Why recips are a safe bet

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Below are excerpts from a paper titled, ‘The Optimal Generation for the European Economy - Wärtsilä 50SG Gas Engine’ was presented at Power Gen Europe 2015 by Johan Bertula.

Gas-fired generation supports two elements of a cleaner energy system: increasing integration of renewables and displacing coal-fired generation. Shifting gas-fired generation towards flexible operation opens up competition among generation technologies: internal combustion engines, open-cycle gas turbines, combined-cycle gas turbines (CCGTs) and even fuel cells could become attractive. In regions with ambitious deployment plans for renewable electricity, part-load efficiency, ramp rate, turndown ratio and start-up times are more relevant for gas-fired plants than full-load efficiency.

Reciprocating engine characteristics like fast loading, load following and unloading, starting and stopping are more and more important in today's market. Recips can achieve the following: Synchronisation readiness from standstill in 30 seconds; potential non-spinning secondary reserve; fast loading capabilities; from standstill to 100% load in less than 5 minutes; fast unloading; from 100% to stop in 1 minute.

For example, a power plant with 10 gensets can correspondingly operate at 3% of its total nominal output. The LCEC generation plant in New Mexico, USA takes less than 5 minutes to full load. The superior reserve operation 18V50SG loading rate, running engine from 10% load to 100% load in just 42 seconds is available for loads between 10% and 100%. This is for a running engine that has reached nominal operating temperatures.

Smart power generation in multiple generating units

In multi-engine solutions, there are huge possibilities for operational flexibility and operation strategies are easy to switch from season to season, based on production forecasts on daily variations or market situations. A few engines running while others standstill, enables stand-by spinning reserve capacity. Minimum number of units in production at a high load level ensures high efficiency over a wide load range.

The largest gas combustion engine existing on the market is W18V50SG. It has the highest efficiency existing today, among all simple cycle power plants with ratings of 50 Hz/500 rpm 18,3 MWel, 60 Hz/514 rpm 18,8 MWel and heat rate of 7411 kJ/kWh. The electrical efficiency is 48.6 %. The engine has high efficiency in CHP mode due to Dynamic District Heating (DDH).

Dynamic District Heating


DDH can enable smart power generation in Europe due to the operational flexibility. The engine is capable of adapting to all electrical markets (day ahead, intra day & balancing markets), balancing markets especially in secondary control reserves, quick starting capability (< 5 min). It has no minimum up/down time constrain, low CAPEX/ Stepwise investment, thanks to modular units.

DDH can result in high electrical efficiency, high power-to-heat ratio and high plant part load efficiency.

The W18V50SG brings the following value proposition:

1 Faststart

Value - Grid stability support and ancillary service market

Features - Power to grid in <1min, 2 to 5 min to full power, start up efficiency

2 Baseload

Value - Competitive life cycle generation cost, and any output, same generation cost

Features - Highest simple cycle efficiency, multi unit -> high firm capacity, flexicycle TM,

3 Load Following

Value - Wind balancing, ancillary service market

Features - Part load efficiency unaffected, No EOH cost for cycling

4 Low-load Operation

Value -  “low load” = No load, not running when no revenue

Features - 1min shutdown, no minimum down time, zero fuel cost and zero emissions.

5 Fast Stop

Value - Not running when no revenue, PV enabler

Features - 1min shutdown, no minimum up time, no EOH calculation

The world’s largest engine power plant by Wärtsilä is balancing the power system in Jordan. The engines IPP3 - 573 MW 38x18V50DF (Gas, HFO, LFO) COD July 2014  and the IPP4 - 250 MW 16x18V50DF (Gas, HFO, LFO COD) October 2014 provide flexible power balancing. Before the engine plants were installed, all plants were cycling with low efficiency (sub-optimal). After the 850 MW engine plants were installed, steam plants and CCGT plants are able to operate at stable output at high efficiency. Engine plants provide load following capacity with high efficiency.


Flexible internal combustion engines have high part load efficiency, quick starting capability and fast ramping rate. They balance the power system in any electrical market. It is a proven concept that they are reliable and available.