Environmental Engineering Reference
In-Depth Information
cubic meter [kg/m
3
], H = hydraulic head height in meters [m], g = accelera-
tion due to gravity [m/s
2
], and η = efficiency.
The study of small scale applications of UPHES is even less common
than studies of large scale uses. The UPHES literature is essentially devoid
of research on small scale (hundreds of kilowatts) installations. It is pos-
sible that, under certain conditions, a small scale UPHES system may make
economic sense and provide added benefits for utilizing variable renewable
energy sources. In cases where water is used extensively for crop irrigation,
modifying an existing irrigation and well infrastructure to accommodate a
small UPHES system may be feasible. Subsequent sections of this chapter
give an in-depth review of such a system known as aquifer UPHES.
LiteratureReview
Research and studies of UPHES systems are not numerous. Since the incep-
tion of the commercial concept of UPHES in the 1970s, relatively little research
has been done. Most of the literature and studies surfaced in the late 1970s
and early 1980s, followed by a drought of academic, government, and private
interest in the topic. Most UPHES studies focused on large, gigawatt scale
(1000 MW) systems. The concept has been studied mainly as a method to
match variable load demands of large urban centers to the constant power
outputs of coal or nuclear plants.
A large UPHES system is a major undertaking requiring careful plan-
ning, long term financing, advanced machinery, and large scale excavation.
Uncertainty about the structural integrity and detailed layouts required for
underground hard rock structures further complicate the plant design and
planning. For these reasons, historical studies that analyzed specific sites for
UPHES have not inspired the funding and massive effort required to build
a large system.
A good overview of the economics and challenges of UPHES appears in a
1978 Aerospace Sciences Meeting paper
1
that addressed the basic concepts and
layouts of large UPHES systems as well as expected economical sizing. Tam,
Blomquist, and Kartsouns of the Argonne National Laboratory presented a
review of UPHES status, technologies, and market in 1979.
2
Allen, Doughtry,
and Kannberg of The Pacific Northwest Laboratory studied the concept in
the early 1980s.
3
Findings from these research efforts suggest that the eco-
nomical size of a UPHES system is in the range of 1000 to 3000 MW, suitable
for large urban areas of about a million people or more. Both reports call for
modernized turbo machinery capable of higher head (pressure) operations,
further studies of underground cavern geology, and system optimization.
A 1981 U.S. patent granted to James L. Ramer of Waukesha, Wisconsin,
claimed intellectual property over the concept of using UPHES with
