By Huck Fairman
New Jersey draws its electrical power from a relatively clean mix of sources, which include nuclear, natural gas and solar.
If the state adopts plans for off-shore wind farms, the new wind generation will make New Jersey even cleaner. However, as wind and solar expand, the storage problem, due to their intermittent nature, becomes more significant.
What is needed is large-scale energy storage. The phrase “energy storage” usually leads people to think of batteries, however the largest form of energy storage for electricity by far is not batteries; it is pumped storage hydroelectricity (or pumped hydro). Pumped hydro is orders of magnitude less expensive than batteries for a given amount of energy stored. The phrase “pumped hydro” leads many people (including many industry experts) to think about the need for a dam on a river.
There is, however, another, little-known storage technology that is quietly being used, and it’s clean, cheap, and could be utilized far more than it is now, with modest, further investment: pumped hydro without a dam. It has been introduced in Michigan at the Ludington pumped hydro facility, and in Germany, near the town of Bad Sackingen, along the Rhine River.
The relatively simple requirements for all pumped hydro systems are a supply of water at a relatively low elevation and a nearby storage reservoir for water at a higher elevation. The elevation difference should be at least several hundred feet, but ideally 1,000 feet or more. The amount of stored energy is proportional to both the elevation difference and the usable volume of water in the storage reservoir.
An important point to note is that the low level water supply can be a reservoir behind a dam but it can also be a free-flowing river or stream. New Jersey and New York have many hills and cliffs along the Delaware and Hudson rivers that provide the needed height. The elevated storage reservoir could be simply and inexpensively bull-dozed or excavated at the top of a hill or cliff near the river and when surrounded by trees or local shrubs, it would blend into the landscape. The pipes carrying water up and down can be buried underground or left on the surface.
Its mechanics are simple: water from a stream, river or lake would be pumped to the relatively higher reservoir. When electricity is needed, water would be released and would flow back down to the original low-level source, turning turbine blades that power a generator to produce electricity. For Michigan’s Ludington Pumped Storage facility — which serves Chicago — the low-level source is Lake Michigan, and in Germany’s Bad Sackingen complex, it is the free-flowing Rhine River.
Not only is this technology inexpensive, it can last for over 40 years, and can be very unobtrusive. New Jersey’s power companies are using pumped hydro but not with a free-flowing river. The Yards Creek Generating Station is a pumped-storage hydroelectric plant in Blairstown and Pahaquarry in Warren County, New Jersey. The top reservoir is within the Worthington State Forest area.
Since 2011, natural gas and nuclear power have supplied more than nine-tenths of the electricity generated in New Jersey. Through 2013, nuclear power typically supplied about half of New Jersey’s net electricity generation. But the share of generation from natural gas has been growing and — in 2016, for the first time — natural gas supplied more than half of the state’s net generation. At some point the state will turn to cleaner and cheaper power sources. Pumped hydro offers the potential to store cheap, clean energy to combine with solar and wind when they are not producing. To make this happen, however, there will be a need for multiple pumped hydro locations along many free-flowing rivers, streams, or lakes. Building expensive dams will not be necessary.