myanmar off-grid renewable energy demonstration project ... · mechanical, electrical, project...

Microhydro training – Day 2

Mechanical, Electrical, Project

proposal

Myanmar Off-Grid

Renewable Energy

Demonstration Project

(ADB TA 8657 MYA)

1 – 4 Nov, 2016

Taunggyi, Shan State,

Myanmar

Day 2: system design, metering, tariffs, monitoring and

evaluation, and business models, grid interconnection

• Turbine options

• Reaction (Francis, propeller, etc) and impulse turbines (Pelton, Turgo, etc.)

• Head and flow curves

• Generator types

• Synchronous

• Induction

• Permanent magnet

• Load calculations (use spreadsheet to aggregate individual load data and create load

curve).

• Load controllers

• GridShare

• Metering and tariffs

• Interconnecting with the main grid

• Attributes of attractive projects

• Q&A

Confidential

Any questions from yesterday?

0 30 60 90 120 150 180 210 240 270 300 330 360

Flow [m3/s] 1986 1987

1988 1989

1990 1991

1992 1993

1994 1995

1996 1997

1998 1999

2000 2001

Watersheds

Micro-hydro turbine types

Pelton Turgo CrossflowPropeller/ Kaplan

Centrifugal pump

Francis

Turbine application

http://www.tycoflowcontrol.com.au/pumping/welcome_to_pumping_and_irrigation/home4/hydro_turbines/turbine_selection (April 18, 2003)

Efficiency and Flow

0.2 0.80.60.4 1.0Fraction of Maximum Flow

%Pelton and

Crossflow

Francis

Propell

Confidential

ADB Myanmar Off-Grid Renewable Energy Demonstration Project

• Preferred turbine for hydro-power,

when the available water source

has relatively high hydraulic head at

low flow rates.

• Vary from 40 watts to 400 MW

Pelton turbines

Confidential

Pelton

Confidential

Cross-flow turbines

Cross-flow turbines: Simple, affordable

The runner can easily be adapted to the flow, by changing its width.

Thus it is easily possible to build the turbine to fit precisely the site

conditions.

The simple design allows good

standardisation and manufacturing

without sophisticated manufacturing

facilities.

The costs are low compared

with other turbine designs.

Cross-flow turbine Entec T-15

Confidential

Crossflow

Confidential

Propeller (Kaplan)

Confidential

Propeller

Confidential

Propeller

Francis turbine

Francis

Pump as turbine – Mae Wei village, Tak Province

Confidential

Quality Measured in Water analogy

Power Watts (W)

Kilowatts (kW = 1000W)

Megawatts (MW = 1000 kW)

(power)

Voltage Volts (V)

Kilovolts (kV = 1000 V)

Pressure

Current Amps (A) Flow

Resistance Ohms (Ω) Resistance to flow

Electricity

Power = Voltage x current (Watts = volts x amps)

Generators

• Permanent magnet

• Wound rotor synchronous

• Induction (Asynchronous)

Permanent magnet

stator

Permanent Magnet Generator

Rotor has permanent magnetsAdvantagesNo brushes

Efficient

DisadvantagesGenerally limited in size to several kW

field not adjustable

Used in many all stand-alone applications.

Single phase up to 10 kW.

Three-phase up to 70,000 kW

Advantage:

Industrial standard

Frequency and voltage regulation

Disadvantage

Wound rotor – not tolerant to overspeed

Harder to connect to grid

(wound rotor) Synchronous Generator

(Wound rotor) Synchronous Generator

Most large machines use field coils to generate the magnetic field.

Rotating magnetic field induces alternating current in stator windings.

Rotor Field WindingExciter Winding

Exciter Field WindingStator Output WindingRectifier

(wound rotor) synchronous generator

Big50,000,000 watts

small2,000 watts

Asynchronous (Induction) Generator

Just an induction motor with negative slip.

Used with:

grid-tie system (up to 1 MW)

Off-grid stand-alone (often in ‘C-2C’ configuration)

Can be used with battery based systems

Induction motor/generator

Induction Generator

AdvantagesSimple and robust.

Tolerant to overspeed

Readily available

inexpensive

DisadvantagesFrequency regulation ‘loose’ in stand-alone applications

Requires external excitation

When used in off-grid,

an Induction Generator Controller

(IGC) ‘IGC’ controls voltage

Induction grid-tie example

1 MW Mae Ya

Selecting a Generator

Type (synchronous, induction, permanent magnet)• Stand-alone or grid-tie

Single or Three phase

Voltage• Loads• Transmission

RPM• 3000 rpm (single pole), 1500 rpm (double-pole), or 750 rpm (four-pole)

• Where possible, pick generator speed and turbine combination that avoids gears or belt drive to minimize friction losses and additional moving parts

Selecting a generator: IP rating IP = Ingress Protection.

