Santos Tarbat Oil Field

Description

Global energy giant Santos was looking for a new power generation solution for its Tarbat oil field, located in Southwest Queensland.  The oilfield consists of about 70 wells with linear rod pumps, across approximately 100 km of private high voltage (HV) network, a central processing facility and a workers’ camp. 

The facility was previously operating on a single large gas turbine, which was designed for much higher power demands than what was currently needed. Optimal was tasked with providing an alternative solution to modernise the site's power reliability and efficiency. The challenges that were involved in developing such a solution were multifold.

The first issue was that linear rod pumps operate out of sequence, resulting in the generators having to deal with a highly variable cyclic load. These types of loads cause significant challenges for traditional power generation equipment. Santos was also engaged in driving emissions reduction targets for these facilities, with a focus on energy efficiency and integration with renewables. Moreover, the site is unmanned, and in an extremely remote and harsh environment. A key challenge was to keep the solution autonomous and be able to meet the high ambient temperatures frequently experienced on-site.

A Capstone C1000S (comprising 5 x 200kW modules) was selected. The modular design provides the ability to continue to operate while servicing individual modules and also individual turbines to be switched off and run part-load when site demand reduces, improving overall efficiency. Capstone microturbines use power electronics to convert high-frequency AC at the generator to DC, then back into 400/480V digital 3-phase power. The integrated battery in the package provides instant transient load response, allowing the turbines to meet load peaks and troughs.

The modular inverter-based microturbines provided key benefits to the project, however high cycling loads would significantly shorten microturbine battery life, and potentially lead to reliability issues if failed. Furthermore, the high ambient temperatures present at the site were also predicted to impact the battery’s lifespan.

Our engineering solution to address all of these challenges included an Optimal designed ultracapacitor-based load/grid stability module (LSM) to reduce the amplitude of peaks and troughs, significantly reducing cycling load on the microturbine batteries. It also encompassed externalised microturbine batteries in a refrigerated container, 250kW of integrated Solar PV and a ComAp hybrid controller to provide full microgrid capability for the microturbine, LSM and PV.

The integration of Optimal’s hybrid solution demonstrates the flexibility of the Capstone microturbine and it enabled a solution that was more efficient, more flexible, more reliable, and significantly cleaner. Our solution led to a 50% fuel and emissions reduction and more than 99% system availability.