MASTER THESIS REMENA PROGRAM DISPATCHABLE … · by: mahmoud hosny ibrahim mahrous (batch 6) supervisors: prof.dr. adel khalil (ucai) prof.dr.sc- techn.dirk dahlhaus (ukas) dipl.-ing.massimo

BY : MAHMOUD HOSNY IBRAHIM MAHROUS (BATCH 6)

SUPERVISORS: PROF. DR. ADEL KHALIL (UCAI)

PROF. DR. SC- TECHN. DIRK DAHLHAUS (UKAS)

DIPL.- ING. MASSIMO MOSER (DLR)

EXAMINERS: PROF. DR. ADEL KHALIL

PROF. DR. MOHAMED EL-SOBKI

PROF. DR. SAYED KASSEB

DISPATCHABLE RENEWABLE POWER

TECHNOLOGIES THROUGH THE INTEGRATION

OF [PUMPED] THERMAL ENERGY STORAGE

MASTER THESIS – REMENA PROGRAM

6 / 9 / 2015

OUTLINE

1. Motivation and Intention

2. Introduction

3. Aim of Work

4. Energy Storage Technologies

5. Compressed Heat Electricity Storage (CHEST) Model

Setup

6. CHEST Sensitivity Analysis

7. Case Study – Future Study

8. Conclusion and Outlook

6/9/2015 2 M.SC . MAHMOUD H. I. MAHROUS – REMENA



The need for Electricity

Pollution

Global warming.

Bridge temporal and geographical

gaps between energy supply and

demand

Dispatchable Renewable Power

Technology

Source: Smart Energy for Europe Platform GmbH

(SEFEP): Technology Overview on Electricity

Storage; June 2012.

Flexibility requirements in the electricity grid © RENAC

OUTLINE


2. Introduction

3. Aim of Work



Setup





2. INTRODUCTION


Energy Storage Demand Supply

• Store excess energy

• Transition to a power system with high shares of fluctuating renewables bridge

the physical distance and the time difference between supply and demand

BLUE MAP – ENERGY STORAGE CAPACITY WORLDWIDE (2005-2050)


Source: IEA. Prospects for Large Scale Energy

Storage in Decarbinaisation Power Grids. Paris:

OECD/IEA : s.n., 2009.

OUTLINE


2. Introduction

3. Aim of Work



Setup





3. AIM OF WORK


Batteries

Pumped Hydro-

Storage (PHS)

Compressed Air

Energy Storage

(CAES)

Pumped Thermal

Electricity

Storage(PTES)

Energy Storage

Technologies Drawbacks

Low Energy

Density

Geographical

Constraints & Bad

Effect on the

Environment

Technically : ηRT

(CHEST)

OUTLINE


2. Introduction

3. Aim of Work



Setup





4. ENERGY STORAGE TECHNOLOGIES

10 M.SC . MAHMOUD H. I. MAHROUS – REMENA

Energy Storage

Technologies Application

Conventional

Resources

Renewables

Common Name Discharge Time Application

Power Quality Seconds to Minutes Frequency Regulation

Bridging Power Minutes to

approximately 1 hour

Contingency Reserves,

Ramping

Energy Management Hours Load Leveling, and

Firm Capacity

Source: Paul Denholm, Erik Ela, Brendan Kirby, and Michael Milligan.

The Role of Energy Storage with Renewable Electricity Generation.

s.l. : National Renewable Energy Laboratory- NREL, January 2010.

Technical Report. NREL/TP-6A2-47187.


Energy

Manage-

ment

Bridging

Power

Power

Quality

Source: Paul Denholm, Erik Ela, Brendan Kirby, and Michael Milligan.

The Role of Energy Storage with Renewable Electricity Generation.

s.l. : National Renewable Energy Laboratory- NREL, January 2010.

Technical Report. NREL/TP-6A2-47187.


Storage System

Design

Cost

(LEC) Efficiency

(ηRT )

OUTLINE


2. Introduction

3. Aim of Work


5. Compressed Heat Electricity Storage (CHEST)

Model Setup





5. CHEST – MODEL SETUP


Simplified scheme of the CHEST concept

Source: W.D. Steinmann. The CHEST concept for facility scale thermo

mechanical energy storage, German Aerospace center (DLR), Institute of

Technical Thermodynamics, Pfaffenwaldring 38-40, 70569, Stuttgart,

Germany, 8 April 2014.

