As renewable energy capacity climbs, steel and metal producers are contributing to the growth, reports Duncan Moore
As Chinese authorities continue to clamp down on highly polluting manufacturing processes in order to improve air quality, China and other nations are looking to renewable energy sources to reduce greenhouse gas emissions. The signing of the 2015 Paris Agreement on Climate Change by members of the United Nations Framework Convention on Climate Change has added further momentum to the development of, and investment in, renewable and clean energy sources.
Biomass, geothermal and hydropower are among them, but solar and wind remain the fastest growing. The International Energy Agency in its Executive Summary of the World Energy Outlook 2017, which examines the future of renewable energy, states: Rapid deployment of solar photovoltaics (PV), led by China and India, helps solar become the largest source of low-carbon capacity by 2040, by which time the share of all renewables in total power generation reaches 40%. In the European Union, renewables account for 80% of new capacity and wind power becomes the leading source of electricity soon after 2030, due to strong growth both onshore and offshore.
According to The International Renewable Energy Agency (IRENA): Wind power is one of the fastest-growing renewable energy technologies. Usage is on the rise worldwide, in part because costs are falling. Global installed wind generation capacity onshore and offshore has increased by a factor of almost 50 in the past two decades. IRENA quotes figures supplied by the Renewable Energy Policy Network for the 21st Century that show installed wind generation capacity has risen from 7.5 GW in 1997 to 487 GW by 2016.
To facilitate this rapid uptake in clean renewable energy, along with the aluminium and copper cable needed to transfer the power generated to local power grids, both steel and aluminium are used extensively in the infrastructure of solar and wind farms.
Generation of electricity by means of solar energy for commercial purposes is sometimes done through the use of concentrated solar power (CSP) systems or, more commonly, large arrays of photovoltaic panels.
Following the news in late-2017 that the worlds largest concentrated solar power project is being launched by the Dubai Water and Electricity Authority (DEWA), as part of Dubais Clean Energy Strategy 2050, which aims to generate 7% of the countrys total power from clean energy by 2020, then ramping up to 75% by 2050, Dubai-based cable manufacturer Ducab announced its new SolarBICC product line. SolarBICC is a new, 1.5 kV DC voltage cable line developed specifically for use in the UAEs growing solar energy sector.
The first stage of the DEWA CSP project, which will be built at the Mohammed Bin Rashid Al Maktoum Solar Park, is expected to generate 1 GW of power at less than $0.08 per kilowatt-hour. Once complete, the five-facility solar park is expected to reduce carbon emissions by 6.5 million tonnes per year.
The largest concentrated solar power project currently in operation, at Ivanpah, California, US, generates about 392 MW of power annually.
While the concentrators used to reflect the suns rays in CSP projects are predominantly silvered glass, research is taking place into the use of highly polished, curved metal sheets as a cheaper alternative.
However, an established use of metal in solar power generation is aluminium and steel for the racks used to support banks of photovoltaic cells. ArcelorMittal is one steelmaker that supplies this market. At the beginning of January, it announced the acquisition of French business Exosun, which specializes in the manufacture of trackers for solar farms. Trackers racks that allow rotational movement of cells are an emerging solution to increase the profitability of solar farms. According to ArcelorMittal, such trackers now account for 25% of the large solar farms market and are estimated to potentially account for up to 50% of that market by 2020.
The addition of Exosun to the ArcelorMittal portfolio is an extension of its interest in solar power generation which already sees it manufacturing steel solar frames in Europe, China and Egypt, using its corrosion and abrasion-resistant Magnelis steel.
At the time of the acquisition, ArcelorMittal said in a statement that it expects the global photovoltaic energy market to grow by 15 GW a year of installed capacity from 2017 to 2020, growing from an installed base of 75 GW in 2016, half of which will be in large-scale solar farms.
In the US, at the Nevada Solar One CSP plant, built in 2007, over 7 million lbs (over 3,175 tonnes) of extruded 6061 alloy aluminium components provide the mounting/tracking system for the 760 parabolic concentrators comprising over 182,000 mirrors. The 400-acre site near Boulder City, Nevada has a nameplate rating of 64 MW, sufficient to power over 14,000 homes annually while avoiding carbon dioxide emissions equivalent to 20,000 cars.
