Articles

I'm glad to see that the author realizes that Hydropower is an important adjunct to wind energy production. In addition to being a "renewable" energy source itself (It rains, water runs downhill thru a turbine, it exits as water, evaporation occurs, it rains, etc.), it has an efficiency rate of 85 - 90% (potential energy of the water to electrical energy), which far exceeds the 59.6% "maximum" efficiency (Betz coefficient) of wind generators.
In addition, pumped storage plants are a proven technology with over 400 plants in existence worldwide. Pumped storage plants have a round trip efficiency greater than 72% (85% plus for generation, and 85% for pumping)which far exceeds other "large" energy storage systems. Battery systems are just not feasible from a long term maintenance/replacement standpoint when you exceed 10 MW; and capacitors are a more transient (seconds/minutes/to hours) than the day/week storage system of a pumped storage facility.

I'm so glad someone has finally recognized that pumped storage is a vital energy storage component when used in conjunction with wind power. There are over 400 pumped storage facilities in existence worldwide. They have a long term track record of reliability, have a life existence of 75 - 100 years , and have the highest round trip efficiency (72% plus) of any large scale energy storage facility. Pumped storage facilities are far superior to battery storage, thermal storage, and compressed air energy storage because they can store hundreds of Megawatts of energy for days or weeks, and it has a proven track record with low maintenance requirements.
The capacitor storage mentioned in the article is a good momentary (seconds/minutes/a few hours) energy storage, but cannot match the scale of energy storage needed to be useful for most utility systems.