General Idea


CHEST Cycles:






Cascaded system of CHEST concept

1. Ammonia (NH3)

compression cycle works

at low temperature levels

(<100 oC)

2. Steam compression cycle

works at high temperature

levels (>100 oC)

3. Steam expansion cycle


Three Aspects :

1. Thermal Storage for Steam cycle

Minimize Entropy generation resulting from of Charging and discharging

Adiabatic System

2. Compression of Steam


Cooling of compressed steam between two stages







Comparison of volume of saturated steam related to heat of evaporation depending on saturation

temperature

3. CHEST concept depends on the electrical excess energy produced from

Wind Power






First Cycle: Ammonia (NH3) Compression Cycle


Assumptions:

At inlet stage

1. Saturation pressure = 6.25

bar

2. Evaporation temperature =

10.5 oC

3. Mass flow rate = 1.0 kg/s

4. Maximum pressure = 42 bar

5. Condensation temperature =

80 oC

6. Polytropic efficiency

(compressors) = 0.90

7. Efficiency (Motor) = 0.97

Schematic diagram of the Ammonia compression cycle



Tool: Ammonia table online calculator is used here to present the T-S

diagram for ammonia compression cycle http://www.ammonia-

properties.com/NH3TablesWeb.aspx

6/9/2015

http://www.ammonia-properties.com/NH3TablesWeb.aspx





Points [kg/s] P [bar] T [oC] h [kJ/kg] W

[kW]

Q [kW] Extracted [kg/s]

From To From To From To Value Symbol

1a-1b 1 6.25 12.6 10.5 55.8 509.3 608 98.67

2a-2b 1.2895 12 27.3 30.2 88.2 523.6 640.7 150.977

3a-3b 1.6156 26 44.1 59.8 98 526.7 590.4 103.06

3d-3a 25.2 26 59.8 59.8 -365.1 526.7 1,440.75 0.1722 l

3d-2b 25.2 27.3 59.8 88.2 -365.1 640.7 154.69 0.1538 z

2d-2a 11.6 12 30.2 30.2 -480 523.6 1,294.28 0.1539 y

2d-1b 11.6 12.6 30.2 55.8 -480 608 147.424 0.1355 x

3d-2c 25.2 26 59.8 59.8 -365.1 -471.5 137.20 1.2895 1+x+y

3b-3c 44.1 42 98 80.7 590.4 -358.7 1,533.48 1.6156 1+x+y+z+l

2d-1c 11.6 12 30.2 30.2 -480 -616.1 136.1 1

1d-1a 6.25 6.25 10.5 10.5 -620.4 509.3 1129.71 1


Ammonia compression results


Total work required for ammonia (NH3) compression process: WNH3, compress

352.71 kW

Heat energy delivered from NH3 to H2O compression cycle for evaporation of H2O at 75 °C is: QNH3toH2O

1,533.48 kW

COP NH3, Compression 4.34



Second Cycle: Steam Compression Cycle

Assumptions:

At inlet stage

1. Saturation Pressure = 0.039

bar

2. Saturation Temperature = 75 oC


4. Maximum pressure = 110.25

bar

5. Saturation Temperature

at p max = 318.1 oC



7. Efficiency (Motor) = 0.97

0C

Schematic diagram of the steam compression cycle



Tool: The tool steam table online calculator is used here to present the

T-S diagram for steam compression cycle

http://www.steamtablesonline.com/steam97web.aspx

6/9/2015



Stages in

[kg/s]

P

[bar]

h

[kJ/kg]

T exit

[°C]

W comp

[kW]

desuperheat

[kg/s]

Q sto

From

Liquid

[kW]

extract

[kg/s]

Q sto

From

Extract

[kW]

Points Value Symbol Value Value Symbol Value Value

1 1a 1b 180.87 m 0.0629 98.83 k 0.0608 162.59

1 1 2,815.4 160.3

2 2a 2b 202.36 l 0.0728 122.96 0 0

1.002 2.6 2,875.1 193.4

3 3a 3b 250.04 z 0.0969 173.92 0 0

1.074 7.4 2949.1 236.8

4 4a 4b 295.16 y 0.1340 247.84 0

1.171 21 3,014.6 285.1

5 5a 5b 293.59 x 0.1823 321.13 g 0.319 893.56

1.306 52.5 3,023.2 325

6 6a 6b 205.67 0 321.09 0 0

1.168 110.25 2,970.2 361.5




Heat from desuperheating after compression stage 6 (points: 6b-6d) at (t > 361.5 °C)

296.92 kW

Heat from condensation after compression stage 6 (points: 6d-6c) at (t = 361.5 °C)

