Conduit hydropower opportunities in South Africa (High … vanDijk Mon... · 1 Conduit hydropower...

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www.clean-power-africa.com

Conduit hydropower opportunities in

South Africa (High and low head)

Marco van Dijk, Lecturer, University of

Pretoria, South Africa

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Do you know how an electrician tells if he's

working with AC or DC power?

If it's AC, his teeth chatter when he grabs the

conductors. If it's DC, they just clamp together.

What's the difference between a woman and a

battery?

A battery has a positive side.

Conduit hydropower opportunities in South

Africa (High and low head)



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Our involvement

Title: Energy generation from distribution

systems

Period: 2 years

Funding: Water Research Commission with a

number of collaborating organisations



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What is conduit hydropower?

Description

South-African context

Identifying potential sites

Potential sites in Tshwane

PvRCHP

Bloemwater hydropower

Design process

Way forward

Layout of the presentation



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Conduit hydropower is where excess

energy available in pressurised conduits

(pumping or gravity) is transformed into

clean, renewable hydroelectric energy by

means of a turbine.

The excess energy is normally dissipated

by means of pressure control valves but by

conveying it through a parallel dissipating

system, the water turbine, the pressure

head and flow is utilized to generate

hydroelectric power.

What is conduit hydropower?



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What is conduit hydropower? Uitkijk reservoir

Brandkop reservoir

1 400

1 420

1 440

1 460

1 480

1 500

1 520

1 540

1 560

1 580

0 10 000 20 000 30 000 40 000 50 000 60 000

Chainage (m)

Ele

va

tio

n (

m)

Longitudinal profile

HGL static conditions

HGL maximum flow

ΔHmax = 83.2 m, Qmin = 0 m³/s

Qmax = 1.42 m³/s, ΔHmin = 15 m

ΔH



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What is conduit hydropower? Uitkijk reservoir

Brandkop reservoir

1 400

1 420

1 440

1 460

1 480

1 500

1 520

1 540

1 560

1 580

0 10 000 20 000 30 000 40 000 50 000 60 000

Chainage (m)

Ele

va

tio

n (

m)



HGL maximum flow

When flowing at 70% of design capacity

ΔH70% = 47.1 m, Q70% = 1.0 m³/s



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Description



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Drivers to consider “conduit hydropower”:

Renewable energy source

Rising energy costs

Utilizing existing water infrastructure

Financial incentives

Public perception

Job creation

Extending the operational life of control valves

Remote power (alarms, communications etc.)

Description



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South African context

Who is looking into conduit hydropower:

Rand Water Board (4 sites total 15 MW)

Bloem Water (2 x 350 kW)

Umgeni Water

Lepelle Northern Water (3 sites total 370 kW)

City of Tshwane (5 sites total 1.6 MW)

Ethekwini Municipality (various)

George Municipality (various)

Amatola Water

ESKOM (5-7MW)

City of Cape Town



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South African context

City of Cape Town



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High head and low head

Q, H, generation time and assurance of

supply (probability distributions)

Accessibility

Reservoir storage to accommodate

fluctuating demands

Generated electricity consumption?

Bypass alternative

Safety mechanisms

Feasibility

Identifying potential sites



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Geographically speaking the City

of Tshwane has a lower elevation

then the bulk service Reservoirs

of Rand Water which is the main

water supply.

Water is then distributed through a

large water system that includes

160 reservoirs, 42 water towers,

10677 km of pipes and more than

260 pressure reducing

installations (PRV’s) that operates

at pressures of up to 250 m.



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Reservoir site

Estimated

average

capacity (kW)

Estimated annual

generation

potential (kwh/a)

Estimated

development

cost (R) *

Estimated

revenue (year

1) (R)##

Garsfontein 550 3 854 400 R 12 100 000 R1 504 000

Wonderboom# 330 2 312 640 R 7 260 000 R902 000

Heights# 380 2 663 040 R 8 360 000 R1 040 000

Akasia# 260 1 822 080 R 5 720 000 R711 000

Waverley# 80 56 0640 R 1 760 000 R220 000

Total 1 600 11 212 800 R 35 200 000 R2 873 000

Notes: * Initial planning, design and capital costs

# Based on IMQS data (no historical data available)

## Utilizing a conservative load factor of 0.8, turbine system efficiency of 70%, averaged

Megaflex tariff of 50 c/kwh and subtracting anticipated O&M costs



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Pierre van Ryneveld Conduit Hydropower Plant



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Supply

line

Isolating

valve

Cross flow turbine

“ballast tank”

Control

panel

“pinch valve”

Guide vane control

15kW



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Launch



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Uitkijk reservoir

Brandkop reservoir

De Hoek reservoir

1 400

1 450

1 500

1 550

1 600

1 650

0 20 000 40 000 60 000 80 000 100 000

Chainage (m)

Ele

va

tio

n (

m)

Uitkijk - Brandkop profile

De Hoek - Uitkijk profile

HGL maximum flow




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Bloemwater hydropower (Uitkijk)



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Bloemwater hydropower (Brandkop)



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Generating potential (Uitkijk to Brandkop)

Uitkijk reservoir

Brandkop reservoir

1 400

1 420

1 440

1 460

1 480

1 500

1 520

1 540

1 560

1 580

0 10 000 20 000 30 000 40 000 50 000 60 000

Chainage (m)

