In an article today from the U.S., it is said that “the North Brawley plant in California’s Imperial County has encountered delays thanks to high levels of sand in the geothermal fluid. These ‘un-dissolved solids’ are limiting the plant’s capacity; Ormat maintains that the reservoir can support the planned 50MW power plant.

Over the course of 2009, Ormat executives discussed the challenges they faced that North Brawley. Finding un-dissolved solids in geothermal fluid is not unique to this site, Ormat chief operating officer Yoram Bronicki told analysts in May, “but I think that the magnitude is probably unique”.

While the technology to remove sand from water is not breakthrough, it becomes complicated with high-pressure, high-temperature geothermal fluid. The company has not been able to use off-the-shelf water treatment equipment.

It has made ‘substantial progress’ using temporary measures to manage the un-dissolved solids and can now maintain the 17MW output level at North Brawley, which was estimated to cost in the range of $300m. Permanent equipment is on order, but even when in place, Ormat may face continued challenges meeting the planned 50MW capacity, in addition to the higher capital costs for fixing the problem.

“[I]t appears that even with the solids in check, the injection capacity of some of the wells is disappointing and the Company is evaluating how to increase the injection capacity and bring the plant to its rated design,” Ormat says in a statement. “The Company plans to request the power purchase agreement off taker to extend the firm operation date to the end of the year, which it expects allows sufficient time to bring the power plant to its design capacity of 50MW.”

On the bright side, Ormat’s approach to removing the sand at North Brawley can be incorporated into the design at the nearby East Brawley site, a 30MW project that is anticipated to face the same problem with un-dissolved solids.”

Source: RECharge, Ormat news piece