Around one-third of all food produced in the world ends up as waste or is lost along the food chain, the United Nations Food and Agriculture Organisation (FAO) estimates. The financial impact of this wastage is high, with the global cost estimated to be around $600 billion a year. There is also an environmental price to pay, with the FAO estimating that the global carbon footprint of food waste, excluding land use change, is 3.3 billion tonnes of CO2e, equivalent to around 7% of global greenhouse gas emissions.
However, it is not all doom and gloom. If action is taken through food waste reductions, by 2030 global greenhouse gas emissions could be lowered by at least 0.2 billion tonnes and possibly as much as 1 billion tonnes CO2e per year, the UK charity Waste & Resources Action Programme (Wrap) estimates.
And perhaps one of the most promising findings from Wrap is that many of the actions needed to reduce food waste by businesses rely on low-cost solutions such as “changes to processes, procedures and interactions between organisations”.
Low-cost manufacturing solutions
Andrew Griffiths, sustainability manager at Nestlé, says the company uses a waste hierarchy to manage reduction. The hierarchy starts off with the most desirable approach – preventing or eliminating waste by optimising existing process technologies and production lines – and ends with the least desirable: disposal of waste.
In 2012, Nestlé publicly committed to send zero waste from all its UK factories to disposal, and full recovery of unavoidable by-products, by 2015. Nestlé UK sites achieved this target two years ahead of schedule. The company is now looking at further goals. “Following this, we’re looking more broadly at Nestlé Waters, and our EU factories in terms of achieving the zero waste to landfill by 2020,” says Griffiths.
Achieving the zero waste goal requires a site-by-site analysis rather than a one-size-fits-all approach. For example, at Nestlé’s Tutbury site in Staffordshire, new systems and training were put in place, with an area dedicated to each of the factory’s 16 waste streams so that the materials could be carefully observed and segregated. Contractor waste is managed in the same way, to maintain consistency. Investment in balers has made the handling and management of packaging waste easier, and reduced both the space needed at the factory and the transport footprint.
Griffiths says that reducing waste doesn’t necessarily involve sophisticated technology. “Segregation of by-products is key to optimising their reuse, and their subsequent value as well. The technology solution is relatively low-tech but very effective. Sometimes we get blinded by high-tech solutions, but when it comes to waste the low-tech is usually the best.”
Where possible, Nestlé sends its by-products back into the human or animal food chain. It also redistributes surplus, fit-for-consumption food from the food and food-service industry to charities, such as FareShare in the UK. Another of the company’s key goals is training its employees on waste management and food waste at work and home, adds Griffiths.
Technology intervention
For waste that can’t be reused or redistributed, the next step on the waste hierarchy is recycling. This approach has been taken at Nestlé’s Rowntree factory in Newcastle, with the installation of an anaerobic digester. A year on from its official launch, the anaerobic digester at the Fawdon factory has the capacity to convert four tonnes of solid waste and 200,000 litres of liquid waste into renewable energy and clean water each day. The biogas created from the process fuels a combined heat and power engine, which can produce 200kW of electricity, and is projected to meet 8% of the site’s energy needs.
In addition, greenhouse gas emissions at the factory have also improved, projected to fall by around 10% as a result of the heat and power generated from the biogas produced at the Fawdon site.
However, this is just one site, and Nestlé is a vast and sprawling food manufacturer with factories spanning the globe. So how does it ensure its food waste is cut at all its sites around the world and across its vast supply chain? “From a technology perspective, it is about continuing to build the infrastructure – and this is not just Nestlé – to help manage those opportunities and develop the circular economy,” says Griffiths.
He points to a recent example of Nestlé reviewing the milk infrastructure in Pakistan, where it found high levels of milk were being wasted in the supply chain, particularly during transport to its factory in Renala. “We worked with the guys over there to invest in the infrastructure itself, and provided secure and refrigerated vehicles to reduce the waste in the value chain as a whole,” he says. The move led to a halving of milk losses between the cooling facilities and the factory in Renala, according to Nestlé’s latest Global Creating Shared Value report.
Cold-chain value
Better refrigeration equipment could eliminate 25% of food waste in the developing world, the IMechE estimated in 2014. Dr Tim Fox, global ambassador for clean-cold technology firm Dearman, is a strong advocate for improving the refrigeration of food and the development of a robust global cold chain: linking cold stores, pre-coolers and transport units to get food to market.
“Within the developed world, we tend to take the cold chain for granted,” says Fox. “It is critical in reducing waste, getting the nutritional value in the food to the consumer, ensuring that the food is safe, and ensuring that the producer at the beginning of the supply chain can realise the maximum return on investment.”
However, in both developed and developing economies, there are difficulties in creating a robust cold chain.
For developing economies, much of the challenge is the need for greater investment in infrastructure. In India, to meet demand, $15 billion would need to be invested in the cold chain between 2013 and 2018, the country’s National Centre for Cold-chain Development (NCCD) has estimated.
For developed economies, the problem is increasing the energy efficiency of the refrigerator systems and reducing the polluting nature of the food supply chain. The auxiliary engines that run on typical transport refrigeration units on trucks can produce a significant amount of NOx and particle emissions, says Fox – up to 29 times as much particle matter and six times as much NOx as the modern diesel engines powering the vehicle itself. “By 2025, we expect the global refrigerated truck fleet to have grown from the current 2.1 million to upwards of 15.5 million. If all that growth is based on diesel transport refrigeration units, then the potential for damage to air quality, and rise in greenhouse gas emissions, is enormous.”
Dearman is tackling this challenge by producing a zero-emissions transport refrigeration unit for lorries and trucks. The unit replaces the diesel-fuelled, highly polluting auxiliary engine with a system that is based on the use of liquid nitrogen to produce both power and cooling for the truck and its refrigeration systems.
A tank located under the vehicle stores liquid nitrogen at 3bar (300kPa), which is then pumped to 40bar and transferred to a vaporising heat exchanger, where it provides cooling for the chilled compartment. Because the liquid nitrogen is so cold – starting off at -196ºC – the food in the container effectively acts as a heat source to vaporise the liquid nitrogen in the heat exchanger. “Approximately two-thirds of the total cooling supplied comes from this source” says Fox.
The liquid nitrogen is then fed to the Dearman engine, where after being combined with heat exchange fluid it expands the gas quasi-isothermically – still at very low temperatures – producing shaft power. This power is then used to support ancillary systems, such as feed pumps, an alternator and fans for air circulation. “When the food truck is dropping off a delivery it doesn’t need to keep the diesel engine on to run its ancillary systems, which leads to much reduced emissions, improved air quality and reduced noise when delivering,” he says.
The process will also drive the compressor of a vapour compression refrigeration cycle that provides additional cooling, with one-third of the total cooling supplied coming from this source.
The heat exchange fluid is then reclaimed and used to harvest heat from the condenser of the refrigeration cycle, which has the advantage of roughly doubling its efficiency.
The heat exchange fluid is then reused in the engine, and the only emission released back to the atmosphere is air or nitrogen.
As well as significantly reducing NOx and particulate emissions, Dearman’s transport refrigeration system results in “substantial well-to-wheel CO2 savings”, says the company. Operation savings are expected to be between £1,000 and £4,000 a year compared with a standard diesel system, and payback is likely to be in less than one year.
The transport refrigeration system will enter its first real-world commercial field trial later this year. European trials are expected to start in 2016, followed by manufacture and commercial availability in 2017.
Developing economies
If emerging economies had the same cold-
chain provision as the developed world, 200 million tonnes of food that would otherwise perish as food loss could be preserved, the International Institute of Refrigeration estimates. However, the burgeoning middle classes in developing countries means the predicted growth of food truck fleets in developing economies is going to be “absolutely enormous” in the coming decades, says Fox. “We expect an additional 3 billion middle class in the next five years in Asia, leading to greater demand for chilled and frozen food products, and that creates demand for refrigerated trucks.”
Dearman hopes its own transport refrigeration systems will help to improve cold-chain infrastructure in such regions, and will allow developing economies to leapfrog over the dirty, auxiliary diesel-powered refrigeration units that are used around the world.
“The Dearman refrigeration unit for transport delivers because it is a commercially viable, competitive unit with a very low operating cost that is robust and relatively easy to manufacture – the last two points in particular are key when looking at developing economies,” says Fox.
The company plans on taking into developing countries not only the technology but also its own manufacturing knowhow and process capability, to help develop business models to enable local manufacturing and commercialisation of the product. “We have to provide assistance to enable those who wish to access the technology to access it.”
The process has seen Dearman working internationally with governments to help identify opportunities in countries such as Malaysia, Singapore and China. The company has also been working closely with the Indian government and the NCCD there, to look at how to bring its technology into the country.
Global collaboration
Tackling the issue of food waste will take effort by governments, organisations and business, as well as a shift in behaviour on an individual level. Significant reductions are achievable, however, if the private and public sector collaborate. As Wrap says in its report, Strategies to Achieve Economic and Environmental Gains by Reducing Food Waste, “Investments of time and money will be required, but the potential economic and environmental benefits are huge, and the consequences of not taking sufficient action are serious – for billions of individuals and countries.”