Photo/Illutration Wind turbines in Horonobe, Hokkaido (Kengo Hiyoshi)

Environmental researchers have plugged into a simple solution for boosting the spread of renewable energy and it's hanging in the air overhead. 

The Institute for Global Environmental Strategies (IGES) believes that overhead power lines have adequate spare capacity to accommodate an increased flow of electricity generated by renewable energy.

The public interest incorporated foundation predicts that tapping into "the grid" of high-voltage transmission lines could boost the share of renewable energy in the production of electricity in Hokkaido up to nearly 50 percent.  

In many regions in Hokkaido, where renewable energy such as wind power has been popularized, increasing the current in the lines is required when a new connection is established.

During normal demand periods, most transmission lines maintain spare capacity.

The economy ministry is expected to promote increased use of these lines to solve a capacity shortage, which has often shackled the renewable energy industry.

However, the change requires a sufficient capacity of electric power lines to accommodate the electric power facilities for renewable energy and other types of energy.

An attempt to move more electricity through existing power lines has often been rejected by major electric power companies because it could lead to a capacity shortage during peak demand hours.

The ministry has urged major electric power companies to power down the renewable energy output only during peak hours so that renewable energy operators can utilize the spare capacity.

Tokyo Electric Power Co. has implemented such a system in some areas.

Researchers of the IGES studied how much renewable energy can be implemented without overtaxing major transmission lines when a similar system is introduced in Hokkaido.

In the study, they assumed that 1.95 million kilowatts of wind power, which is 4.3 times more than the actual number in fiscal 2018, and 1.86 million kilowatts of solar power, 1.16 times more than the actual amount in fiscal 2018, were generated.

As a result, the rate of renewable energy, including hydropower, rose to 46 percent of the total electricity generated. That percentage is 1.8 times more than that of fiscal 2018, when the share was 26 percent.

Solar and wind power accounted for more than 30 percent in total.

Changes in the weather that cause variations in generation can be met by coordinating thermal power generation and other means, researchers said. In addition, they said the number of days when the output of renewable energy is reduced would be 10 days a year.

To maintain a stable supply of electricity, certain technologies still need to be developed, researchers said.

"The simulation demonstrates that renewable energy can be supplied without increasing the capacity of the current electrical grid and without often putting limits on output,” said Katsuhiko Naito, an IGES senior fellow.

He said the operation is “sufficiently doable in other areas.”

The researchers said they will study how renewable energy can be increased by utilizing the capacity of power lines nationwide.

(This article was written by Rintaro Sakurai and Junichiro Nagasaki.)