Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology]

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

DEVELOPMENT OF HYDROKINETIC POWER GENERATION SYSTEM: A REVIEW Anurag kumar1, Dr. R. P. Saini2, 1

Student, M.Tech. Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Uttarakhand, India, [email protected] 2 Associate professor, Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Uttarakhand, India, [email protected] Abstract Small scale hydropower is one of the renewable energy source of energy which has vast potential. Hydrokinetic turbines are suitable to tap this potential and the technology is recent which produces electricity from flowing water. Hydrokinetic turbines are more suitable to convert kinetic energy in the river and marine current. An extensive literature review has been carried out and presented in this paper. This paper basically summarizes existing hydrokinetic turbines and projects implemented so far. Based on literature review it is found that lot of work is being carried out on hydro kinetic turbines which are suitable to install at power channel, river and canal. However, optimum parameters for different types of hydro kinetic turbines have not been found to develop the standard size hydro kinetic turbines for different sites.

Index Terms: hydro kinetic turbine, Tidal, horizontal axis, vertical axisetc. --------------------------------------------------------------------- *** -----------------------------------------------------------------------1. INTRODUCTION Today energy demand is increasing day by day and thus new innovations in hydro energy conversion are emerging. Smallscale hydropower generation is one of the types of renewable energy. It is well established till date so it has to be known as conventional form of hydro power. Hydrokinetic energy conversion is one of these concepts to produce electricity from the runoff water in river, canal and power channel. It can be used in existing structures like barrages, bridges etc. Hydro kinetic technology is well suited to enhance the rural, and village areas where the huge civil work do not require. This technology can be adopted easily and can run efficiently with less environmental impact. Energy can be extracted from the ocean and river currents by using submerged turbines, which are similar in function to wind turbines, capturing energy through the processes of hydrodynamic, rather than aerodynamic, lift or drag. Turbines can have horizontal, vertical or inclined axes of rotation [1]. The kinetic energy conversion in the river is most valuable research, which is invented by man that is natural flow is converted to the mechanical energy. The energy in flowing water current is a good choice of small-scale hydropower. Water provides the renewable energy option with a possibility of a continuous supply because this kind of energy does not need the storage [2]. The schematic arrangement of hydrokinetic turbine system is shown in Fig. 1. The working of a water current turbine is similar to that of a wind turbine and most of the components are same such as gear box generator, inverter, and battery

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system. This concept is not new, and was investigated by different researchers since 1979. A typical hydrokinetic power plant and their component are shown in Fig. 2. According to Hydro kinetic Power Equation (Eq.1), power is proportional to cubic velocity of flow. The augmentation of channel provides a narrow pass of water to increases flow velocity where the velocity of flow is less than 0.5-1 m/s [3].

Fig-1: Schematic view of hydrokinetic turbine system [2] Hydro kinetic energy conversion has no requirement of large civil structure that’s why it can easily install in river and marine environment. However, the technology needs research in numerous issues including rotor design, platform, and generator for flowing on current etc. under this literature review various types of energy harvesting kinetic turbines which are theoretically and practically investigatedare discussed, introduced new energy conversion concepts which

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology] are suitable for water current river as well as marine are also discussed.

2.PRINCIPLES OF HYDRO KINETIC ENERGY CONVERSION To estimate the power extraction capability of a hydrokinetic energy extraction device (HEED), the method commonly used in the field is to use an ideal power calculation as per the Eq.1. Power equation of hydrokinetic turbine is similar to wind turbine since both systems involve fluids and either air-foil or hydrofoils [4, 5, 6]. Mathematically power equation for hydrokinetic turbine is given as; 𝑃𝑖𝑑𝑒𝑎𝑙 =

1 2

𝜌 𝐴 𝑉 3 𝐶𝑝

1

Where, P is the power from HEED ρ is the density of fluid (water), A is frontal area of hydrokinetic turbine, Cp is turbine power coefficient and it can be defined as; 2

𝐶𝑝 =

𝑉 𝑉 1+ 𝑜 ( 1− 𝑜 ) 𝑉𝑖

𝑉𝑖

2

2

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

localized increased extraction [8-9]. As in wind energy conversion, turbines are considered the system of choice. However, some non-turbine systems have been proposed (mostly at the proof-of-concept stage) and may become the innovative expectations in this new technological field [10]. The choice of turbine rotor configuration requires considerations of a broad array of technical and economic factors. As an emerging field of energy conversion, these issues become even more dominant for hydrokinetic turbines. A general classification of these turbines based on their physical arrangements is shown in Fig.3. Based on rotation of the axis of shaft with respect to the flow of water HKTs are classified as; Horizontal axis, vertical axis cross flow. The vertical axis turbines are similar as wind turbine. The horizontal axis (axial-flow) turbines have axes parallel to the fluid flow and employ propeller type rotors. Horizontal axis turbines are common in tidal energy converters and are very similar to modern wind turbines from concept and design point of view.

