Coal is a fossil fuel and fossil fuels are commonly used so the equipment isn't as expensive. The pumped storage process is a safe process because it doesn't involve any dangerous substances. Making large scale electricity this way is kind of 50/50 in efficiency. It takes more electricity to carry water from the lake up to the reservoir than what releasing the water creates. But it can create electricity during the time of highest need. They can store the electricity during off hours and it can be released during peak hours. One bad thing about pumped storages though is that it can't be used anywhere on the earth. For pumped storage you need a large body of water and not a lot of places have access to
Coal is a fossil fuel and fossil fuels are commonly used so the equipment isn't as expensive. The pumped storage process is a safe process because it doesn't involve any dangerous substances. Making large scale electricity this way is kind of 50/50 in efficiency. It takes more electricity to carry water from the lake up to the reservoir than what releasing the water creates. But it can create electricity during the time of highest need. They can store the electricity during off hours and it can be released during peak hours. One bad thing about pumped storages though is that it can't be used anywhere on the earth. For pumped storage you need a large body of water and not a lot of places have access to