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Weeds Under Solar Panels Cut by Riding-type Grass Cutters (2)

2018/11/13 11:27
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo
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Continued from Weeds Under Solar Panels Cut by Riding-type Grass Cutters (1)

Cutting height can be raised to 17cm for use at solar power plants

Vehicles of "Uchino-Masao," Chikusui Canycom's main riding-type grass cutter, are seen frequently on mega solar power plant sites during our visits to them for interviews (example of use by a mega solar power plant in Miyama City, Fukuoka Prefecture). It is regarded that the model is one of the riding-type grass cutters most frequently introduced to solar power plants.

The machine seems to have become successful because not only does it have the high durability and operation performance as well as original features suitable for grass removal at solar power plants, but also a number of functions were introduced in the design with use at solar power plants in mind.

The rotary blades that cut grass can be raised up to a height of 17cm, for example. Blades of general riding-type grass cutters cannot be raised to this height. The risk of catching stones on the ground and causing them to fly outwards decreases when the height of rotary blades increases. The requirement was not considered for designing conventional vehicles for agricultural use.

The rotary blades can be adjusted between 0 and 17cm despite its compact body because the machine incorporated a "shaft drive mechanism" activated by the screws.

The machine can be operated stably on slopes angled up to 30° (Fig. 2, Video 2). Many of the general riding-type grass cutters can be operated at angles up to 15 to 20°. Tall grass that grows on steep slopes can be cut effectively by traveling up and down the slopes if you use the machine.

Fig. 2, Video 2: Grass on steep slopes typical of former golf course sites can be cut easily. A demonstration at a mega solar power plant constructed on a former golf course site in Ibaraki Prefecture. The vehicle travels at approximately 14km/h while not cutting and approximately 8km/h during grass cutting operation. (source: Nikkei BP)

Specifications assuming use at solar power plants were also added. To improve durability, the body cover, which was conventionally made of resin, was replaced with a metal cover, for example. Durability was improved estimating that the frequency of use will be about five times compared with the use at orchards.

Covers for conventional machines were made of resin to prevent damage to branches and fruit in orchards caused by the machines coming into contact with them.

Grass that is taller than humans is sometimes cut at solar power plants. Assuming such situations, the width of the trimming port at the front of the vehicle was increased and the structure was configured so that grass is pressed toward the trimming port. Because of the structure, tall grass and dense grass are inclined and effectively caught by the rotary blades. The horse power was increased from 22 for conventional machines to 25, aiming for effective cutting of dense grass.

The vehicles are exposed to a lot of dirt when they are used at solar power plants, posing a risk of engine seizure. To reduce the risk, a cyclone-type air cleaner was added to the engine.

The vehicles are designed to allow traveling on public roads. When they are used at orchards, etc., they seldom move off-site. However, solar power plants are often laid out on both sides of roads, or power producers sometimes operate multiple plants on sites that are close to each other. Consideration was given to such situations.