Where, V0 is outlet velocity of the fluid and Vi is inlet velocity of fluid. It is an approximation of the amount of energy that can be extracted through a wind turbine but a detailed analysis with blade shape and surface, and the corresponding fluid interactions, would give more accurate results [7]. Cp is a factor of the conservation of mass through a fluid stream tube approach. For an ideal turbine in an unbounded free stream, Cp tends to reach a Betz limit of 0.59. The Betz limit signifies the maximum theoretical limit of power from fluid based hydro kinetic turbine [7]. Fig 3 shows the power coefficient curves of HKT turbines. Technological advancement in tidal energy conversion, which employs the same principle as river turbines, is rather mature than (RCECS). River current energy conversion systems (RCECS) are being proposed as small power units with floating structures that can be easily placed in a river channel. In contrast, tidal turbines are generally larger in size, rigidly moored, and operate under periodic tide motion. Nevertheless, information on tidal energy systems is extremely valuable in understanding the river turbine technology [3].

3. HYDRO KINETIC TURBINES Hydro kinetic turbine is newly growing turbine which works on flowing current that convert the natural flow force to mechanical power and the electrical energy to grid or load.The various hydrokinetic energy technologies have some overlap but can be generally categorized as: axial and cross flow turbines, vortex shedding, and dynamic augmentation for

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Fig- 3: Classification of hydro kinetic turbine rotors [10] Based on performance of wind turbine at different tip speed ratio, power curves of different turbines are shown in Fig. 4. It can be seen from the Fig.4 the Darrieus type turbine has wide working range for different Tip speed ratio (TSR). However, 3-blade axial flow rotor is working at high power coefficient. Turbines with solid mooring structures require the generator unit to be placed near the riverbed or sea-floor. Various arrangements of axial turbines for use in hydro environment are shown in Fig. 5 and 6 [11, 12, 13].

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology]

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

(a) Squirrel cage Darrieus

(b) H- Darrieus (c) Darrieus

Fig-4: Power coefficient variation with their blade tip speed ratio [8]

(d) Gorlov

(e) Savonius

Fig-6: Vertical axis kinetic turbines [9]

(a) Inclined axis

(b) Rigid mooring

(c) Non submerged generator(d) Submerged generator Fig-5: Horizontal axis kinetic turbines [9] Inclined axis turbines have mostly been studied for small river energy converters. Most of these devices were tested in river streams and were commercialized in limited scales [13]. However it is not clear whether these latter devices are still being commercialized [7]. The cross flow turbines have rotor axes orthogonal to the water flow but parallel to the water surface.

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These turbines are also known as floating waterwheels. These are mainly drag based devices and inherently less efficient than their lift based counterparts. The large amount of material usage is another problem for such turbines [13, 14, 15]. Darrieus type turbines are used in many hydrokinetic projects [16]. However, use of H-Darrieus or Squirrel-cage Darrieus (straight bladed) turbine is very common, examples of Darrieus turbine (curved or parabolic blades) being used in hydro applications is non-existent [9]. Available designs and various parameters have been carried out in literature [4, 17]. The Gorlov turbine is another member of the vertical axis family, where the blades are of helical structure [17-20]. Savonius turbines are dragging type devices, which may consist of straight or skewed blades [20-23].Hydrokinetic turbines may also be classified based on their lift/drag properties, orientation to up/down flow, and fixed/variable (active/passive) blades pitch mechanisms. Different types of rotors may also be hybridized (such as, Darrieus Savonius hybrid) in order to achieve certain performance features [9]. Different types of simulation based hydro kinetic conversion technologies are shown in Fig.7. The marine turbine HCD technology based turbine some time differ from the river, canal and irrigation channel Some of them has been investigated such as multiple blade turbine from Lunar, UEK

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology] three blade turbine, Free Flow Power Tech turbine, Horizontal and vertical Darrieus, Gorlov helical from Lucid Energy,

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

Multiblade from Uni-Southampton. Lunar energy offers a system which uses tidal current to produce electricity.

