Which is Better For The Environment? Glass or Plastic?
When you look up zero waste, you’re bound to notice tons and tons of pictures of glass jars everywhere. From the trash jar to the jars lining our pantries, glass is pretty popular in the zero waste community. But what’s our obsession with glass? Is it really so much better for the environment than plastic? Plastic tends to get a really bad rep from environmentalists – that’s got a lot to do with the fact only 9 percent of it is recycled. That said, there’s so much more to think about in terms of what goes into manufacturing and recycling both glass and plastic, not to mention its afterlife. Which is truly the eco-friendliest choice when you get down to it, glass or plastic? Well, perhaps the answer isn’t as clear cut as you may think. This is a long post but worth it.
Is glass or plastic more environmentally friendly?
Let’s start by analyzing every zero waster’s beloved material: GLASS
First, it’s important to note that glass is endlessly recyclable, back to its original use.
It never loses its quality and purity, no matter how many times it’s recycled…. but is it actually being recycled?
An Overview of the Problems with glass: First up, making new glass requires sand.
While we have tons of sand on beaches, deserts and under the ocean, we’re using it faster than the planet can replenish it. We use sand more than we use oil, and only a specific kind of sand can be used to get the job done (no, desert sand can’t be used). Mostly, sand is harvested from riverbeds and seabeds.
Taking sand out of the natural environment also disrupts the ecosystem, considering microorganisms live on it which feed the base of the food chain.
Removing sand from the seabed leaves shore communities open to flooding and erosion.
Since we need sand to create new glass, you can see where this would be an issue.
Another problem with glass? Glass is heavier than plastic, and breaks much easier during transit.
This means it produces more emissions in transportation than plastic, and costs more to transport. Yet another thing to consider is most glass isn’t actually recycled. In fact, only 33 percent of waste glass is recycled When you consider 10 million metric tons of glass is disposed of every year in Australia, that’s not a very high recycling rate.
There are many reasons glass recycling is so low: Glass put into the recycling bin is used as a cheap landfill cover to keep costs low.
Consumers participating in “wish-cycling” where they toss non-recyclables into the recycling bin and contaminate the entire bin.
Colored glass can only be recycled and melted down with like-colors. Windows and Pyrex bakeware are not recyclable because of the way it’s manufactured to withstand high temperatures.
Last but not least, glass takes one million years to decompose in the environment, perhaps even more in a landfill.
In total, that’s about four major problems with glass that impact the environment. Now, let’s analyze the lifecycle of glass bit closer. Raw Materials: Glass is made from all-natural resources, such as sand, soda ash, limestone and recycled glass. However, it is important to note that we’re running out of the sand that’s used to make glass in the first place.
Worldwide, we go through 50 billion tons of sand every year. That is twice the amount produced by every river in the world.
Once these raw materials are harvested, they’re transported to a batch house where they are inspected and then sent to the furnace for melting where they’re heated to 2600 to 2800 degrees Fahrenheit. Afterwards, they go through a conditioning, forming and finishing process before becoming the final product.
Once the final product is created, it’s transported so it can be washed and sterilized, then transported again to stores for sale or use. Once it comes to its end of life, it’s (hopefully) collected and recycled.
Unfortunately, each year only one-third of the roughly 10 million metric tons of glass that Americans throw away is recycled.
The rest goes to a landfill. When glass is collected and recycled, it has to begin this process of being transported, going through batch preparation, and everything else that follows again.
Pollution: As you can imagine, this entire process to make glass, especially using virgin materials, takes up a lot of time, energy and resources. Also, the amount of transporting the glass has to go through adds up too, creating more emissions in the long run.
A lot of the furnaces used to create glass also run on fossil fuels, thus creating a lot of pollution. The total fossil fuel energy consumed to make glass in North America, primary energy demand (PED), averaged to 16.6 megajoule (MJ) per 1 kilogram (kg) of container glass produced.
The global warming potential (GWP), aka climate change, averaged to 1.25 MJ per 1 kg of container glass produced. These numbers encompass every stage of the packaging life cycle for glass. If you’re wondering, a megajoule (MJ) is a unit of energy equivalent to one million joules. A property’s gas usage is measured in megajoules and is recorded using a gas meter.
To put the carbon footprint measurements I gave into perspective a little better, 1 liter of gasoline is equal to 34.8 megajoules, High Heating Value (HHV).
In other words, it takes less than a liter of gasoline to make 1 kg of glass. Recycling Rates: However, if a glass manufacturing facility used 50 percent recycled content to make new glass, then there would be a 10 percent decrease in GWP.
In other words, the 50 percent recycle rate would remove 2.2 million metric tons of CO2 from the environment. That’s the equivalent of removing CO2 emissions of nearly 400,000 cars every year.
However, this would only happen assuming at least 50 percent of glass was recycled properly and used to make new glass. Currently, only 40 percent of glass thrown into single-stream recycling collections actually gets recycled.
While glass is completely recyclable, unfortunately there are certain facilities that choose to crush the glass and use it as a landfill cover instead.
This is cheaper than actually recycling the glass, or finding another cover material for landfills. Cover material for landfills are a mix of organic, inorganic and inert components (such as glass).
