Environmental Engineering Reference
In-Depth Information
exclusions, it appears that this act applies to aquifer UPHES systems contem-
plated here as Class V wells. The Underground Injection Control (UIC) pro-
gram defines a well as any bored, drilled, or driven shaft or a dug hole whose
depth is greater than the largest surface dimension used to discharge fluids
underground. To comply, the owner or operator of a Class V well is required
to submit basic inventory information and operate the well such that drink-
ing water is not endangered. Note that because ASR and aquifer recharge
wells are authorized by rule, they do not require permits unless required to
do so by the Underground Injection Control (UIC) Program Director under
40 CFR §144.25.
Further regulations, rules, and permitting specifications may be man-
dated by the state in which an aquifer UPHES project will reside. These
regulations and activities required to meet them must be evaluated and
understood. Some generalities can be made about site preferences for
such systems. Designated basins will probably not be advantageous sites
for a number of reasons. For example, the depths of wells associated with
designated basins are typically too shallow for the necessary head; these
are typically over-appropriated water sources. The permitting process is
more complex. Between tributary and non-tributary sources, non-tribu-
tary types appear more advantageous because of the manner in which
water rights are allocated and the accounting mechanisms for water
use. In addition, wells for non-tributary water sources will usually be
deeper.
Economics
The cost of an aquifer UPHES system depends on many factors, many of
which are site-specific. The amount of well modification required, the pres-
ence of an existing surface reservoir, and the possibility of using existing
irrigation machinery may significantly reduce the total system cost. Site
characteristics such as transmissivity and depth to water exert important
effects on the cost of a system. Designers must strive to locate aquifer UPHES
systems in areas where the beneficial pameters are maximized.
Compiling a levelized cost estimation for an aquifer UPHES system may
be instructive, but the result depends heavily on the assumptions made. In
this section, an attempt is made to suggest the expected levelized cost of
energy associated with such energy storage systems.
Levelized cost is defined as the cost per unit energy of the installation,
averaged over its lifetime. Cost ranges for an aquifer UPHES are estimated
below for a system sized to provide up to 300 kWh of energy per cycle. It
should be noted that this is an energy storage system, so rather than pro-
ducing energy, it consumes a small amount (due to efficiency losses). Thus,
the levelized cost calculated here is applicable to an energy storage system
only—one that is not coupled to a generating source and does not produce
