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Surge Protection Device for Solar PV installation

Effects of Lightning Strike on Solar PV system: A solar PV installation is vulnerable to the effects of lightning stroke. The potenti...

Friday, 22 January 2016

Automatic Power Factor Controller for Industries

Induction motor accounts for more than half of the industrial load and are responsible for the poor power factor. The power factor of an induction motor varies with the load on the motor. Lightly loaded motor has a very poor power factor. Poor power factor results in reduced capacity of transformers, cables and other equipments and are also responsible for higher power losses because of increased current flow. They also cause additional voltage drop.

Motivation for power factor improvement:  

Utilities usually encourage the consumers to improve the power factor of their installation by incorporating power factor based penalty/rebate in the power tariff structure.

Figure shows the Electricity Bill of a Hotel for the month of Dec 2016. The premises, which is fed from 11 kV, is having an average power factor of 0.63 (as can be seen in the picture) for which the consumer has to pay a penalty of 28,759 INR ( a hefty amount indeed, for sheer casual approach)

Tuesday, 12 January 2016

Coal-fired Power Plants: Hazardous to your Health

The aspiration for rapid economic growth leading to express industrialization, accelerated urbanization and mechanization of agriculture has been responsible for the increasing energy demand ever since the independence in India. In the recently concluded 21st Conference of the Parties to the UN Framework Convention on Climate Change (UNFCCC) in Paris, a resolution on limiting the use of coal across countries was proposed for consideration. Coal-fired power plants are among the most polluting industrial facilities. This is of particular relevance in the Indian context as coal fired power plants form the back bone of Indian electricity generation sector.

Pollution from Coal-fired Power Plants

In 2014, nearly 79% of the electricity generated in India was from thermal power plants. Power plants in the country use different qualities of coal, different combustion technologies and operating conditions. As a result these plants have different efficiencies and different emission levels. Main emission from lignite based coal-fired  power plants are CO2, NOx, SOx and air borne particles such as fly ash, soot, Suspended Particulate Matter (SPM) and other trace gases. 

As per the Central Electricity Authority (CEA) report the best specific coal usage for any Indian coal-fired power plant is less than 0.6 kg/kWh whereas the worst has been 1.0 kg/kWh. The Indian coal has high ash content (35-50%) and low Calorific Value (CV), about 2500-5000 kCal/kg. Low CV means more coal usage and high ash disposal requirements. 

The emissions per unit of electricity generated (kWh)  are estimated to be in the range of 0.91 to 0.9 kg/kWh for CO2, 6.94 to 7.2 g/kWh for SO2 and 4.22 to 4.38 g/kWh for NO during the year 2010. The future emission scenario (for the year 2020-21), based on the projected coal consumption in Indian coal-fired power plants is in the range of 714976 to 914680 Gg of CO2, 4734 to 6051 Gg SO2 and 366 to 469 Gg of NO. The continued use of older coal-fired power plants, many of which have minimal or no pollution controls and the construction of more of these power plants will only worsen the situation.

Health Hazards from Coal-fired Power Plants

So these coal-fired power plants, by burning of coal, releases a lot of Green House Gases (GHG) and other harmful pollutants into the atmosphere. These pollutants such as Sulphur-dioxide, Nitrogen Oxides and particulate matters released in the air and water, may cause respiratory problems along with other serious health consequences. Pollution produced by these plants is responsible for thousands of non-fatal heart attacks and millions of Asthma attacks each year.

Coal-fired power plants annually produce millions of tons of Coal Combustion Waste (CCW) – coal ash, scrubber sludge and other by-products. This waste contains toxics such as arsenic and heavy metals. Arsenic increases the risk of skin, lung, bladder, liver, kidney and prostate cancer. It can also cause liver disease, anaemia, gangrene and various skin diseases. Heavy metals such as cadmium, chromium, lead, mercury, nickel etc. can cause cancer, nervous system and brain damage and learning and behavioural problems in children.

A single large power plant may require several hundred acres of landfill space to dispose of its coal ash causing damage to the green land. The pollutants in the coal ash can get into the soil and contaminate the nearby ground water and make the drinking water hazardous.

Pollution from NTPC's Badarpur Coal-fired Power Plant: An example

Barely 25 km from the Central Delhi, a 40 year old coal-fired power plant run by NTPC is working way beyond its life. Along with other reasons this power plant is responsible in listing Delhi, the Indian capital, as one of the worst air polluted cities in the world. It is ranked at 11th position among the most polluted cities on the Earth with worst air quality, a WHO report says.  

New Delhi has the world's highest levels of tiny, toxic particles that lead to respiratory diseases, lung cancer and heart attacks as already mentioned above. The city averaged 153 micrograms/cubic meter in the year 2013 as per the WHO report. The level of pollution reported is 15 times higher than the WHO's recommended pollution level. PM 2.5 level has been increasing in the city since last 5 years and the measured average annual PM 2.5 was 122, whereas WHO recommends that it should be kept below 10.  Residents nearby the power plant go out using handkerchiefs as masks to avoid breathing soot and fly ash. Eye burns and headaches because of coal dust are common to many residents.

National Thermal Power Corporation (NTPC) is now seeking to cut emissions across its facilities in the country and is planning to spend 12 billion INR annually on technology upgrading to enhance efficiency and reduce the pollution.      

Future Agenda

Now the question is who is responsible for all this, the government, the utilities, the pollution controlling agencies or somebody else. Can we play a more interactive role in reducing the deadly pollution? The answer is YES. To meet the future energy needs safely while protecting Human health and the nature, we must:

  1.        Judiciously use the energy with greater efficiency i.e. increase energy efficiency and conservation, and
  2.          Aggressively pursue RE resources such as Solar, Wind, Bio-mass etc.
  3.        We must eliminate these polluting power plants in phases like France.