Landfill covers are used to control the offensive smells landfills give off, deter pests, prevent waste fires, discourage scavenging, and limit rainwater runoff.
Unfortunately, using glass to cover landfills doesn’t help the environment or reduce emissions because it’s essentially downcycling glass and preventing it from being reused. Glass recycling is a closed-loop system, so it doesn’t create any additional waste or by-products.
End Of Life: You’re probably better off holding onto glass and repurposing it before you toss it into the recycling bin.
As mentioned, glass takes a VERY, very long time to break down. In fact, it can take a glass bottle one million years to decompose in the environment, possibly even more if it’s in a landfill. Because its life cycle is so long, and because glass doesn’t leach any chemicals, it’s better to repurpose and reuse it over and over again before recycling it.
Because glass is nonporous and impermeable, there are no interactions between glass packaging and the products inside, resulting in no nasty after taste – ever.
Plus, glass has an almost zero rate of chemical interactions, which ensures that the products inside a glass bottle keep their flavor, strength and aroma.
I guess that’s why lots of zero wasters encourage people to save all their empty jars for reuse :) Ok, now let's talk Plastic. Raw Materials: First, oil and natural gas are the major raw materials used to manufacture plastics.
Plastic production often begins by treating components of crude oil or natural gas in a “cracking process” where these components are converted into hydrocarbon monomers, such as ethylene and propylene. Even more processing leads to various other monomers, such as styrene, ethylene glycol, terephthalic acid, vinyl chloride and several others.
These monomers are then chemically bonded into chains called polymers.
The different combinations of monomers yield various different kinds of plastics, all with a wide range of characteristics and properties. There are seven major plastics that are used widely such as Polyethylene Terephthalate (PETE), High Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Low Density Polyethylene (LDPE), Polypropylene (PP), Polystyrene (PS) and other plastics (ex: nylon). Pollution & Energy: All these different plastics serve different functions, though some are easier to recycle than others.
As you can imagine, creating all those plastics takes a lot of energy and resources. In fact, the emissions from plastic in 2015 were equivalent to nearly 1.8 billion metric tons of CO2.
It doesn’t help the factories used to create plastic also run on fossil fuels and produce emissions as well.
To be fair though, factories that produce glass also create emissions and run on fossil fuels for the most part. Why we use rPet: rPET stands for recycled polyethylene terephthalate, or recycled PET. PET (polyethylene terephthalate) itself is a polymer used to widely manufacture affordable, durable and recyclable containers and packaging as well as a form of polyester. PET containers are identified by a #1 code on the bottom. By converting post consumer waste into a valuable resource, rPET excels in the sustainability compartment compared to virgin PET bottles. The use of rPET plastic is on the rise as a result of its low carbon footprint (saving raw materials by requiring less energy), recyclability (reducing waste), and strong environmental credentials. As more and more brands continue to adopt the use of rPET, we are setting a standard where rPET is routinely used instead of regular PET bottles. Recycling PET: When PET packaging is recycled/discarded by us, the consumer, it becomes waste. That waste then makes it way to a material recovery facility (MRF) where it is sorted from other materials, baled, and sent to specific PET recycling facilities. At these new facilities, each bottle is washed and contaminants are removed. The bottles then get sorted according to color and are ground into flakes or made into pellets. These flakes and pellets are then sold as raw material that can be used for a range of polyester products (clothing, carpets, insulation, etc) or made back into PET bottles that can be recycled again and again, indefinitely just like glass. Energy Consumption: In the closed loop, bottle to bottle system described above, recycled polymers directly replace virgin polymers to create several major advantages in the realm of energy, greenhouse gas emissions and cost. The process of converting rPET to a virgin equivalent requires much less energy than glass, aluminum, or other materials. Although PET’s is derived from crude oil and natural gas, approximately 40% of that energy is trapped within the PET polymer for recapture and reuse every time PET is recycled. This means rPET leads to a greater conservation of raw materials and a reduction in greenhouse gas emissions by 65%
Since PET is lightweight and more compact, it allows for more product to be delivered with less packaging, less weight and less fuel for transport, and with less trucks on the road.
It takes 27 pounds of glass versus 2 pounds of plastic to deliver 30 L of a beverage.
rPEt plastic means a reduction in breakage and damaged goods compared to glass packaging.
PET virgin bottle resin pellets between 83 and 85 cents a pound, compared to only 58 to 66 cents a pound for rPET pellets.
The reality is that 100% of all PET products can be made from rPET. In addition to all the advantages of rPET plastic, consumers are actively looking for companies that are committed to sustainability, recycling and the overall green agenda.
Last but not least, the closed loop cycle of rPET relies on the consumer to recycle. It only works if this necessary step takes place, so please, always recycle you rPET bottles!
Glass and plastic both have their pros and cons. Phew! I told you this was a long blog post!
The best thing we can do is reduce our reliance on anything single-use! If you use it once and then place it in the recycling bin, try to find another solution. Of course there are exceptions, and there’s no way we’re going to completely eradicate single-use, but we can definitely make a HUGE dent in it by being a little more conscious with our purchases. Generally speaking try to avoid buying new plastic and look for rPet (like we use!) or glass for food products and storage, not Tupperware!