Case Study: Off-Grid Hybrid Power Solutions for China Communications Construction Group

China Communications Construction Group is a leading supplier in construction market. They build a huge Zengtian highway project near Guangzhou city.This highway construction project lacks a local power distribution network. The site primarily uses six 75kW piling machines, which may operate simultaneously or intermittently, causing significant load fluctuations. The motors have high starting currents, and power demands vary during construction. 

The Challenge

Traditional power solutions require two 320kW gensets, leading to high diesel consumption and energy waste. Senmarck needs to propose a new solution to reduce fuel costs and provide stable, quality power for the piling machines.

The Hybrid Power Solution

Senmarck company proposes hybrid power solution of 1pcs* 320kW diesel generator+ 1pcs PowerMore-PDE250(250kW PCS+153kWh BESS) system, which has high power supply reliability and economic benefits.

Detailed technical proposal

The hybridized diesel energy storage system manages diesel generator and battery operations based on load demand, with the diesel generator as the main power and the battery as auxiliary. The operation is as follows:

•        When load is low (

•        If battery power drops below 30%, the diesel generator starts, working with the battery to power the load and charge the battery. The hybrid system also manages diesel generator offload energy recovery and provides reactive power. Once the battery is charged, the generator shuts down.

•        For high load (>100kW), the diesel generator powers the load while the battery handles peak shaving, energy recovery, and reactive power, ensuring efficient diesel generator operation (70%-80% efficiency).

Hybridized Power Solution Advantages

The energy storage system and the generator set provide mixed power supply, and the generator set is always in the high-efficiency range, which improves the fuel efficiency, saves fuel consumption, and comprehensively reduces system noise.

The hybrid operation of the diesel storage system can achieve seamless coupling and automatic off-grid switching without affecting the power supply stability.

Offloading energy can be recovered (similar to the concept of Range Extended Electric Vehicle), reducing energy loss and improving power generation efficiency.

Dollarize the Benefits

Notes,

1. The diesel unit price of 1.12$/liter. The data in the table are calculated based on actual working conditions.

2. Assumes 5 years depreciation for the hybrid BESS.

3. Site works about 8 hours a day.

4. Diesel generator is Cummins diesel engine.

5. The fuel consumption reported in the table is the average fuel consumption as per ground situation.

6. Diesel generator labor costs for manual maintenance for every 250 hours are not included.