Ele

va

tio

n (

m)



HGL maximum flow

ΔHmax = 83,2 m

ΔQmax = 1,42 m³/s



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Q40 = 0,57 m3/s: ΔH = 66,3 m

Q70 = 1,00 m3/s: ΔH = 47,1 m

Q100 = 1,42 m3/s: ΔH = 17,5 m

Generating potential (Uitkijk to Brandkop)



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Option 1: Construct hydropower plants

which will maximize income on this supply

line (300 – 400 kW / site)

Option 2: Construct a smaller pilot plant that

would supply sufficient energy to provide the

Bloemwater Head Office or site with

electricity (

95 kW required)

Options to consider



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Site location Brandkop Reservoir



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IREM Crossflow turbine and generator

Nominal voltage: three/single phase 400/230V 50Hz

Generated electric power: P =

96 kW

Net head axis turbine: H =

40 m

Flow :Q =

350 l/s

ECOWATT Micro hydroelectric power plant type TBS Cross Flow turbine in stainless steel type 4-0.5

Synchronous generator type AZ 100

Revolution multiplier by cogged driving belt

Automatic flow regulation (with electric actuator 230Vac)

Manual butterfly valve

Brandkop Hydropower Plant



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Electric Distribution Board Mod. CT 100.000 a voltmeter, a digital frequency-meter, ammeters indicating the total current

distributed by the generator, ammeters indicating the current drawn by the

consumers

magneto thermal, which protects the generator from possible short circuits

on the consumer line

electronic voltage relay, operating a warning buzzer and a visual signal in the

event the voltage variation exceeds the limits

Electronic Regulating System RMP 12000/B with water

dissipation resistances box unit, which include the electronic control board to micro processor and the

power control

transient voltage protection (TVP)

resistors for dissipation equipped with 9 x 12 kW




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•Pressure and flow measurements

•Conceptual design of system (pipework, turbine room, grid connection point)

•Preliminary costing

Prefeasibility study and site evaluation

•NERSA licence application

•Environmental Impact Assessment

•Water use licencing

•Land ownership

Regulatory and permitting

•Dynamic analysis of pipeline system

•Selection of turbine

•Design of turbine room

•Design of pipe and valve work

•Optimizing of system

Detail system design

•Design of electric control boards

•Design of regulator system

•Design of electric grid connection

Grid integration

•Funding strategy and sustainability

•Detailed cost estimated

•Risk assessment

•Sensitivity analysis

Project finance and feasibility study

•Tender phase

•Tender evaluation

•Equipment procurement

•Construction of facilities

Equipment procurement and construction

•Overall project management

•Site supervision

•Commissioning and testing

Project and construction management

•Routine inspections

•Maintenance plan

•Training

Operation and maintenance

•Recording of flow, pressure, energy, efficiency, reservoir levels etc.

•Evaluation and optimizing of plant operation

Monitoring and evaluation

Design

process



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Why develop small conduit hydropower?

Economically feasible – Garsfontein #1 and others

Why develop micro/pico conduit hydropower schemes?

On site use of electricity

Upliftment of community

Free internet access for an area?

Free electricity for a school?

Mass lighting?

Improved operational control of WDS

Telemetry

Security/Alarm system

Site lighting

Identification and development of other water

infrastructure with hydropower potential (WRC study)

Way forward



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Garsfontein



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Potential for a week = 82 097 kwh

Annual potential = 4 280 000 kwh

Garsfontein



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Way forward - Options



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Way forward - Options



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Developing and other countries shall take initiatives to enhance the

development of micro and small hydropower plants as an environment

friendly resource through the application of advanced and compatible

technologies to meet the demand of growing population on energy

and conservation to protect themselves from future energy crises and

secure a more sustainable development path;

Separate but similar policy for rural electrification should be

formulated in the developing countries by incorporating the role of

isolated and national grid connected micro and small hydropower

plants;

The governments of developing countries shall facilitate the possible

role of micro and small hydropower plants for global green house

gases (GHG) emission reduction;

The governments of the developing countries shall provide financial

and technical assistance to the stakeholders of micro and small

hydropower sector through a dedicated body, which also supports

capacity building as well as Research & Development activities;

Way forward (Katmandu Resolution)



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Governments shall be involved in the process of development of micro

and small hydropower plants in People-Public-Private Partnership

(PPPP) model to facilitate regulatory requirements for installation of

micro-hydel plants as well as for distribution through mini-grids;

Development of micro and small hydropower should be linked with the

burning issues such as climate change, social inclusion, energy

security, sustainability, development of Small and Medium Scale

Enterprises (SMEs), economic empowerment and poverty alleviation;

Effective measures shall be taken by the governments of the

developing countries to ensure the synchronization of mini-grids,

availability of low head turbines and appropriate technologies for non-

mountainous regions, and publish standard operative procedures and

guidelines of the micro and small hydropower plants preferably in

local languages;

For international compatibility, standardization in the designs of the

micro and small hydropower system is desirable for harmonization of

trade in this emerging renewable energy technology among the NAM

and other developing countries to the extent that such attempts do not

discourage the innovation in technology domains and identification of

strategy for upscaling.

Way forward (Katmandu Resolution)



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