Niigata Engine Services

We are the authorized distributor for Gas engines manufactured by Niigata Power Systems Co. Ltd., Japan. Niigata has been a leading manufacturer of Diesel and Gas engines for over 100 years and has always had a high commitment to protecting the environment. Niigata is an IHI group company and provides efficient, reliable and durable Diesel and Gas engines for industrial and marine markets. Neptunus has enhanced Niigata’s reputation in India by excelling at Niigata Engine Services over the past decade.

The current range of AGS Gas engines is the 3rd generation of natural Gas engines produced by Niigata. These are spark ignited with electrical efficiencies of 47.5% using natural gas with methane number (MZ) as low as 65. Niigata’s unique modular auxiliary systems offer the advantage of reduced installation time and saving in space. The engines are very responsive to block loading. The engines are available with electrical output of 2, 2.6, 4, 5.3 and 6 MW.

Neptunus has factory trained personnel who offer complete maintenance solutions for all Niigata engines and Z Pellers in the marine and industrial sector.


  • Electrical efficiency of 47.5%
  • No de-rating up to 400 C ambient temperature
  • Methane Number as low as 65
  • Low operating cost
  • Modular design of auxiliaries
  • Patented knock detection system

Technical Details of Niigata Gas Engines

Bore295 mm
Stroke400 mm
Heat ratekJ/kWe79017884765176187585
NOxppm320 @ 02 = 0%320 @ 02 = 0%320 @ 02 = 0%320 @ 02 = 0%320 @ 02 = 0%

Site Conditions:

  • ISO standard reference conditions (ISO 15550)
  • Generator output subject to efficiency at pf=0.8
  • Generator efficiency 6L and 8L 96%, others 97%
  • Methane number: 65 and above
  • LCV of Natural Gas 41.6 MJ/NM3
  • Gas pressure 5.5 ~ 6.0 bar

Plant Dimensions for a two engine installation

8L28AGS 45000280009000
16V28AGS4900036000 9000
18V28AGS 52000360009000

Engine Dimensions and Mass

ModelsEngine mass (t)Generator mass (t) Total weight with common bed
6L28AGS24 944.5
8L28AGS 3210.7 58
12V28AGS 3814.283
18V28AGS5719.4 125