Norochcholai Coal Power Plant - In retrospect - Treading the wrong path

I believe we have reached the conclusion that coal power was a more suitable option in electricity generation for Sri Lanka through the previous article which discussed the fact comprehensively. This particular article follows it up with the discussion of initial groundwork of the Norochcholai coal power plant and irreparable mistakes occurred along the way. The sole intention is to narrate the history of the power plant, explaining the episodes as they were, preventing any political influence.

The necessity of a coal power plant

Let me take you to the power generation situation in Sri Lanka exactly 10 years back, year 1993, and compare it with the situation in year 2010.

(Source: Sri Lanka Energy Balance 2010)

It is evident that in 1993, 95% of total generation was made of hydropower and that portion has dropped to 53% by 2010, while thermal generation has increased from 5% in 1993 to 47% in 2010. This points us to the fact that by early 1990’s almost all the potential large hydro resources in the country has been utilized to produce electricity and further increase in demand caused the introduction of thermal generation in large scale. Further, to maintain the reliability and stability in an ever growing power system, thermal generation is essential. Walking back in our memory lane to the previous article, we concluded that coal power is one of the best options to maintain such status.

Funding Opportunities and Finding a site

The relevant authorities at that time have also agreed to the idea for a coal power plant as a general plan has materialized and the search for funding opportunities has begun.

The most prominent funding opportunity for the proposed coal fired power plant was provided by the Japan Bank for International Cooperation (JBIC). By early 1990’s JBIC had agreed to fund a feasibility study on the development of a coal fired power plant and fund the subsequent construction of the plant. Four potential sites for the power plant have been identified at that time, three in Puttalam area and one in Gampaha District. Trincomalee had also been a potential site, but it was rejected due to the security situation prevailed in that area. The whole southern coastal belt was rejected by then government under the convincement that building a coal power plant would cause a detrimental impact on the environment.

After studying the merits and demerits of the possible sites selected, it was decided that Narakkalli in Puttalam area as the most suitable site for the plant, mainly due to the adequate coastal area available and less density of population in that area. After official requests sent by the Sri Lankan government to Japan, feasibility study on the plant started in 1995 under the funding from JBIC, and during the study the site was moved further southwards. Even though the original name of the area is Narakkalli, the site went by the name of “Norochcholai” as it was the name of the nearby town.

Protests against project and setbacks triggered from them

The point where things started going wrong occurred in 1997 where the whole project and the ongoing study became highly politicized due to the constant upheavals from the pressure groups. The first considerable resistance on the basis of environmental impacts and resettlement issues, came from the Catholic clergy of the area with the backing of the people from the area and especially the politicians. Politicians were more concerned over there vote base of the area rather than the actual need of the whole country which lead to the situation where between 1997 and 2004, the project would have been approved by the political regime several times, and also would have been “cancelled” or “suspended” several times by the same regime, typically when elections were approaching.

Consequences of delayed implementation of the plant

Amidst this political tug of war, it was the electricity customers in the country who suffered as the government was forced to build 10 oil fired power plants within the time period in which the construction of Norochcholai power plant had been delayed. Political schemes and personal benefits outweighed the actual need of the country as politicians and powerful personnel nested in elevated positions in the hierarchy constantly backed up the construction of the oil fired power plants stating numerous justifications while the coal power plant project was shunned aside hoodwinking the general public with stories of deceit.

As a result of this the electricity customers suffered day by day in the face of ever rising price of crude oil which increased their electricity bills regularly, while the more cost effective and sustainable option of the coal power plant was neglected. This is evident clearly when the crude oil prices and coal prices in that time frame are considered, as the crude oil prices increased dramatically, the coal prices were relatively stable.

Commissioning of the plant

While general electricity customers suffered from the poor decision making triggered by political schemes, the whole power system of the country was setback several years as the coal power plant was to produce electricity from 2004, although luckily in 2004 the project was resurfaced under a new government and people with clear vision up in the hierarchy. But unfortunately at that time funding from Japan was not possible due to various reasons hence government turned to China and a deal was struck to build the plant under Chinese funding which was to produce electricity from 2011, almost exactly 7 years behind the schedule.

