Repowering of Old Power Stations

1

تطوير محطات توليد الطاقة القديمة

Prof. Jamal Othman & Eng. Ahmad Abbas

Amman, 4-5 Sep. 2016

Electricity Efficiency in Generation, Transmission, and Distribution of Electricity Systems

2 Contents

Energy in Jordan 1

Objectives 2

Methodology 3

Results 4

Main Findings 5

6 Future Work

The most serious challenge of development in Jordan

Till 2015, share of the renewable energies in total energy mix is less than 1%.

3

Energy in Jordan

Steam Units, 20.0%

Gas Turbine, 44.9%

Combined Cycle, 28.8%

Renewable, 0.3%

Industrial (Self-

generation), 6.0%

Other, 6.3%

Lack of Conventional

Energy Resources

Increasing Energy

Demand

Dependence on Imported Fossil-Fuel

Jordan has an ambitious target for current energy situation as mentioned in “Updated Master Strategy for Energy Sector in Jordan 2007 - 2020” presented by:

Solar energy is one of the renewable resources that have high potentials in the country. Concentrated Solar Power (CSP) is one of proven solar technologies in worldwide and highly applicable in Jordan.

4 Energy in Jordan

Reduce dependence

on imported energy

sources

Share of RE to reach

10% by 2020 (Solar and Wind Projects)

In this study; integration of one of CSP technologies with existing fossil-fueled power plant (Steam cycle) to be presented.

This integration presented by; substituting turbine’s steam extractions for feedwater heaters in power plant by introducing a CSP technology.

Importance of this work: 1. Improve the performance of existing Rankine cycle

2. Reduce fuel consumption and

3. Reduce greenhouse gases (GHG) emissions.

5 Scope of Work and Objectives

The study will follow below main points:

6 Methodology

Select a Local Existing Power Plant The old 33 MW Unit at HTPP

Study Different CSP Technologies & Conduct a Comparison Between Them

Select One of CSP Technologies

Develop a Simple Simulation Model Based on Energy and Mass Balance

Conduct Technical, Economic and Environmental Aspects

What is CSP? (a Brief Concept of CSP)

C S P

Concentrated Solar Power

CSP is one of renewable solar energy technologies.

CSP technology simply is reflectors/absorber combination:

Reflectors >>> Mirrors ( Flat or curved mirrors )

Absorber >>> Dark receiver ( Tube or cavity )

7

8 Four CSP Technologies

9 Comparison of CSP Technologies PTC LFR CRS DE

Tracking 2D, one-axis 3D, two-axis

Capacity (MW) Up to 360 Up to 40 Up to 400 Up to 1.5

Working Fluid Water/Oil Water Water/Oil/Air H2/He

Fluid Temp. Range ( ̊C )

150 - 550 150 - 450 300 - 1000 250 - 700

Concentration Ratio 30 - 80 200 - 1000 1000 - 3000

Maturity Commercially Proven Pilot Projects

Relative Cost Low Very low High Very High

Storage Yes Shot-term Yes Not yet

Integration with fossil fuel PP

Yes and direct Yes Not planned

Example SEGS / USA (354 MW)

Puerto Errado / Spain (31.4 MW)

Ivanpah SEGS / USA (392 MW)

Maricopa / USA (1.5 MW)

10 Selected CSP Technology

Parabolic trough collector (PTC) with direct steam generation was the selected CSP technology; since PTC has below advantages:

1 Commercially proven CSP technology

2 Low cost (capital and O&M) with respect to CRS and DE

4 Possibility of direct steam generation (DSG)

5

3 Low relative area required

Providing temperatures and pressures close to those required by FWHs

11 Existing Steam (Rankine) Cycle for 33 MW Unit at HTPP

Heat balance diagram for 33 MW unit at HTPP

Six scenarios were assumed for FWHs solar replacement, this options summarized as in below table:

12 Assumed Replacement Options

No. of Option

Replacement Option

Steam Bleed Saved (ton/h)

Thermal Energy Rate (kcal/h)

1 FWH #1 6.88 4,939,152

2 FWH #1+2 13.09 9,220,947

3 FWH #1+2+3 19.81 13,627,923

4 FWH #4+5 6.88 4,232,450

5 FWH #5 1.38 814,200

6 All FWHs 26.69 17,860,373

When first replacement done; this is how will the cycle affected:

13 Results:

As no steam extraction to be occurred from turbine for FWH#1 then, more work output available for generator, as well as the efficiency of current cycle will be increased, and same procedure done for all FWHs replacement scenarios.

