Overview of DG Set NOC Process in India

A diesel generator, or DG set,is used as an alternate power source in many offices, industries, housing societies etc., as a power backup alternative. It combines a diesel engine with an electric generator to generate electrical energy. A DG set user must ensure that the model used by him has a valid Type Approval Certificate and Conformity of Production certificate. Inspection of electrical installations such as DG Set is carried out under Regulation 30 for periodical inspection and Regulation 43 for the approval for installation before the commencement of supply or the recommencement/ restarting after shutdown for six months. However, the applicant has to apply online to the electricity department of the respective state in 2 stages for DG Set NOC. The first application is for the approval of the "Generating Set Plan” and, thereafter,to get his diesel generator inspected (after installation) after submitting a work completion report. After the DG set is inspected, the applicant has to produce an attested copy of the approval to the department for the generating set's 'energisation'. Here in this write-up, we will be discussing the procedure for obtaining No Objection Certificate for installing and operating diesel generators or DG sets and how to get from appropriate authorities for the same.

Criteria for DG Set NOC

DG Sets are categorised based on the power output or engine displacement. For instance, the concentration of pollutants and particulate matter (PM) in the exhaust of gensets. Engine category- below 99cc, 99 to 225 cc and 225 to 800cc, has been used to classify DG sets in the rules and frame guidelines on their emission levels. Also, these emissions are almost similar for the two engines category allowed, i.e. Compression Ignition engines (CI) and Positive Ignition engines (PI). The Emission limits and noise limits have been defined for these gensets. Let’s understand the provisions related to these two factors based on the limits applicable. Apart from the Diesel engines, the following alternate DG set is covered under the rules.

• Engines based on dedicated alternate fuels: i.e. liquefied petroleum gas (LPG), natural gas (NG), natural gas (NG) or liquefied petroleum gas (LPG).
• Engines based on Bi-fuels: I.e. Engines that run either on gasoline or on any one of the alternate fuels mentioned above.
• Engines based on Dual Fuel: i.e. engines that run on diesel and alternate fuels, like natural gas (NG) with diesel or liquefied petroleum gas (LPG) with diesel.

Permitted Pollutant Levels for Air and Noise Pollution for DG Set NOC.

Air Emission Limit for DG Set NOC: The emissions from these DG sets include air pollutants like NOx (oxides of nitrogen), NMHC (non-methane hydrocarbons), CO (carbon monoxide), PM (particulate matter) and RHC (reactive hydrocarbon). The Environment (Protection)Amendment Rules, 2022 defines the limits for air emissions for gensets (up to 800kV) according to the fuel used by the different gensets. Also, the Noise Limit for gensets run with diesel is notified by Environment (Protection) Rules according to the power output of the particular DG set.

Acceptable Noise limit for DG Set NOC: The permissible sound pressure level for the DG genset, with a capacity of up to 800 kW, is 75 dB(A) which must be at 1 metre from the enclosure surface. Therefore, DG sets are provided with integral acoustic enclosures at the manufacturing stage itself. They must be designed so there is a minimum 25 Db(A) insertion loss, or the DG set must comply with the ambient noise standards, whichever is higher.

Requirements in the DG Set NOC Application

The requirement for DG set NOC includes DG Declaration Form, B & L Form, Purchase Invoice, and Test Certificate. The consumer has to get his diesel generator set installed, submit a work completion report as per, i.e. rules, and get his DG set inspected by the electrical inspector and produce an attested copy of the approval to the department.

Approval of Line Diagram: Single Line Diagram of the electrical installation must be submitted showing all details from starting point to the endpoint of the entire installation. Site plan showing the location of the transformer, Generator, Electrical Room, Panels, motors, etc. The approval fee must be paid in some cases, which will be separate from the inspection fee.

Layout Plan: The layout of the installation must show the location of all the equipment about the location of switchboards and distribution boards. Elevations in sections showing overhead clearance, vertical, horizontal and sectional clearances with respect to equipment and ground must be included.

Work Completion Report: Through a work completion report, the owner of the DG set will then submit an undertaking that the DG Set is ready for inspection to the Electrical Inspector.

Documents required for DG Set NOC

Application for DG set installation must be submitted to the Electrical Inspectorate with all the relevant drawings and details listed below in the DG Set NOC process.

• Photocopy of sets of blueprint drawings incorporating the items listed.
• Copy of work award letter
• Requisition Letter
• District Industry Centre Certificate/ Ministry of Commerce & Industry Certificatecopy of occupancy certificate
• Electrical Inspector Charging Permission.
• Copy of permission issued by the pollution control committee for the operation of the diesel generator set.
• Copy of last paid electricity bill
• Purchase invoice of the generating plant
• Rent Agreement of the Own Generating Plants, if applicable.
• Single line electrical diagram showing the detailed load and change-over system with the generating plant/plants.

Advantages of adopting Diesel Genset

• Low installation cost
• Higher efficiency
• Short delivery periods and installation period
• Efficient plant performance under part loads
• Suitable for different fuels in case of large capacities.
• lesser water requirements for cooling(i.e. air-cooled heat exchanger)
• Shorter start-up time

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