Enhanced Geothermal Systems Powering Up
Out in the burnt orange tinged dirt, under a fierce sun, next to a dry river bed, Geoff Ward wears a wide-brimmed hat to protect his bald pate from the extreme conditions in Australia’s Channel County – a harsh, arid area once known for cattle grazing. Behind him are a couple flat roof structures with a series of pipes threading in and out of them.
Here, in nearly the geographic center of a continent, but really in the middle of nowhere, Ward and his team at Geodynamics embraced the dust and sweat to find an untapped fuel source that just may change the way countries around the globe think about energy sustainability.
Clean shaven, with deep hazel eyes and a wide, warm smile, Ward, an engineer by trade with a master’s degree in business, who also worked as an investment banker, is no wildcatter hoping for a lucky strike. As the CEO of Geodynamics, who has worked in the energy industry for 20 years, Ward can kick the dirt off his boots and take care of business behind a desk with a geological survey and compass.
But it’s what’s under his boots, beneath the blood red soil, down through 4,000 kilometers of densely packed sediment that gets Ward excited about the future of renewable energy and keeps him and Geodynamics firmly entrenched in the Cooper Basin.
“We have a mantra at Geodynamics, ‘We do what we say we will,’” Ward says. “The alternative energy industry was hurt by evangelicals who described a great promise but took no risks of achieving it. We bring to it not only the commitment but the willingness to deal with the risks of this new technology.”
What they did do was design and construct one of the world’s first viable Enhanced Geothermal Systems power plant in the Cooper Basin of Queensland and South Australia, an area usually reserved for the hundreds of natural gas and oil wells. The 1MWe Habanero Pilot Plant (yes, named after the spicy chili pepper on purpose) was commissioned in April and will finish its test run in September. The company will use the results of that test to put together a proposal for supplying 5-10 megawatts of power to nearby gas producers.
Enhanced Geothermal Systems
It’s a first step that took a 10 year leap of faith and hard work to accomplish. After using exploration records from the gas and oil industry to recognize that the Innamincka granite formation, which is 300 million years old and about 1,200 square kilometers large, produced a high thermal gradient with increases of about 35 degrees centigrade per kilometer, Geodynamics believed they had found a suitable site for EGS.
The concept of Enhanced Geothermal Systems is instead of using geothermal heat associated with volcanic activity and tectonic activity – for example at The Geysers field north of San Francisco, Calif. – extract the heat that's in dry, hard crystalline rock such as granite. This process opens up the prospect of geothermal power being used more broadly and not just in areas near volcanic activity.
The Innamincka granite, which is naturally heated by decaying uranium, thorium, and potassium isotopes, and insulated by densely compacted layers of sediment, topped 240 degrees centigrade at 4,200 meters deep. When they drilled into the granite at the Habanero well and pumped brine into the rock fractures, the fractures became more permeable and the flow increased, which proved it to be a highly productive system.
Geodynamics operates a two-well closed loop system. The heated brine is pumped out of the well and ran through a series of heat exchanges in order to generate steam and drive a turbine. Then the heat is stripped out of the brine and its re-injected back into the fracture system where it percolates through the system becoming reheated.
Long Term Geothermal Energy
The safe, successful, and smooth operation of the 1MWe Habanero Pilot Plant – while proving that the brine loop can be established and controlled with high reliability – has been a huge achievement for the company and for the growth of EGS.
“We think it’s very important,” Ward says. “The Australian government identified geothermal as an energy source that could provide between 10 and 25 percent of the county’s long term secure energy needs.
“We think when our resource in the Cooper Basin is fully exploited it could produce between 2,000 to 6,000 megawatts of power over a 30 year or more period, which is similar to developing a major brown coal area or a major gas area,” Ward says.
From that perspective, EGS is a piece of significant long term energy infrastructure for Australia. The only options for low carbon emission power plants, which are available 365 days a year and 24 hours a day, are geothermal or nuclear.
“Geothermal has a critical role to play in being able to provide a backbone of a long term energy system,” Ward says.
Most studies indicate that when countries see the retirement of the current coal and gas power they are going to need to replace it with some other reliable programmed large scale source. In the U.S., a comprehensive study released by the Massachusetts Institute of Technology titled, “The Future of Geothermal Energy,” examined the potential of EGS as an energy source. The study concluded that by using Enhanced Geothermal Systems technology, at least 100,000 MWe could be produced in the U.S. within 50 years.
According to the MIT study, “Most of the key technical requirements to make EGS work economically over a wide area of the country are in effect, with remaining goals easily within reach.”
Ward could not agree more. “I anticipate we will see more penetration of intermittent renewables like solar and wind, but there still needs to be a core of reliable and programmable base-load power. EGS potentially presents a significant shift in energy security for a number of countries the same way that the ability to access shale gas more cost effectively has changed the energy security in the U.S.”
In Churchill County, Nevada, Ormat Technologies’ Desert Peak 2 EGS project recently received recognition from the U.S. Department of Energy as the nation’s first Enhanced Geothermal Systems plant. Desert Peak is currently providing about 1.7 megawatts of power.
Meanwhile in the Outback
The township of Innamincka, just north of the Habanero EGS plant, has a permanent population of about 15 people. Also to the north is Lake Eyre, the largest lake in Australia, but only when it fills up, which is about once every 5-10 years. But for Ward, there’s beauty in the flat, sun-baked expanse; along with some significant history.
In 1860–61, Robert O'Hara Burke and William John Wills led an expedition of 19 men with the intention of crossing Australia from Melbourne in the south to the Gulf of Carpentaria in the north, a distance of around 3,250 kilometers. They made it up but not all the way back and the historical markers of their graves are only 20 kilometers from the Habanero site.
“The Burke and Wills expedition really is a terrific story of colonial hubris and exploration that ended in tragedy,” Ward says.
It’s a story that Ward and Geodynamics will make sure not to duplicate while continuing their adventure in the middle of it all.
Drax advances biomass strategy with Pinnacle acquisition
The Group’s enlarged supply chain will have access to 4.9 million tonnes of operational capacity from 2022. Of this total, 2.9 million tonnes are available for Drax’s self-supply requirements in 2022, which will rise to 3.4 million tonnes in 2027.
The £424 million acquisition of the Canadian biomass pellet producer supports Drax' ambition to be carbon negative by 2030, using bioenergy with carbon capture and storage (BECCS) and will make a "significant contribution" in the UK cutting emissions by 78% by 2035 (click here).
This summer Drax will undertake maintenance on its CfD(2) biomass unit, including a high-pressure turbine upgrade to reduce maintenance costs and improve thermal efficiency, contributing to lower generation costs for Drax Power Station.
In March, Drax secured Capacity Market agreements for its hydro and pumped storage assets worth around £10 million for delivery October 2024-September 2025.
The limitations on BECCS are not technology but supply, with every gigatonne of CO2 stored per year requiring approximately 30-40 million hectares of BECCS feedstock, according to the Global CCS Institute. Nonetheless, BECCS should be seen as an essential complement to the required, wide-scale deployment of CCS to meet climate change targets, it concludes.