Up to now the background of the Norochcholai power plant was discussed and more details of the actual project will be discussed in the next article.

(This article is based on “Norochcholai Power plant: A postscript” by Dr Tilak Siyambalapitiya which was published in The Sunday Times on Sunday March 20, 2011 http://sundaytimes.lk/110320/BusinessTimes/bt09.html)

Article By: Asith Kaushalya

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Posted in: Power System

Light the Lights - Comparing options for domestic lighting

There is a diverse range of lighting fixtures and lamps available in the domestic market where each lamp has its own advantages and disadvantages. The diagram below shows some of the basic lighting technologies which are popular in the local market for savvy. But this article mainly focuses on domestic lamps, their advantages and disadvantages and how they can be utilized optimally to serve your requirements.

Basic Lighting Technologies

Terminology

Incandescent Lamps

Incandescent Lamp

The incandescent lamp is a very commonly used lamp type in household applications. If stated in simple terms, the basic operating mechanism of an incandescent lamp is passing of an electric current through a tungsten spiral which heats up to such a level as to emit light.

Advantages

• Inexpensive 
• Dimmable
• A dimmer, which is generally a variable resistor, installed in series with the lamp, renders the capability of controlling the current through the lamp and thereby, the capability of dimming it.
• Great Colour Rendering Capability (100 – the maximum possible)
• Due to the extensive colour rendering capability, colours of objects in the illuminated area can be viewed realistically. Therefore, incandescent lamps becomes the ideal choice for places where differentiation of colours of the objects is of greater concern, such as in jewellery shops. 
• No mercury (environmental friendly)
• Unlike CFLs or Fluorescent Tubes, Incandescent lamps do not contain mercury. Therefore, they do not support environmental pollution or poisoning due to mercury, during disposal of the lamp.
• Fast switching
• Due to the absence of warm up time or pre heating time, incandescent lamp can be turned on instantly to produce full brightness. Further, frequent switching does not affect the lifetime of the lamp. Thus, incandescent lamps can be used where fast switching and frequent switching is a necessity.

Disadvantages

• Low luminous efficacy (8 to 24 lm/W)
• The notable disadvantage is the low luminous efficacy of the incandescent lamp which ranks this lamp in the tier of low efficiency. 
• Lifetime of this lamp is short due to evaporation of the Tungsten filament, typically after 750 to 1000 hrs

Tungsten Halogen

Tungsten Halogen Lamp

The Tungsten Halogen is an advanced form of the Incandescent lamp. Similar to the Incandescent lamp, the filament of the Tungsten Halogen lamp is made of Tungsten metal. But the gas filled inside the Tungsten Halogen bulb is a pressurized halogen, usually Iodine or Bromine, under a pressure of 7 to 8 atm.

To withstand the high pressure involved, the glass bulb is made stronger and thicker than in a conventional incandescent lamp. The halogen gas molecules are capable of capturing the evaporated tungsten atoms from the heated tungsten filament and redepositing them back on the filament. This halogen cycle enables the filament to reach higher temperatures and to produce more luminous flux. Additionally, it increases the lifetime of the lamp.

Tungsten Halogen lamps are used in household lighting, especially as spot lights. They are also used in automobile lamps.

Tungsten Halogen lamps possess advantages and disadvantages similar to incandescent lamps.

Advantages

• Small and light in weight
• Dimmable
• Great Colour Rendering Capability (100)
• No mercury (environmental friendly)
• Fast switching  
• Higher life time than Incandescent lamps as the Tungsten-Halogen cycle reduces the evaporation of the filament. Typical lifetime is 2000-2500 hrs.  

Disadvantages

• Low luminous efficacy (12 - 35 lm/W)

Fluorescent Tube Lamp

Fluorescent Tube Lamp
[Photo: http://www.edisontechcenter.org/lighting/Fluorescent/PreheatFluorescentLabeled80.jpg]

The working principle of fluorescent lamp is different from filament lamps.