14

Results: Replacement of FWH #1:

And table below shows the conclusion of all replacement options:

Replacement Option

Steam Bleed Saved (ton/h)

Thermal Energy Rate (kcal/h)

Cycle Efficiency η (%)

w/o Solar 0 --- 29,175,210 33.63%

FWH #1 6.88 4,939,152 30,076,590 34.67%

FWH #1+2 13.09 9,220,947 30,716,004 35.41%

FWH #1+2+3 19.81 13,627,923 31,180,881 35.94%

FWH #4+5 6.88 4,232,450 29,362,220 33.84%

FWH #5 1.38 814,200 29,177,970 33.63%

All FWHs 26.69 17,860,373 31,315,484 36.10%

Before Solar After Solar Addition

Work output (kcal/h) 29,175,210 30,076,590 901,380 ↑

Cycle Efficiency 33.63% 34.67% 1.04% ↑

15

Turbine Output Work and Cycle Efficiency for Each Option

29,175

30,077

30,716

31,181

29,362

29,178

31,315

33.63%

34.67%

35.41%

35.94%

33.84%

33.63%

36.10%

33.00%

33.50%

34.00%

34.50%

35.00%

35.50%

36.00%

36.50%

37.00%

28,000

28,500

29,000

29,500

30,000

30,500

31,000

31,500

Cyc

le E

ffic

ien

cy

Tu

rbin

e w

ork

Ou

tpu

t (k

ca

l/h

) x 1

000

Replacement Options

Turbine Work Output Cycle Efficiency

Results:

16

Simulation a CSP System

System Advisor Model (SAM) by NREL was used as a simulation tool for optimizing PTC system.

Solar irradiation data available at the Hashemite University were used and weather data were obtained by Atmospheric Science Data Center (administered by NASA) for selected power plant location.

SAM provides:

1. Required solar field aperture area (in m2)

2. System active hours (8670 hours in the year)

3. Out-of-service days (365 days in the year)

17 Results of Simulation for FWH#1

SM: the factor by which solar field amplified in relation to rated capacity required at design point.

Active hours out of 8760 hours

Out-of-service days out of 365 days

Input Parameters Output of PTC

Replacement Option

Solar

Multiple (SM)

Required

Thermal Power

Output (MWth)

Steam

Output/Input

Temperatures

(°C)

Solar Field

Aperture (m2)

Active

Hours (hour)

Out of

Service Days

FWH#1 1.50 5.74 300/160 13,160 2,043 91

18 Results of Simulation for FWH#1

19 Selection a CSP System In order to increase active hours and operating days; larger solar

field required. Then six simulations for each replacement option were done in range of (1.50 - 2.75, with 0.25 step) SM values; in order to determine the optimal SM value.

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00

Ap

ert

ure

Are

a (

m2)

Solar Multiple

FWH #1

FWH #1+2

FWH #1+2+3

FWH #4+5

FWH #5

All FWHs

20 Results Verification

Two methods were used to check validity of calculated solar field aperture area:

1- Mathematical equation for estimation the aperture area proposed by Kalogirou.

By using Kalogirou’s equation, aperture area was found to be about 12,084 m2, which is less than obtained in SAM by 8%.

2- Technical comparison with existing commercial CSP plants:

By obtaining average “area-to-thermal power” ratio (m2/MWth) for plants like Shams 1, Andasol, SEGS, etc. and it was around 1,470

m2/MWth. So aperture area found to be about 12,657 m2 which is less than obtained in SAM by 4%.

21 Cost of PTC System Based on World Bank Report, 2011 and “Cost Model” developed

by NREL; different cost factors were assumed to estimate the cost of installed PTC system.

