Plastics and Zero-Carbon
Clive Thompson, The Worshipful Company of Horners
Plastics are a group of materials that have become fundamental to the lifestyle of every person on this planet. They are just as important as traditional materials but are more versatile. Their properties make them essential for many functions, and indeed without them it will be impossible to work closer to net-zero carbon! Meanwhile, a history of poor design, inappropriate application and careless disposal by a throw-away society has made them prime targets for an increasingly environmentally-conscious society. But make no mistake, a completely plastic-free world is impossible to achieve without having a severely detrimental impact on every person and nation on earth!
Meeting a zero carbon target is a formidable task, one that realistically will never be met. What it really means is reducing carbon emissions to a level that slows and then halts the damage to the atmosphere and slows and halts global warming, which is now internationally determined to mean restricting warming to 1.5⁰ Celsius above pre-industrial levels. Even this is a massive challenge to every industrial, domestic and financial system and will need significant technical and social innovation to meet it.
Before considering net-zero carbon we must recognise the vital part that plastics play in simply making possible our twenty-first-century lives. Electrical systems work only because of plastics insulation on all current-carrying connections. Microchips, essential for all electronic systems, need plastic materials to make them viable. The water pipes carrying and distributing this vital resource are made from plastics. Most modern adhesives and paints have plastics bases. Modern vehicles and aircraft have substantial numbers of plastic components. A very large number of medical items and equipment are made from plastic; managing the current pandemic would have been impossible without them. The response to demand for huge numbers of PPE items would have been very tardy had these been made from traditional materials. Advances in sporting performance have been made possible through specially designed plastic kit, clothing and equipment. Many items of clothing are made from synthetic fibres that are plastics in all but name. The list is truly endless and depends upon the versatility, properties and processability of the many and varied forms of plastics. There is much science, engineering and design in these materials and there is no limit to their potential.
Achieving net-zero carbon targets requires many changes. The essential changes in sources of energy and their distribution are daunting and represent a reversal of decades of energy policy. The sourcing and manufacturing processes for many traditional materials renders them incompatible with achieving net-zero carbon. Means of transport and the lifestyles irrevocably linked to them must undergo considerable rethinking; it is not just about “electric cars” but will involve town planning, financial restructuring and industrial and social change! The employment market will be hardly recognisable with new jobs in new industries.
In facing this serious challenge, plastics have a significant role to play, adding to their existing essential part in twenty-first-century life.
The manufacture of iron and steel, aluminium, glass and also cement consume huge amounts of energy and emit substantial volumes of carbon dioxide. Additionally, all have high densities and their transportation and the articles fabricated from them are major contributors to global warming. They also have the disadvantage that their recycling is energy intensive. The autumn 2021 energy crisis brought about by a natural-gas shortage demonstrated the energy dependence of many traditional industrial processes and the huge task facing them in moving towards net-zero carbon. The technological challenges are immense. As economies and users of these materials move radically to reduce their energy consumption, the changes will result in dramatic changes to commercial and domestic environments.
In this world plastics, because of their basic properties, become significant potential replacements and will be indispensable in meeting low-hydrocarbon-economy targets.
The replacement of hydrocarbons by electricity as a transportation fuel places weight constraints on designs. Already motor vehicles are built with many plastic and composite components and this trend will inevitably accelerate. The cars of tomorrow will be as much plastic cars as electric cars! Similar developments are afoot in aeronautics design, with Airbus already using plastic composites for wing and body sections. The Boeing “Dreamliner” is mostly constructed of composites and it is said that, using traditional materials, it could fly but not carry passengers or freight. Electrically propelled aircraft must be fabricated almost entirely of plastics.
