As global demand for reliable electricity increases, wind energy and solar energy have been focused on combating and meeting the demand. Wind energy and solar energy have had tremendous growth over the past decade. While these sources of energy provide fuel efficient and emission friendly alternatives, the energy provided from these sources is intermittent, that is, not continuous or steady for reliability purposes. If the wind is not blowing and the sun is not shining, how can we generate electricity?
The significant increases in wind energy and solar energy has brought interest in pumped storage development. Recently, professors from Michigan Technological University and Texas A&M University embarked on a study for pumped storage in underground mines, targeting old mine shafts in Michigan and also looking at areas in West Texas. If proven to be successful, this storage may help alleviate the intermittent nature of wind and solar power.
What is pumped storage?
Pumped storage has been around for quite some time: the first pumped storage facility was developed in 1907 in Switzerland. The first pumped storage facility in the United States came in 1930. Today, pumped storage is the leader for energy storage on the electric grid, with the United States, China, and Japan having the most pumped storage capacity. Pumped storage is the process of using abandoned underground mines as powerhouses, storing energy in the form of water. The goal is to store now and pump later when needed. These mines, commonly historic coal, cooper or iron mines, are equipped with electrical facilities, as well as supply and transmission lines connected to the electrical grid. Energy can be stored and saved by pumping water to upper reservoirs during low demand times, thus deferring output until it is needed. During high demand times, the water is released and pushed through turbines to produce electric power, allowing for additional peak capacity.
When grid access is available, pumped storage may prove to be a long-term solution that can offset some of the downfalls of battery use. The pumped storage process, a closed-loop system, should allow for the storage of excess power that is generated on those extra sunny or extra windy days, providing balance for peak and off-peak times. In addition, pumped storage may also help reduce environmental impacts found with other energy sources. The closed-loop system has little to no impact on existing water systems and can be located where grid support is needed the most.
Pumped Storage vs. Batteries
Traditionally, when wind and solar provide excess energy, the energy is stored in batteries. Batteries are commonly used in areas where there is no electricity or no access to the power grid. However, batteries can be sensitive to temperature change and altitude variations, and some may require a need for ventilation. Moreover, using batteries don’t last long and may require yearly maintenance, requiring a more “hands-on” approach.
While batteries are cost-effe
ctive for delivering small loads of stored energy over short periods of time, pumped storage is cost-effective for storing and releasing larger amounts of stored energy. Thus, pumped storage is a competitive option for large scale energy storage. Essentially, pumped storage is a large “water battery” and has historically provided the volume of energy some areas need. Startup cost can be high but once the facility is up and running, costs dramatically decrease. With states beginning to push for more reliable renewable technology, batteries may not be able to keep up, leaving pumped storage as an option.
Locations for pumped storage may cause concerns for some. To avoid impacting sensitive areas and preserve areas of scenic land, abandoned mines are quickly becoming the choice for location of pumped storage facilities. The professors from Michigan Technological and Texas A&M Universities hope to deliver a blueprint for those looking for continuous power from intermittent renewable energy sources, while studying methods to environmentally store energy to support existing grids. The professors are looking at the historic copper and iron mines in upper Michigan and, if successful, the group may be able to provide high-demand power sources and support the growing renewable energy sector.
For more information on the pumped storage research taking place in Michigan, visit:
For a detailed review of pumped storage options in West Texas, check out: