MINE POWER
microgrids , was one of the reasons behind this acquisition , according to Suraj Narayan , Sales Director , Australia & Oceania , for Wärtsilä ’ s Energy Business .
“ We saw the potential increase in renewable penetration in on- and off-grid solutions and the opportunity to manage the inherent variability that comes with the generation of this energy ,” he told IM . “ Our engines are already capable of balancing that variability – they are quite flexible , as such – but when you want a millisecond-level response , you need the battery solution there .”
This is where Wärtsilä , a company able to offer a holistic energy storage technology portfolio ‒ from fully-integrated hardware platform to services and a proprietary GEMS Digital Energy Platform ‒ excels .
While renewable energy integration may be the most obvious fit for these energy storage solutions , Narayan said there was also a case to be made for using them in more ‘ conventional ’ diesel- or gas-powered systems within mining , with potential savings to be had in terms of cost and carbon emissions .
“ Most mines want to ensure an uninterrupted power supply to their process and , to ensure that , they often run extra engines ( spinning reserve ) to cater to a situation where you might have an engine tripping because of a fault ,” he explained . “ You don ’ t want the whole system to black out and take out the mining process , so you run extra engines at a lower load to cater to that potential situation .”
By running these extra engines at a less-thanoptimal load , they generate system inefficiencies .
“ If you put in a flexible battery solution to accommodate the biggest engine unit in the plant , then you don ’ t need to run that extra spinning reserve ,” Narayan said . “ In case of any disruption in power generation , the battery will kick in instantaneously and prevent a blackout of the system . That way , you can optimise the load on the other engines for improved efficiency – both cost and carbon reductions .”
This is worth considering in the context of the desire to integrate renewables into the mix at existing mine sites looking to increasingly electrify equipment , according to Narayan .
“ There is a lot of talk of battery-powered vehicles and fuel cell trucks at the moment ,” he said . “ More electrification will lead to more demand on the power station . The question for miners looking to generate this increased electricity through wind , solar or other renewable means is : do you have all the space needed to fit in the required renewables ?”
If space isn ’ t an issue , such as on greenfield mines being designed today , the decision might hinge more on cost and , as OZ Minerals discussed , the flexibility needed for effective load scheduling .
“ Most mining companies try to run a pretty flat process with a baseload-type of application with some peaks and troughs ,” Narayan said . “ It is all about how well the industry can adapt to the renewable generation realities . You can , of course , put in a lot of renewables and energy storage for a 100 % renewable system , but it is going to be expensive due to oversizing to cover for days where renewables cannot generate energy .
“ For those situations you will likely always need some sort of thermal solution – whether that is gas or hydrogen . An optimised mix would have different technologies – renewables , energy storage and engines .”
Wärtsilä has talked up its use of hydrogen across multiple industries , with its engines already able to combust hydrogen / natural gas blends with up to 25 % hydrogen . It has also tested engines with pure hydrogen and is working towards an engine and power plant concept for pure hydrogen operations .
The plan is to go to 100 % carbon-neutral fuelled engines and , together with energy storage , potentially supplement wind and solar in powering future mines .
Changing models
Rolls-Royce ’ s business unit Power Systems is making a similar hydrogen transition with its mtu engines in stationary power applications .
In October , it announced that generation sets powered by mtu Series 500 and Series 4000 gas engines could operate with a gas blend of 10 % hydrogen , but , at the start of 2022 , operation with a hydrogen content of 25 % would be possible .
Intensive trials on test benches and pilot installations at customer sites in 2022 could then lead to Rolls-Royce continuously marketing new mtu Series 500 and Series 4000 gas engines with up to 100 % hydrogen , beginning in 2023 . And , on a-design-to-order basis , conversion kits to allow already installed gas engines in the field to run on 100 % hydrogen could also become avaialable .
These developments have been helped by the company leveraging a 250 kW fuel cell demonstrator at its site in Friedrichshafen , Germany . This is being used to test and present future CO 2- free energy systems to customers . The entire hydrogen ecosystem , including the infrastructure for supply , conversion , test benches and future production , is also being mapped in the company ’ s own plants .
Armin Fürderer , Director Hydrogen Solutions at Rolls-Royce business unit Power Systems , said the company is improving its hydrogen infrastructure for its test beds as a pre-requisite for blending hydrogen and natural gas in its engines .
“ To manage the step from 10 % to 25 % hydrogen , primarily an optimisation of ignition timing and Lambda setting are necessary ,” Fürderer told IM . “ In addition , the turbocharger tuning and flame arrestor setting have to be adjusted .”
Moving from 25 % hydrogen to 100 % hydrogen requires several engine changes , including forming the air / fuel mixture ahead of the turbocharger to the port injection technology , he explained .
Fürderer said Rolls-Royce ’ s latest generation mtu stationary gas engines would have conversion kit options for hydrogen blending and 100 % hydrogen . “ As a customer , you can buy a natural gas engine today and you can convert it in the future to 100 % hydrogen ,” he said . “ Our products are hydrogen-ready and future-proof .”
To help customers make the hydrogen switch , Fürderer said the company could provide not only the engine or fuel cell , but also hydrogen storage , hydrogen production and the respective logistics associated with delivering hydrogen to customers .
“ Furthermore , we will consult with our customers on how a transition to hydrogen can be made ,” he said .
Fürderer said , in the future , one of the company ’ s main applications for hydrogen would be mining – with the possibility of huge wind and solar installations opening the door for on-site hydrogen production and usage .
However , the company did see other “ efuels ” playing a role , evidenced by Rolls-Royce ’ s involvement in Methquest , a German project focused on ‘ green ’ methane production on an industrial scale .
IM
Rolls-Royce ’ s business unit Power Systems plans to have mtu Series 500 ( pictured ) and Series 4000 gas engines operating with a hydrogen content of 25 % this year
50 International Mining | JANUARY 2022