1. Feasibility Study of Pumped Hydro Energy Storage
for Ramea Wind-Diesel Hybrid Power System
Sheikh Mominul Islam, EIT, M.Eng.
Email: mominul511@gmail.com
Newfoundland Electrical and Computer Engineering
Conference
November 4th, 2010
St. John’s, Newfoundland

2. Outline
 Introduction
 Motivation
 Sizing
 Dynamic simulation
 Conclusion

3. Introduction:
 Isolated southern island of Newfoundland which was first incorporated to the province in
1951.
 It has population of 674.
 Nearest community is Burgeo which is about 20kM away by ferry service.
 Average fuel consumption is 18,000L/week in summer and 22,000L/week in winter.
 Electricity selling price is 0.1495/unit.
Over view of Ramea

4. Introduction:
Over view of Ramea Electrical system
 2775kW diesel plant, Six 65kW wind
turbines and three 100kW newly
installed wind turbines
 The average load is 550kW
 312.5kW fuel cell system under
construction
 200kW load for dumping excess
energy produced by the system
 30kVAR fixed capacitor bank for
each 65kW wind turbine for
supplying reactive power demand.

5. Motivations:
Analysis of existing Ramea wind-diesel-hydrogen system:
 HOMER is used for analyzing the existing wind-diesel-hydrogen system.
 Average wind speed is 6.08m/s at 10m
height
 Maximum wind speed during winter is
21.6m/s
 Daily load profile varies from
350kW to 610kW
 Maximum load goes to
1100kW during winter

6. Motivations
Analysis of existing Ramea wind-diesel-hydrogen system:
 Excess electricity from the wind turbines is converted to hydrogen
using an electrolyser.
 Hydrogen is compressed and stored in three large tanks.
 Stored hydrogen is used to generate electricity when needed
 Expected renewable
fraction is 37% with the
contribution of 1% from
Hydrogen system
 Cost of Energy is
0.248$/kWhr
 Hydrogen generator will
run 702hrs/yr

7. Sizing
Analysis of proposed Ramea wind-diesel-pumped hydro system:
 Overall efficiency of the battery was reduced to 70% to represent a pumped hydro
energy storage system.
 A 250kW converter is considered between AC and DC bus
 Renewable energy fraction is considered 37%

8. Sizing
HOMER simulation result of Ramea wind-diesel-pumped hydro system:
 Battery bank (consisting of Trojan T-105 batteries) should have 500 batteries.
 Cost of Energy is 0.218$/kWhr
 Diesel required 783, 529L/yr

9. Sizing
Electrical performance of Ramea wind-diesel-pumped hydro system:
 Total energy required 4,281,096 kWh/year and 37% of that will be met by the wind energy
 Almost only one diesel generator is running at a time
 Diesel required 783, 529L/yr

10. Expected energy in and out of battery system:
Sizing
 Battery will be most used in July and August while it will be least used in May.
 Maximum power output from battery storage is 147kW during the month of
April.

11. Calculations:
The hybrid system required 500 Torjan T-105 batteries (each 1350Whr).
So the potential energy stored in the upper reservoir should be.
Potential Energy = mgh,
→ 1350 × 3600 × 500 = mgh = (volume * desnsity)*g*h
Volume, V =
100081.9
50036001350


h
For a head h = 63m, required reservoir size will be V = 3932m3
For area of 2000m2, required reservoir height will be 2m

12. Calculations:
Possible maximum daily average power , 147kW ~ 150kW
gHQP 
For, H = Gross head in m (63m), g = 9.81 m/s2 and
η = Hydro turbine efficiency = 70%.
The flow rate, Q = 0.347 m3/s

13. For the Ramea site the expected flow rate is 0.347 m3/s and head is 63m therefore the best
selection is a Pelton or Turgo type turbine.

14. Dynamic simulation of grid connected PHS:
 The pump is considered as a 150kW centrifugal pump with induction
machine
 The hydro turbine is considered as 150kW unit with a synchronous
machine coupled to the system bus.
 Community load is considered as a constant load
 The system was simulated for 24s
 During off peak hour the pump will be operating for pumping water to
upper reservoir
 During peak demand the hydro turbine will be operating.

15. Dynamic simulation of grid connected PHS:
SIMULINK representation of Diesel-wind-hydro hybrid power system in Ramea

16. o
vwt
v
t
atw
V
z
TtmV
Tdt
dV
VVV
5.10
),(
1
, 
Wind field equation:
Vw = the wind speed
Va= Average wind speed
Vt= Turbulent component of wind speed
mw(t)= Random white noise
Z = Turbine height
V0= Maiden wind speed
Dynamic simulation of grid connected PHS:

17. Dynamic simulation of grid connected PHS
Expected power changes in a transient condition in the Ramea Hybrid power system
Hydro pump is
operating
Hydro turbine is
operating

18. Dynamic simulation of grid connected PHS:
Expected transients in the Ramea hybrid power system
Hydro turbine is
operating
Hydro pump is
operating

19. Conclusions:
 Diesel fuel saved by 94,782L per year
 Cost of energy reduced by 0.03$/kWh
 All excess electricity will be stored in hydro storage
 Available sea water can be used
 63m height is available for water head.
 No extension of power line is required as Man of War hill
is near to the existing system
 Voltage and frequency variation are within limit

20. Future recommendation:
 Battery system can be replaced by actual pumped hydro system.
 Soft starter can be used for reducing system transients.
 Variable speed hydro pumped storage can be considered.
 Variable load can be considered.

21. Acknowledgement:
 M. Tariq Iqbal
 Nalcor energy (Newfoundland Hydro)
 The Leslie Harris Centre of Regional Policy and Development,
MUN

22. Thank you
For your attention and presence
Question / Comments