Sean Spencer, Solution Development Manager
5 minute read
It has played a vital role in our past, and present, and will remain essential to our future progress too. Its superior thermal energy qualities make it a fundamental element in producing so much of what we take for granted, every day. And, thanks to rapidly evolving technology and engineering breakthroughs, we can look forward to enjoying its many benefits in a net zero world tomorrow.
There was no need to invent it; it's been on Earth for longer than we have. You can still see it in its most natural state, bursting from geysers, creating breathtaking displays. Their sheer power and force give a hint as to why steam is the most widely used heat-carrying medium in the world. And they highlight its elemental nature.
Its ability to hold a significant amount of energy that can be used either mechanically, to turn a turbine for example, or as heat to enable many processes, makes steam a key sustainable, renewable resource. Thanks to the steam and condensate loop, the water it uses can be recycled by efficient systems, saving energy as it does so.
With high efficiency, low toxicity, ease of movement, superior heat capacity, and low cost compared to other alternatives, a world without steam is unthinkable. We have steam to thank for many of the tremendous technological advances in society over the past 300 years. Whilst the mechanisms that use, and need steam may have changed, steam itself has remained fundamental to our evolution.
It plays a key role in the pharmaceutical industry, ensuring medicines and vaccines can be produced safely, reliably, and in large quantities. Healthcare facilities rely upon steam to keep instruments risk-free when treating us. Both the chemical and petroleum industries need steam to keep their plants running smoothly, and in creating the many products we rely upon for everyday living. From plastics to polyester (the world's most common clothing material), to ammonia production, which provides fertilisers to feed the world. And its many uses in the food and beverage industry mean we do not need to think twice about the safety and lifespan of so many things we eat and drink to live.
These are just some of the benefits steam gives us. It’s the reason we see steam not just as a useful phenomenon, but as natural technology. A safe, sustainable, reliable means of improving our quality of life, almost without comparison.
But, beyond a photo opportunity, geysers do not have much practical use for us, and, except for a few places on earth, steam as geothermal energy is not an option. That means to harness its value, steam has to be generated by us. And that is where the test for guaranteeing its sustainable future lies.
We need steam in vast quantities to maintain our growth and quality of life. It is vital we move away from generating steam using gas, coal, or oil to renewable, efficient sources of energy, as swiftly as possible.
The global energy crisis is accelerating major shifts in how we generate our power. First, there is a rapidly growing share coming from renewable sources (mainly wind or solar, but with variable output). Second, the potential for green hydrogen based on renewable power and electrolysis is growing day by day. Third, there is a growing acceptance of the need for the electrification of heat in industry and buildings. And finally, new technologies for both heat and power storage are emerging, and soon will be available at scale.
Such paradigm shifts in how industry operates will not happen overnight. But time is of the essence if we are to meet those exacting net zero targets. That is why practical options to bridge the gap between electricity supply and demand is so critical to achieving sustainable operations. Innovations like thermal energy storage, where capturing peak renewable supply, converting it to useful steam, and then holding it until it's needed will be pivotal in the transition. Figure 1 illustrates why we need to find ways to maximise our efficiency when it comes to making the most from renewable sources, like solar energy:
Taken as a whole, heat is responsible for more than double the energy demand of global electricity generation, and produces 55% of global energy emissions¹. Getting that number down is a significant decarbonisation² goal, but up to now, attempts have often been siloed, looking at areas like electrification, hydrogen, biomass, and carbon capture, utilisation, and storage (CCUS) separately, and focusing on specific end uses.
That is why the path to carbon neutrality sometimes seems so difficult, waiting for new technologies to replace those we have relied upon for decades or even centuries. Thankfully, the means to use sustainably-generated steam are well within reach.
As the need to decarbonise our planet becomes more urgent, it is reassuring that with steam, that does not mean losing it altogether. We all know that the days of driving petrol or diesel vehicles will come to an end, that our use of natural gas will be restricted, and difficult decisions will have to be made if we are to ensure our planet's future.
This is not the case with steam. Moving away from fossil-fueled boilers does not require waiting decades for new alternatives to arrive. Nor does it mean a complete overhaul of existing systems. The ability to retrofit boilers with electric heating technology is here, now. When old equipment needs replacing, new, more efficient electric options are readily available. As the power generation shift away from coal, gas, and oil, steam will be ready to prove its carbon-neutral potential.
Alongside, there will be an increasing need to do more with less, continually assessing and improving efficiency measures that will make steam even more important to so many industries that rely upon it. Data-driven, system-wide approaches will be the most effective means of doing so.
Because steam is so widely used by so many diverse industries, there is a huge variety of steam system sizes, configurations, end-use applications, and operational practices. This means there are many options to identify opportunities for improving steam system performance.
Just as steam has helped civilisations around the world grow and develop, now it is the turn of engineers to help steam continue its place in our history. Steam has taken us on a rewarding journey so far, and will continue to do so for centuries to come.
It is engineers from every discipline that will design, build, retrofit, operate and make safe the infrastructure and technologies for a decarbonised UK to be fully achievedNational Engineering Policy Centre, Royal Academy of Engineering
¹ “Global Energy Perspective 2022,” McKinsey, April 26, 2022.
² Note that reaching net zero is not just about CO2 emissions but all greenhouse gases, including methane and F-gases. Here we use decarbonisation to cover all relevant emission reductions.
National Engineering Policy Centre, Royal Academy of Engineering (https://raeng.org.uk/media/b4jpdttw/net-zero-a-systems-perspective-on-the-climate-challenge-final-nepc.pdf)
“Net-zero heat: Is it too hot to handle?”, McKinsey Sustainability, July 22, 2022. (https://www.mckinsey.com/capabilities/sustainability/our-insights/sustainability-blog/net-zero-heat-is-it-too-hot-to-handle)
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