3 blade verdant Power

3- blade Hammer fest

Multi blade from UEK

Multi blade from Free flow PowerTech

Gorlov Helical from GCK Tech.

Helical Darrieus from Lucid Energy

Ducted turbine lunar Energy

Multi blade from Southhampton

Savonius from Hydro-Volts

Fig.-7: Different types of HCD technology [10, 12, 24, 25, 26, 27] The Lunar turbine system is known as Rotate Tidal Turbine and is a fully submerged ducted turbine with the power conversion system inserted in a slot in the duct as a cassette [24]. Two river projects have been applied by Verdant Power for river application RITE Project and CORE Project. RITE

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Project has been established in New York East River. Where, a new turbine of 5 m diameter has been installed. This turbine is of capacity of 35 kW and rotates 32 rpm [24-25].

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology] A dual UEK system is designed for stream velocities from 2 to 4 m/s for optimum usage. The turbine has a diameter of 3.3 m. This dual system gives approximately 75 kW at 2 m/s velocity [26]. Free Flow Power Technology (FFPT) has an integrated turbine generator system, which is called SMAR Turbine Generator. The system has a ducted structure. This company is currently developing a project in the Mississippi River Basin. They planned 100 hydrokinetic sites on Mississippi, Ohio and Missouri Rivers [28]. Alternative Hydro Solution Ltd

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

suggested that the Darrieus turbine is the best choice for small and medium river sites. The blade and the arms are made from Aluminum -6063T5. Their turbines are available in four different diameters: 1.25, 1.5, 2 and 3m [25].The smallest turbine has a diameter of 1.25 and the height of 0.5 m [29]. Gorlov A.M invented a Helical Darrieus turbine which works on same working principle as Darrieus turbine. Gorlov helical turbine consists of two or three-blade with helical form welded between two discs [15].Blue energy technology produces

Fig-8(a): Rochester Venturi system from HydroVenturi (b) Paddle wheel (c) installed paddle wheel system [30] Davis Hydro Turbine, Which is a similar to H-Darrieus. The system has four fixed hydrofoil blades which are connected to a shaft that drives a variable speed electrical generator [30]. HydroVolts provide Flipwing turbine which are designed and developed by some engineering student at the University of Washington. The turbine can be constructed with 3, 4, 5 or 6 blades. The turbine blades spin with the water current, generating their force from drag [31].

4. ADVANCED TECHNOLOGIES IN HEED Various turbine technologies have been developed (Fig. 8), the prototypes of these technologies are installed and they are generating power in river and tidal based resources. According to surveyed hydro kinetic technologies shown in Fig. 9 (a), Energy’s Aqaunter turbine is installed in Australia. The AN400 is a 400kW shallow water hydro kinetic turbine shown

in Fig. 9(c) which has been installed in marine hydro kinetic (MHK) project Gujarat (India) [32].

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Other turbine-based systems are categorized as; Cross-Flow turbines, Venturi systems, and Gravitational-Vortex systems. In the non-turbine category: Flutter-Vane, Piezoelectric, and Oscillating- Hydrofoil, Fan-Belt, and Paddle-Wheel are recently developed systems. Turbine and non-turbine based systems are investigated and described as follows. Venturi system as shown in Fig.8 (a) uses Bernoulli's principle to accelerate water through a choked duct. The pressure drop in the device drives turbines which can be placed above water or onshore. Venturi systems have no moving parts and no electrical components underwater, which may lead to robust low-cost systems with minimal maintenance costs, no visual impact, and no shipping-obstruction issues. One generator may be driven by several Venturi conduits giving a scalable system [33].

Floating paddle-wheel system has lots of superstructure and high cost. Fig. 8(b) and (c) show the Floating Power Station from Eco Hydro Energy LTD, and Fig. 9(a) shows the River Bank Hydro Turbine from Encore Clean Energy Inc. from Australia. This turbine is suitable for existing structures.

