Mitsubishi Heavy Industries Technical Review Vol. 56 No. 2 (July 2019)
1Demonstration Testing of Triple-Hybrid Power Generation
System toward Era of Distributed Power Sources- Development of “EBLOX” and “COORDY” -MASAYUKI TANAKA*1 YOSHIYUKI HANASAWA*2
EIJI TAKAHASHI*3

YUSUKE ISOBE*4

MASATO MITSUHASHI*5 HAZUMU ABE*6

Advancing toward a Low-carbon society, as represented by the increasing use of renewableenergy, a global shift of introducing electric vehicles (EVs) and conversion from centralized todistributed power sources, the environment surrounding the engine-based power generation
business is facing a paradigm shift. Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.
(MHIET) has constructed a demonstration facility of a hybrid power generation system called“EBLOX” on the premises of the Sagamihara Machinery Works. EBLOX is a combined power
generation system of an engine generator plus a renewable energy source such as solar power
generation and an energy storage system (ESS). With EBLOX, MHIET is proceeding withdemonstrations with a view to acquiring technologies crucial to develop a triple-hybridstand-alone power supply system to be used in off-grid areas for which demand is expected toarise, as well as developing a system in which a gas engine generator operates in combination withenergy storage batteries to serve as the primary balancing power for the domestic electricity
balancing market that is expected to gather momentum. This report presents the outcomes that
MHIET has obtained from the demonstration testing to date.

|1. Introduction
Against a backdrop of a global shift toward a carbon-free society in recent years, changes
such as the increasing use of renewable energy and conversion from centralized to distributed
power sources have been rapidly taking place and the business environment surrounding
engine-based power generation systems has reached a major turning point. Global environmental
programs such as Sustainable Development Goals (SDGs) have presented eco-friendly andsustainable development goals, in which stand-alone power supply systems in off-grid areas areincluded. There is also increasing need for power sources that can independently operate in timesof natural disasters. Under these circumstances, MHIET constructed at the Sagamihara Machinery
Works a triple-hybrid power generation facility called “EBLOX” in which the engine-based power
generation system operates in combination with a renewable power generation system such as solar
energy and energy storage batteries. Demonstration testing has been underway since November
2018.
In addition to the validation of the stand-alone power supply system with three power supply
sources, MHIET is planning to perform further demonstration testing of the combined gas engine
generator and energy storage battery system with a view to serving as the primary balancer offrequency containment reserve or FCR for the electricity supply-demand balancing market that is*1

Chief Staff Manager, Engine Engineering Department, Engine & Energy Division, Mitsubishi Heavy Industries Engine &*2

Executive Vice President Chief Regional Officer, Asia Pacific and India, Mitsubishi Heavy Industries, Ltd. President Mitsubishi*3Senior Manager, Engine & Energy Division, Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.

Turbocharger, Ltd,Heavy Industries Asia Pacific Pte.Ltd., ex-President Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.
*4Manager, Engine Sales Department, Engine & Energy Division, Mitsubishi Heavy Industries Engine & Turbocharger, Ltd,

*5Chief Staff Manager, Electricity & Applied physics Research Department, Research & Innovation Center, Mitsubishi Heavy*6Engine Engineering Department, Engine & Energy Division, Mitsubishi Heavy Industries Engine & Turbocharger, Ltd,Industries, Ltd.

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 2 (July 2019)2scheduled to be introduced in Japan.
For EBLOX, MHIET has developed a proprietary control system called “COORDY,” thatcontrols these power sources in a coordinated way, determines the optimal power output
assignment and controls the facility in response to frequency fluctuations. The validation isongoing.

|2. Features of EBLOX and COORDY
2.1Features of EBLOXThe name “EBLOX” was coined as a hybrid between energy (E) and building blocks(BLOX). The name has been chosen in expectation that, with EBLOX, multiple combinations ofvarious energy sources such as engine generators, renewable energy and energy storage batteries
can be made as if handling toy building blocks of energy sources to best suit the situation andultimately supply the optimal power solution to each customer.
Table 1 lists the specifications of each piece of equipment that configures the EBLOX
demonstration facility constructed at the Sagamihara Machinery Works and Figure 1 gives thefacility layout. MHIET’s 500kW gas engine generator set with a GS6R2 engine is selected as theengine generator. For solar power generation, 1152 photovoltaic (PV) panels with a total output of300 kW are installed on the rooftop of Factory Building No. 3. A battery-based ESS with an outputof 500 kW and an energy storage capacity of 331kWh is included in the system.
For the purpose of the validation of this three-source stand-alone power supply facility,MHIET introduced a 500kW dummy load and two units of 125kW air compressors as an inductive
load on the premises. Arrangements were made so that the air compressed by the compressors isused by the production facilities in the factory. Each piece of equipment can also be connected tothe electrical grid by switching the disconnector. Moreover, the gas engine generator andbattery-based ESS have been arranged to have an option to enable connection to the grid for future
FCR testing. The facility has been designed in such a way that it can also be used as a private
power plant for the factory when no testing is carried out.
Table 1 List of the installed equipment
Equipment

1. Gas engine generator

Specifications

GS6R2-PTK
Output: 500kW

Panel
YGE 60 CELL
270 W × 1152 units
Total output: 311.04 kW
2. Solar power generation system
PCS
RPI M50A
50 kW × 6 units
Total output: 300 kWPCSDES10JB125K01
125 kW × 4 units
Total output: 500kW
3. Energy storage system

Lithium battery
Capacity: 331 kWh × 1 unit

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 2 (July 2019)
3Figure 1

2.2

Facility layout

Features of COORDY

It is essential for the EBLOX demonstration facility to properly control the three powersources. MHIET named its control system “COORDY,” which was coined from the term“coordinate” in expectation of appropriately and efficiently regulating and combining the threepower sources. A diagram of the EBLOX and COORDY system configuration is depicted inFigure 2.
The control system, COORDY, is characterized by the following two features.

Figure 2

EBLOX and COORDY

Feature 1: Optimal control of multiple power sources
When using multiple power sources, it is indispensable for the system to have thefunction of determining how much output should come from which power source and optimallyassigning each of the power sources the amount of power to generate for the stable supply ofpower. COORDY is therefore equipped with the following functions.
(1) Optimal power output assignment for stand-alone power supply
Stand-alone power supply denotes providing electricity to areas with no electrical grid(i.e., off-grid areas) for loads that consume electricity. With this power output assignment
function, the following become possible; generate power via solar as much as possible on
sunny days and shut down the engine generator, and when the PV output starts dropping in
the evening, start the engine generator and gradually increase its output; if clouds appear andMitsubishi Heavy Industries Technical Review Vol. 56 No. 2 (July 2019)4

cause the PV output to fall, supply power from the energy storage battery to compensates forthe drop and start the engine generator.
(2) Optimal control of battery state of charge (SOC)
COORDY constantly monitors the SOC of the energy storage battery. With thisfunction, when SOC is low, the output from the solar power generation and the engine
generator will be controlled accordingly to allow the battery to be charged to a sufficientlevel.
(3) FCR control by gas engine generator and energy storage battery (future function)
FCR refers to using operating reserves to provide balancing capacity (ΔkW) to theelectrical grid by increasing or decreasing the output within 10 seconds after detecting adeviation in the frequency. In the case of MHIET’s gas engine generator, it takes about 7
minutes until it reaches the rated output from shut-down state. During this period of time,
therefore, COORDY selects the energy storage battery as the primary power source and later
controls the output in connection with the output from the engine generator.
Feature 2: Stabilization of the local grid during stand-alone operation
The local grid frequency and voltage depend on the grid system if it is connected to acommercial grid, hence even if there is a large load fluctuation, it can be absorbed by the grid.
In the case of a stand-alone power supply system, however, such fluctuation in the loads affects
the local grid frequency or voltage, involving the working power supply unit paralleling off
from the local grid (i.e., open the circuit to stop the supply) and leading to a power failure in theworst-case scenario. Apart from sudden load fluctuations, output from renewable energy
sources (e.g., solar or wind power) is susceptible to sudden fluctuations because of suddenchanges in the weather, which is considered to be a factor that causes sudden frequency andvoltage fluctuations in the local grid.
COORDY is therefore equipped with a function to stabilize the local grid by immediately
commanding the battery to charge or discharge when the local grid frequency or voltage
fluctuates. This new control was made possible by combining the virtual synchronous generator
technology of the MHI Research & Innovation Center with MHIET’s droop control
technologies and technology for coordinating the different types of motors that MHIETacquired through many years of engine generator development.
Using the analogy of the human body, COORDY’s feature 1 corresponds to the activitiesof the human brain; just like when we move our bodies while taking in the surroundings
through the eyes, ears, etc., this function monitors various information and the condition ofeach piece of equipment to provide proper instructions. Feature 2 works like our reflexes; when
you touch a heated object by accident, you involuntarily and nearly instantaneously snatch yourhand away without even thinking. Likewise, this function controls the energy storage battery bymaking an instant response to changes in the local grid conditions. With these two features,COORDY can realize the stable supply of power from a system with multiple power sources.
When using renewable energy in a stand-alone power supply system, it is necessary toconsider fluctuations in the power supply caused by the weather or time of day. Especially inthe case of combining solar power generation with an engine generator, the fluctuations fromthe solar power generation have to be absorbed by the engine generator, which generally limits
the maximum acceptable capacity of the solar power generation to 20% of the rated capacity ofthe engine generator. However, with the EBLOX system and COORDY control, a solar power
generation system with capacity equivalent to the engine generator can be introduced, whichenables the stand-alone power supply system to make full use of the advantages of renewableenergy.

