Online vs high street shopping – what’s more energy efficient?

The question is not as straightforward as it seems, as each product has its own carbon footprint as part of its creation or manufacture. Then, when we think about the movement of goods, there are separate elements to each journey. We need to take the journey of the product to our house from the retailer into account, as well as the retailer’s own logistics supply chain, which is not something most of us can account for.

The 2009 World Economic Forum Supply Chain Decarbonisation report estimates that 5.5% of global carbon emissions come from the logistics and transport sector – essentially from transporting products.

The speed goods are delivered matters – whether that’s from the manufacturer to a warehouse, or from there to your home. Typically, a slower delivery will emit less – a ship takes a lot longer to move your product than a plane, for example. Slower land deliveries also allow retailers to consolidate goods, and move more products at once. This means, if you can, it’s a good idea to avoid expedited deliveries.

However, some logistics companies claim that the speed of delivery doesn’t make much difference as they optimise their routes and further reduce emissions by investing in new technologies. Certainly faster deliveries will emit less carbon once more companies make the switch to zero-emitting fleets (of electric vehicles, bicycles or even drones).

The graph below shows the typical emissions for different modes of transport.

Consolidation is key to reducing the impact of your shopping choices. If you drive to a shopping centre and buy a range of goods once a month, then your travel will create fewer emissions than if you drive there every day. Equally, if your delivery driver brings you a variety of goods in one visit, the impact is lower than when each item arrives separately.

A 2010 UK study focused on the impact of a product’s ‘last mile’, which refers to the final stage of a product’s journey to a customer’s home. It concluded that you would have to buy 24 items in a store to make your drive there and back equal to the carbon footprint of one item ordered online. If you took the bus, you’d need to buy eight items.

On this basis, supermarket deliveries to your home are particularly efficient, especially if the supermarket has managed to pick a route that minimises the distance travelled. In a welcome move, some retailers, such as Sainsbury’s, have started to encourage customers to pick a ‘green delivery slot’, where their drivers can combine several deliveries in one area.

Initial studies of the impact of online shopping seem to indicate that it is generally a more energy efficient mechanism, as it reduces the amount of passenger journeys. Most retailers will have a complex logistics operation that is designed to be as efficient as possible – they don’t want to spend more money on fuel than necessary after all.

UPS famously has a ‘no left-turn’ policy (or no right-turn in the UK) where their logistics software plans routes to minimise the amount of time their vehicles spend waiting to turn against the traffic. This reduces fuel waste, which, when spread across a large fleet of vehicles, makes for significant financial and emission savings.

Major logistics companies are also pioneering the use of new hybrid and zero emission technologies. Although there’s a high initial cost of switching over to an electric fleet, there are long-term benefits, such as lower fuel and maintenance costs.

A 2012 study into data from a German clothing retailer compared the emissions created by shoppers in stores, after surveying them on how they’d got there, to those created by the online division making trips between the company’s warehouse and customer’s houses. The results showed that at short distances (under 8.6 miles or 14 kilometres one way) the store shoppers were slightly more energy efficient but their emissions per transaction rose sharply the further away they lived, while the online shoppers’ emissions remained constant.

Put simply, if you shop locally then you create lower carbon emissions – particularly if you can walk to the store. If you live further away, then it’s better to shop online. The World Economic Forum 2009 report estimated that home delivery was around four times more efficient in carbon emissions terms, assuming that home delivery eliminated your travel emissions altogether.

But the online revolution isn’t all good news, despite the promise of those early surveys. Why? Partly because our shopping habits have changed. As the online world has opened up more opportunities, the UK has got used to buying more.

And we don’t always buy multiple items at once. In fact, the advent of internet shopping has encouraged us to buy single items, whenever we want them. Increased numbers of delivery vans clog up residential roads that were not designed for freight, reducing air quality, particularly in urban areas. Van traffic is growing faster on Britain’s roads than any other vehicle, and the RAC estimates that it will double by 2040.

We’ve also got used to using our bedrooms as changing rooms and returning large volumes of goods. Around 30% of online purchases are returned, compared with a return-rate of less than 9% from traditional stores. When you focus on fashion brands that return rate doubles – a BBC survey of 1,000 online shoppers found 63% had returned women’s clothing.

When you add up the impact of increased journeys from returned items and missed deliveries, internet shopping ceases to look like such an environmentally positive choice. For products that you need to try on, or sample before you buy, it can often be a better idea to travel to the store.

So, which is more energy efficient – online or high street shopping? The answer, as with so much in life, is, it depends. We’ve put together the following tips to help you reduce your carbon emissions when you shop.