A research by the **Tohoku University** has revealed that the combination of [solar panels on roofs](https://noticiasambientales.com/energia/energia-limpia-asi-es-la-mayor-instalacion-de-tejas-solares-en-francia/) and electric vehicle (EV) batteries would allow to supply **85% of Japan’s annual electricity demand**, also achieving to **reduce CO2 emissions**.
This model does not require large investments in external infrastructure, as it takes advantage of existing rooftops and the [growth of the electric vehicle fleet](https://noticiasambientales.com/energia/crecen-casi-un-300-las-ventas-de-autos-electricos-en-mexico/).
## Geographic Challenges and Decentralized Solution
Japan faces **topographic limitations**, with a mountainous terrain that restricts the expansion of **large-scale solar farms**.
However, it has more than **8,000 km² of rooftop surface** and a growing market for **electric vehicles**, which opens the door to a **decentralized model** of energy generation and storage.
This system, called **“SolarEV City”**, is proposed as a viable alternative to achieve **national carbon neutrality**.
## Study Results and Projection to 2030
The analysis, which covered **1,741 municipalities**, considered a scenario where:
– **70% of roofs** have **20% efficiency photovoltaic panels**.
– EVs use **40 kWh batteries**, of which **50% is used for the grid**.
The results showed:
– **1,017 TWh generated per year**, surpassing Japan’s consumption in **2022**.
– Only with **solar panels**, **45% of the demand** is covered; with **EV support**, the figure rises to **85%**.
– **33% decrease in energy costs** by **2030**.
## Impact on Urban and Rural Areas
– **Rural areas**, with larger roofs, could even generate **surplus electricity**.
– **Cities like Tokyo**, with less available space, would benefit from **energy storage in electric vehicles**, stabilizing **peak demand**.
## The Role of Public Policies in Emission Reduction
For this transformation to be effective, it requires:
– Investment in bidirectional infrastructure (V2H and V2G).
– Support for battery integration in smart grids.
– Citizen awareness of the energy self-sufficiency model.
– Plans to reduce regional inequalities, especially in the north, where **solar radiation is lower** and **energy poverty is more critical**.
Currently, there are **subsidies for solar panels and electric vehicles**, but **they are not enough**. **Infrastructure and regulations** must advance at the same pace as **technological innovation**.
## A Scalable and Sustainable Model
The **“PV + EV”** system is not exclusive to Japan and could be implemented in **other nations with similar urban and automotive development**.
Among its benefits are:
– Energy decentralization, reducing dependence on large plants and grids.
– Increased resilience to power outages or natural disasters.
– Decreased use of fossil fuels, including contaminating materials like asbestos on old roofs.
– Local job creation in the installation and maintenance of clean technologies.
– Promotion of the energy circular economy, where households produce, store, and consume their own electricity.
This approach turns each **building and vehicle** into an active part of the energy system, granting greater **independence to citizens** and accelerating the transition to a **cleaner, more efficient, and equitable model**.