|3. Demonstration testing outcomes
The demonstration of EBLOX currently focuses on the following tasks. Presented here arethe outcomes that we have obtained so far.
(1) Control of stand-alone power supply system incorporating an engine generator and energy
storage battery against fluctuations in loads
When a load fluctuates while power is being supplied from a stand-alone engine

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 2 (July 2019)5

generator, the fluctuation is normally absorbed by governing the engine speed. However, whena large, instantaneous load fluctuation occurs, such governing control fails to avoid the effect,causing considerable reduction of the local grid frequency and worsening the quality of thepower supplied. In the worst case, such instantaneous and excessive fluctuation can cause theengine to stall, which can then lead to a power outage (Figure 3).
COORDY, if used in this situation, can instantly detect the change in the frequency
caused by the load fluctuation through the aforementioned feature. By demanding the energy
storage battery to provide the optimal output, COORDY can minimize the amplitude offrequency fluctuations affecting the engine generator, as shown in Figure 4.
With regard to the initial load acceptance performance, COORDY has made it possible toaccept as much as 50% of the rated output of the gas engine generator though it is generally
around 30% (Figure 5).

Figure 3

Frequency amplitude in relation to load change (with engine generator only)

Figure 4

Frequency amplitude in relation to load change (with engine generator + COORDY)Mitsubishi Heavy Industries Technical Review Vol. 56 No. 2 (July 2019)
6

Figure 5

EBLOX output behavior with 50% initial loading(2) Stabilization of PV power output during stand-alone operation with three power sources
Even when the electricity is supplied by the combination of three power sources and PV
output is negatively affected by clouds (Figure 6), COORDY’ can stabilize the local gridfrequency by immediately supplying electricity from the energy storage battery via its feature 2,
as depicted in Figure 7. When the evening hours bring a gradual decline in the PV power
output, COORDY’s feature 1 increases the output of the gas engine generator, thus achieving
the optimal power output assignment (Figure 8).

Figure 6

Output fluctuations of solar power generation

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 2 (July 2019)7

Figure 7

EBLOX output from three sources (absorb PV output fluctuations)Figure 8

Power generation proportion during stand-alone operation|4. Conclusion
Starting construction in April 2018 and testing from November, MHIET has so far obtained
the outcomes described in section 3. To realize a control that can fully respond to much larger
fluctuations in loads, MHIET will continue the optimization of each of the control parameters ofCOORDY to offer MHIET’s stand-alone power supply systems to off-grid areas where acommercial grid is not available.
For FCR as well, the detailed requirements of which are undetermined at this point in time,
MHIET will continue to make efforts to add value to our product and create additional value forcustomers by identifying feasible functions through the utilization of COORDY’s feature 1 inanticipation of the expansion of the electricity supply-demand balancing market.