Green Steel Is A Crucial Part Of Our Renewable Future
One of the things about agreeing to speak on a popular radio station is that you are sure to get a tricky question or two, especially if you are talking about climate change.
During a recent interview on Britain’s LBC radio station, I spoke about a future where renewables were the dominant form of energy. The challenge came through from a listener that to build the solar and wind infrastructure, surely, we were going to need steel, and we can’t make steel without coal.
This was a fair question and it prompted me to find out where we are with the development of zero carbon steel and what will it take to leave coal out of the equation altogether.
Steel is arguably the single most important resource when it comes to constructing our future infrastructure. The origins of steel manufacture dates back to as early as 1800 BC in Anatolia and the principles of making steel from pig iron haven’t changed much over the centuries. Aside from some evolution from using coal to coking coal, today, steel production is still an energy intensive process with the vast majority of that energy coming from fossil fuels. Worldwide, steel is responsible for around 7-9 percent of all direct emissions from fossil fuels, and most of these come from burning of coal.
Clearly, the challenge for the steel industry is to reduce its carbon emissions. Energy constitutes between 20 and 40 percent of the cost of steel production, so the reality for most major producers is that “green steel” is simply not affordable. Fortunately, 30% of the world’s steel production use electric arc furnaces fed with recycled steel or iron smelted with natural gas and hydrogen. Recycling is obviously a priority to reduce demand for new steel, but steel is already mostly recycled, and we will need new steel.
To put into context the relative carbon emissions related to the two forms of steel production, the World Steel Association states that the average blast furnace needs 800kg of coal to produce a tonne of steel while the average electric arc furnace (using mainly recycled steel) needs just 16kg of coal.
Steel industry advocates are quick to point out that plenty of the steel it produces is used within the renewable energy sector and more than makes up for the carbon footprint over its lifetime. A three-megawatt wind turbine, for example, can deliver 80 times more energy over 20 years than is used in its production and maintenance materials.
On a more positive and progressive note there are pioneering companies out there bringing new ideas to market. The Swedish company HYBRIT recently began a pilot program for a “fossil-free” steel making plant. This ground-breaking program aims to bring fossil-free steel to the market by 2026. It plans to replace coking coal with electricity from renewable energy sources and hydrogen in a process that will produce steel and water as opposed to steel and carbon dioxide.
With the rapid advancements in hydrogen energy we could see hydrogen alongside renewable energy become more widespread in creating a new way of developing carbon free steel.
One such accelerator could be the development of hydrogen hubs and how these might work here in the UK. Such a hub would use excess renewable energy, converted into green hydrogen, and used in a localised industry loop. Green steel could be the perfect solution here in the UK where we constrain our wind power by up to 7% a year already and we could easily benefit from hydrogen hubs in the Northeast of England using offshore renewables and bringing back “green” steel to historic manufacturing centers, such as Teesside.
All these ideas have their place, but we need to make rapid progress to turn them into mainstream technologies. Higher levels of investment into innovation from government and business will be needed to fast-track the innovations needed for this industry to produce zero carbon steel. We are already building our renewable future and green steel can’t be left behind.
 Pig iron is made by smelting iron ore at a temperature exceeding 1600x, and releases the iron from the ore in the form of pig iron, a brittle material containing up to 4.5% carbon. The carbon content is then reduced to produce a useful metal.