Tag Archives: off-grid power

Bellevue Gold on its way to achieving ‘holy grail’ with EDL pact

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Bellevue Gold Limited says it has taken a pivotal step towards its aspirational goal of becoming Australia’s first ASX-listed gold miner with net-zero emissions by signing an Early Works Agreement with Energy Developments Pty Ltd and locking in long-lead items for its power station, ready for the processing plant commissioning in mid-2023.

The purchasing of the long lead items will see the company continue its carbon mitigation strategy, based off proven technologies with a Tier 1 power supplier, it said.

This agreement is a key step in Bellevue’s strategy to be powered by a forecast average of 80% renewable energy each year using a wind, solar and battery hybrid power solution.

EDL built, owns and operates a similar turnkey power solution at the Agnew gold mine, around 35 km south of the Bellevue gold project.

Bellevue and EDL are currently negotiating a Power Purchase Agreement for the project, which is subject to approval by the boards of both EDL and Bellevue.

Bellevue says its power solution is central to the company’s goal of generating the lowest carbon emissions per ounce of gold produced by any major Australian gold mine, with forecast emissions of between 0.15-0.20 t of CO2e/oz.

“As well as being the lowest emitter on a per ounce basis, the project is forecast to have the lowest total Scope 1 emissions of any major mine in Australia,” it said. “This will give the project the cleanest power supply in Australia based on a greenhouse gas per kilowatt hour basis of power generation.”

By reducing greenhouse gas emissions, with a renewable energy power station and undertaking other sustainable initiatives, Bellevue aims to produce carbon-neutral gold, giving the company a major competitive advantage in global investment markets, it says. This also provides potential for the company to seek a premium for the sale of ‘green gold’, it added.

The power station will prioritise the use of renewable energy and will also include a gas engine configuration, which, it says, will ensure there is sufficient power for the mine, even in the rare absence of solar and wind resources.

EDL will supply trucked LNG to the project to maintain optionality for any future technological innovations in thermal generation alternative fuels. Trucked LNG provides a much cleaner fuel than diesel, which was an important consideration to reduce emissions as far as possible, it said.

At a steady-state production rate of 1 Mt/y, renewable energy is expected to meet up to 80% of the project’s annual electricity needs, taking advantage of the region’s strong solar and wind resources.

Bellevue says it has been modelling the wind speeds and direction with a SODAR unit, which has allowed for the integration of wind turbines to increase the renewable energy penetration rate.

Maximising renewable energy uptake has been a key design consideration for the processing facility. The facility will have the ability to use more power – such as crushing and heating – when increased renewable energy is available, reducing thermal requirements, according to the company.

The planned infrastructure includes an oversized crushing circuit to facilitate a processing rate of more than 1.5 Mt/y (against current throughput rate of 1 Mt/y), allowing the operational flexibility in this area for an optimised match up of the renewable energy demand to the renewable energy resource.

The designed infrastructure will allow Bellevue to have a cost-effective renewable energy supply and optimise the power demand curve to better align with key daytime (solar) and night time (wind) energy peaks and troughs. Through the generation of power from renewable energy sources, it will create the optionality for the crushing circuit to maximise crushing in peak renewable energy generation periods. This will have the potential to offset more than 1 MW in demand on thermal power generation and lead to a direct cost saving and emissions reduction.

Bellevue Managing Director, Steve Parsons, said: “EDL is a leader in hybrid off-grid power stations. Their skills and experience will help ensure we maximise the use of renewable energy at the Bellevue gold project.

“Bellevue is forecasted to be a 200,000 oz a year gold miner with low all-in sustaining costs of A$1,000-A$1,100/oz ($644-$708/oz) powered by circa-80% renewable energy, with a pathway to net-zero emissions as a world-leading company in the race to decarbonise the mining sector.

“Our pre-production carbon mitigation strategy has been strategic and is world leading. It achieves the ‘holy grail’ of lower emissions and a direct cost reduction in power generation.

“The combination of these metrics is expected to will position Bellevue as one of the most sustainable and financially successful Australian gold miners, maximising returns for all stakeholders. It will also underpin the company’s strong appeal to global investors, who demand performance on both financial and ESG measures.”

On the same day as the EDL announcement, the company signed a Native Title Agreement with Tjiwarl (Aboriginal Corporation) RNTBC, being the native title rights and interests holders and traditional owners of the land which hosts the Bellevue gold project.

CSIRO talks up carbon dioxide game changer for low emission mining operations

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Australia’s national science agency, CSIRO, says a next generation supercritical carbon dioxide (sCO2) powerplant could help accelerate mining operations to low emission outputs and meet large renewable energy targets.

Constructed by the Gas Technologies Institute (GTI), General Electric and other industry partners in the United States, these sCO2 powerplants are being explored in a collaborative program involving CSIRO.