1,503.87 kW

Heat from cooling of liquid condensate (modular sensible heat storage system from sto_1 to sto_6) at (75 °C < t < 361.5 °C)

1,285.79 kW

Heat from condensation of saturated steam stored in (sto_6, sto_2) because of mass flow rates (k, g) extraction at (t = 100 °C, 263 °C)

1,056.16 kW

Total Heat to storage 4,142.74 kW

Total Compression work 1,427.72 kW

Heat required for evaporation of 1kg/s water at (p = 0.386 bar) (points: 0c-1a)

2,320.72 kW

COP Steam, Compression 2.90

Steam compression results



Third Cycle: Steam Expansion Cycle

Assumptions:

At inlet stage

1. Maximum Pressure = 80 bar

2. Saturation Temperature = 295 oC


4. Super heated steam

temperature = 340 oC

5. Reheated steam temperature =

270 oC

6. NaNO3: Solidification

Temperature = 305 oC



8. Efficiency (Generator) = 0.97

Schematic diagram of the steam expansion cycle



Tool: The tool steam table online calculator is used here to present the

T-S diagram for steam expansion cycle


6/9/2015




Point Work Heat

Process From To kW kW

High pressure

expansion

1 2 366.33 0

Intermediate

superheating

3 4 0 190.17

Low pressure

expansion

4 5 724.61 0

Condensation 5 6 0 1,878.75

Preheating low

temperature

6 7 0 588.35

Preheating high

temperature

7 8 0 554.4

Evaporation 8 9 0 1,441.53

Superheating 9 1 0 195.25

Points T

[°C]

P

[ bar]

h

[kJ/kg]

[kg/s]

1 340 80 2,953.9 1

2 179.9 10 2,587.5 1

3 179.9 9.7 2,777.1 0.906

4 270 2,987 0.906

5 27 0,035 2,187.1 0.906

6 113.2 0.906

7 179.9 10 762.7 1

8 295 80 1,317.1 1

9 295 80 2,758.6 1

Steam expansion results



Steam expansion results

Total Expansion work = W Exp, tot 1,091 kW

Total Heat required/added = Q3-4 + Q6-7 + Q7-8 + Q8-9 + Q9-1 2,969.7 kW

Total heat rejected during the cycle = Q5-6 1,878.7 kW



Combination between NH3 and H2O compression cycles

The required mass flow rate to provide the same amount of

heat from NH3 to Steam compression cycles =

QH2O, evaporate / QNH3 to H2O = 2,320.72/1,533.48

1.513 kg

The compression work in the NH3 cycle is increased from 352.71 kW to

533.78 kW

The sum of compression work in both cycles = 533.78 +

1,427.72

1,961.51 kW



Discharging cycle

The resulting roundtrip efficiency is [Energy-out / Energy-in] *ɳGenerator

*ɳMotor = [1,521.9/1,961.51] *0.97 *0.97

73 %

The resulting Thermal efficiency is [W Total, Turbine / Q add, Storage] =

1,521.9/4,142.7

36.73 %

System Energy Balance = Q add, Storage – Q rejected, Condenser – W Total, Turbine

= 4,142.7 – 2,620.8 – 1,521.9

0

• The discharging cycle requires 2,969.7 kW heat if 1kg of steam is evaporated and provides

1091 kW work; during charging, 4,142.74 kW have been stored.

• The mass in the evaporator of the discharging cycle can be increased to

(4,142.74/2,969.7) = 1.39 kg

• Because of the increasing in mass flow rate, the mechanical work is increased from 1,091

kW to 1,521.9 kW


Round-trip efficiencies for CHEST, PHS and CAES

80

60

73

0

10

20

30

40

50

60

70

80

90

100

0 0.5 1 1.5 2 2.5 3 3.5

Ro

un

d-t

rip

eff

icie

ncy

(%

)

Round-trip efficiencies (%) for PHS, CAES and CHEST storage

technologies

Round-trip efficiency (%)

Different cases of thermal energy storage technologies

CHEST

CAES

PHS

OUTLINE


2. Introduction

3. Aim of Work



Setup





6. CHEST – SENSITIVITY ANALYSIS


Parameters Symbol

1. Steam evaporation temperature T Steam evaporation (oC)

2. Maximum cycle temperature (expansion cycle) T Max = T 1 (oC)

3. Polytropic efficiencies (compressors and turbines) ɳ c, ɳ T (%)

4. Steam pressure ratio (compression cycle) β Steam

5. Motor and generator efficiencies ɳ M, ɳ G (%)

6. Ammonia mass flow rate (compression cycle) NH3 compression (kg/s)

7. Steam mass flow rate (compression cycle) Steam compression (kg/s)

8. Steam mass flow rate (expansion cycle) Steam expansion (kg/s)

Polytropic efficiencies



0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0.65 0.70 0.75 0.80 0.85 0.90 1.00

