Once the largest gold mine in the country, the Kidston Gold Mine has been the source of great wealth for well over a century.
Located 270km northwest of Townsville, the Kidston township has seen a number of magnificent booms and busts as the mine transitioned between operation and closure.
Turning to 2017, one innovative company is now continuing this extensive mining history, only this time the valuable gold resource once mined has been replaced with ‘solar resource mining’.
ASX-listed company Genex Power (GNX) is now heavily into the construction phase of a 50MW Solar Project, constructed on top of the tailings of the gold mine (figure 1.1).
“The tailings dam was formed during the mining operation once non-mineralised materials were deposited in this area, creating a flat, consistent and stable topography ideal for a solar farm foundation,” Genex Power executive director Simon Kidston said.
“The favourable ground conditions allow each piling [the supporting structure for the panels] to be punched in every seven seconds.”
At 50MW, this project will be one of the largest in the country, with approximately 540,000 solar modules to be installed. This is enough renewable energy to power about 26,500 homes and to offset approximately 120,000 tonnes of CO2 every year.
Besides the ideal terrain, this location was selected because of several other key factors, one of which is that this region falls within the highest solar resource zone in the country, resulting in the highest capacity output per module in Australia (figure 1.2).
“This site was absolutely perfect for our proposed projects,” Mr Kidston said.
“We purchased the site for $1 off the previous mine owners and it came with a number of important infrastructure pieces which we were able to utilise for our projects.”
However, Genex Power was initially established as a result of the anticipated instability and volatility that would arise from the increasing use of renewables, given renewable projects such as wind and solar are intermittent and cannot be reliably dispatched.
Co-founders Michael Addison and Simon Kidston foresaw this potential issue and after years of research concluded that storage was soon to be the next transition in the energy economy.
This is now what we are seeing, particularly in regions with high renewable penetration like South Australia. Storage is a necessity in order to evenly match demand and supply.
Currently the most efficient, low-cost and abundant form of storage is known as pumped hydro storage. The Kidston Gold Mine was the solution to this issue.
“The Kidston mine was selected because of the existing infrastructure pieces, in particular the two large mining voids that are now filled with enormous volumes of water, forming two large reservoirs (figure 1.3),” managing director Michael Addison said.
“Because of the size of these pits and the height differential between each pit, this was an ideal pumped storage hydro project site. The idea for the solar projects was actually formed after this initial hydro proposal, simply because of the incredibly high solar irradiance in this region, and the existing transmission line directly into the national electricity market.”
The 250MW Kidston Pumped Storage Hydro Project is the flagship project of Genex Power. The project alone will significantly contribute to the stability and reliability of the Queensland electricity network. The project will generate electricity during peak consumer periods when prices are highest and will pump the water back uphill during low demand periods, capturing this price difference.
This pumped hydro project will also be paired with a co-located 270MW solar project, with the solar energy powering the pumping cycle during the day. This will be the first integrated project in the world to operate this way, although there are hundreds of stand-alone pumped hydro schemes worldwide, with three currently operational in Australia.
Together the three projects (the 50MW Solar Project, the 250MW Pumped Storage Hydro Project and the 270MW Solar Project) make up the Kidston Renewable Energy Hub.
This hub has received strong support from both the state and federal governments, with the 50MW Kidston Solar Project supported by the Australian Renewable Energy Agency (ARENA) with a $8.9 million grant, and a 20-year revenue support deed with the Queensland Government.
Further to this, ARENA have provided $4 million in funding for the pumped hydro feasibility and the Queensland Government recently declared the hub a project of critical infrastructure to the state due to the economic, social and environmental aspects that will result.
The 50MW Solar Project began construction in February 2017, and is expected to energise in Q4 of 2017.
Phase Two (the integrated hydro/solar project) is anticipated to begin construction in the second half of 2018, and has already received first-stage board approval from the Northern Australia Infrastructure Facility (NAIF) for potentially supplying concessional debt funding.
With the recent political focus on renewables, energy prices and stability, this hub will provide the solution to these political concerns, allowing renewable energy to stored and reliably dispatched on demand, resulting in affordable, reliable and secure energy for the Australian people.