Q&A related to photovoltaic power generation facilities

The introduction of photovoltaic power generation facilities has environmental, economic and disaster prevention benefits.

• In terms of the environment, the use of electricity generated by solar power can reduce energy consumption derived from fossil fuels and contribute to the reduction of carbon dioxide emissions.
• On the economic front, we can expect to reduce monthly utility costs by using solar-powered electricity and reducing the amount of electricity purchased from power companies.
• In terms of disaster prevention, even in the event of a power outage due to a disaster, etc., the electricity generated by the independent operation function of the photovoltaic power generation equipment can be used, so it is possible to charge smartphones.

[Reference Materials] Recommendation of Yokohama Renewable Energy (City of Yokohama, Housing and Architecture Bureau) (PDF: 7,672KB)

When a 4.3 kW solar power generation facility is installed, approximately 2,060 kg of carbon dioxide emissions per year are emitted. ※1 can be reduced. This is the amount of carbon dioxide absorbed by about 230 cedar trees in one year. ※It is equivalent to 2.
※1 Electricity: CO2 emission factor of 4,700 kWh of electricity: Calculated using 0.438kg-CO2/kWh (national average)
※2 Calculated based on information published by the Forestry Agency

Initial costs include equipment costs for photovoltaic power generation facilities (solar panels, power conditioners, etc.), equipment costs such as mount costs fixed to the roof, and construction costs for wiring on the roof.
The average cost of installing solar power generation equipment in a new house is approximately 280,000 yen / kW. ※It is estimated that the initial cost for introducing 4.3 kW is approximately 1.2 million yen.
※　The amount obtained by adding 10% consumption tax to 255,000 yen shown in the source material.
[Source] Opinion on procurement prices, etc. from FY2025 onwards (Feb. 2025 Procurement Price Calculation Committee)

Energy-saving performance at ZEH level ※If a 4.3 kW solar power generation facility is installed in a house, the use of solar power (self-consumption) will reduce the amount of electricity purchased by about 1,400 kWh per year, and the electricity cost will be reduced by about 50,000 yen per year. Will be
About 14.3 years after the installation of photovoltaic power generation facilities, the total effect of reducing the amount of electricity purchased and selling electricity was about the same as the total installation cost and annual operation maintenance cost, and thereafter the total economic effect exceeded the calculation result.

※　Reduce primary energy consumption excluding renewable energy by 20% from the standard value of energy conservation standards that meet heat insulation performance grade 5.
[Source] Recommendation of Yokohama Renewable Energy (City of Yokohama, Housing and Architecture Bureau) (PDF: 7,672KB)

As a method of introducing solar power generation equipment in a house, in addition to being owned by the homeowner himself, on-site PPA type (third-party ownership model) in which the company installs equipment on the roof of the house, There is a "lease type" in which equipment is leased and installed.
　In the on-site PPA type and lease type, solar power generation facilities can be introduced without initial investment, and the homeowner pays the electricity or lease fee for the electricity used out of the generated electricity to the operator. , Collecting initial costs.
[Source] Recommendation of Yokohama Renewable Energy (City of Yokohama, Housing and Architecture Bureau) (PDF: 7,672KB)

Since solar power generation facilities change the amount of power generation depending on the sunshine conditions, it is important to first collect information on how much power generation is expected when the equipment is installed at home, and the company announces It is possible to utilize simulations such as the amount of power generation and the number of initial cost recovery years.
　There are two ways to introduce solar power generation facilities: self-owned type, self-owned type, on-site PPA type (third party-owned model) and lease type, which do not require initial costs. There is also a method of introducing solar power generation facilities by joint purchase. ※。 About each characteristic, we can confirm in Motoichi brochure and web page of Ministry of the Environment, Kanagawa. Based on the introduction method, please consider inquiries to businesses that handle solar power generation facilities.
※　In Kanagawa Prefecture, a joint purchase project for solar power generation and storage batteries for residential use (outside site) (recruitment ended in 2024)
"Renewable energy start" portal site (outside site) (Ministry of the Environment web page)
Initial cost of 0 yen, solar power generation! 0 yen Solar (outside site) (Kanagawa web page)

The reflected light of solar panels installed on the southern roof is generally reflected in the direction of the sky, and the reflected light in the direction of the ground is less likely to occur. On the other hand, when sunlight hits solar panels installed on the west and north sides, reflective light may head to the ground depending on the position and altitude of the sun, so it is necessary to consider surrounding houses.
If the reflected light from the solar panel affects the windows of a nearby house, consider installing a solar panel to reduce the reflected light.
[Source] Guidelines for Precautions for Installation of Renewable Energy Facilities (City of Yokohama, Housing and Architecture Bureau)

Appropriate maintenance and periodic inspections are required in order to demonstrate the capabilities of photovoltaic power generation facilities and use them safely.
It is a good idea to check whether there is any abnormality in the amount of power generated on a monitor that displays the amount of power generated every day. If you notice an abnormality, such as extremely low power generation or damage to equipment, contact the housing manufacturer, construction shop, or solar power generation equipment manufacturer that supplied the house.
[Source] Recommendation of Yokohama Renewable Energy (City of Yokohama, Housing and Architecture Bureau) (PDF: 7,672KB)

Generally, the life of solar panels is said to be about 25 to 30 years, and the power conditioner is about 15 years, and it is necessary to renew because it deteriorates over time like other equipment and equipment.

Depending on the solar panels, harmful substances such as lead may be used, and proper disposal is required through a specialist when disposing of them. When disposing of it, consult with the housing manufacturer, construction shop, or solar power generation equipment manufacturer at the time of installation.

The processing of solar panels and the use of sorted materials are being technically established. At present, survey results have been obtained that glass separated and recycled from solar panels is often used for roadbed materials, etc., but the government is considering establishing a system that requires recycling to promote recycling. We are.

[Source] Central Environment Council Recycling-Oriented Society Subcommittee Photovoltaic Equipment Recycling System Subcommittee / Industrial Structure Council Innovation / Environment Subcommittee Resource Recycling Economy Subcommittee Photovoltaic Equipment Recycling Working Group Joint Meeting (8th) Reference Materials

Care must be taken if the solar power generation equipment is damaged along with the house due to an earthquake, as there is a risk of electric shock. For restoration, consult with the housing manufacturer, construction shop, or solar power generation equipment manufacturer at the time of installation.

The mounting strength of the solar cell module on the roof is designed to withstand wind and other loads by calculating the load based on JIS C 8955 (How to calculate the load for designing support for solar cell arrays).
In addition, the glass surface of the solar cell module uses tempered glass that conforms to JIS standards, and it is a condition that an ice ball with a diameter of 25 mm (hyo) does not break even if it hits at a speed of 23 m per second (about 83 km / h).
[Source] Japan Photovoltaic Power Generation Association (JPEA) FAQ website

In the event of a fire in a house where a solar power generation facility is installed, fire fighting activities are carried out by water discharge while ensuring safety.
In fire fighting activities, we pay attention to safety, such as spraying water and wearing insulating protective equipment as necessary.
In addition, after the fire is extinguished, measures are taken such as covering solar panels with sheets, etc. as necessary.