Published: 2 December 2013

How green is 3D printing?

Kath Kovac

3D printers are the latest craze. But is this revolutionary manufacturing technology environmentally sustainable?

What can a 3D printer print? A design may already exist in the online repository, <a href="http://www.thingiverse.com" target="_blank">Thingiverse</a>. Think household goods, jewellery, lampshades, garden tools, guitars: even cars. This entire car body was 3D printed, with its inventor describing the <a href="http://korecologic.com" target="_blank">‘Urbee’</a> as ‘the greenest practical car ever made, [using] eight times less energy than the average little car.’

What can a 3D printer print? A design may already exist in the online repository, Thingiverse. Think household goods, jewellery, lampshades, garden tools, guitars: even cars. This entire car body was 3D printed, with its inventor describing the ‘Urbee’ as ‘the greenest practical car ever made, [using] eight times less energy than the average little car.’

Credit: Urbee 2

Some say 3D printers will change the face of manufacturing forever, spelling the end of mass production and ushering in a new era of personalised manufacturing. Others disagree, insisting they will merely fulfil a niche role for hobbyists.

Either way, like all new forms of technology, 3D printing will come with its own set of environmental impacts.

Also known as additive manufacturing, 3D printing has been in use for more than 30 years. A material, usually plastic or metal, is heated and fused layer by layer to build up a 3D object, with the design directed by a computer.

The invention of the open-source desktop ‘RepRap’ printer at Bath University in 2004 has since spawned a proliferation of similar machines, with a raft of companies now selling their own commercial versions.

3D printing is a useful weapon in the fight against planned obsolescence, extending the life of products after a damaged or worn part is out of production – which has to be a good thing for sustainability. A recent economic analysis¹ of home-based 3D printers has shown the average family could save thousands of dollars by printing commonly used objects at home, instead of buying ready-made.

But it’s not just about consumer products. 3D printing has made its way into science laboratories. Medical researchers have already printed personalised hip replacements, skull patches and prostheses.

The aerospace industry and NASA have welcomed the technology, with lighter ‘printed’ parts leading to massive fuel and greenhouse gas savings.

CSIRO is in on the 3D printing revolution, too, using the light metal, titanium, for example, to print tags for tracking big fish such as marlin, tuna and sharks.

CSIRO’s titanium 3D-printed fish tags are strong, non-toxic and resist the salty corrosiveness of seawater. 3D printing allows quick design and manufacture of different variations that can be tested simultaneously in the field, speeding research.

Credit: CSIRO

Waste and transport factors

So what are the environmental impacts of 3D printing? Is it really a ‘greener’ form of manufacturing? One clear advantage is its ability to reduce waste, especially when using metal.

John Barnes, leader of CSIRO’s titanium technologies research, says using 3D printing to make fish-tracking tags saves up to 90 per cent of the waste generated by the conventional manufacturing process of machining solid metal blocks.

For titanium this is especially important, because the metal is incredibly energy-intensive to purify from ore.

Reduced transport costs and emissions have also been cited as environmental benefits of 3D manufacturing compared with conventional fabrication. But Tim Grant, a specialist in life cycle assessment (LCA) and Director of Life Cycle Strategies Pty Ltd, isn’t so sure.

‘There’s an assumption somewhere that if we can make things locally, it’d save all the transport and a whole load of impacts,’ says Grant.

‘But transport isn’t really that significant [as part of an LCA]. I think we overemphasise its impact.’

He also reminds us that the raw materials used for printing still need to be transported to the location of the printer in the first place.

Energy hungry – or not?

Critics claim 3D printing machines use a lot of electricity. Electricity consumption is certainly a factor in some of the large industrial machines. A 2008 UK study showed that, within a manufacturing environment, large 3D printers using heat or a laser to melt plastic consumed 50–100 times more electrical energy than conventional injection-moulding to make similar objects.

HOwever, for custom production, the opposite is true, says Dr Christopher Tuck from the University of Nottingham in the UK. This is because for each new product made by injection moulding, new tooling is required, resulting in more energy consumption than, for example, laser sintering.

CSIRO’s John Barnes says standard laser 3D printers, which need to run chillers and other equipment, are far less efficient than the electron-beam units CSIRO uses for titanium printing.

The electricity consumption argument is not really applicable to smaller desktop 3D printers, according to Joshua Pearce from Michigan Technological University in the US.

Professor Pearce says his team’s research on the environmental and economic effects of desktop 3D printing compared with traditional manufacturing show the claim that these printers are energy-hungry is ‘simply not true’.

‘They have the power draw approximately equivalent to a laptop computer,’ he points out.

Prof. Pearce says home 3D printers will soon use even less energy. ‘Many desktop 3D printers are now shipping without heated beds, as this reduces costs – a heated bed is not necessary,’ he explains.

