The described barge is a novel concept for combining a compressed air energy storage system with an offshore electrical substation serving a deep-water floating offshore wind farm. The concept combines existing offshore technologies with floating compressed air energy storage (CAES) system driven by off-shore wind farm energy. The result is higher efficiencies and lower levelized cost of storage.
The floatation system of the barge is comprised of a series of pressure vessels that provide:
- Floatation for barge
- Energy storage
The wind farm is sized to provide more energy than is required during the windy periods. This excess collective electrical energy from the wind farm drives a compressor aboard the barge that pressurizes the 1200 psig compressed air tanks below deck. When the wind subsides but electrical energy demand needs to be met, the compressed air is discharged through a turboexpander/generator set. Not only is electrical power supplied but the same thermal power is supplied (high mass flow of super-chilled air exhausted from the expansion turbine).
The storage tank supplies electrical power storage with output of useful thermal chill power. This replaces batteries that only supply electrical power storage but no thermal chill power and no buoyancy.
Figure 1 shows the version where the storage vessels are in horizontal planes. Also the other applications of the chilling power are shown as cold storage facility, air conditioning and equipment cooling.
Figure 2 shows the version where the storage vessels are in vertical planes. In both figures, there are the same advantages. In addition, the long lifetime (more than 50 years) and simple maintenance of the turbocompressor generator set compared to batteries become available. In addition, the submersion of the pressure vessels in water provides the heat sink that would have been required of a thick walled pressure vessel in the land-based version.