Total capital cost for first case (FWH#1, SM=1.5) was calculated as below:

Parameter Cost Factor Cost of FWH#1, SM=1.5 (US$)

Direct Capital Cost

Site Improvement (US$/m2) 10.0 131,600.0

Solar Field (US$/m2) 400.0 5,264,000.0

HTF System (US$/m2) 5.0 65,800.0

Contingency (% of total direct cost) 3% 163,850.0

Indirect Capital Cost

EPC (Engineering, procurement and construction) (% of total direct cost) 10% 562,530.0

Total Capital Cost (Direct & Indirect) 6,187,780.0

Annual Running Cost

O&M (labor and material) (US$/kW-year) 12.0 68,880.0

22 Cost of PTC System Share of direct and indirect parameters in total capital cost for

FWH#1:

Site Improvement

2%

Solar Field 85%

HTF System 1%

Contingency 3%

EPC 9%

23 Fuel Savings Fuel savings for FWH#1 with different SM values were as below

table:

Based on this, cost for all FWHs replacement options with different SM values were done. After that, SPBP was carried out for all options.

SM Solar Field

Aperture (m2)

Total

Capital

Cost (M.US$)

US$/kWth Ratio

Actual Active Hours (hour)

Thermal Energy

Saved (kcal×109/yr.)

Fuel

Saving

(US$/yr.)

Simple

Payback

Period (year)

1.50 13,160 6.188 1,077 2,002 11.237 541,046 11.44

1.75 15,275 7.182 1,251 2,377 13.344 642,476 11.18

2.00 17,390 8.177 1,424 2,649 14.868 715,834 11.42

2.25 19,505 9.171 1,597 2,853 16.012 770,918 11.90

2.50 21,855 10.276 1,789 3,018 16.941 815,674 12.60

2.75 23,970 11.271 1,962 3,105 17.425 838,979 13.43

24 Optimizing PTC System: Relation between SM values, total capital cost and SPBP for FWH#1:

Optimal SM value for this case at SM=2.00, and optimal values for other replacement options ranges between 1.75 - 2.00 SM values.

10.0

10.5

11.0

11.5

12.0

12.5

13.0

13.5

14.0

6

7

8

9

10

11

12

1.50 1.75 2.00 2.25 2.50 2.75

Sim

ple

Pa

yb

ac

k P

eri

od

(ye

ars

)

To

tal C

ap

ital C

ost

(US

$)

Millio

ns

Solar Multiple

Total Capital Cost Payback Period

25 Sensitivity Analysis

10.05

12.69

11.11

11.20

11.28

11.35

12.80

10.38

11.73

11.64

11.56

11.49

10.0 10.5 11.0 11.5 12.0 12.5 13.0

Solar field (400 ± 50 US$/m2)

Price of Fuel (488.2 ± 10% US$/ton)

EPC (10 ± 3% of total direct cost)

Contingency (3 ± 2% of total direct cost)

Site Improvement (10 ± 5 US$/m2)

HTF System (5 ± 2.5 US$/m2)

Payback Period (years)

Input Decreased Input Increased

26

Economic Analysis: Presented by cash flow diagram and Net Present Value (NPV).

Financial parameters (ex: inflation, discount rates, etc.) were assumed.

