# Analysis of Energy Storage Implementation on Dynamically Positioned Vessels

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## Abstract

**:**

## 1. Introduction

_{r}, for modern medium speed diesel engines). On the other hand, when DGs are running with an optimal load in closed bus bar configuration, the power system becomes more sensitive to step load increase caused by the sudden loss of one or more online generators, which may result in activation of appropriate protection circuits and very likely a partial or total blackout [2].

## 2. Closed Bus Bar Operation and Blackout Prevention

_{DG}

_{max}relative to DG rated power P

_{r}during closed bus bar operation for different numbers of online generators N can be expressed as:

- Case A: the stand-by DG will start according conditions defined in (1),
- Case B: the stand-by DG will start if P
_{DG}_{max}≥ 0.9P_{r}.

## 3. Simulation Model of an Electrical Power System with ES

_{m}, T

_{em}, and T

_{f}are externally applied mechanical torque, electromagnetic torque developed by the diesel generator, and frictional torque in Nm, respectively, p is the generator pole number, ω

_{r}is the rotor angular speed in rad/s, and J is the moment of inertia in kgm

^{2}.

_{ref}is compared with the actual generator speed ω

_{r}. The error signal is fed to the input of the controller modeled as a second order system with the transfer function:

_{p}is gain and t

_{1c}, t

_{2c}, and t

_{3c}are controller time constants. The actuator transfer function is:

_{1a}, t

_{2a}, and t

_{3a}are actuator time constants [23].

_{r}in order to get the required mechanic power P

_{m}used in the synchronous generator model. Generator voltage V

_{g}is compared with its reference value V

_{ref}and the signal difference is the input of the voltage regulator with transfer function:

_{vr}is gain and t

_{vr}is the voltage regulator time constant. In order to prevent oscillations of V

_{g}, the following damping filter is used:

_{f}is gain and t

_{1f}, t

_{2f}, and t

_{3f}are filters time constants. The exciter is a modeled PI controller with time constants t

_{e}and gain K

_{e}[24].

_{d}and U

_{q}are voltages at the point of common coupling (PCC) and I

_{d}and I

_{q}are inverter currents [25].

_{d}, U*

_{q}, I*

_{d}, and I*

_{q}are d and q components of the inverter reference voltage and current.

_{s}on each remaining generator after one DG loss is:

_{total}(m) is the total instantaneous electrical consumption when m DGs are online (before fault). The maximum step load increase ∆P

_{s}

_{max}is usually given by the diesel engine manufacturer or can be arbitrarily set in PMS. For stable operation of an electrical power plant it is required that ∆P

_{s}≤ ∆ P

_{s}

_{max}in all possible fault conditions, which affects the amount of required spinning reserve for safe operation and consequently the safe DG continuous load P

_{safe}(m). In order to run DG units at the desired (near optimum) load and taking into account that DG can supply 110% of rated power in an emergency situation, the minimum required ES output power P

_{ES}for P

_{safe}(m) = P

_{des}is:

_{des}is the desired DG load set by operator.

_{ES}is determined for the worst case scenario, which according to (13) is one DG loss when m = 2, such ES can cover all expected load variation with respect to required power, including compensation of short term peak power demands. However, maximum ES utilization time depends only on its capacity which has to be determined by simulation for any scenario of interest.

_{es}) over the time interval from the ES activation (t

_{1}) to the end of the discharge process (t

_{2}).

## 4. Model Parameters

_{d}and X

_{q}, generator leakage reactance X

_{l}, transient reactances X

_{d}’and X

_{q}’, subtransient reactances X

_{d}’’and X

_{q}’’, stator resistance R

_{s}, generator mechanical time constant T

_{m}, time constants for subtransient state T

_{d}’’and T

_{q}’’, and constant of inertia H. Equations which relate the standard parameters with variables in (2) and (3) can be found in [21] (pp. 302–304). Simulation parameter settings used in the proposed model are given in Table 1.

## 5. Simulation and Results

- Under frequency protection was set to 90% of the rated frequency with a 5 s time delay.
- Over current protection was set to 120% of the rated current with a 20 s time delay.
- Under voltage protection was set to 70% of the rated voltage with a 2 s time delay.

- two DGs are running in parallel, each loaded with 95% of nominal power on the common bus,
- at t = 10 s, DG2 is disconnected from the grid due to a sudden failure,
- ES and DG1 instantly take the remaining load, provided that PMS limits the DG1 maximum load to 110% of the rated power and sends the start signal to stand-by DG3,
- DG3 is ready to take the load 30 s after starting with the rate of 0.05 P
_{r}/s.