IP rating is used to specify the strength

of the enclosure that surrounds

electronic equipment

Micro-hydro: IP44

Voltage and Frequency Regulation

Confidential

Voltage Regulation

230 volts

Voltage and frequency control

• Controlled by generator’s Automatic

Voltage Regulator (AVR)

• Controlled by Electronic Load

Controller (ELC)

Confidential

Electronic load controller (ELC)

Turbine &

generator

Electronic Load

Controller (ELC)

Ballast

Electronic Load Controller

Confidential

Mechanical Governing

As load varies, mechanical control keeps frequency constant by

varying water flow

Advantage:

Saves water

Disadvantage:

Electro-mechanical moving parts

Slower reacting

More expensive

Confidential

Determining load

Confidential

Load aggregation – household example & Excel lesson!

Detailed analysis for MHP systems >30 kW

demand estimate for a typical representative household (domestic use)

to be filled in

to be calculated

Time of day

Hourly load curve, by year from 1985 to 2000. Graph based on an appliance usage survey of 35 families in Mae Kam Pong village, April and June 2001.

Demand estimate for social infrastructure

Demand estimate for productive end use

Confidential

total demand

Typical load curve over the day

1 3 5 7 9 11 13 15 17 19 21 23

Time [h]

Productive use

Social Infrastructure

Domestic use

Detailed analysis for MHP systems >30 kW

Confidential

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

200,000

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

Year of MHP Operation

Demand growth

productive use

Demand growth

social infrastructure

Demand growth

domestic use

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

Year of MHP Operation

Peak D

Projection of demand growth

Confidential

Gridshare – a technology to share limited micro-hyropower

ELC keeps electricity stable when there is surplus…

GridShare can help when there isn’t enough

Rukubji Micro-Hydro System

• Installed 1986• Rated at 40 kW

Limitations of Mini-Grids

Rukubji’s isolated micro-hydroelectric

system experienced daily brownouts

during times of peak loading.

Peak loads consisted

of resistance-heating

kitchen appliances

used at meal times.

Power supply transformer Voltage regulator

Current transformer

Micro-controller

Voltagedivider

Smoothing capacitor

Image credit: Tom Quetchenbach

GridShare Circuit Breaker

Utility Meter

GridShare Final Design

Three-Prong Approach to Shift Demand

FeedbackGreen light: low demandRed light: brownout

EnforcementDuring brownouts, prevents the use of large appliances

EducationHelp residents understand their electrical system and discuss ways to alleviate brownouts

GridShare Installation 2011

GridShare Results

•Electrical data indicated a reduction of over 90% in severe brownouts

•LED lights helpful and appreciated

•Reduced spoiled rice, residents stated the grid was more predictable

•Some expressed frustrations with restrictions of red LED

•Community decided to keep GridShares installed

Confidential

Metering and tariffs

Confidential

• Mechanism for providing revenue to pay for project and keep it operating

• Can encourage energy conservation

• Can encourage use of electricity at times when there are surpluses

Metering: purposes

Time of day

Confidential

Tariff type #1: everyone pays the same

Advantages Disadvantages

Simple No incentive to conserve or

load-shift

Not fair (people who use

more should pay more)

Confidential

Tariff type #2: based on appliances & lights

Simple No incentive to conserve

Easy to cheat

Confidential

Tariff type #3: subscription tariff – load limiter

Simple Still have to collect monthly

payments

Fair Inconvenient to consumers

when load shuts off

Some incentive to load-shift

Inexpensive

Subscription tariff example:

0.25 Amp (60 watts) = 3000 kyat/month

0.50 Amp (120 watts) = 7000 kyat/month

Confidential

Tariff type #4: conventional kWh meter

Simple Requires monthly meter

readings

Fair Does not encourage load

shifting

Confidential

Tariff type #4: pre-pay meter

Simple Meters are more expensive

Can be programmed to be

cheaper in off-peak time

(time of use – TOU rate).

Pre-pay means no need for

bill collection

Users buy electricity in advance like pre-pay cell phone minutes

Confidential

Interconnection to the main grid

Mwenga 4 MW hydro800 households in 15 villages (expanding to 4000) & sells

to the grid

Tanzania

Large Plants

Customers

Mini-Grid

Customers

NationalGrid

Small Power Producer

Key: = power from utility = power from SPP = meterM

Before the grid arrives

Large Plants

NationalGrid

Customers Customers

Mini-Grid

Small Power Distributor (SPD)

Large Plants

NationalGrid

Customers

Mini-Grid

Small Power Producer (SPP)

Both SPP and SPD

Large Plants

NationalGrid

Customers

Small Power Producer(may operate as emergency

backup plant)