ArcelorMittal is also active in wind power generation. The company installed three wind turbine towers at the Port of Hamburg, Germany, on land shared with its steelworks, at the end of 2017. In partnership with Hamburg Energie, the citys municipal green electricity supplier, the steelmaker installed the turbines which have a capacity of 3 MW each.
Commenting on the new installation, Lutz Bandusch, chief executive officer of ArcelorMittal Europe, Long Products, Bars and Rods, said: With the installation of the three wind turbines, ArcelorMittal is making another contribution to sustainable steel production in Hamburg. We are already a particularly environmentally friendly and energy-efficient steel manufacturer with a direct reduction plant. We continue to drive forward investments in the future. As an industrial company, we are also involved in the new district heating project to supply the city of Hamburg.
ArcelorMittal also supplies steel for the construction of offshore wind farms. In 2015, for example, the companys plant in Gijón, Spain, supplied 23,000 tonnes of heavy steel plate for the construction of 29 jacket foundations for the Wikinger wind farm sited in the Baltic Sea. The 1.4 billion ($1.7 billion), 350 MW wind farm, made up of 70 turbines, prevents almost 600,000 tonnes of CO2 from being released into the atmosphere each year from fossil fuels.
With steel used in the towers of both offshore and onshore wind turbines, the use of other metals in them depends on the location. Owing to the generally lower wind speeds encountered by onshore turbines, the manufacturers of these units tend to prefer coil-driven generators connected to the turbine blades via a gearbox. These generators make use of large amounts of copper wire. Offshore wind turbines which, thanks to much greater wind speeds, utilize direct-drive generators to create electricity, generally require the use of rare-earth-metal-containing permanent magnets (such as neodymium) to generate electricity.
The covers of the nacelle, which encase the generators on wind turbines, are made of either steel or aluminium. However, due to their weight, which the World Steel Association states can be as much as 300 tonnes, the equivalent of 14% of the weight of a large offshore turbine, manufacturers are increasingly making use of aluminium for the nacelle covers.
Changing from steel to aluminium, according to Marijn Rietveld, Market Sector Director Marine, Offshore & Rail at Norsk Hydro, provides more space for the nacelle components and allows for faster production at a lower overall cost due to the elimination of the galvanized steel beam internal support structures needed in a steel equivalent. In addition, he suggests aluminium nacelle covers can help the offshore wind industry become more sustainable and environmentally friendly. The cover that we have developed consists of multiple pieces, and the complete structure is self-bearing. It saves costs, it saves production time, and it is perfectly recyclable, he says.
Just as Ducab is manufacturing specialist cables for solar farm use, Nexans is focusing on cable services for wind farm applications. In mid-January, Nexans announced its acquisition of BE CableCon, a supplier of cable kits to some of Europes major wind turbine companies. Commenting on the transaction, Alain Robic, vice-president of Nexans Industry Solutions and Projects division, said: In addition to wind turbines, we will now be able to develop new growth opportunities for cable-kitting solutions in other industry segments.
GFG Alliance, the parent company of steel and aluminium producer Liberty House, also operates renewable power specialist Simec Energy. In December 2017 Simec Energy acquired Green Highland Renewables (GHR) to expand its portfolio of hydro assets in the UK and overseas. Simec already owns and operates two hydro-electric power stations in Fort William, Scotland, which supply power to Liberty Aluminiums smelter in the same part of the country.
Following the news of Simecs acquisition of GHR, the company announced plans to build 1 GW of renewable power generation capacity in the UK within three years, supporting fellow GFG company Liberty Steels ambitious target to develop five million tonnes of low-carbon Greensteel production in the UK within five years. As part of this proposal, Simec is consulting with local communities in the Scottish Highlands on a plan for a £170 million ($242 million) wind farm at Glenshero, designed to generate 164 MW of power.
By: Duncan Moore