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology]

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

Fig. 9 (a) The River Bank Hydro Turbine (b) The Oscillating Cascade Power Energy's Aquanator turbine Australia [27] From Encore Clean Energy Inc. [27]

(c) Atlantis System [27]

Other turbine-based systems are categorized as; Cross-Flow turbines, Venturisystems, and Gravitational-Vortex systems. In the non-

turbine category: Flutter-Vane, Piezoelectric, and OscillatingHydrofoil, Fan-Belt, and Paddle-Wheel are recently developed systems. Turbine and non-turbine based systems are investigated and described as follows. Venturi system as shown in Fig.8 (a) uses Bernoulli's principle to accelerate water through a choked duct. The pressure drop in the device drives turbines which can be placed above water or onshore. Venturi systems have no moving parts and no electrical components underwater, which may lead to robust low-cost systems with minimal maintenance costs, no visual impact, and no shipping-obstruction issues. One generator may be driven by several Venturi conduits giving a scalable system [33]. Floating paddle-wheel system has lots of superstructure and high cost. Fig. 8(b) and (c) show the Floating Power Station from Eco Hydro Energy LTD, and Fig. 9(a) shows the River Bank Hydro Turbine from Encore Clean Energy Inc. from Australia. This turbine is suitable for existing structures. Flutter vane Oscillating Cascade Power System is shown in Fig. 9 (b) has a series of long, straight, symmetrical hydrofoils set in quartettes so that the blades move towards and away from each other in a paralleling approach. The pitch of the blades varies in such a way that they are alternatively attracted and repulsed by adjacent blades. A mechanical gear translates this oscillatory motion into rotational energy to drive a generator [27].on a belt sliding on an oval track 57 macross and 9 m high as shown in Fig. 9(c). The structure is mounted completely underwater. When the tide shifts, the belt rotates in the opposite direction [34-35].

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Fig-10: The parachute HCD concept [35] Fan belt hydro kinetic technology has been developed by Atlantis energy and this Aquanator turbine had installed at San Remo, Australia, in 2008. Fig. 9(c) shows another concept similar to the Aquanator, the 4P Aureola Spanish turbine. In terms of the HCD itself, the ―parachute concept reported in DOI/ MMS-URL (2010). The parachute HCD concept as shown Fig. 10, where the energy is captured by a barge moored in the current stream with a large cable loop to which the parachutes are fastened. The parachutes would be pushed by the current, and then closed on their way back, forming a loop similar to a large horizontal water wheel [35].The Hydrovolt’sFlipwing (Fig.11) is a cross-flow hydrokinetic turbine invented. it uses blades hinged on their outer edges and naturally swing open to greatly reduce their resistance to the current on the upstream stroke, which has an effect on the loads exerted on the mooring system by a Seattle company [31]. This turbine is mostly suitable for river and canal installation.it has feature Simple construction, easy installation Level or spillway installation.

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology]

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

The unique, flying-saucer-shaped (Fig 12) turbine is designed to sit on a riverbed. A set of ridged contours on top catch the current, causing it to spin and generate electricity. Verterra Energy is among a flood of companies working to develop hydrokinetic or run-of- river turbines, which do not require damming turbines, which don’t require damming or diverting water flow [35].

Fig-12: Flying saucer shaped turbine [35].

Fig-11: The Hydrovolts Inc.'s Flipwing turbine [31]

Inclined axis stream turbine concept is shown in Fig. 13(a). It is similar to a vertical axis turbine, however, the turbine axis swings around the pivot on a supporting structure or on a float. The device can be installed on onshore structure or on a float as shown in Fig. 13(b). The array of moored turbines captures water stream energy efficiently as shown in Fig. 13(c). Floating axis tidal turbine is based on Floating Axis Wind Turbine (FAWT) concept [27]. Various turbines discussed above, some of them are in developing stage and others prototype are tested. Available hydrokinetics turbines have been investigated by Alaska Center for Energy and Power (2010) [36] and their status are given in Table 1.Most of the turbines are in developing stages and only scale models are available.

