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Attending Microhydro Workshop in CRCS ITB (Part 1)


On 11-12 December 2018, I had an opportunity to participate in national seminar on instrumentation, control, and automation, as well as microhydro workshop. This event was held by CITA ITB (Center for Instrumentation Technology and Automation Institut Teknologi Bandung, Indonesia). It was a really awesome event, especially workshop on microhydro. In this post, I want to share to you what I got from the workshop.

The microhydro workshop was presented by Ir. Kusetiadi Raharjo, owner and director of PT Heksa Prakarsa Teknik. PT Heksa Prakarsa Teknik is one of microhydro technology provider and training provider on microhydro in Bandung, Indonesia. Ir. Kusetiadi Raharjo is alumni of engineering physics department of ITB.

Ir. Kusetiadi Raharjo
Ir. Kusetiadi Raharjo

If you follow this blog, you see that I shared several posts on renewable energy resources, such as solar photovoltaic, wind power, hydro power, geothermal, etc. I was so excited that my interest is matched with this workshop. In this post, you will see potential of microhydro power and several photos of microhydro turbines.

[Read more: Renewable Energy Sources: Solar, Wind, and Hydropower]

Microhydropower is one of potential source of energy. It is renewable, applied in small scale, and to maximize it, it can be combined with other type of renewable energy source, such as solar photovoltaic, to become hybrid renewable energy. Potential of microhydropower will be maximum during rainy season. During dry season, solar photovoltaic utilization will be at its peak.

Microhydro

Solar Photovoltaic

Wind power

Biomass

Investment cost per kW

IDR 5-10 million

IDR 50 million

IDR 50 million

IDR 12 million

Service range

Village

House

Village

Village

Electricity supply continuity

High

Moderate

Low

Low

Ease of maintenance

Moderate

Moderate

Low

Moderate

Local content

High

Low

Low

Moderate

Project planning difficulty

High

Low

High

High

Power utilization flexibility

High

Low

Low

Low

In term of range of power produced, there are several differences. Microhydro power plant will generate electricity less than 500 kW. While minihydro power plant will generate 500 kW – 5 MW electricity, and megahydro power plant will generate more than 5 MW electricity.

For microhydro power, local content has already achieved 100%. Furthermore, PT Heksa Prakarsa Teknis already exported water turbines to several countries, such as Japan, Africa, and Europe.

Mr. Kusetiadi Rahardjo believes that microhydro technologies can compete with China products. It is because, microhydro power is tailor-made, it is not mass products. The product should considered actual field condition.

Microhydro power plant is actually suitable for location where access to electricity or main electricity grid is far. Power generated can be distributed off-grid or on-grid. The power can also be utilized for centrifugal pump for irigation.

In Indonesia, most old hydropower plant can be utilized. The turbines are still OK. However, the generated must be repaired because long time ago, Indonesia used 110 V system. But now, we used 220 V.

How can we know if we can build microhydropower plant? This table show the guidelines.

Potential Location of Mini or microhydro

Range Head (RH), in meter

Range Debit (RD), in liter/sec

Range Power (RP), in kW

Drop structure at irigation channel

3-6

200-600

4-240

Drop structure at intake weir

3-10

3000-10000

60-680

Slope open channel

6-30

200-4000

8-820

Earth channel (traditional irigation channel)

6-30

100-300

4-60

Run of river

3-100

200-10000

4-6860

Water fall (single/cascade)

3-200

200-5000

4-6860

Small dam

6-30

200-4000

8-820

Circulating water of cooling tower

6-15

100-200

4-20

Potential location for minihydro power plant

Nowadays several softwares are used to model turbines so that the turbines are efficient. Those softwares are CAD, Solidwork, and Ansys.

Microhydro power plant projects usually consist of 70% civil work and 30% mechanical.

Basic energy equation of water to power is very simple:

Pnet = eo * 9.8 * Q * hgross

Basic energy equation of water to power is very simple:

Pnet    = power generated, in kW

eo    = overall efficiency (function of efficiency of civil works, penstock, turbine, generator)

Q    = flow of water through turbines, in m3/s

hgross    = gross head/geodetic on turbine, in meter

For microhydro power, debit data is taken annually.

There are several ways to measure head of potential place for micro and minihydro power.

Method Comments Advantages and Limitations Accuracy Precautions
Water-filled tube and rods (or person)
  • Weight: light
  • Expense: low
Long-winded for high heads Approx. 5% Repeat measurements
Water-filled tube and pressure gauge
  • Calibration chart must be drawn up
  • Weight: light
  • Expense: low
Fast, quite foolproof, can measure penstock length at same time Good (<5%) if gauge is calibrated Recalibrate the gauge. Repeat measurements
Spirit level and plank (or string)
  • Weight: light
  • Expense: low
  • Unsuitable for long gentle slopes.
  • Slow to use
  • Best done with two people
Approx. 5% on steep slopes
10-20% accuracy on gentle slopes (1:10)
Repeat measurements
Altimeter
  • Weight: can be heavy, some are light
  • Expense: high
  • Useful on medium and high heads (>40 m)
  • Can be fast, but more reliable if continuous monitoring undertaken
  • Gross error (30%) possible.
  • Used with skill, 2% at high heads
Experience and skill needed.
Must be calibrated and temperature corrected

 

Head measurement by using pressure gauge method
Head measurement by using pressure gauge method

 

Debit measurement by using velocity are method
Debit measurement by using velocity are method

 

Debit measurement by using salt dilution method
Debit measurement by using salt dilution method

 

Debit measurement by using weir method
Debit measurement by using weir method

There are several steps in developing micro and minihydro power plants, which are desk study, reconnaissance visit, pre-feasibility study, feasibility study, and detailed design.

Development steps of minihydro power plants
Development steps of minihydro power plants
  • Desk Study. The purpose is to become familiar with the physical, hydrologic and socio-economic profile of the project area without visiting the site but using maps, data from Bureau of Water Resources (BWR) and the statistical office only. In many cases, the desk study will reveal the absence of a good hydropower potential and time and expenditures for travelling to the proposed site can be saved.
  • Reconnaissance Visit. It is a short (one-day) visit to the proposed site (upon invitation by project promotor) to verify the hydropower potential and the approximate power demand.
  • Pre-feasibility Study. The purpose is to determine which of several proposed projects or sites are most attractive for minihydro power development and therefore deserve priority development and further investigations.
  • Feasibility Study. The purpose is to definitely assess whether the implementation of the proposed scheme is desirable or not.
  • Detail Design. The purpose is to prepare the scheme layout, the canal and structure drawings in final detail.

I can’t believe that this post will be this long! This is not end yet. This post will be continued in the second post.

I hope you find this post is useful.

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