrams==
 * [[Media:CCNGCAES.pdf|Flow & T-s (temperature-entropy) diagrams]]
@@ Line 157: / Line 159: @@
 Recall that the compressor stage is six lines of four compressors - and the expansion stage has 24 air turbine generators and 18 steam turbine generators

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-=Close-coupled nuclear generation & compressed air energy storage (CCNG-CAES)=
+==Close-coupled nuclear generation & compressed air energy storage (CCNG-CAES)==
 This case study – original work © Fluke – illustrates the scale of operation needed to provide 1.1 GW (one gigawatt) of electricity on a twelve hours on, twelve hours off cycle. This could be used for peak shaving renewable energy or balancing periods of low and high demand.
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 It is also informative to compare this with SSE’s Coire Glas pumped hydroelectric scheme – 30 GW-h storage with 1.5 GW input/output
 ==Void requirement==

← Older revision		Revision as of 09:44, 20 October 2020
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	\|}		\|}
		+
		+	==Mechanical equipment==
		+
		+	Siemens Energy offer a range of single-stage radial compressors:
		+
		+	* Volume flow rates up to 1,000,000 m³/h / 590,000 cfm
		+	* Pressure ratio up to ~3 (up to ~6.5 in case of 2 units)
		+	* Suitable for electric motor, steam turbine or gas turbine drive
		+
		+	The size and scale of one compressor unit can be gauged from the access ladders in the following illustration:
		+
		+	https://assets.siemens-energy.com/siemens/assets/api/uuid:f3c024e1-a924-44a5-b0f6-b7adf8fe990f/width:640/quality:high/gearlesscompressor-ss-overhung.jpg
		+
		+	Recall that the compressor stage is six lines of four compressors - and the expansion stage has 24 air turbine generators and 18 steam turbine generators

@@ Line 23: / Line 23: @@
 ==Compression stage==
-Fresh air intake (design conditions 20°C, 1 bar) is compressed in four stages with intermediate and final pressures respectively 2.8 bar, 7.8 bar, 22 bar and 60 bar (6 MPa); the pressure ratio at each stage is ~2.8. Compression is carried out with an assumed isentropic efficiency of 0.85 and the procedure can conveniently be calculated by spreadsheet, using an equation of state for air that provides temperature as a function of (pressure, enthalpy) or (pressure, entropy); enthalpy function of (temperature, pressure) or (pressure, entropy) and entropy as a function of (temperature, pressure). For this study the equation of state used was the NIST Refprop 9.0 program. The following table illustrates the basic equations used to construct the spreadsheet
+Fresh air intake (design conditions 20°C, 1 bar) is compressed in four stages with intermediate and final pressures respectively 2.8 bar, 7.8 bar, 22 bar and 60 bar (6 MPa); the pressure ratio at each stage is ~2.8. Intercooling to 35°C is provided between stages and after the final stage prior to storage. Compression is carried out with an assumed isentropic efficiency of 0.85 and the procedure can conveniently be calculated by spreadsheet, using an equation of state for air that provides temperature as a function of (pressure, enthalpy) or (pressure, entropy); enthalpy function of (temperature, pressure) or (pressure, entropy) and entropy as a function of (temperature, pressure). For this study the equation of state used was the NIST Refprop 9.0 program. The following table illustrates the basic equations used to construct the spreadsheet
 {|
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 ==Expansion stage==
 {|

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 |-
 |2'
-|Compression(IE=0.85)
+|Compression (IE=0.85)
 |T2'=fn(P2',h2')
 |P2'=P2
@@ Line 66: / Line 66: @@
 |-
 |4'
-|Compression(IE=0.85)
+|Compression (IE=0.85)
 |…
 |-
 |5
 |Intercooling
 |…
+|