_{r}and the maximum power limit to 110% of P

_{r}

_{.}The recorded power trend of an actual DP vessel for a duration of 400 s was used in simulation. At t = 122 s a power peak occurred, which caused the load increase on connected DG units above the PMS load limit and initiation of a third DG unit (point A). When load demand exceeded the DG power limit, total available power was limited (point B), which in some cases may affect the vessel’s ability to keep the desired position. Approximately 30 s after the start request, the stand-by DG was connected to the grid and loaded (point C). Now all online DGs were running with lower than optimal load and consequently higher specific fuel consumption and exhaust gas emissions.

## 6. ES Utilization Scheme

_{min}required for proper function of ES is set according to its type and specifications. The proposed utilization scheme allows use of available spinning reserves for ES charging during periods with lower electrical consumption (i.e. during periods between peak shavings, or to compensate ES idle losses).

## 7. Overview of Available ES Technologies

## 8. Evaluation Model for ES Implementation on DP Vessels

## 9. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

- International Marine Contractors Association (IMCA). A Guide to DP Electrical Power and Control Systems; M-206; IMCA: London, UK, 2010. [Google Scholar]
- Settemsdal, S.O.; Haugan, E.; Aagesen, K.; Zahedi, B.; Drilling, S.A. New enhanced safety power plant solution for DP vessels operated in closed ring configuration. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 14–15 October 2014. [Google Scholar]
- May, J.J.; Foss, H. Power Management System for the “Deepwater Horizon” a dynamically positioned all weather semisubmersible. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 17–18 October 2000. [Google Scholar]
- Laghari, J.A.; Mokhlis, H.; Bakar, A.H.; Karimi, M.; Shahriari, A. An intelligent under frequency load shedding scheme for islanded distribution network. In Proceedings of the Power Engineering and Optimization Conference (PEDCO), Melaka, Malaysia, 6–7 June 2012; pp. 40–45. [Google Scholar]
- Lauvdal, T.; Ådnanes, A.K. Power management system with fast acting load reduction for DP vessels. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 17–18 October 2000. [Google Scholar]
- May, J.J. Improving engine utilization on DP drilling vessels. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 16–17 September 2003. [Google Scholar]
- Radan, D. Integrated Control of Marine Electrical Power Systems. Ph.D. Thesis, Norwegian University of Science and Technology, Trondheim, Norway, 2008. [Google Scholar]
- Cargill, S. A novel solution to common mode failures in DP Class 2 power plant. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 9–10 October 2007. [Google Scholar]
- Mathiesen, E.; Realfsen, B.; Brievik, M. Methods for reducing frequency and voltage variations on DP vessels. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 9–10 October 2012. [Google Scholar]
- Det Norske Veritas (DNV). Offshore Stabdard DNV-OS-D201—Electrical Installations; DNV GL: Oslo, Norway, 2011. [Google Scholar]
- McGroarty, J.; Schmeller, J.; Hockney, R.; Polimeno, M. Flywheel energy storage system for electric start and an all-electric ship. In Proceedings of the IEEE Electric Ship Technologies Symposium, Philadelphia, PA, USA, 27 July 2005; pp. 400–406. [Google Scholar]
- Holsonback, C.; Webb, T.; Kiehne, T.; Seepersad, C.C. System-level modeling and optimal design of an all-electric ship energy storage module. In Proceedings of the Electric Machines Technology Symposium, Philadelphia, PA, USA, 22–24 May 2006. [Google Scholar]
- Domaschk, L.N.; Ouroua, A.; Hebner, R.E.; Bowlin, O.E.; Colson, W.B. Coordination of large pulsed loads on future electric ships. IEEE Trans. Magn.
**2007**, 43, 450–455. [Google Scholar] [CrossRef] - Tsekouras, G.J.; Kanellos, F.D. Optimal operation of ship electrical power system with energy storage system and photovoltaics: Analysis and application. Trans. Power Syst.
**2013**, 8, 145–155. [Google Scholar] - Kanellos, F.D. Optimal power management with GHG emissions limitation in all-electric ship power systems comprising energy storage systems. Trans. Power Syst.
**2014**, 29, 330–339. [Google Scholar] [CrossRef] - Det Norske Veritas (DNV). Dynamic Positioning Vessel Design Philosophy Guidelines; DNV GL: Oslo, Norway, 2012. [Google Scholar]
- Garg, K.; Weingarth, L.; Shah, S. Dynamic positioning power plant system reliability and design. In Proceedings of the Petroleum and Chemical Industry Conference Europe Electrical and Instrumentation Applications, Rome, Italy, 7–9 June 2011; pp. 1–10. [Google Scholar]
