The low-hanging fruit has not yet all been picked when it comes to energy savings in Dutch industry. The energy-guzzling giants, such as Tata Steel or Akzo Nobel, may lead the way when it comes to efficient consumption, but there is still a world to be gained from small and medium-sized companies. This is demonstrated in practice by Pepsico's Lay's chips factory in Broek op Langedijk.
Upon entering the hall of Pepsico's North Holland chip factory, large cubes hang from the ceiling about water, energy and climate. About 250 people work there, and a million bags of chips roll off the production line every day.
It is not self-evident for a factory to save on energy, says Dave van Braak. He is sustainability and facilities manager at the North Holland Lay's factory. “Gas and electricity prices have only fallen, which is little incentive to save.”
Laws of environmental Conservation
Companies such as Akzo Nobel, DSM and Tata Steel have been working towards energy efficiency for years, but the industry as a whole is slow to make progress when it comes to energy efficiency. Although the Environmental Management Act stipulates that all measures with a payback period of less than five years must be taken, research shows that in practice only measures with a payback period of two years or less are implemented.
So why does Pepsico do it? “As a company we want to take responsibility,” says Van Braak. He mentions the Environmental Management Act. “We do our best to find those projects within the company.”
Pepsico is therefore ahead of other companies. Entrepreneurs do not lack the will to become more sustainable, but they do lack time and knowledge, says Margreet van Gastel, ambassador for Energy Challenges 2020 at the Ministry of Economic Affairs. Management is consumed by current affairs and has little time to delve into energy efficiency. As a result, opportunities are missed. Van Gastel gives the example of pipe insulation, which often has a payback period of several months. “But do entrepreneurs know that?”
Compressed air
Van Braak came up with the idea of looking at the use of compressed air in the factory. Each kW of compressed air costs 7 kW of electricity to produce. Reuse of compressed air is an existing technology with a short payback period, stated the Berenschot report on transition paths to electrification in chemistry. Energy savings can already be achieved there, just like in the efficient use of compressed air and the proper adjustment of the process.
Pepsico, like many other companies, uses compressed air or compressed air to control all kinds of processes: to open and close valves in machines, to blow clean the pipe network, to remove "bad chips" and ditto potatoes from the flow on the current blow tire. This air is guided through the factory via a pipe network that is continuously under pressure.
Energy-guzzling monster
Specialist Geveke Compressed Air Technology redesigned the system, and the Lay's chip factory now saves 60% on electricity consumption.
“You build a factory, the company grows, you add something and tie it together. Before you know it, you have built an energy-guzzling monster,” says Pascal van Putten, owner of VPInstruments, which supplied the measuring equipment for Pepsico's North Holland factory. “But if the production process is running well, no one wants to touch it.”
The people at Pepsico dared to do it. First, the entire system was checked for leaks and bottlenecks. “Some couplings were attached with a tie-wrap,” says Van Braak. “That's leaking.”
The pressure in the pipe network was then slowly reduced from 7 bar to 5.3 bar. Each bar less resulted in 15% less leakage in the system, and 7% less power consumption. Instead of keeping the entire system at the highest required pressure, small ones were used boosters placed in places where higher pressure was required.
Result
The result: instead of four compressors with a total capacity of 315 kW, of which 250 kW was used, Pepsico now has an installed capacity of 275 kW, of which a maximum of 140 kW is in use simultaneously. That means a saving of 50%. At night and on weekends, the system runs on a 15 kW compressor, for example to keep the water purification going. It may not stop, but many other processes do stop. “That saves 2,000 hours on the large compressor,” says Van Braak, and that saves an additional 10 percentage points, bringing the total energy savings to 60%.
Geveke made energy savings possible by integrating a flow pressure regulator, a compressor management system and an online energy monitoring system that complies with ISO standards. The factory in Broek op Langedijk is Pepsico's most energy-efficient factory in Europe.
The factory also burns biogas from its own water treatment plant to keep the ovens at the right temperature. That accounts for 3% of energy consumption during baking. Low-grade heat is recovered from the cooking fumes released during frying, which is used to heat the buildings and to a small extent in the process. However, the majority of the oven heat dissipates through the chimney. Pepsico is looking for a better destination for the residual heat.
Payback period
“You have to look at the life cycle costs and challenge people accordingly,” says sustainability manager Van Braak. “Then it is a little more expensive to purchase, but you earn that back.” The investments in compressed air efficiency even paid for themselves within a year.
The sustainability manager would like to do more, but sometimes an adjustment in a factory elsewhere in Europe yields more environmental benefit per euro invested, so the parent company then makes a different choice. Van Braak: “But I have some great plans that are definitely interesting, especially if energy prices go up.”
The article was written by Energeia, www.energeia.nl. Published 2017, May 3.
Nederlands