Wednesday, 6 January 2016

Get ready for the Net Metered Solar PV System

Rapidly depleting fossil fuel reserves, higher energy demands, ever increasing global pollution- the present scenario has made it essential for us to look for other sources of energy. Solar PV energy has emerged as a convenient, pollution free and mature solution to this problem.

In India, the solar PV system has generated much curiosity among the common people about its use, the subsidies granted by various government agencies, the business opportunities in solar industry etc. It has created an atmosphere of awareness among the masses. It will promote de-centralized electricity generation thereby reducing the transmission and distribution losses, which is significantly high in the country.   
The state of Madhya Pradesh is bestowed with high solar radiation (5.5 kWh/m2/day on an average) and around 300 days of clear sunny day per annum. The state has a proposed Solar PV capacity addition target of 2200 MWp by 2022. The Madhya Pradesh Solar Policy 2012 has given the much needed thrust for installation of grid connected Solar PV projects. 

The most recent and much talked about development that has caught the attention of the people is the Net-metering. The state policy for ‘Net metering based solar applications: 2015’ has been structured so as to promote generation and self consumption of energy generated from solar PV system by individuals. Now let us see what the net metered solar PV system is all about.

What is Net-Metering or Net-metered solar PV system?

In the grid connected system, the solar PV system is installed at the roof top or within the premises of the consumer (existing electrical energy user). The power produced by solar PV system will be used by the consumers for their own use. The energy produced in excess of the consumer’s requirement could be injected into the utility’s LT network. In case the energy need of the building is more than that generated by the solar PV system, then the required additional energy will be drawn from the LT lines.

A bi-directional or import-export energy meter has to be installed for keeping the energy record. The electrical energy thus exported could be adjusted against the import by the consumer from the utility network. Such type of solar PV system is known as ‘Net metered Solar PV system’. The consumer, after settlement of energy within the settlement period, shall pay for the net energy purchased by him/her from the utility.

The concept seems to be good, but the question arises is who can install the net metered solar PV system?  

Who can apply for Net-metered solar PV system (Eligibility Criteria)?

All categories of electrical consumers who have installed solar PV system in their premises, or are willing to install, to balance part or all of their electrical energy needs are eligible for ‘net metering’ Solar PV scheme. The solar PV system can be either self owned or third party owned.  

Every activity or installation in which any government organization is involved, has its own set of sanction procedures. Now the question is, where the interested party can apply and what are the approval procedure? 
What is the Approval Procedure?

The eligible consumer is required to fill and submit an on-line application form along with the necessary fee and documents such as current electricity bill. The form is available at the MP Urja Vikas Nigam (MPUVN) and the Distribution Companies (DISCOM) website.

Once the solar PV beneficiary (a person who is willing to install the solar PV system at his/ her own premises) applies for "Net metered" solar PV system at his premises along with the registration fee of 1000 INR (as on May 2017), the Discom official shall visit the said premises for verifying the technical feasibility for grid connection of the proposed Solar PV system. They will inspect the available LT network, in case the application is for residential use. The available capacity of the concerned distribution transformer should also be ascertained before giving the sanction. The applications are to be handled on first come first serve basis. As per current rules, the total capacity of grid tie solar PV system on any distribution transformer cannot exceed 30% of the transformer's kVA capacity. The approval procedure is supposed to take nearly 30 days from the date of application.

The eligible consumers have to complete the installation of the approved Solar PV system within 3 months from the date of approval by DISCOM, otherwise the sanction will be cancelled.

This solar PV system is supposed to feed back the extra energy produced to the grid, means you are connecting your solar PV to the utility grid. For this you certainly have to follow a set of safety and technical rules and regulations. What are these rules and regulations?  

What are the safety and technical points of the system?

The Solar PV system is expected to have a lifespan of 25 years. Also the system is to be grid tied; hence utmost care should be taken during the installation process so as to ensure that every safety and technical standards are followed. 

The interconnection with the LT network shall be made as per the technical standards for “connectivity of distributed generation resources regulations” notified by Central Regulatory Authority (CEA). Similarly, metering arrangements should confirm to MP Electricity Regulatory Commission (MPERC) “Grid connected Net metering Regulations 2014” and subsequent amendments thereof and CEA Regulation 2006 for the “Installation and Operation of meters”.   

One of the most important and typical safety requirement of Net- metered or Grid-Tie solar PV system is the "anti-islanding" feature. In this feature it is mandatory that the grid-tie solar system must be shut down automatically in case of grid failure so as to ensure that the associated utility network and equipments are safe to work on. This safety feature is essentially incorporated in the grid-tie inverter. 

MPUVN ltd., New and Renewable Energy department, Government of Madhya Pradesh, shall be the nodal agency for Net-metering based Solar PV systems in the state. To ensure quality work the consumer has to get the installation work done by developers/facilitators empanelled with the MPUVN.

Is there any tax benefit or financial assistance for the system?

Installation of Solar PV systems under the policy shall be exempted from wheeling, cross-subsidy and open access charges. The energy generated from the solar PV system shall be exempted from electricity duty and cess. All eligible consumers can avail the financial assistance from Ministry of New and Renewable Energy (MNRE) as per the applicable schemes. The equipments for the solar PV system under this policy shall be exempted from VAT and entry tax.    

Even after the steep growth in this sector if you have not installed a roof top solar PV system at your house, it is high time now to awaken from your slumber and acknowledge the technology; at least for the sake of your future generation.