Drilling operations at Indonesia’s $1.5-billion, 330-MW Sarulla geothermal power plant are progressing “at speed,” according to Hila Gantz, spokesperson for Ormat, the facility’s designer. Sarulla, in Tapanulia Utara district, North Sumatra, will be one of the world’s biggest geothermal plants when construction is completed in 2018.

Engineering, procurement and construction contractor Hyundai and drilling contractor Halliburton have reached an advanced stage in infrastructure works, according to Gantz. Investors and other stakeholders, who from the sidelines have witnessed a two-decade shelving of the project attributed mainly to the late-1990s Asian economic crisis, have welcomed the news.

Last year, Rida Mulyana, renewable-energy director general of Indonesia’s Energy and Mineral Resources Ministry, announced the recommencement of drilling. In September 2014, when the first spudding-in took place, Rida commented, “We are waking up a sleeping giant. The project has been idle for 23 years, and this is a good start.”

Sarulla Operations Ltd., a consortium consisting of Medco Power Indonesia (37.5%), Itochu Corporation (25%), Kyushu Electric Power Company (25%), and Ormat International (12.5%), is developing Sarulla. The partners will jointly own and operate the plant under a framework of a joint operating contract (JOC) and energy sales contract (ESC) signed on April 4, 2013.

Under the JOC, PT Pertamina Geothermal Energy (PGE), the concession holder for the project, provides the consortium with the right to use the geothermal field, and under the ESC, PT PLN, the state electric utility, will be the off-taker at Sarulla for a period of 30 years.

The project is being built in three phases, each of around 110MW, using both steam and brine extracted from the geothermal field to increase the powerplant’s efficiency.

Gantz says the consortium’s drilling contractor, Halliburton, has established a number of production wells to date and is continuing with the injection wells. The gathering facilities—including pipework—for the three separate electricity-generating units and the transmission facilities connecting the units to PLN’s substation will follow. The turbines are to be supplied by Toshiba, while Ormat Technologies will supply its Ormat Energy Converters to the three units. The project will be self-operated but will benefit from technical support provided by Itochu and Kyushu for at least the initial years of operation.

Darmoyo Doyoatmojo, chairman of Sarulla Operations, says some 1,000 personnel are involved in the construction phase on infrastructure and drilling.

“But it is difficult to find the specialists we need. There is a scarcity of drillers all over the world, even in oil. With increasing activity in North Africa and Russia, we lost people,” he says.

Recommencement of the contract follows the drilling of four deep exploration wells to over 1,500 meters at the resource field in the 1990s. These, Darmoyo explains, demonstrated a 275º C liquid-dominated system. A total of five deep exploration wells were drilled at between 1994 and 1998 to a maximum depth of 2,300 m demonstrating upwards of 310º C.

Originally under development for Unocal, PLN took over the company’s interest in the JOC and power purchase agreement in 2006, when the Medco-Ormat-Itochu consortium won the bid to develop the project.

Medco Power President Director Fazil Alfitri says he expects Sarulla’s first phase of development of 110 MW to be completed by the middle of 2016. “We will need to drill 30 wells in total. As many as 13 of them have been drilled before [by previous developers]. Most of the 13 wells are for the first phase of development,” he explains.

Overall power demand in Indonesia is projected to grow by more than 8% per annum until 2029. Consequently, the government of Indonesia aims to feed sustainable growth demands by increasing the share of renewable energy in the country’s primary energy supply to 25% by 2025 from 5% in 2010, according to the Asian Development Bank.