High Voltage electrical installation

High Voltage refers to voltages exceeding 7000V and is utilized in large-scale facilities such as factories and large buildings where high-capacity power is required. High voltage electrical works differ from regular installations, requiring stringent regulations and the installation of large-scale equipment, demanding advanced technical expertise.

A mega solar system with 49,140 panels, generating a total output of 17,690.4 kW

The construction, which took about a year from December 2018 to the end of September the following year in Hitachi Juoucho, Ibaraki Prefecture, was the first high voltage mega solar project undertaken by the JESCO Group. The scale of the project involved 49,140 panels with a total output of 17,690.4 kW, generating electricity equivalent to the daily usage of 5,000 households.

The construction was undertaken by a team of four individuals from the JESCO Eco Plant Business Division: Yusuke Yashima, Group Manager, Masakatsu Nakajima, Chief Engineer, along with four young engineers. The overall project was conducted by Division Director Hisao Wagai.

The JESCO Group was in the charge for the installation and adjustment of various components, including connection boxes to gather electricity from approximately 50,000 panels into one location, 17 power conditioners equipped with the functionality to convert direct current to alternating current for general use, and the installation of high voltage transformation facilities for stepping up the voltage to transmit electricity to power company overhead lines.

For the installation of the core power conditioners and high voltage transformation equipment, precision down to the millimeter level accuracy was required.

It was the first large-scale solar power construction project for Mr. Yashima, who served as the on-site representative. However, the project was primarily led by Mr. Nakajima and others with extensive experience in high-voltage construction at a major power company, following Mr. Yashima's instructions.
Mr. Yashima said that "The most challenging aspect of the construction was the installation work for the 'Key Parts' of the power generation facilities, the power conditioner, and the high voltage transformer facilities," says Mr. Yashima. The power conditioner installed this time is a large equipment measuring 6 meters in length and 2 meters in width. In the installation work for power conditioners and transformer facilities, precise accuracy at the millimeter level is required to ensure the stable operation of the equipment."
In addition, the installation of mechanical equipment requires experience and meticulous construction, as it is concentrated towards the end of the construction process. According to Mr. Yashima, "If errors occur, it becomes impossible to finish on schedule.

Mr. Yashima approached the construction with a thorough understanding of the power conditioner's mechanism. By seeking advice from veteran technicians, carefully proceeding while issuing instructions to collaborating companies, Mr. Yashima was able to successfully complete the construction of the first extra-high voltage mega-solar project.

Looking back on the construction, Mr. Yashima remarked, "Installing large-scale mechanical equipment is challenging beyond experience. We owe a lot to experienced individuals like Mr. Nakajima.

The Division Director, Mr. Wagai, also commented, "High Voltage projects require special skills and experience, and the role of veteran technicians is significant.

We carefully studied specifications and construction documents, keeping equipment functions in mind during the construction process.

Mr. Yashima, with a decade of experience in solar power construction, values President Taichi Kotegawa's advice: "80% of the construction works done according to the first planning. The success hinges on pre-execution planning, determining the smoothness of the construction process.

Mr. Yashima, in this construction project, meticulously studied the specifications, construction documents, and user manuals to grasp the intricacies of the power conditioner, often referred to as the heart of the construction. When facing uncertainties, he consulted the manufacturer's representatives and carefully reviewed the design plans before commencing the construction.

After successfully completing the construction, Mr. Yashima expressed, "Being involved in my first high voltage mega-solar project and achieving its completion safely brought an unparalleled sense of accomplishment." He then added, "However, I was worried until the inspections were completed after the construction.

On-Site Achievement Accumulation and Specialized Training for Solar Power Generation Engineers

In our country, in 2009, to address global warming and diversify energy sources, the fixed price purchase system (FIT) was launched, wherein power companies buy surplus electricity from solar power generation at a fixed price, leading to the rapid proliferation of solar power generation.

In 2012, the FIT system underwent revisions, extending the purchase program to include renewable energies beyond solar power, such as wind, bioenergy, and geothermal. This expansion, coupled with the aftermath of the Fukushima Daiichi nuclear power plant incident during the 2011 East Japan earthquake and tsunami, further intensified the momentum for the widespread adoption of renewable energy.

Among them, solar power generation garnered significant attention as a key player in renewable energy due to factors such as fewer restrictions on installation locations.

10-Year Record: 262 MW Solar Projects at 202 Locations

It's been about ten years since the JESCO Group entered the solar power business. They have completed projects at 202 locations across Japan, totaling 262 MW. Over this time, they have built up experience and technology, allowing them to offer everything from consulting and design to construction and maintenance for solar power plants.

They also use a system to visualize solar radiation and power generation online, helping customers optimize their energy use. Wagai states, "JESCO's strength is in meeting all customer needs."

Their efforts have been recognized as an "emerging force supporting decarbonization" in Nikkei's NEXT1000.

Applying Years of Expertise: Undertaking a 50MW Mega Solar Construction Project in Fukuoka Prefecture

Mr. Yashima, accumulating the experiences in solar power construction, takes the helm as on-site representative for a 50MW mega solar project in Munakata City, Fukuoka Prefecture, Surpassing Facilities in Hitachi Juocho.
Mr. Yashima notes, 'The accumulation of experience from small-scale projects has proven valuable in aspects such as coordination with relevant authorities, construction, and management.' However, he anticipates that in the future, as the purchase prices for solar power decline, there will be a reduction in large-scale solar power facilities for business purposes," according to Mr. Wagai. Therefore, what JESCO Group is currently focusing on is the installation of self-consumption-type solar power systems on rooftops of factories, commercial facilities, and large buildings.

Self-consumption-type solar power generation faces the challenge of being unable to directly feed excess electricity into the power company's transmission lines. This necessitates the installation of safety devices. Furthermore, when the self-consumed power is low, it requires clever strategies, such as controlling the output of power conditioners to suppress electricity generation. In this sense, Wagai expresses significant expectations for self-consumption-type solar power generation, stating, 'From consulting to design, construction, and maintenance, JESCO Group's role with comprehensive technical expertise and experience will continue to expand.

Organizing Cooperative Companies for Nationwide Expansion in Solar Power Generation Projects

The JESCO Group is considering nationwide expansion in solar power generation projects. By organizing cooperative companies across the country that have collaborated on previous electrical and communication projects, we aim to achieve nationwide deployment in solar power generation projects.

In our country's energy policy, the goal is to increase the proportion of renewable energy from 18% in fiscal year 2019 to 36-38% by fiscal year 2030. In the future, the role of renewable energy, including solar power generation, is undoubtedly set to grow.

The JESCO Group has identified solar power generation as a significant pillar of its business and plans to build a framework that can address the entire lifecycle of solar power generation, including recycling solar panels. This forward-looking approach aims to establish a one-stop solution for the solar power industry.

（November 2022）