ROCKWOOL is looking at the possibility of switching power during its manufacturing process from gas to green hydrogen.
The insulation giant has linked-up with Marubeni Europower and Mott MacDonald to develop a potential end-to-end hydrogen solution at its South Wales plant in Bridgend.
The research is being funded by the Net Zero Innovation Portfolio (NZIP) under the Department of Business, Energy and Industrial Strategy through the Industrial Hydrogen Accelerator programme.
The current process for the manufacture of ROCKWOOL’s stone wool insulation uses natural gas in the combustion systems and curing ovens. This new scheme will investigate the viability of converting natural gas usage to on-site produced green hydrogen.
Rafael Rodriguez, Managing Director of ROCKWOOL Ltd said: “The group has set ambitious decarbonisation targets verified and approved by the Science Based Target initiative, and in line with this, we are looking forward to enhancing our own understanding about the potential for green hydrogen use in our business.”
Claudio Tassistro, Energy General Manager for Mott MacDonald, said: “Our multidisciplinary team has worked on green hydrogen generation and storage projects across the world and will bring with it a wealth of knowledge, and technical and economic expertise.
“The development of green hydrogen production projects like this are critical to achieving our net-zero ambitions and meeting the challenges posed by the climate crisis.”
Mining trucks are monstrous machines that guzzle fuel at a scarcely believable rate.
Weighing 220 tonnes, they can get through 134 litres of diesel every hour.
Little wonder then that mining companies are focusing their attention on these vehicles as the first step to reducing their carbon footprint.
Anglo American, in collaboration with several partners, is retrofitting a mining haul truck with hydrogen power technology.
A first of its kind, the monster mining vehicle is being piloted in Limpopo, South Africa, at the firm’s Mogalakwena platinum mine.
Due to be launched in early 2022, the truck will be hybrid, with a hydrogen fuel cell providing roughly half of the power and a battery pack the other half.
Instead of having a tank of diesel that powers the motor, hydrogen enters the fuel cell and mixes with oxygen to create water in a chemical reaction catalysed by platinum, which generates the electricity needed to power the motors that drive the wheels.
It only emits water vapour and the company says it has the potential to reduce on-site diesel emissions by up to 80%.
By rolling out this technology across its global truck fleet, Anglo American says it will be “taking the equivalent of half a million diesel cars off the road”.
Mining trucks can get through 134 litres of diesel an hour
The trucks also harvest regenerative energy created when driving downhill and braking, which is stored in the battery and extends the range of the vehicle.
Anglo is developing the truck along with partners Engie, NPROXX, First Mode, Williams Advanced Engineering, Ballard, ABB, Nel and Plug Power.
However, reducing the carbon footprint of the mining industry is a formidable task.
The construction sector, which includes mining, accounted for 36% of global final energy use and 39% of energy-related CO2 emissions in 2017, according to Davide Sabbadin, senior policy officer for climate and circular economy at the European Environmental Bureau (EEB).
He says the sector will need to reduce its energy consumption by a third if it hopes to be compatible with the Paris Agreement.
Hydrogen-powered trucks are a good start but need closer inspection, says Diego Marin, associate policy officer for environmental justice at the EEB.
“While electric-powered vehicles, generally speaking, are less damaging to the environment than internal combustion engines on a life cycle analysis, this does not mean that they are green,” he says.
Mr Marin points out it all hinges on how the hydrogen is produced. Some hydrogen is created using fossil fuels, which of course means there are substantial emissions as a result.
Hydrogen is not the cure-all for mining’s environmental problems, says Davide Sabbadin
Anglo American says it is pulling out all the stops in an attempt to attain carbon neutrality by 2040.
Its hydrogen-powered hauler uses green hydrogen, which is made by splitting water atoms into oxygen and hydrogen, through electrolysis.
Even that is treated with caution by the EEB.
“We should refrain from presenting hydrogen as a technological solution to all problems… all forms of hydrogen come at an environmental cost – water use, impacts on nature,” says Mr Sabbadin.
The EEB also points out that hydrogen power has a shorter storage life than other renewables and is substantially more expensive to produce.
Whether it be investment for the mining industry’s green goals or hydrogen power as a broader power solution, the issue of cost is definitely a pertinent one in South Africa.
Jarrad Wright, an energy consultant and principal engineer for the Council for Scientific and Industrial Research (CSIR) explains.
“Hydrogen for power production is still quite expensive and unlikely to compete for some time.”
This is largely due to a lack of supporting infrastructure for the new forms of energy to be created, distributed or stored.
But, Mr Wright adds that it is possible to migrate to hydrogen in specific applications.
There is a plan to make Mogalakwena mine the centre of a hydrogen production network
At the moment South Africa’s hydrogen power infrastructure is still sparse.
But the government and private partners are exploring ways to transform the country’s platinum belt into a “hydrogen valley”, with a focus on producing green hydrogen.
Anglo American is one of the private partners in this hydrogen infrastructure plan, which aims to create a regional renewable energy ecosystem.
The starting point for this ecosystem is due to be built at the Mogalakwena mine itself, through the construction of a hydrogen production and storage complex. It incorporates the largest electrolyser in Africa, a solar power field, and will generate approximately 140MW of green power.
