The Water Purchase Agreement for the proposed Carlsbad seawater reverse-osmosis desalination plant in California was released on 27 September 2012 by the San Diego County Water Authority (SDCWA).
The total price for the water – including costs to make improvements to the SDCWA’s pipelines and treatment plant to accommodate the new supply – is estimated at US$ 2,042‑2,290 per acre-foot (US$ 1.65‑1.86/m³ in 2012 dollars, depending on annual quantities purchased. This is slightly more at the lower end than previously estimated.
The 189,000 m³/d Carlsbad plant will be developed by Poseidon Resources. The water would meet SDCWA’s long-term water supply reliability goal of having 7% of its region’s water supply met with seawater desalination by 2020.
The authority’s board has not approved the agreement and will set a date for voting on it after it has had the opportunity to receive public comment and to review and deliberate the terms. It will host two evening public meetings in early October to hear public comments.
Under the agreement, the SDCWA will have no responsibility or liability for the design, permitting, financing, construction and operation of the project. It would purchase at least 48,000 acre-feet (59.2 million m³) of desalinated water annually at a predetermined price for 30 years once commercial operations begin.
Water in excess of this amount would be purchased at the Water Authority’s discretion at a lower rate. The agreement can be extended by 3 years due to unexpected or uncontrolled events.
At the end of the agreement, the SDCWA will be able to buy the plant for US$ 1. It also has an option to buy it after 10 years.
Poseidon also will design and build a new 10-mile (16 km) pipeline to convey desalinated water to the SDCWA’s regional water delivery system. The authority will own and operate the new pipeline.
The agreement can be terminated under a number of conditions, one of which is if the plant fails to pass acceptance tests by a certain date, as happened recently with the Adelaide desalination plant in Australia.
The SDCWA’s 24 local member agencies must declare within the next 60 days whether they intend to purchase a portion of the desalinated seawater supply directly from the water authority as a local supply at the full cost per acre-foot. Local supplies help improve water agencies’ water-supply reliability, especially during times of drought or shortages in imported water supplies.
Poseidon vice-president Peter McLaggan told D&WR that he expects to close the project’s financing and issue a notice-to-proceed to the engineering, procurement and construction (EPC) contractor approximately 30 days following approval of the Water Purchase Agreement by the SDCWA. The EPC contractor is Kiewit‑Shea Desalination (KSD), a joint venture consisting of Kiewit Infrastructure and JF Shea Construction.
IDE Technologies is a major subcontractor to KSD responsible for engineering and procurement of the desalination technology and is also operation and maintenance contractor. The construction, start-up and performance testing schedule is 35 months. Updated on 2 October 2012