A whole-of-life view

According to LCA experts, the most important ‘green’ aspect of 3D printing is determined by the embodied energy within the base material used for printing.

The most commonly used material, apart from metal, is plastic, in particular, acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA). ABS is a petroleum-based polymer, and thus less environmentally friendly, whereas PLA is a biodegradable corn-based plastic.

‘Depending on what your base material is, it can have a high or low environmental impact before you even print,’ explains CSIRO senior scientist, Greg Foliente.

‘If it will print things from waste plastic, for instance, before you print you are already in good shape, environmentally.

‘But, if you use a virgin material from high-impact resource with a high processing cost, like titanium, it pushes the boundary. So, if you have a cheap and low environmental-impact based material, then you’re already on a winner.’

CAPTION: Senior CSIRO research scientist Dr Anne Ammala is investigating new polymer materials – some of which are biodegradable – and studying controlled polymerisation and advanced polymer processing. This image shows the intricate structures made possible with 3D printing.

Credit: CSIRO

Mr Barnes says his research group is trying to up the green credentials of titanium 3D printing.

‘We’re commercialising some technology that really reduces the energy content, because it makes titanium metal through a solid-state method,’ he says.

‘It comes out like a particle – not as fine as the powder used in a 3D printer, but it wouldn’t take a whole lot more energy to convert it into regularly shaped spherical particles, in which case the energy embodiment you have with today’s current powder goes away.’

Material matters

Dr Foliente’s example of recycled plastic may soon be a reality. So-called ‘RecycleBots’ are being developed that will reuse plastic from failed print runs, milk bottles and the like, instead of the standard plastic filament used by desktop printers.

An LCA takes in the energy use and GHG emissions for every aspect of production, from the extraction of raw material to the finished product. Only one LCA study on desktop 3D printers has been published, from Prof. Pearce’s Michigan lab. ² His team found that not just the type of base material, but the quantity used, can make the difference in environmental credentials between 3D printing and conventional fabrication.

The study compared the embodied energy and GHG emissions of three everyday objects – a child’s building block, a watering can spout and a citrus juicer – produced by conventional manufacturing and 3D printing using ABS and PLA plastics.

As long as the ‘fill’ of the plastic objects printed was less than 79 per cent (ie the objects were not 100 per cent solid plastic), the cumulative energy demand (CED) was less for the objects made on a 3D printer.

For objects printed with PLA at less than 25 per cent fill, which the authors say is easily achieved, the CED could be reduced by 41–64 per cent; and by even more (55–74 per cent) when using solar power to drive the printer – a pretty impressive reduction, by any standards.

As Prof. Pearce concludes: ‘The bottom line is that in most cases, printing objects at home uses less energy and creates less emissions than sourcing products using conventional manufacturing and distribution techniques.’

¹ Wittbrodt BT et al. (2013) Life-cycle economic analysis of distributed manufacturing with open-source 3-D printers. Mechatronics 23: 713–726.
² Kreiger M and Pearce JM (2013) Environmental Life Cycle Analysis of Distributed 3-D Printing and Conventional Manufacturing of Polymer Products, ACS Sustainable Chemistry & Engineering, Just Accepted Manuscript/Open Access

Published: 19 January 2015

Mapping East Asia’s disappearing tidal flats

Nick Murray

Who speaks for the tidal flat? There are many voices for the mangrove forest, the coral reef and the seagrass meadow, but the chorus for the mud, sand and silt flats that sit hidden under shallow water for most of the tidal cycle is often silent.

In China alone more than 1.2 million hectares of wetland reclamation has taken place in the last 50 years, perhaps accounting for more than 5 per cent of the worlds’ tidal wetlands.

Credit: Nick Murray

Not only do hundreds of species of migratory bird depend on them for their existence, this coastal ecosystem also protects large chunks of humanity and provides ecosystem services to hundreds of millions of people around the world.

A zone under pressure

The problem for all coastal ecosystems is the shifting character of the coastal zone. The last 50 years has seen the global human population migrating rapidly to coastal regions. As a result, coastlines around the world have become a focus of expansion of urban, agricultural and industrial areas.

This development is having a major impact on coastal ecosystems, which has resulted in the widespread loss and degradation of ecosystems such as mangroves, seagrasses, coral reefs and tidal flats. And that has major consequences for humans and nature.

In terms of the human cost, coastal ecosystems are a frontline defence that protects billions of dollars of infrastructure from storms and sea level rise, and maintaining their integrity is among the most cost-effective options for coastal protection.

Tidal flats are a widespread coastal ecosystem that is frequently overlooked in the planning and management of coastal resources. They are among the most widespread of any coastal ecosystem and, as well as providing ecosystem services to hundreds of millions of people worldwide, they sustain a suite of threatened and declining species.