Initially, it will be to support the 24-hour operation of the new truck, but once operational, the aim is for numerous complexes such as this one, to serve as local and regional hubs for the emerging hydrogen economy.
“The ecosystem would not only help us reduce our… emissions, but would also provide the foundation for green hydrogen production, facilitating the roll-out of hydrogen-powered haul trucks across South Africa,” Anglo says.
There is a $205-billion opportunity in renewable energy for Southeast Asia from which China, Japan, and South Korea could benefit as the biggest energy lenders to smaller countries in the region, Greenpeace has said in a new report.
“These three East Asian countries are top global energy investors, with established ties in Southeast Asia. But coal finance is drying up and banks are struggling to get a grip on clean energy finance. The climate crisis depends heavily on the flexibility and ingenuity of East Asian finance. And state-backed public development banks once again need to play the trailblazer role to engage new markets,” according to Insung Lee, project manager of Greenpeace Japan’s climate and energy team.
Southeast Asian countries, according to the report, will need investments of some $125.1 billion for solar energy over the next ten years, as well as $48.1 billion for wind energy, assuming they want to pursue the renewable energy path instead of sticking to fossil fuels. And China, Japan, and South Korea are in a position to convince them to choose the renewable energy path by investing in solar and wind rather than fossil fuels.
However, the report notes that the three East Asian powerhouses are also large exporters of coal infrastructure and lenders for coal power plants to their neighbors in Southeast Asia. This has to change if they are to reap the benefits of the nascent renewable energy financing market in the region, the report says.
“East Asian finance will be as important for renewable energy in Southeast Asia as it was for coal. Over the past two decades, we’ve seen East Asian banks skew the margins towards coal to keep the fossil fuel profitable despite ballooning financial risk. Over the next decade, we’ll see them apply the same ingenuity to unlock renewable energy from the restrictions of their own financial framework,” Greenpeace Japan’s Lee also said.
Geothermal electricity produces emissions but is categorised with wind and solar power as a renewable source of power. Why? Can we reduce the emissions geothermal plants produce?
Geothermal resources occur where magma has come up through the Earth’s crust at some point in the distant past and created large reservoirs of hot rock and water.
The geothermal reservoirs are vast in both size and stored energy. For example, the Ngatamariki reservoir extends over seven square kilometres and is more than a kilometre thick.
The geothermal resource is more consistent than hydro, solar and wind, as it doesn’t depend on the weather, but the geothermal heat in a reservoir is finite. Environment Waikato estimates that if the thermal energy in New Zealand were extracted to generate 420MW of electricity, the resource would likely last for 300 years. The current generation is more than twice this rate, so the reservoirs will last about half as long.
Geothermal energy is extracted by drilling up to 3km down into these hot zones of mineral-laden brine at 180-350 degrees Celsius. The engineering involves drilling a number of wells for extraction and re-injection of the brine, and the big pipes that connect the wells to the power plant.
The power plant converts the thermal energy into electricity using steam turbines. These plants generate nearly continuously and can last for more than 50 years.
The brine contains dissolved gases and minerals, depending on the minerals in the rocks the water was exposed to. Some of these are harmless, like silica which is basically sand. But some are toxic like stibnite, which is antimony and sulphur.
Some gases like carbon dioxide and methane are not poisonous, but are greenhouse gases. But some are toxic. For example, hydrogen sulfide gives geothermal features their distinctive smell. The carbon dioxide dissolved in geothermal brine normally comes from limestone, which is fossilised shells of sea creatures that lived millions of years ago.
The amount of greenhouse gas produced per kWh of electricity generated varies, depending on the reservoir characteristics. It is not well known until the wells are in production.
The New Zealand Geothermal Association reports the greenhouse gas emissions for power generation range from 21 grams CO2 equivalent per kWh to 341gCO2(equiv)/kWh. The average is 76gCO2(equiv)/kWh. For comparison, fossil fuel generation emissions range from 970 to 390gCO2(equiv)/kWh for coal and gas combined cycle plants.
The gases have to be removed from the brine to use it in the plant, so they are released to the atmosphere. The toxic gases are either diluted and released into the atmosphere, or scrubbed with other substances for disposal. The Mokai power plant supplies carbon dioxide to commercial growers who use it in glasshouses to increase the growth rate of vegetables.
Finding ways to use less energy
All energy-conversion systems can be made better by employing engineering expertise, investing in research and enforcing regulations, and through due diligence in the management of the waste products. All energy-conversion technology has costs and consequences. No energy resource should be thought of as unlimited or free unless we use very small quantities.
We tend to think about energy transition in terms of technologies to substitute “bad” energy with “green” energy. But the transition of how energy is produced and consumed will require a massively complex re-engineering of nearly everything.
The installed capacity for wind and solar has been growing over the past decade. In 2018, however, New Zealand consumption of electricity generated by wind and solar was 7.72PJ, while oil, diesel and LPG consumption was 283PJ and geothermal electricity was 27PJ. Another consideration is lifetime; wind turbines and solar panels need to be replaced at least three times during the lifetime of a geothermal power plant.
A successful energy transition will require much more R&D and due diligence on products, buildings and lifestyles that need only about 10 per cent of the energy we use today. An energy transition to build sustainable future systems is not only possible, it is the only option.
Susan Krumdieck is professor and director at the Advanced Energy and Material Systems Lab at the University of Canterbury.
