One of the largest and most advanced projects under development today is the 50 MGD Carlsbad seawater desalination plant (Figure 1). This project is collocated with the Encina coastal power generation station which currently uses seawater for once-through cooling. The Carlsbad seawater desalination project is developed as a public-private partnership between Poseidon Resources and eight local utilities and municipalities.
Since 1999 a team of planners, scientists, engineers, equipment manufacturers and environmental experts have been working on the development and evaluation of the desalination project. The environmental impact assessment and local land use permit for the Carlsbad desalination project have been approved in the first half of 2006. In August 2006 the project was granted ocean discharge permit for disposal of the high-salinity concentrate generated during the reverse osmosis membrane separation process and in November of 2007 California Coastal Commission has confirmed project viability. Project permitting was completed in August 2008 and plant construction is expected to begin in the spring of 2009. The Carlsbad project is planned to be operational by the end of 2011 and to supply 6 to 8 % of the drinking water in San Diego County. When completed, this project would be the largest seawater desalination plant in the USA and one of the five largest in the world.
In 2006 California legislation introduced the AB 32 Global Warming Solutions Act which aims to reduce the greenhouse gas (GHG) emissions of the state to 1990 levels by year 2020. In proactive response to this legislation, the project proponent, Poseidon Resources, has voluntarily taken upon the commitment to completely offset the carbon footprint associated with desalination plant operations. In order to make this challenging task a reality, Poseidon has developed a Climate Action Plan which outlines a portfolio of operational and design technologies and measures; green energy supply alternatives and carbon emission offset initiatives. The key components of the Climate Action Plan are described below.