Customers

but with backup electricity provided by old generator

Mini-GridM

Buyout option

Co-existence

Large Plants

NationalGrid

Customers Customers

Extension of

NationalGrid

Assets abandoned

Induction generator connecting at 380/220 volts

Utility distribution system 22 or 33 kV

Utility distribution transformer

Utility distribution system 380/220 volt

Zone of utility responsibility

Zone of VSPP responsibility

Other Customer

Circuit breaker at

interconnection

Load of

Relay function Details Location

27/59 Undervoltage/Overvoltage Trip CB-A

81 Underfrequency/Overfrequency Trip CB-A

Confidential

Initial micro-hydro assessment

Form NEP-9: Components of Mini-Grid Project Proposal

Confidential

Myanmar National Electrification Program

Form NEP-9 Components of Mini-Grid Project Proposal

Mini-grid project proposals should be 10 pages or less, and provide succinct summaries of the following:

1. Village location (including state/region, township, village, and GPS coordinates) and distance away from the

nearest existing medium voltage distribution network (a minimum of 10 miles).

2. Number of households to be served (a minimum of 50 households required)

3. Description of village loads including description of any productive use loads (kW and hours of operation)

4. Estimated daily demand in kWh, including residential, business and public facilities (schools, clinics,

religious buildings, etc)

5. Planned mini-grid fuel type (e.g. micro-hydropower, solar/diesel, biomass, wind, etc.)

6. Measurement of planned renewable energy resource (e.g. flow, head for hydropower)

7. Planned mini-grid capacity (kVA)

8. Description of existing mini-grids (diesel, micro-hydro, etc. – if any) and opportunities to make use of these

assets.

9. Village map showing planned powerhouse and mini-grid, if available

10. Evidence of willingness to pay tariffs by users.

11. Prior experience of the developer in minigrid

Assessment of Attractiveness of Project

What makes a potential project attractive?

Technical Characteristics of Promising Projects

A micro hydro power site is more likely to be technically attractive, if one or several of the

following criteria are fulfilled:

1. Pressure head: Pressure head is more than 40m.

Explanation: low (<20m) and lower medium head schemes (<40m) tend to be

less attractive because all the hydraulic structures need to be designed for large

quantities of water and have thus considerable size.

This is not only a question of costs but also of complexity and engineering risks.

Exceptions are hydropower plants on irrigation channels (drops), which can be

attractive with heads of down to 7m.

2. Site layout: slope of water conductor system or ratio of water head to canal

length is 10% or better.

Explanation: the shorter the canal length required to generate a certain water

head, the more attractive the site is as cost and risks involved will be smaller.

3. Flow: firm capacity is more than demand estimate.

Explanation: firm capacity may be defined here as the power output which can

be generated with the dry season flow. Sites where firm capacity cannot meet

the demand are less attractive because an alternative source of energy would

have to be added.

4. Technical risks: low degree of difficulty/risks.

Explanation: a scheme in mostly difficult topography (steep river banks and hill

sides with no space for hydropower structures), in a large and/or meandering

river, in difficult geo-technical conditions (unstable slopes), and with no road

access to or near the site is considered to be of high risk and is thus a less

attractive project.

The degree of difficulty is estimated by assigning the terms high/medium/low

degree of difficulty.

5. Distance: Distance of powerhouse to load center/grid connection point is

less than 1 km per 100 kW installed capacity.

Explanation: A small hydro power project with a considerable distance to the

load center/grid connection point is less attractive because of the cost of the

required transmission lines.

6. Consumer density in case of isolated systems: Consumer density is

greater than 30 connections per 1km of transmission and distribution lines.

Explanation: a higher consumer density means that the specific cost for

transmission and distribution facilities are lower.

General Characteristics of Promising Projects

Note: Technically attractive projects are not necessarily promising projects! Economic,

financial, social, political and institutional aspects are equally important as purely technical

aspects of Small Hydropower projects.

Broad perspective required to identify promising projects

Promising projects usually have at least 2 of the following characteristics:

• Limited number of technically critical parts

• Synergies with other projects or installations, e.g. irrigation

• Equipment requirement can be manufactured locally

• Substantial equity contribution to project cost is available

Promising projects fulfill all of the following criteria:

• Broad political support at all relevant levels can be secured

• No social conflicts due to project implementation to be expected

• No major adverse environmental impacts to be expected

Criteria that further increase the attractiveness of a project:

• Part of the project cost can be covered by a grant or a soft loan

• The project can be linked to other projects to generate synergies

Considerations when introducing end uses:

• What is the peak load?

• Can you control peak load? If it is spread amongst many consumers most

likely not

• Is there the possibility to centralize end uses and supply via an independent

transmission? This is preferable?

• Do you have a reliable control system which can handle varying electrical

loads?

Confidential

Thank you!

Contact information

Chris Greacen, Micro-hydro consultant, (chrisgreacen@gmail.com)

Tin Myint Deputy Team Leader (Yangon) (tinmyint@suntactechnologies.com)

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