Po

wer

(k

W)

Turbine & Compressor eff (%)

Effect of polytropic efficiencies on Work and Heat

WNH3 comp T (kW)

W Steam comp T (kW)

W Steam exp T (kW)

Q NH3 to H2O (kW)

Q Steam comp T (kW)

Q Steam exp T (kW) 0.95

1.00

1.05

1.10

1.15

1.20

0.65 0.70 0.75 0.80 0.85 0.90 1.00

Ma

ss f

low

rate

rati

o


Effect of of polytropic efficiencies on (m.) between

compression cycles

mass flow rate ratio from

NH3 to Steam compression

mass flow rate ratio from

Steam Charge to discharge

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0.3

0.4

0.6

0.7

0.9

1.0

0.65 0.70 0.75 0.80 0.85 0.90 1.00

CO

P

Eff

icie

ncy

(%

)


Effect of polytropic efficiencies on (COP, thermal and roundtrip

efficiencies)

η th exp (%)

η RT (%)

COP of NH3

Compression

COP of Steam

Compression



Result´s analysis and discussion

Parameter Affected values Symbol W NH3 comp

tot (kW) W Steam comp

tot (kW) WSteam exp tot

(kW) Q NH3 to H2O

(kW) Q Steam comp

tot (kW) Q Steam exp tot

(kW)

T Steam evaporation

(oC)

___ Decrease ___ ___ Decrease ___

T Max = T 1 (oC) ___ ___ Increase ___ ___ Increase

β Steam ___ Increase ___ ___ Increase ___

ɳ c, ɳ T (%) Decrease Increase Decrease Appr. Constant Decrease Appr. Constant

ɳ M, ɳ G (%) ___ ___ ___ ___ ___ ___

NH3 compression

(kg/s)

Increase ___ ___ Increase ___ ___

Steam

compression (kg/s)

___ Increase ___ ___ Increase ___

Steam expansion

(kg/s)

___ ___ Increase ___ ___ Increase



Result´s analysis and discussion

Parameter Affected values Symbol COP NH3

Compression COP Steam

Compression η th exp (%) η RT (%) ratio NH3 to

Steam

compression

ratio Steam

Charge to

discharge

T Steam evaporation

(oC)

___ Increase ___ Increase Decrease Decrease

T Max = T 1 (oC) ___ ___ Appr. Constant Increase ___ Decrease

β Steam ___ Decrease ___ Decrease ___ Increase

ɳ c, ɳ T (%) Increase Decrease Increase Increase Increase Increase

ɳ M, ɳ G (%) ___ ___ ___ Increase ___ ___

NH3 compression

(kg/s)

___ ___ ___ Decrease Decrease ___

Steam compression

(kg/s)

___ ___ ___ Decrease Increase Increase

Steam expansion

(kg/s)

___ ___ ___ Increase ___ Decrease

OUTLINE


2. Introduction

3. Aim of Work



Setup





7. CASE STUDY – FUTURE STUDY


Power SM 2 SM 3

P parasitics (sf+tes+pb) 5 7.2 MW

Pel net 45 42.8 MW

Q to be cooled 83.3 83.3 MWth

Gross turbine efficiency 0.375 0.375 -

Qturb 133.3 133.3 MWth

Solar field & storage SM 2 SM 3 Unit

Q sf (considering SM)design 267 400 MWth

A sf 0.513 0.769 km2

Number of loops 156 234 -

Number of collectors rows

per subfield

39 59 -

Required land for solar

field

1.69 2.54 km2

TES capacity 752 1,504 MWhth

FLH 3,755 5,177 hr

The modeled CSP plant in southern Spain - 50 MW - Parabolic Trough technology

DNI =2,118 kWh / (m2*year).

1. CSP combined with Molten salts storage model


Investment

assumptions SM 2 and

SM 3 Spec inv SF 220 €/m2

Spec inv TES 44 €/MWhth

Spec inv back-up

boiler 270 €/kWel

Spec inv PB 1,000 €/kW

Spec inv. cooling 150 €/kWel

Debt Period 25 y

Discount rate 8 %

O&M Rate 2 % of Tot.

Inv./y Insurance Rate 0.5 % of Tot.

