The Energy Policy Journal calculates that 3D will cut greenhouse gas emissions by up to 525.5 megatons by 2025, which is equivalent to 105 million cars taken off the road. On the other hand, researchers at Loughborough University claim 3D printers consume 50 to 100 times as much electricity as injection moulding, to produce an item of the same weight. Michigan Technological University disagrees, calculating that cheap 3D printing uses 50% less energy than importing items from factories abroad.
All the experts can’t be right, so what are the main arguments?
3D printing service providers print as close to the customer as possible, and about 80% of major manufacturers now have an in-house 3D printing service. Transportation is responsible for 22% of energy-related greenhouse gas, so by reducing transportation, 3D printing shrinks a manufacturer’s carbon footprint.
Another way that 3D will reduce transportation overheads is often forgotten – its effect on transportation itself. Cars, ships and aeroplanes are all poised to become lighter because of the cellular and laminated materials made possible by 3D. Lighter vehicles mean savings on all transported goods, not just 3D ones.
Mining, cultivating and assembling uses energy. Karl Marx observed that the exchange value of a product reflects this work investment in its production. As Henry Ford agreed, more energy-efficient production brings products to market at cheaper prices. The ultimate judgement on whether 3D manufacturing is more or less of an energy burden on the environment is therefore whether it can compete in the market. The success of the 3D printing bureau is its own vindication.
3D printing outcompetes other methods for small runs, hence its uptake for prototyping. It also excels in niche areas where it produces things that are impossible using other techniques, with biotechnology being one example. Expect 3D to slowly shift consumer demand away from mass production and toward bespoke and unique products. In effect, this is a quality upgrade, and higher value products are equivalent to saving energy.
3D also contributes savings in the production of non-3D products. For example, General Electric recently announced that 3D printed turbines allow them to produce desalinated seawater 20% more cheaply.
At least 23% of electrical equipment collected at recycling centres could be refurbished. One reason this equipment is not refurbished is that spares are hard to get, and holding large stocks of every part is a huge burden on manufacturers and suppliers. 3D printing means that stockpiles of parts can be replaced by libraries of designs that are simple to maintain and available forever, reducing waste and landfill.
Milling and machining can use 30lb of material to produce a 1lb product. As well as less waste, 3D products are easily recycled. Shredders are being developed, to enable home recycling, and these will even turn plastic milk containers into 3D raw material.