The 10 MW-electric sCO2 pilot plant, currently being constructed in Texas, USA, will demonstrate a fully integrated power cycle that can be easily configured to operation on renewable energy, CSIRO says. When completed in June 2021, it will be the largest sCO2 powerplant demonstration facility of its kind in the world and will represent a significant step toward sCO2 technology commercialisation, it added.

While most powerplants use steam turbines to produce electricity, sCO2 powerplants use high temperature CO2 instead. By avoiding the use of water, advanced sCO2 power plants using renewable energy inputs have significant potential to transition mining operations to a low emission future, CSIRO says.

“The advantage is that sCO2 is a higher density working fluid, which means sCO2 power plants can be smaller, more efficient and not reliant on water for steam and cooling,” it said. “sCO2 powerplants can also be autonomous and operate using a wide range of heat sources.”

This makes such powerplants an ideal candidate to replace diesel generation in off-grid mining operations, as renewable energy can be used to power their operations for longer periods of time.

Many mining companies are committed to transitioning to low emissions technologies and widespread implementation of sCO2 power generation technologies could be a game changer for the mining industry globally and help accelerate the world’s transition to a low carbon future, according to CSIRO.

CSIRO’s partnership in the Gas Technologies Institute Program will improve understanding of how sCO2 powerplants can enable lower and zero emission technology solutions, and how they might be used in remote off-grid mining and community locations as a low-cost alternative to diesel fuel power generation, it said.

The powerplants also provide a potential future replacement for large grid-connected electricity generation.

A renewable energy solution

For CSIRO, the use of concentrated solar thermal (CST) technologies to provide the renewable energy solution for these sCO2 power plants is also a focus. CST technologies capture and store heat, which make it an ideal solution for a sCO2 powerplant. The Australian Solar Thermal Research Institute (ASTRI), which is managed by CSIRO, is leading efforts in this area.

For mining operations, the use of portable, scalable and low-cost thermal energy storage (TES) will be a critical enabler for sCO2 power plants. TES can be used to store heat, which can then be used day or night to run a sCO2 power plant.

The addition of TES can make 24/7 renewable mining operations a reality, CSIRO says. Australia’s TES efforts under the GTI Program will be delivered in partnership with Graphite Energy.

Keith Vining, Research Group Leader for Carbon Steel Materials, CSIRO Mineral Resources, said taking advantage of Australia’s solar resource to operate sCO2 powerplants for the purposes of mineral processing is a positive development.

“Metal production is highly energy intensive,” Vining said. “In most cases metal production from Australia’s mineral resources is performed overseas using traditional fossil fuel energy sources.

“In a low carbon world, there is an opportunity to perform more on-shore processing and replace traditional fossil fuel energy sources with renewable energy resources in the commodity value chain. The use of sCO2 powerplants operating on renewable energy could make this opportunity a reality.”

This research is part of the Joint Industry Partnership of the Supercritical Transformational Electric Power (STEP) project known as STEP Demo.

The construction of the STEP project demonstration plant is nearing completion, with equipment installation underway in San Antonio, Texas. It is expected to be operational in mid-2021.

The site will be able to demonstrate performance over a range of operating conditions and allows flexibility to be reconfigured to accommodate ongoing testing and technology optimisation, according to CSIRO.

The supercritical CO2 cycles will be able to operate using a wide range of heat sources, including fossil fuel (natural gas), renewables (concentrated solar, biomass, geothermal), next-generation nuclear, industrial waste heat recovery, and ship-board propulsion.

Barrick’s Loulo gold operation readies for introduction of off-grid solar hybrid plant

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Barrick Gold is to install a 24 MW off-grid solar hybrid plant to support its existing 63 MW thermal power station at the Loulo mine in Mali as it looks to cut costs and reduce greenhouse gas emissions at the operation.

The renewable energy project is part of Barrick’s wider strategy of moving away from thermal power in Africa, where lack of infrastructure means many mines rely on self-generated diesel energy, making this their largest cost item, the company said.

“Utilising hydropower in the Democratic Republic of Congo, grid power in Côte d’Ivoire, and heavy-fuel baseload generators in Mali, Barrick has already cut its energy costs significantly, and the continuing roll-out of renewable energy sources will ensure that its future needs are met in the most cost-efficient and environmentally friendly manner,” Barrick said.

The solar feasibility study at Loulo forecasted that the photovoltaic plant will replace 50,000 MWh/y of thermal generation, saving 10 million litres/y of fuel and reducing CO² emissions by 42,000 t over the same period. The introduction of the solar component is also expected to cut the complex’s energy cost by around 2 cents/kWh.

Construction of the project—which meets Barrick’s investment criteria of generating at least a 20% internal rate of return—will start later this year. The plant is scheduled for commissioning in late 2020.

“The plant will use the latest weather prediction models, which will enable the power management system to switch between thermal and solar without compromising the micro-grid,” Barrick said.

Barrick’s 80%-owned Loulo-Gounkoto operation is expected to produce 520,000-570,000 oz of gold in 2019 at all-in sustaining costs of $810-850/oz.