- Adnanes, A.K. Status and inventions in electrical power and thruster systems for drillships and semi-submersible rigs. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 28–30 September 2004. [Google Scholar]
- Radan, D.; Johansen, T.A.; Sorensen, A.J.; Adnanes, A.K. Optimization of load dependent start tables in marine power management systems with blackout prevention. Trans. Circuits Syst.
**2005**, 4, 1861–1866. [Google Scholar] - Sørfon, I. Power Managemenet Control of Electrical Propulsion Systems. In Proceedings of the Dynamic Positioning Conference, Houston, TX, USA, 9–10 October 2012. [Google Scholar]
- Wartsila 32 Product Guide. Available online: https://www.wartsila.com (accessed on 10 October 2018).
- Ong, C.M. Dynamic Simulation of Electric Machinery: Using MATLAB/SIMULINK; Prentice Hall PTR: Upper Saddle River, NJ, USA, 1998. [Google Scholar]
- Luo, L.; Gao, L.; Fu, H. The control and modeling of diesel generator set in electric propulsion ship. Inf. Technol. Comput. Sci.
**2011**, 2, 31–37. [Google Scholar] [CrossRef] - IEEE Power Engineering Society. IEEE Recommended Practice for Excitation System Models for Power System Stability Studies; IEEE Power Engineering Society: Piscataway, NJ, USA, 2005. [Google Scholar]
- Khalifa, A.S. Control and Interfacing of Three Phase Grid Connected Photovoltaic Systems. Master’s Thesis, University of Waterloo, Waterloo, ON, Canada, 2010. [Google Scholar]
- Surprenant, M.; Hiskens, I.; Venkataramanan, G. Phase locked loop control of inverters in a microgrid. In Proceedings of the 2011 IEEE Energy Conversion Congress and Exposition, Phoenix, AZ, USA, 17–22 September 2011; pp. 667–672. [Google Scholar]
- Chen, H.; Cong, T.N.; Yang, W.; Tan, C.; Li, Y.; Ding, Y. Progress in electrical energy storage system: A critical review. Prog. Nat. Sci.
**2009**, 19, 291–312. [Google Scholar] [CrossRef] - Fuchs, G.; Lunz, B.; Leuthold, M.; Sauer, D.U. Technology Overview on Electricity Storage; ISEA: Aachen, Germany, 2012. [Google Scholar]
- Hadjipaschalis, I.; Poullikkas, A.; Efthimiou, V. Overview of current and future energy storage technologies for electric power applications. Renew. Sustain. Energy Rev.
**2009**, 13, 1513–1522. [Google Scholar] [CrossRef] - Nikolaidis, P.; Poullikkas, A. A comparative review of electrical energy storage systems for better sustainability. J. Power Technol.
**2017**, 97, 220–245. [Google Scholar] - Luo, X.; Wang, J.; Dooner, M.; Clarke, J. Overview of current development in electrical energy storage technologies and the application potential in power system operation. Appl. Energy
**2015**, 137, 511–536. [Google Scholar] [CrossRef][Green Version] - Donaldson, A.J. Energy Storage—New technologies and new roles. In Proceedings of the Marine Engineer in the Electronic Age, Alexandria, VA, USA, 29–30 April 2002; pp. 237–245. [Google Scholar]
- Hockney, R.; Polimeno, M.; Daffey, K. Flywheel Energy Storage Integration into a Naval Power System. In Proceedings of the Turbo Expo 2006: Power for Land, Sea, and Air, Barcelona, Spain, 8–11 May 2006; pp. 25–33. [Google Scholar]
- Un-Noor, F.; Padmanaban, S.; Mihet-Popa, L.; Mollah, MN.; Hossain, E. A comprehensive study of key electric vehicle (EV) components, technologies, challenges, impacts, and future direction of development. Energies
**2017**, 10, 1217. [Google Scholar] [CrossRef] - Bolund, B.; Bernhoff, H.; Leijon, M. Flywheel energy and power storage systems. Renew. Sustain. Energy Rev.
**2007**, 11, 235–258. [Google Scholar] [CrossRef] - Mihet-Popa, L.; Saponara, S. Toward Green Vehicles Digitalization for the Next Generation of Connected and Electrified Transport Systems. Energies
**2018**, 11, 3124. [Google Scholar] [CrossRef] - Li-Ion Technology for Surface Ships Advanced Energy Storage for New Generation AES. Available online: http://alpha-energy.ru/D/0000009803/EU_Saft_LiIon_Mt_SurfaceShips_32027-2-0409_200904_en.pdf (accessed on 15 October 2018).
- Chen, J.W.; Lindtjørn, J.O.; Wendt, F. Hybrid Marine Electric Propulsion System; ABB: Cary, NC, USA, 2012. [Google Scholar]

