Since 2018, Santos has been undertaking an Australian-first project in the Cooper Basin in South Australia and Queensland to assess the viability of converting crude oil beam pumps to solar and battery power in an effort to reduce its greenhouse gas emissions from oil and gas production. Following a successful pilot, the company has started rolling out the technology with the aim to install it at over 200 sites.
Driving energy efficiency
Santos has established a dedicated Energy Solutions team to drive energy efficiency and emissions reductions across the business, with this project one of the initiatives that aims to support the company’s target to reduce its emissions across the Cooper Basin and Queensland by five per cent by 2025.
There are over 200 existing beam pumps across the Cooper Basin that could be converted and Santos aims to use solar power as the standard energy source for new onshore oil wells.
By converting the beam pumps from crude oil to 100 per cent renewable power, it is expected to deliver environmental and commercial benefits by increasing system uptime and production, removing reliance on oil-fired generators which are not always reliable, reducing fuel usage, and reducing operational costs associated with maintenance and trucking of fuel.
The project will cost just over $16 million and received a grant of just over $4 million from the Australian Renewable Energy Agency’s Advancing Renewables Program, which supports a broad range of development, demonstration and pre-commercial deployment projects with the potential to provide affordable and reliable renewable energy in Australia.
A solar and battery solution
The system uses high-efficiency ground-mounted solar panel arrays that are deployed on existing well pads.
The DC electricity these arrays generate is then converted to AC via an inverter to drive the beam pump, with any excess power used to charge the batteries via an AC/DC inverter.
When the beam pump load exceeds the PV generation, such as at night, the batteries discharge the stored energy via the inverters to power the pump.
A control system manages the charging/discharging of the batteries using remote monitoring and control that is carried out over Santos’ private LTE network.
Santos Managing Director and Chief Executive Officer, Kevin Gallagher, said, “This is a great example of renewable energy and battery storage working together to solve the problem of intermittency with solar and wind.”
Designing the system
There are a number of factors that need to be considered when designing and installing the system on any individual site.
As beam pumps have a cyclic load that varies with both the up and down stroke, as well as the speed of the pump – which is automatically optimised by variable speed drives to maximise oil production, and may vary with the life of the well – a key design consideration is the sizing of the units to meet the load demand.
Other considerations include the layout of the arrays onsite to allow for ongoing access to the well head for both daily operations and maintenance such as workover rigs to repair downhole pumps.
Santos plans to commercialise this technology through supply chain and execution synergies that come with scale.
From trial to rollout
A pilot has been running at Limestone Creek in South Australia since August 2018, using solar PV and batteries to power the beam pump that brings oil to the surface from deep underground reservoirs.
Mr Gallagher said the pilot had proven that solar PV and batteries can maintain reliability and availability in the harsh, off-grid environment of the Cooper Basin.
“This nation-leading project is good for the environment, it’s good for reducing fuel consumption and it is good for the bottom line,” Mr Gallagher said.
“This was Australia’s first oil well running on solar and battery, and following the success of the pilot, Santos has converted 23 more wells to solar in 2019, with a further 34 conversions planned this year.”
However, Mr Gallagher said that the project had not been without its challenges, but the company was learning how to overcome these.
“The remote nature of the project provides many logistical challenges including the delivery of goods to site and site installations,” Mr Gallagher said.
“With more than 20 solar beam pumps now installed, we are learning all the time and we are looking forward to the next 34
being installed throughout the course of this year.”
The COVID-19 pandemic has also presented challenges for the project. “Just like all aspects of the Santos business, we have put in place robust protection measures so that we can keep production going safely during the COVID-19 restrictions,” Mr Gallagher said.
“That means our installation timelines remain on track despite all of the challenges COVID-19 has presented.”