The electrodes at the two ends of the lamp are heated up so that they start to emit electrons. Emission of electrons is governed by the ballast and the starter. These electrons collide with the atoms of argon (noble gas) near the electrodes of the tube and ionize them. This starts an avalanche ionization process throughout the lamp, creating a path for the current to flow through the lamp. Subsequently the electrons get the opportunity to easily collide with the vaporized mercury atoms. During these collisions, ultra-violet (uv) photons are released. When these photons meet the phosphorous layer of the tube, visible light is emitted.

Fluorescent tubes are very useful in efficient lighting of houses and offices. They are ideal for areas where diffused lighting is necessary rather than focused lighting.

Advantages

• Higher luminous efficacy (80 – 100 lm/W)
• Long life - typically 20,000 hrs
• Diffused light - To places where diffused light is necessary
• Fairly good CRI value (75-85)

Disadvantages

• Cannot dim with a series variable resistor.
• Switching frequency and voltage variations directly affect the life time
• Higher the switching frequency, lower the useful lifetime of the lamp. Higher the voltage increments than the rated voltage, lower the useful lifetime of the lamp. (Note: useful lifetime is the time period until the luminous flux output of the lamp drops down to 70% of the rated luminous flux output.)
• Not environmental friendly due to mercury content.
• Cannot turn on quickly as it needs a warm up time of few seconds.

Compact Fluorescent Lamps (CFL)

Compact Fluorescent Lamp (CFL)

The CFLs have a similar working principle to that of the fluorescent tubes. CFLs normally come with electronic ballasts integrated to the lamps themselves. They are designed to fit in to the holders generally used for incandescent lamps, making it easier for the consumers to replace incandescent lamps with CFLs without any special changes to the existing wiring arrangements.

CFLs are an energy efficient substitute for incandescent lamps in situations where colour rendering capability is not vital.

Advantages

• High luminous efficacy (50 to 85 lm/W)
• It should be noted that the luminous efficacy of CFL is lower than the fluorescent tube but greater than the incandescent lamps.
• Longer life - typically 6,000 to 12,000 hrs
• Fairly good CRI value (80)

Disadvantages

• Not dimmable with a series variable resistor.
• Mercury content pollutes nature at disposal
• Switching frequency affects the lamp adversely

LED (Light Emitting Diode)

LED (Light Emitting Diode)
[http://www.edisontechcenter.org/lighting/LED/ScrewInBulbLEDarray326.jpg]

LEDs are type of semiconductor diodes, which emits light when they are forward biased. The mechanism of light emitting has to be explained at the atomic level. But that process can be explained in simpler terms.

An electron releases energy when it drops from a higher orbital to a lower one. This energy is released in the form of a photon. A greater energy drop releases a higher-energy photon, which is characterized by a higher frequency.

Free electrons moving across a diode can fall into empty holes from the P-type layer. This involves a drop from the conduction band to a lower orbital, so the electrons release energy in the form of photons. This happens in any diode, but you can only see the photons when the diode is composed of certain material.

Visible light-emitting diodes (VLEDs) are made of materials characterized by a wider gap between the conduction band and the lower orbitals. The size of the gap determines the frequency of the photon. In other words, it determines the color of the light.

Lamps made using LEDs are available in the market and they have a much higher luminous efficacy; thereby saving a lot of energy.

Advantages

• High lifetime - typically 100,000 hrs
• High luminous efficacy (150 lm/W)
• No mercury content
• Fairly good CRI value (70)
• Dimmable using a PWM (Pulse Width Modulation) circuit.
• Durable 

Disadvantages

• High heat dissipation causes the need of heat sinks making the lamp bulky and costly.

References

• Seminar on LED Technology and Applications 2012, Regional Center for Lighting
• http://www.edisontechcenter.org
• http://www.howstuffworks.com/led2.htm

Article By: Supun De Silva

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Posted in: Sustainable Energy and Policy