Coordination between diesel generator sets and energy storage

The cooperation between diesel generator sets and energy storage systems is an important solution to improve reliability, economy, and environmental protection in modern power systems, especially in scenarios such as microgrids, backup power sources, and renewable energy integration. The following are the collaborative working principles, advantages, and typical application scenarios of the two:
1、 Core cooperation method
Peak Shaving
Principle: The energy storage system charges during low electricity consumption periods (using low-cost electricity or surplus power from diesel engines) and discharges during high electricity consumption periods, reducing the high load operation time of diesel generators.
Advantages: Reduce fuel consumption (about 20-30%), minimize unit wear and tear, and extend maintenance cycles.
Smooth output (Ramp Rate Control)
Principle: The energy storage system quickly responds to load fluctuations, compensating for the shortcomings of diesel engine start-up delay (usually 10-30 seconds) and regulation lag.
Advantages: Avoid frequent start stop of diesel engines, maintain stable frequency/voltage, suitable for supplying power to precision equipment.
Black Start
Principle: The energy storage system serves as the initial power source to quickly start the diesel engine, solving the problem of traditional diesel engines requiring external power to start.
Advantage: Improve the reliability of emergency power supply, suitable for scenarios of power grid failure (such as hospitals and data centers).
Hybrid Renewable Integration
Principle: The diesel engine is combined with photovoltaic/wind power and energy storage to stabilize renewable energy fluctuations, with the diesel engine serving as a backup.
Advantages: Fuel savings can reach over 50%, reducing carbon emissions.
2、 Key points of technical configuration
Component functional requirements
The diesel generator set needs to support variable frequency operation mode and adapt to energy storage charging and discharging scheduling (such as being taken over by energy storage when the automatic load reduction is below 30%).
The energy storage system (BESS) prioritizes the use of lithium iron phosphate batteries (with long lifespan and high safety) and power types (such as 1C-2C) to cope with short-term impact loads.
The energy management system (EMS) needs to have multi-mode switching logic (grid connected/off grid/hybrid) and dynamic load distribution algorithms.
The response time of the bidirectional converter (PCS) is less than 20ms, supporting seamless switching to prevent reverse power of the diesel engine.
3、 Typical application scenarios
Island microgrid
Photovoltaic+diesel engine+energy storage, diesel engine only starts at night or on cloudy days, reducing fuel costs by more than 60%.
Backup power supply for data center
Energy storage prioritizes supporting critical loads for 5-15 minutes, with shared power supply after the diesel engine starts to avoid momentary power outages.
Mine power supply
Energy storage can cope with impact loads such as excavators, and diesel engines operate stably in the high-efficiency range (70-80% load rate).
4、 Economic Comparison (Taking 1MW System as an Example)
Initial cost of configuration plan (10000 yuan) Annual operation and maintenance cost (10000 yuan) Fuel consumption (L/year)
Pure diesel generator set 80-100 25-35 150000
Diesel+energy storage (30% peak shaving) 150-180 15-20 100000
Recycling cycle: usually 3-5 years (the higher the electricity price, the faster the recycling)
5、 Precautions
System compatibility: The diesel engine governor needs to support rapid power adjustment during energy storage intervention (such as PID parameter optimization).
Safety protection: To prevent overloading of the diesel engine caused by excessive energy storage, a hard cut-off point for SOC (State of Charge) (such as 20%) needs to be set.
Policy support: Some regions provide subsidies for the “diesel engine+energy storage” hybrid system (such as China’s 2023 new energy storage pilot policy).
Through reasonable configuration, the combination of diesel generator sets and energy storage can achieve an upgrade from “pure backup” to “smart microgrid”, which is a practical solution for the transition from traditional energy to low-carbon. The specific design needs to be comprehensively evaluated based on load characteristics, local electricity prices, and policies.