Inv./y spec inv FUEL 20 €/MWh

Boiler efficiency 0.85 -

Cost SM 2 SM 3

Annual Capital

cost 20.3 28.7 Mio. €/ y

O&M cost 4.3 6.1 Mio. €/ y

Insurance cost 1.1 1.5 Mio. €/ y

Fuel cost 0 0 Mio. €/ y

Total cost 25.7 36.4 Mio. €/ y

Levelized Electricity Cost (LEC)

SM 2 SM 3

Electricity (net

production) 147.5 191 GWhel /

year

Total cost 25.7 36.4 Mio. €/ y

LEC 17.45 19.03 €cent/kWh


1. CSP combined with Molten salts storage model


2. Wind Power Park (50 MW) combined with CHEST concept model

Aggregated Wind Power Park electricity production each week for one year of 50 MW capacity in

Northern Germany



2. Wind Power Park combined with CHEST concept model

0

5

10

15

20

25

30

35

40

45

50

1 5 9 13 17 21 25 29 33 37 41 45 49 53

Win

d e

lect

rici

ty p

rod

uct

ion

(M

W)

Number of weeks for one year

The effect of multiple base loads on the storage of the wind park electricity

production of (50 MW) capacity

Aggregated wind park production

value per week (MW)

Baseload_case 1 (25 MW)

Aggregated excess energy value per

week_case 1 (MW)



week_case 2 (MW)



week_case 3 (MW)

Generation, Load and excess energy curves of 50 MW capacity




Installed Wind Capacity 50 MWel

Base Load 20 MWel

Turbine Capacity 20 MWel

Round-trip-efficiency 73 %

1 $ 0.9 €

1 kW 1.341 hp

Cost Compressors 7190$*hp^0.62

PCM 100 €/kWh

Sensible Heat material 50 €/kWh

Turbine 1000 €/kW

Assumptions




FLH Wind (total, without losses) 3,191 h/y

FLH wind, direct 2,164 h/y

FLH CHEST 187 h/y

FLH (Sum wind, direct + CHEST) 2,351 h/y

FLH Fossil backup 1,153 h/y




Inputs

Installed Wind Capacity 50 MWel

Base Load 20 MWel

Turbine Capacity 20 MWel

Round-trip-efficiency 73 %

Storage Capacity 160 MWh

PCM (52 % total TES capacity) 83.2 MWh

Compressor capacity 30 MWel

Power Generation (Wind + CHEST) 118 GWh/y



Investment assumptions

Wind 1,250 €/kW

Compressors 172 €/kW

Turbine 1,000 €/kW

PCM 100 €/kWhth

Sensible Heat material 50 €/kWhth

Debt Period 25 y

Discount rate 8.0 % %

O&M Rate 2.0 % %of Tot. Inv./y

Insurance Rate 0.5 % %of Tot. Inv./y

spec inv FUEL 20.0 €/kWh

Investment

Wind 62.5 Mio. €

Compressors 5.1 Mio. €

Turbines 20 Mio. €

PCM 8.32 Mio. €

Sensible material 3.84 Mio. €

Total Investment 99.8 Mio. €




Cost

Annual Capital cost 9.3 Mio. €/ y

O&M cost 2.0 Mio. €/ y

Insurance cost 0.5 Mio. €/ y

Fuel cost 0.0 Mio. €/ y

Total cost 11.8 Mio. €/ y

LEC

El prod net 117.6 GWh el/year

Total cost 11.8 Mio. €/ y

LEC 10.08 €cent/kWh



OUTLINE


2. Introduction

3. Aim of Work



Setup





8. CONCLUSION AND OUTLOOK Conclusion

Innovative storage types are required which are as far as possible free of the aforementioned constrains (CHEST concept), which has been recently proposed by DLR.

Main findings

CHEST concept has no specific geological requirements and negligible environmental impact.

It can integrate low temperature heat sources which is used instead of the NH3 compression cycle (Solar Water Heaters).

It can work for the small scale and large scale systems (1MW-100 MW)

ɳRT = 73 % and ɳth = 36.73 %.

Future requirements

Preliminary economic analysis still has to be performed.

CHEST concept integration in large scale electricity networks should be evaluated with adapted tools such as REMix.


THANK YOU


MASTER THESIS REMENA PROGRAM DISPATCHABLE … · by: mahmoud hosny ibrahim mahrous (batch 6) supervisors: prof.dr. adel khalil (ucai) prof.dr.sc- techn.dirk dahlhaus (ukas) dipl.-ing.massimo

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