-8,1

76,7

00

475,4

73

496,4

56

518,1

72

540,6

23

563,8

06

587,7

14

612,3

33

637,6

44

663,6

21

690,2

30

846,6

58

888,9

91

933,4

40

980,1

12

1,0

29,1

18

1,0

80,5

74

1,1

34,6

02

1,1

91,3

32

1,2

50,8

99

3,4

82,9

66

-$10,000,000

-$8,000,000

-$6,000,000

-$4,000,000

-$2,000,000

$0

$2,000,000

$4,000,000

$6,000,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

-8,1

76,7

00

-7,7

01,2

27

-7,2

04,7

71

-6,6

86,5

99

-6,1

45,9

76

-5,5

82,1

70

-4,9

94,4

56

-4,3

82,1

23

-3,7

44,4

80

-3,0

80,8

59

-2,3

90,6

29

-1,5

43,9

72

-654,9

81

278,4

59

1,2

58,5

71

2,2

87,6

89

3,3

68,2

62

4,5

02,8

65

5,6

94,1

97

6,9

45,0

96

10,4

28,0

62

-$15,000,000

-$10,000,000

-$5,000,000

$0

$5,000,000

$10,000,000

$15,000,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

NPV of

+191,503 US$

PBP of 12 years

and 6 months

27 Sensitivity Analysis for NPV

11.38

-5.60

-4.29

4.20

3.61

3.00

0.87

2.38

2.06

2.05

-6.10

10.44

7.89

-0.37

0.22

0.83

2.96

1.45

1.76

1.77

-7.0 -5.0 -3.0 -1.0 1.0 3.0 5.0 7.0 9.0 11.0

Discount Rate (7 ± 1%)

Inflation Rate (5 ± 1%)

Lifetime (20 ± 2 Years)

O&M (12 ± 3 US$/kWth)

Income Tax Rate (14 ± 2%)

Insurance (0.3 ± 0.1%)

Salvage value (10 ± 2% of total cost)

Debt Fraction (70 ± 10% of total cost)

Loan Rate (6 ± 1%)

Loan Term (10 ± 2 Years)

Net Present Value (NPV) x 100000

Input Decreased Input Increased

28 Sensitivity Analysis for PBP

13.14

12.19

12.26

12.33

12.36

12.38

12.39

12.43

11.89

12.75

12.67

12.59

12.56

12.54

12.54

12.49

11.80 12.10 12.40 12.70 13.00 13.30

Inflation Rate (5 ± 1%)

O&M (12 ± 3 US$/kWth)

Income Tax Rate (14 ± 2%)

Insurance (0.3 ± 0.1%)

Discount Rate (7 ± 1%)

Debt Fraction (70 ± 10%)

Loan Term (10 ± 2 Years)

Loan Rate (6 ± 1%)

Payback Period (years)

Input Decreased Input Increased

29 Environmental Consideration

GHG emissions, (specifically CO2 emissions) were considered.

In addition to protecting the environment, other potential of reduction the investment cost was considered.

77.4 ton of CO2 could be avoided per each 1 Tera joule of energy saved (77.4 ton CO2/TJ). And each ton avoided will save 26 US$.

0

5,000

10,000

15,000

20,000

25,000

1.50 1.75 2.00 2.25 2.50 2.75

Am

ou

nt

of

CO

2 A

vo

ide

d (

ton

CO

2/y

ea

r)

Solar Multiple

FWH#1

FWH#1+2

FWH#1+2+3

FWH#4+5

FWH#5

All FWHs

CO2 saving contributes in reducing SPBPs by about 15% with respect to SPBP before considering CO2 emissions.

30 Environmental Consideration

11.44

11.18

11.42

11.90

12.60

13.43

9.73

9.51

9.72

10.12

10.72

11.43

1.50

1.75

2.00

2.25

2.50

2.75

0.0 2.5 5.0 7.5 10.0 12.5 15.0

So

lar

Mu

ltip

le

Payback Period (years)

PBP (Fuel + CO2) PBP (Fuel Only)

31

Main Findings

Te

ch

nic

al Increasing the efficiency of existing Rankine cycle up to

2.47% (from 33.63% to 36.10%);

due to increasing turbine‘s output work by up to 7.5% to the base case (33.92 to 36.41 MW)

Eco

no

mic

Optimum solar field SM range between 1.75 - 2.00

Fuel savings up to 6,200 ton of HFO (3 Million US$) per year Payback periods around 11 years

En

vir

on

me

nta

l

Up to 17,500 ton of CO2 avoided per year With additional savings of 450,000 US$ per year Payback period around 9 years

32 Future Work

Based on findings of the study in hand, future work is recommended as below:

1 Using Linear Fresnel Reflectors (LFR) instead of PTC

2 Introducing thermal energy storage systems

4 Integration with combined-cycle power plants (IPP1 & IPP2)

5

3 Applying same study on other HTPP units (i.e. 66 MW Unit) and other power plants in Jordan

Studying solar field configuration and orientation for selected CSP technology

6 Studying how to connect selected CSP system with FWHs or the application/component that integrates directly with CSP system

33

Thank You!