Energy generation and distribution represent a massive transition for which there is no alternative. The UK has built a heavy dependency on natural gas, a legacy from our rich North Sea oil and gas fields, with the network that distributes gas to 23 million homes now facing redundancy. At this stage there is no apparent strategic approach; pilot studies that should have been completed a decade ago are still at the planning stage. Wind power is already well developed, and its growth will expand the market for composite turbine blades. Solar power technologies have advanced considerably in recent years, partly as a result of the development of plastic components. A drawback of wind and solar is that they are light- and climate-dependent and must be accompanied by new forms of electricity storage. They can be helped by the use of plastics to make lighter materials and improve storage methods.
Inevitably, new power sources will need to be developed. Hydrogen is widely discussed as a CO₂-free fuel. However, hydrogen presents many problems: it is mainly produced by the electrolysis of water, a process that is dependent upon major supplies of electricity, adding to existing network distribution capacity demands. An alternative source of energy could be fuel cells that employ a polymer membrane and steam reformation of natural gas [methane]. Both processes still need proving at industrial scale. Hydrogen is light and its small molecules can pass through many materials, such that containment and transportation of this highly explosive material would require use of specialised impermeable polymers. Energy of ignition of hydrogen is low, adding to safety concerns and making it likely that use of hydrogen will have only controlled and, perhaps, limited application.
All sources of power require changes in domestic usage, for heating and cooking. The switch to all-electricity domestic energy will demand an increase in power generation and distribution capacities. The expanded networks will depend upon many different forms of plastic insulation. Wind and solar power, likely to continue their use as sources of power, are major users of polymeric and composite materials.
As climate change increases uncertainty over food production, improvements in food productivity and reductions in food waste become essential. Water conservation, poly tunnels and other innovations will feature in the development of an increasingly vegetarian diet. Novel forms of horticulture, such as hydroponics and vertical gardening, use many types of polymeric materials. Polymer food wrapping is a proven means of food conservation and thus has an increasing role in reducing global warming. An Institute of Mechanical Engineers report recently calculated that 1.2 to 1.5 billion tonnes of food is wasted annually [30-50% of the total]. When left to decompose in land-fill, this will generate millions of tonnes of greenhouse gases. By helping to reduce food waste, polymers can also help reduce gaseous pollution.
The health of an ageing population is an area that will demand increased innovation, so as to improve health-care delivery and to introduce new treatments. The recent pandemic has amply demonstrated the dependence of health systems on polymers at all levels of expertise. Transportation and storage of blood and fluids are totally dependent upon plastics. Modern hospital designs and working systems are dependent upon novel treatments that are, in turn, dependent upon easily cleaned polymeric materials.
Wherever you look, you find that plastics make a fundamental contribution to everyone’s life in the twenty-first century. Yet paradoxically these materials have come to embody all that is worst in our throw-away society. It is many of their valuable properties–lightness and buoyancy, durability and ubiquity–that make them stand out from other litter and waste. Government policies on waste disposal have not helped, by ignoring the need for action and instead exporting our waste to less fastidious nations. The plastics industry has been aware of these problems for decades; it is now striving to set up systems to reduce applications for single-use plastics and improve the systems for and volume of recycled materials. New plastics designs and applications now consider every aspect, from material selection and design to end of use. Manufacturing and processing systems are more energy-efficient and minimise waste. Meanwhile, the range of specialised plastics with precisely specified properties is increasing, expanding the range of applications, designs and markets.
A net-zero carbon world will be very different from today and failure to see this change coming has been a significant factor inhibiting progress. The costs and timescale are daunting and economists are struggling to devise ways to restructure financial systems to pay for the revolutions required in the economy and lifestyles. There will be no escape from the fact a net-zero carbon world will be more expensive and that tax-payers will be asked to fill gaps left by fuel duties and other revenue changes. This paper has sought to illustrate the vital role that plastics are playing on the road to net zero. These materials will have an even greater role in the world of the future. They will become a strategically important use of hydrocarbons, far too important to burn or throw away.
We should recognise the crucial role plastics play in achieving net zero, but also in reshaping and rebuilding industry, the economy and lifestyles for everyone.