(a)

(b)

(c)

Fig-13: Floating axis tidal turbine [27] Table-1: River and tidal current hydrokinetic turbines and their stage of technology development. [36]

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology]

Company

Location

Blue Energy

CANADA

C-Energy Lucid Energy Technologies LLP New Energy Corporation Inc. Ponte di Archimedes International S.P.A. Sea Power International AB Atalantis Resources corporation

NETHERLANDS

Clean current Power System

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

Capacity

Stage of progress

250kW

Scale model sea trials

30kW

Scale model sea trials

20kW

Scale model sea trials

CANADA

Device Blue Energy Ocean Turbine Wave Rotor Gorlov Helical Turbine En-Current Turbine

5-250kW

Full scale prototype

ITALY

Enermar

25kW

Scale model sea trials

SWEDEN

EXIM

48-72kW

Scale model sea trials

UK

Nereus

150 kW

Scale model sea trials

CANADA

Clean current Tidal turbine generator

65 kW

Full Scale Prototype

Small turbine Generator

10 kW

Osprey Tidal stream Turbine Hydro coil

1 kW 300 kW 20-40 kW 35 kW 300 -1200 kW

commercial

GOSHEN, IN

Free flow 69 Hammerfest storm UK Hydro Coil Power Inc.

GLOUSCESTER, MA UK UK WYNEWOOD, PA

Hydro green Energy

HOUSTON, TX

Hydro+

Maine Current Turbine

UK

Sea gen

HIGHLAND, NY

RED HAWK tidal turbine

125 kW

Scale model sea trials

UK

Evopod

1 kW

Scale model sea trials

FALL RIVER, MA

ORPC turbine Generating Units

32 kW

Scale model sea trials

IRELAND UK

Open Centre Turbine Swan turbine

150 kW 330 kW

SMD Hydro Vision

UK

TIDEI

500 kW

Tidal Energy Pty. Ltd.

AUSTRALIA

Davidson Hill Venturi turbine

Unavailable

Tidal Generation Ltd.

UK

Triton

10 MW

Tocardo Tidal Energy Ltd.

NETHERLANDS

Tocardo Aqua 2800

32 kW

Full Scale prototype Scale model sea trials Scale model tank testing Scale model sea trials Scale model tank testing Full Scale prototype

University Of Strathclyde Verdant Power Bio Power System

UK NY AUSTRALIA

Contra rotating Marine turbine Free Flow System Bio-Stream

30 kW 35 kW – MW 250 kW

Pulse Generation Ltd.

UK

Pulse Hydro Foil

100 kW

Vivace Under Flow Water Wheel Minneapolis Company

US US, ALSKA US

Vortex Induced Vibration Under flow Water Wheel Soccer turbine

Unavailable Unavailable Unavailable

Free Flow Power

Natural Current Energy Service Ocean Flow Energy Ocean Renewable Power Company Open Hydro Robort Gordon University

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Scale model Tank Testing Scale model sea trials Full scale prototype Scale model Sea trials

Full scale prototype

Scale model sea trials Full Scale Prototype Detailed Designed Scale model tank testing Scale model Testing Conceptual Conceptual

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Anurag Kumar* et al. [IJESAT] [International Journal of Engineering Science & Advanced Technology]

ISSN: 2250-3676 Volume-4, Issue-6, 464-477

Table.2: Details of Hydrokinetic projects Projects

Capacit y (kW)

Turbine

Cost per (kW)

Maintenanc e Cost (`)

PL F

Roto r Dia (m)

Velocit y (m/s)

RTT 2000 MCT SMD hydro vision UEK UEK Verdand power RITE kobold (state of Messina ) Mythos project

2000 2500 1000

Ducted Axial Axial Propeller 2 Blade Axial

105400 155000 141882

15500000 5202000

24 40

25 18 18.5

400 10000 35.9

Ducted Axial Flow Ducted Axial Flow 3 Bladed Axial Blow

73284 68278 138161

2517200 2517200 -

57 64 -

150

3 Blade Darrieus

82152

336000

-

500

3 Blade Darrieus

336000

18

Savonius Turbine

24645. 6 248000

Roza Canal, near Yakima Nenana, Alaska Hydrokinetic RivGen™ Power System Project Eagle at Yukon river Iguigig plant at Kvichak river Whitestone at Tanana

-

67

25

Horizontal Axis Darrieus

485776

-

-

61

Horizontal Axis Axial Turbine Horizontal Axis Axial Turbine Horizontal Axis Axial Turbine

259600

822244

465000 192200

42 593

2

Cut In Spee d (m/s) 1 0.7 0.7

Area (m )

Drive Train Efficienc y

Generato r Efficiency

System Efficienc y

3.1 3 2.3

Dept h of Wate r (m)