An analysis is presented of compressed air energy storage (CAES) and its
potential for mitigating the intermittency of wind power, facilitating
access to remote wind resources and transforming wind into baseload
power. Although CAES has traditionally served other grid support
applications, it is also well suited for wind balancing applications due
its ability to provide long duration storage, its fast ramp rates and
its high part load efficiencies. In addition, geologies potentially
suitable for CAES appear to be abundant in regions with high-quality
wind resources. This is especially true of porous rock formations, which
have the potential to be the least costly air storage option for CAES.
The characteristics of formations suitable for CAES storage and the
challenges associated with using air as a storage fluid are discussed.
An optimization framework is developed for analyzing the cost of
baseload plants comprised of wind turbine arrays backed by natural
gas-fired generating capacity and/or CAES. The optimization model
analyzes changes to key aspects of the system configuration such as the
wind turbine rating, the relative capacities of the system components,
the size of the CAES storage reservoir and the wind turbine spacing. The
response of the optimal system configuration to changes in natural gas
price, greenhouse gas (GHG) emissions price, capital cost, and wind
resource is also considered. Wind turbine rating is given focused
attention because of its substantial impact on system configuration and
output behavior. The generation cost of baseload wind is compared to
that of other baseload options. To highlight the carbon-mitigation
potential of baseload wind, the competition with coal power (with and
without CO2 capture and storage, CCS) is given prominent attention. The
ability of alternative options to compete under dispatch competition is
explored thereby clarifying the extent to which baseload wind can defend
high capacity factors in the market. This analysis indicates that CAES
might be well suited for balancing wind power output and enabling wind
to achieve deep reductions in GHG emissions from power generation
globally.