PTO hasn't been used for some years in the central San Joaquin Valley on a commercial scale. This is article about 100 to 150 HP stationary diesel engines pumping high volumes of water on the east side of the valley and huge Caterpillar diesel engines on the west side of the valley pumping from several hundred feet.
A few specialty PTO rigs as still used but they're specialized for siphon pumping from large canals. These mobile giants are built on a D8 frames and the finished platform contains tractor, pump and a 48", hydraulically articulated siphon pipe. They must me mobile as they crawl along the canal bank to water each crop check individually.
Along the secondary roadways on the west side of the valley there are still examples of massive electric motors, moved only slightly away from their old well heads, because PG&E regulated them out of existence.
I stopped using a small 12 HP electric in 1997 to irrigate a 40 acre walnut grove because the power bill was exceeding $1,500/mo from May through September. A 75HP diesel could do a better job for 1/2 the cost including the payment for the rig.
The largest motor I ever used was a 30hp and then two 25's which would kick in or out based on about twenty five variables.
Municipal sewage pumping relay stations use diesel engines over electric motors or at best use electric motors which fall back on diesel when electric cannot keep up or electricity goes out. Those engines are about 25hp each and the next one kicks in series up to three.
Nobody would drive a system like that of irrigation pumps on just one electric moter. They would have banks of smaller ones which compliment each other based on demand, bad bearings or impellers, maintenance needs, and efficiency. Ten fifteen horsepower motors sure would be a lot smarter than one 150hp motor.