New Strategies Needed to Sell Solar Heat for Mining

The Hybrid Solar Receiver Hydrogen Combustor for mining processes at 800 ° C In close cooperation with companies such as Alcoa, BHP, GFG and OZ Minerals, the CET team has shown on a laboratory scale that their combination of combustion chamber / solar reactor is fuel-independent: it can be 100% operated with solar radiation or 100% by fuel combustion or with any combination of the two heat sources as a direct hybrid. IMAGE @ A. Chinnici University of Adelaide Center for Energy Technology

Direct solar heat – Concentrated Solar Thermal (CST) – is a potential renewable resource to replace the heat from burning fossil fuels for industries like mining, as their technologies generate heat directly from sunlight between 150 ° C and 1500 ° C. However, the use of CST for mining processes stands in the way of a lack of information on both sides, according to the authors of a paper just published by Applied Energy.

“The challenge for them in our conversations with the mining industry and others is that they don’t know exactly how renewable energy could be used in their operations,” said Jill Engel-Cox, who heads NREL’s Joint Institute for Strategic Energy Analysis and is the author of the report Integrating Renewable Energies in Mining Operations: Opportunities, Challenges and Approaches

“So there are a lot of questions on the industry side of how it would work, the funding, the versatility, and then the reliability and resilience of the technology itself. The industry is pretty conservative about how it uses and generates electricity,” she noted.

For their part, CST firms have yet to capitalize on the potentially massive renewable heat opportunities for the mining industry, especially downstream of extraction, according to solar finance expert Travis Lowder, a project manager at NREL’s Integrated Applications Center, who noted the industry remains focused on power .

“In the discussions we have had with them and the solar industry itself, a business model seems to be missing; it’s not there yet, ”he said. “Serving industrial customers is still something that is relatively new, and right now we are realizing that there just isn’t a great understanding of how solar thermal can serve the mining industry. So a business model has to be developed to meet the requirements of industrial processes. “

Variety of CST technologies required for different processes

Lowder noted that no single technology will win, but many configurations and applications are required to meet the diverse needs of an industry such as mining and metalworking.

Some examples of the variety of solar thermal configurations that could be suitable for supplying heat to mining processes are Fresnel modules coupled to a turbocharger to provide high temperature air for drying processes at 400 ° C, or a solar reactor that operates with a hydrogen flame at 800 ° C ° C is hybridized ° C in Australia for mining processes or high-temperature thermochemistry in solar reactors at 1500 ° C for the direct provision of solar heat for cement production with the separation of the carbon naturally emitted during limestone calcination.

Synhelion supplies solar heat to CEMEX for cement production with simultaneous CO2 separation “Since our own process for the production of solar fuels is designed to feed in CO2, it is easy for us to extract the CO2 emissions from the calcination reaction in practically pure form. “PICTURE @ Synhelion

“We wouldn’t just look at the initial ore smelting phase or the bauxite reduction phase. It could be that CST and other renewable technologies are appropriate for certain parts of this process, ”stated NREL Cost and Systems analyst Parthiv Kurup.

“With DLR and NREL, we are discussing some possible work on the use of CSP for processes such as manganese and ore sintering, which do not necessarily require such high temperatures. There are intermediate steps and processes that would be very well suited for CST to provide the renewable heat. “

Need for a different business model

Lowder’s background was in the PV industry, which could use power purchase agreements to meet the renewable mandates to quickly ramp up usage. After construction, solar and wind parks will remain in place for the entire term of a 20-year contract and probably beyond.

“So I and others in the field have been researching how the business model of heat would need to change in order to effectively sell it as an industrial product,” said Kurup, co-author of the NREL publication Opportunities for Solar Industrial Process Heat in The United States.

“A heat purchase agreement, as we call it. Heat as a service perspective helps to decouple the capital expenditure of the CST system. We see that in Europe. There are now companies that use ESCO models for heat in order to be able to provide heat directly as a contract, similar to an electricity purchase agreement. “

However, according to Engel-Cox, entering into purchase agreements with a mine as opposed to an industrial site brings with it another major challenge.

“How long will the mine be in operation? That’s the other piece we’ve heard of; there is variability in demand, ”she emphasized. “A mine often lasts for decades, but it can be fully operational for five years, then it could be semi-decommissioned for a couple of years, then it could be completely decommissioned, and then it could open. If you have a fossil fuel source; You can turn it on when you need it and you can turn it off when you don’t need it. But with renewable energies, if there is a contract, you have to accept the purchase of the energy over a lifespan of 20 years. “

So her team found that mining companies were very concerned about agreeing to large heat or power contracts if they couldn’t accurately predict their energy needs over a long period of time. “If the price of their mined product has dropped sharply and the mines can no longer operate profitably, they will be scaled back so they may not always operate at full capacity,” she said.

IMAGE @ SolarReserve Proposed 450 MW Likana CSP project to supply the Chilean mining industry (recently sold to EIG partners offering Likana for under 4 cents / kWh for day / night solar in Chilean auctions in 2021)

The other problem is that even with a relatively mobile, modular system, a CST company would not be able to adapt as mines tend to operate in remote areas and are often the greatest demand in that area (at least in of this order of magnitude). downtime by relocating its solar systems to another industry or community nearby. If heat could be made available to an industrial cluster, a decrease in heat demand could possibly be offset by transferring it to other industrial locations.

A side business with solar hydrogen?

However, due to the portability of hydrogen, a DLR solar hydrogen pilot could offer a solution for one type of mine – copper. The DLR Hybrid-Sulfur (HyS) project has developed a solar thermochemical technology that generates 100% solar hydrogen by decomposing sulfuric acid (H2SO4) in a two-stage cycle with a solar reactor that is heated by a solar field made of concentrating mirrors.

When processing copper ore, sulfuric acid is also produced indirectly, and copper mines buy hydrogen for the desulfurization process. Instead, the HyS technology would produce solar hydrogen on site from H2SO4 using its solar field and solar reactor. So when the copper mine is down, it could keep producing that solar hydrogen but deliver it to others as hydrogen can be transported on trucks or pipelines (and Caterpillar will be offering generators that run on hydrogen this year).

“You’re going to want to get a return on your investment by doing this thing as often as possible and producing as much material as possible because of the capital intensity of this asset,” noted Lowder.

Whatever the solution, the bottom line is market research to figure out what would work for everyone involved, Engel-Cox concluded.

“I think if CSP wants to reach the industrial sector, and I think there is promise there as the PV is not able to provide heat – or there has to be some kind of intermediary – I think the industry has to be speaking to the industries that have these needs and being able to adapt their technology and business models to those industrial needs. It just takes a lot of discussions and possibly some pilot projects to make it work. “

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