IEEE Power & Energy Magazine - September/October 2017 - 56

figure 4. The monolith substation and BESS facility in
-Tehachapi, California. (Source: Google Earth.)
Smart Microgrid Project by Goldwind Technology
in Beijing, China

This project is representative of BESSs in distributed systems
and microgrids. It was built by the Goldwind Technology
Co., Ltd., in the Beijing Yizhuang Economic Development
Area in April 2012. The electricity generated is primarily
used for industrial manufacturing in the zone and for residential electricity consumption.
The system consists of 2,500 kW of wind power, 503 kW
of photovoltaic arrays, 540 kWh of BESSs, 300 kW of induction motors, 130 kW of microgas turbines, and other supporting facilities. The main BESS energy types in this project are Li-ion batteries and vanadium flow batteries, which
are used for tie-line power control. The EES power types
are supercapacitors and flywheel energy storage, which are
primarily used for instantaneous power regulation.
The system can generate approximately 2.6 million kWh of
power per year, of which self-consumption accounts for approxBatteryManagement
System and
Battery

Power-Conversion
System

Distribution-Control
Switchboard

imately 1.7 million kWh: the surplus electricity can be sold to
the grid company. The power price in Beijing at peak load
hours is 0.789 renminbi (RMB)/kWh. Assuming that the self--
consumed power is used entirely during the peak-load hours,
the estimated maximum savings from the self-generation will
be 1.34 million RMB per year. The annual electricity revenue
from selling the surplus electricity to the electric grid company will be 0.4 million RMB if the tariff is assumed to be the
benchmark price of the thermal power. As a result, the annual
benefit is around 1.74 million RMB.
This project played an important demonstration role that can
be replicated in high-energy-consuming enterprises and development zones. In Jiangsu Province, for example, the electricity
prices at peak, flat, and valley load hours of large industrial users
are, respectively, 1.112, 0.667, and 0.322 RMB/kWh. In this type
of region, the economic benefit of EES will be more significant.
Beizhen Wind Power Project in
Liaoning Province, China

This project is representative of BESSs used in the integration of
renewables. The EES system was installed in the Beizhen Wind
Farm, Liaoning Province (Figure 5). The EES system is connected to the 35-kV bus of the Beizhen transformer -substation,
and it is primarily used to reduce power fluctuations, follow generation schedules, and reduce wind curtailment.
The capacity of the Beizhen Wind Farm is 99 MW, and
the BESSs were installed in two periods: one 5 MW/10 MWh
of lithium/iron-phosphate battery and one 2 MW/4 MWh of
vanadium redox flow batteries were put into operation at
the end of 2014; in November 2015, 1 MW times 2 min of
supercapacitors was added. The wind power plant and EES
system cost a total of 104.6 million RMB.
With the BESSs running, control of the wind power plant's
power fluctuation clearly improved, with the fluctuation over
one half hour controlled within 3%.
The ability of the wind power plant
to follow generation schedules also
improved. It was estimated that this
energy storage project can reduce
wind curtailment by 2,000 MWh
per year. The annual benefit of curtailment reduction is approximately
1.22 million RMB, according to the
benchmark price (0.61 RMB/kWh) of
wind power in Liaoning Province.
Substation

EES Project in the Baoqing
Substation in Shenzhen, China
Supervisory Control and
Data Acquisition and Wind-Energy Prediction System
dc

Communications

figure 5. The system structure of the Beizhen Wind Farm Plus storage project.
56

ieee power & energy magazine

This project is representative of
EES in transmission and distribution systems. It was built in the distribution grid in Shenzhen and put
into operation in September 2011
as the first megawatt-level EES
power station in China. The major
september/october 2017

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - September/October 2017