Yanmar Launches 700kW High Efficiency Gas Cogeneration System

November 21, 2011
Yanmar Energy System Co., Ltd.

  Yanmar Energy System has developed and commenced sales of the EP700G, a gas cogeneration system in the 700kW*1 rated output class, with a maximum generating efficiency of 41.8%.
  The newly developed 12-cylinder gas engine of the EP700G is based on the 6-cylinder engine of the Yanmar EP350G*2, the 350kW gas cogeneration system developed in 2003.
  Yanmar Energy System is approaching hospitals, hotels, factories, office buildings, and district heating and cooling systems about renewing their power generating systems or newly installing the EP700G. They are committed to developing cogeneration technologies and building a diverse and innovative product lineup to support business and industry with energy efficient and lasting power solutions.

1. Product Features

1-1.Unrivalled energy efficiency with low NOx emissions
By utilizing an improved version of the electronic engine control system used in the EP350G, the EP700G realizes 41.8% efficiency (LHV*2), highest in the 700kW class. Whereas, high combustion efficiency normally leads to high nitrous oxide (NOx) emissions, the EP700G is specially configured*3 to reduce them, realizing emission levels of less than 200ppm (corrected for excess air*4), without the use of a NOx removal device.

1-2.Simple and compact design
The power unit can be broken into three pieces for simple delivery and installation into existing structures. It also has a smaller footprint than Yanmar Energy System’s 600kW gas engine cogeneration system, so that it can be installed even where space is at a premium*5.

1-3.Sophisticated engine control
Previous versions of the generator management system automatically shut down the engine when it detected operation outside of accepted parameters, to protect the engine from damage. The newly developed system can evaluate whether the exceptional event is likely to cause damage, and if not, will continue to run the generator at a lower output, in order not to interrupt the power supply. This is expected to reduce unplanned system shutdowns with corresponding savings from reduced use of supplementary power sources*6.

2. Gas Cogeneration


  Gas cogeneration systems use city gas supplies to generate electricity where it is needed, and then utilize the waste heat from power generation to produce steam or hot water which can be used for heating and cooling, and hot water supply. Cogeneration can be achieved where gas engines, gas turbines and fuel cells release heat in generating power.
  The unit can be located where electricity is needed, and both heat and electricity from the system can be utilized realizing an environmentally sound, highly efficient and economical system. Yanmar Energy System also stands ready to assist customers in protecting their important power loads from outages, by offering the right power distribution and battery storage combinations to deliver Business Continuity Plan (BCP) solutions.


*1: The output is suitable for hospital or hotel space of the order of 50,000m2 or a small to medium sized factory.
*2: Lower Heating Value (LHV): determined by subtracting the heat of vaporization of the water vapor from the higher heating value. This treats any H2O formed as a vapor. The energy required to vaporize the water therefore is not realized as heat. (HHV or Higher Heating Value assumes that the heat of vaporization is recovered and all water from combustion is in liquid form. LHV ≈ 0.9 x HHV.)
*3: By making the fuel-air mixture leaner, the temperature of combustion and the NOx concentration can be lowered, however, this may result in unstable combustion. The EP700G maximizes combustion, producing stable, efficient and low NOx operation.
*4: Excess air supplied to ensure complete combustion of fuel can dilute the exhaust gases, giving misleading results for emissions. Here, the excess air is measured in the exhaust and measured emissions are corrected to a reference figure of 0% O2.
*5: The power unit of the 600kW gas engine cogeneration system requires an area of 18.0 m2 for installation compared to only 13.9 m2 for the EP700G. This is a reduction of 34% per kW.
*6: Many customers use in-house power generation and supplement this with a back-up supply from a power company. If the in-house power supply is interrupted by testing, maintenance, repair, or breakdown, the supplementary power is supplied by the power company at a higher pricing structure than for normal power supply, as specified in the in-house generation supplementary energy supply contract.

3. EP700G Gas Cogeneration System

Outdoor Type
Three-part Power Unit

4. Inquiries:

Public Relations Group,
General Affairs Dept., Yanmar Co., Ltd.