**Figure 2.**Specific fuel consumption of a medium speed diesel engine [21].

**Figure 10.**Simulation scenario for 3.6 MVA generator loss when two DGs are running in parallel, each loaded with 95% of nominal power.

Synchronous Generator Parameter | |

Rated power | 3600 kVA |

Line voltage | 6600 V |

Frequency | 60 Hz |

X_{d} | 1.54 pu |

X_{d}′ | 0.29 pu |

X_{d}′′ | 0.175 pu |

X_{q} | 1.04 pu |

X_{q}′′ | 0.175 pu |

X_{l} | 0.052 pu |

T_{d}′ | 3.7 s |

T_{d}′′ | 0.05 s |

T_{q}′′ | 0.05 s |

R_{s} | 0.0036 pu |

H | 1.5 s |

Speed Regulator Parameters | |

Regulator gain K_{p} | 12 |

Regulator time constants | T_{1 r} = 0.01 s; T_{2 r} = 0.02 s; T_{3 r} = 0.2 s |

Actuator time constants | T_{1a} = 0.25 s; T_{2a} = 0.009 s; T_{3a} = 0.038 s |

Mechanical torque limits | T_{min} = 0; T_{max} = 1.1 pu |

Voltage Regulator Parameters | |

Voltage regulator gain K_{a} | 400 |

Voltage regulator time constant | T_{1rn} (s) = 0.02 s |

Output voltage limits | V_{g}_{min} = 0; V_{g} _{max} = 2.2 pu |

Damping filter gain K_{pf} | 0.03 |

Damping filter time constant | T_{1f} = 1 s |

Generator Power (kVA) | Required ES Capacity (kWh) | Minimum Required ES Power (kW) |
---|---|---|

2000 | 12.44 | 1280 |

2300 | 14.31 | 1472 |

2600 | 16.18 | 1664 |

3000 | 18.67 | 1920 |

3300 | 20.53 | 2112 |

3600 | 22.42 | 2304 |

4000 | 24.89 | 2560 |

Technology | Specific Power (W/kg) | Charge Time | Charge/Discharge Cycles | Efficiency (%) | Power Cost $/kW | Energy Cost $/kWh | Operation and Maintenance Costs S/kW per year |
---|---|---|---|---|---|---|---|

Lead Acid | 700 | Slow | ≤1200 | 70–85 | 300–600 | 200–400 | 50 |

NiCd | 700 | Slow | ≤5000 | 60–70 | 500–1500 | 800–1500 | 20 |

Li-Ion | 2000 | Slow | ≤8000 | 90–97 | 1200–4000 | 600–2500 | - |

Super capacitors | 10,000 | Instant | >100,000 | 90–95 | 100–300 | 300–2000 | 6 |

Flywheel | 5000 | Very fast | >100,000 | 95–99 | 250–350 | 1000–5000 | 20 |

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**MDPI and ACS Style**

Cuculić, A.; Vučetić, D.; Prenc, R.; Ćelić, J. Analysis of Energy Storage Implementation on Dynamically Positioned Vessels. *Energies* **2019**, *12*, 444.
https://doi.org/10.3390/en12030444

**AMA Style**

Cuculić A, Vučetić D, Prenc R, Ćelić J. Analysis of Energy Storage Implementation on Dynamically Positioned Vessels. *Energies*. 2019; 12(3):444.
https://doi.org/10.3390/en12030444

**Chicago/Turabian Style**

Cuculić, Aleksandar, Dubravko Vučetić, Rene Prenc, and Jasmin Ćelić. 2019. "Analysis of Energy Storage Implementation on Dynamically Positioned Vessels" *Energies* 12, no. 3: 444.
https://doi.org/10.3390/en12030444