The plastics industry has traditionally used fossil fuel to function, but manufacturers are exploring new eco-friendly technologies to conserve our planet’s natural resources for the future.
Oil-based plastics make up the majority of those we use today, consuming around 350 metric tonnes of oil globally every year. While the industry is keen to evolve with new materials to protect the environment, the financial impact of the move must also be considered.
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How are plastics made?
More than 90% of plastics are currently made from petrochemicals derived from natural gas and oil. Projections suggest plastics will be the biggest source of new demands for oil in the near future.
Made by combining small molecules, known as monomers, into larger molecules or polymers, using a process known as polymerisation; natural gas, crude oil or coal are refined to extract the necessary chemicals to make plastic.
Crude oil is extracted by pumping it from underground and sending it to an oil refinery. Heated to a high temperature, it is then separated into components known as fractions. One of them, naphtha, contains propene and ethane, which are two important components of plastics.
How plastic is made from oil
The molecules are broken down at high temperatures in furnaces and reassembled into chains during polymerisation to create polymers. Plastics’ properties are enhanced through stabilisers, plasticisers, pigments, flame retardants and fillers.
Once soft, the plastic is poured into a mould to be shaped, hardening into the required shape as it cools. It can be moulded into almost any shape and the finished product is durable, lightweight and strong.
The process itself can be harmful to the environment, as the materials used can be hazardous when heated and burned. Despite the potentially negative impact, plastics remain in high demand and continue to require oil.
What plastics sectors are dependent on oil?
Multiple sectors are dependent on oil, including petroleum-based plastics used for packaging materials for food, shampoo, cosmetics and other items.
Polyester fibres used to make garments are derived from petrochemicals, while other plastics that rely on oil include PVC, polyethylene, polypropylene, acrylic, polystyrene and nylon.
In economic terms, using crude oil to manufacture plastics is one of the cheapest options. However, according to a report by Carbon Tracker, the plastics industry is increasingly being scrutinised due to its environmental impact.
While the International Energy Agency has predicted plastics production will drive almost 50% of the growth in oil demand by 2050, green campaigners suggest this may not be the case if governments back the current drive to reduce the use of fossil fuels.
Alternatives to oil-based plastics
Is there a viable argument for using alternatives, such as hydrogen-based, bio-based or recycled plastics? They all provide an opportunity to move away from fossil fuels, but there are several variables to consider.
Plastic manufactured from oil and gas is the cheapest, so it could be challenging persuading industry to move away to eco-friendly types. Bioplastic and plastic derived from green hydrogen are the most expensive, but in terms of preserving the planet, they win hands down.
It costs around £1,400 to produce one tonne of plastics from oil or naphtha, compared with £3,500 for fossil fuel-free bioplastics and £5,600 for green hydrogen-based alternatives. Only time will tell whether there’s a way of reducing the price of producing eco-friendly plastics.
Experts suggest one way of persuading industry to go green is to offer subsidies, although it isn’t clear how the government could fund this. Another suggestion is to impose mandatory production targets for oil-based plastic, or impose a higher tax on it when it is made from gas or oil.
However, in the case of green hydrogen-based plastics, even with a reduction of 90% in production costs by improving the technology, they would still be more expensive than those made with fossil fuels.
Challenges of bio-based plastics
Studies show bioplastics can potentially reduce carbon dioxide emissions by at least 30% and possibly more. They can cut manufacturers’ carbon footprints by around 42% and consume 65% less energy than oil-based products. Bio-based plastic can be manufactured from renewable sources including corn starch, vegetable fats, straw, sawdust, wood chips and recycled waste food.
The European Commission has put in place a number of safeguarding criteria including sustainable harvesting practices, forest biodiversity, soil quality, carbon protection, land use and emissions accounting procedures.
Bioplastics benefit the environment because they avoid depleting natural resources, such as oil and gas. It’s possible to grow and renew biomass in a lifecycle spanning months when waste from crops is used, or years in the case of tree branches. This compares favourably with the hundreds of years needed to form oil and gas.
In addition, there are less CO2 emissions from the manufacture of bioplastics in comparison with the gas or oil method.
Recycling plastics
Most used plastic worldwide is still sent to landfill or incinerated, even in Europe, where data from Nova Institute suggests only 8% is recycled. This figure is described as “shocking” by environmental campaigners, as plastic waste is causing widespread pollution.
Emissions can be reduced by using recycled plastic instead of manufacturing virgin materials, as less oil is needed for recycling. Less waste is produced when we recycle, in terms of both CO2 and the volume sent to landfill or ending up in the ocean.
Chemical recycling is the way forward, according to some experts, as it uses various technologies to recycle plastic waste into raw materials to create new products. Current chemical recycling methods include gasification, which heats plastic in a controlled oxygen environment to produce synthesis gas to convert into other materials.
Future of plastics
While it’s possible that the industry can survive without oil, government policies must play a major role in encouraging the shift away from oil-based plastics, mainly due to the higher costs of producing eco-friendly options.
Current regulations, such as bans on single-use plastics and government support for more research and development, can foster innovation, but this must be balanced with a need to keep the industry viable. Suggestions include reducing the costs of fossil-free plastics to make them more competitive and using more renewable energy sources, such as solar and wind power, to produce plastics with net-zero emissions.
Using renewable materials such as vegetable oils, sugars and recycled food waste is currently used for only 1% of plastics, so a greater take-up rate is required, but until the production prices decrease, industry may find it challenging to move onto more eco-friendly methods.