For instance, tidal flats support the majority of the world’s migratory shorebird species, enabling their yearly migration from the arctic to areas as far south as Patagonia. Unfortunately, their proximity to centres of human population have also made these areas targets for cheap and rapid coastal development.

Drawing a mud map

So, what’s the magnitude of the problem?

Until now we have had no way of knowing just how much of this declining coastal ecosystem has been destroyed, or how much and where it remains. The principal reason for the lack of accurate maps of this ecosystem is due to the rapidly changing conditions they encounter: changing tides either expose or cover them, severely limiting the application of classical remote sensing methods.

To solve this problem, our small team of remote sensors and spatial ecologists have been developing methods to map tidal flats over very large areas.

Using the heavily developed tidal flats of mainland East Asia as a case study, we have developed a rapid mapping approach for identifying the distribution of tidal flats while assessing their changing status at continental scales.

The tidal flats in this region – which fringe the countries of North Korea, South Korea and China – are among the largest in the world, measuring up to 20 kilometres wide in some places. Our methods – utilising free data from the US Geological Survey’s Landsat archives and freely available regional tide models – allow fast implementation across thousands of kilometres.

Indeed, with more than 28,000 images to choose from, we determined the changing status of tidal flats across more than 14,000 kilometres of coastline.

Easily overlooked, and invisible for much of the tide cycle, mud flats are disappearing right before our very eyes. And their loss comes with an enormous cost.

Credit: Nick Murray

Impacts of reclamation

Our results demonstrate that tidal flats in East Asia are being destroyed at rates similar to other major at-risk ecosystems, such as tropical forests and mangroves. The principal cause of these losses related to coastal development. Changes to sedimentation regimes due to the damming of major rivers is also an issue as this results in offshore losses of tidal flats.

In East Asia, land scarcity is a severe issue and often the cheapest method of acquiring land for large coastal developments is through land creation, often termed reclamation. Tidal flats, which are generally characterised by low-sloping flats in areas protected from severe weather, have proven an ideal environment for cheap and rapid coastal development.

This radical transformation involves the construction of seawalls, infilling and finishing for land use. These areas are then developed into new parcels of land for aquaculture, agriculture, suburbs and industry.

Loss of coastal wetlands to land reclamation is a global problem that is severely affecting the world’s coastlines. In China alone more than 1.2 million hectares of wetland reclamation took place in the last 50 years, perhaps accounting for more than 5 per cent of the world’s tidal wetlands according to some estimates.

This is clearly a symptom of China’s rapid coastal urbanisation. This arc of growth will form one of the world’s largest urban areas by 2030 – a continuous coastal urban corridor over 1800 kilometres long.

The rapid pace of coastal population growth and sea-level rise – as well as increasing demand for aquaculture, coastal wind farms, and tide energy – will certainly apply further pressure to the world’s tidal flats in the future.

The loss of tidal flats along migratory pathways, especially staging sites (where birds must replenish their energy stores during migration for long, energetically expensive flights) can have extreme consequences for shorebird populations. For the millions of shorebirds that migrate through the East Asian-Australasian Flyway, the intertidal areas of Asia are a crucial migratory bottleneck.

Credit: Nick Murray

Uncertain future

An effective conservation strategy must manage the complex economic and social trade-offs that drive coastal development.

Decision-making that simultaneously plans for coastal development and coastal conservation along the world’s most rapidly developing shores is clearly needed.

For example, places where natural values have effectively been lost due to sediment depletion and coastal subsidence could be prioritised for development. As part of a carefully integrated plan, this could ease pressure on a functioning network of coastal protected areas and ensure continued delivery of ecosystem services.

Not only might this avert catastrophic extinctions of coastal biodiversity, it will also help us ensure we have a coastline capable of adapting to an increasingly uncertain future.

Dr Nick Murray is a Research Associate at the Centre for Ecosystem Science, University of New South Wales. He carried out this research in association with the Environmental Decisions Group (EDG), while completing his PhD at the University of Queensland. The EDG is a network of conservation researchers developing the science of effective decision making to better conserve biodiversity, and includes a number of Australian and International research centres, including CSIRO. This article first appeared in Decision Point – a free monthly online publication from the EDG.

More information

‘Tracking the rapid loss of tidal wetlands in the Yellow Sea’, published in Frontiers in Ecology and the Environment

‘Continental scale mapping of tidal flats across East Asia using the Landsat archive’, published in Remote Sensing

‘IUCN situation analysis on East and Southeast Asian intertidal habitats, with particular reference to the Yellow Sea (including the Bohai Sea)’, IUCN occasional paper

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