Excel works... until it doesn't
Interview with Denise Lelle, Business Development, OPTANO GmbH
Excel is an indispensable part of the daily work of many companies. Over the years, it has become the central tool for planning, analysis, and decision support. It is flexible, available, and a matter of course for many.
Denise Lelle is a Business Development Manager at OPTANO and deals daily with the question of how companies can better structure and make more informed complex planning and decision-making processes.
At the same time, the requirements for planning have fundamentally changed. Markets have become more dynamic, interdependencies more complex, and decisions more interconnected. What could once be viewed in isolation must now be understood in its overall context.
This raises a crucial question: When does a tool that has worked well for a long time become the limiting factor itself? In the interview, we speak with her about why Excel hits structural limits in many cases, how companies can recognize this, and what it means to rethink planning.
Excel is deeply embedded in planning processes in many companies. What makes it so difficult to break away from it?
Excel is so deeply entrenched primarily because it is extremely accessible. Most people come into contact with it early on – in school, university, or vocational training. It is available everywhere, ready to use immediately, and works without major IT dependency. This is a tremendous advantage, especially in specialized fields. You can get started quickly, build your own solutions, and work independently.
Over the years, this results in highly individual systems. Many of these Excel solutions contain an impressive amount of experience, logic, and detailed knowledge. And that's precisely what makes it so difficult to break away from them. Because as long as something *feels* like it's working, there's no acute pressure for change, even when there are objectively better ways.
You just mentioned „it feels like it's working.“ What exactly do you mean by that?
A plan that looks plausible is not automatically a good plan. That's precisely the problem. Excel provides results, but it doesn't provide certainty about whether they are truly optimal. In complex systems, there are almost always better alternatives that simply remain invisible in the existing approach.
„Excel works, but not for today's reality.“
Excel is so popular precisely because of its flexibility. Is this flexibility sufficient when planning requirements increase?
Accessibility and flexibility are Excel's greatest strengths. Initially, they help in quickly building solutions and accommodating diverse requirements. However, as complexity increases, merely representing things is no longer sufficient. Understanding relationships and systematically deriving decisions becomes crucial.
A simple picture: You can also complete a triathlon with regular sneakers and an old bicycle. You might even reach the finish line... but it's highly unlikely to be a personal best.
This is exactly how it is in planning. With every additional variable and every new dependency, it becomes more difficult to keep track. Flexibility remains, but it doesn't replace structure. And it's precisely at this point that it becomes clear: Excel can do a lot, but it's not made for complex planning problems.
The planning environment, particularly in industries like chemicals and pharmaceuticals, has changed significantly in recent years. From your perspective, what are the most important drivers behind this?
I would say the biggest difference is that planning has become significantly more dynamic today. In the past, many processes were more stable and predictable. Today, we have more uncertainties in the market, stronger cost pressure, and at the same time, much greater demand volatility. Additionally, overall complexity is increasing. Portfolios are broader, networks are changing, and significantly more data is available than before. On one hand, this is an opportunity, but it also makes planning more challenging.
Of course, regulation plays a role in these industries, especially because it restricts flexibility. For example, you can't just move a product to another location.
But from my perspective, it's not the real driver of the challenges we see today. What has really changed is the demand on planning. It's no longer enough to create a stable plan. Companies today need to compare scenarios, better assess risks, and identify potential.
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Many planning decisions are closely intertwined – capacities, materials, costs. Why does this quickly become a problem in Excel?
Planning systems are highly interconnected. A single decision simultaneously affects many other areas. For example, if a production quantity changes, it impacts capacities, raw material requirements, campaign planning, and costs at the same time. If a raw material is missing, it affects multiple plants, products, and customers simultaneously.
These interactions happen in parallel. However, Excel forces us into a linear logic. Interdependencies are mapped out step-by-step – and this is precisely how crucial interactions are lost.
This leads to decisions being made in isolation. The consequences are often only visible later. In the end, local optimization is achieved, but not an optimized overall system. This can make a big difference in terms of a company's efficiency.
„The real problem isn't Excel, but how we make decisions.“
Many professionals have developed a very fine intuition for their processes and planning over the years – that's real capital. What happens when this implicit knowledge is suddenly transferred into a model? Do planners ultimately make themselves redundant?
In practice, the exact opposite is happening. Many experts are heavily burdened with operational tasks today. A large portion of their time is spent on data preparation and model maintenance. A solution that alleviates this burden primarily creates one thing: free space.
The existing knowledge is not lost; it is structured and made scalable. Experience actively flows into models, making it usable for the entire company.
At the same time, the role of planners is changing. Less manual calculation, more evaluation, control, and strategic positioning. The system merely provides mathematically sound decision support. Planners become decision architects. And therein lies the real added value.
Is there a typical moment when companies realize they can't get any further with Excel?
In my experience, this typical „aha moment“ is rare, but there are clear signals. A common sign is when results are no longer plausible or understandable. Or when there is uncertainty about whether the underlying data is even correct. The large number of coordination loops is also an indicator. If more time is spent discussing numbers than making decisions, something is fundamentally wrong.
Sometimes it becomes noticeably practical too: models suddenly work slowly or become unstable. These are all small indicators, but at the latest when different scenarios are evaluated and different side conditions are to be incorporated into the model, it becomes clear: this approach no longer scales.
„Complexity cannot be modeled away – only better understood.“
When Excel reaches these limits, what does an optimization-based approach, like the one OPTANO offers, fundamentally do differently?
The key difference is that decisions are no longer made in isolation but within the overall system. An optimization-based approach considers capacities, materials, costs, and restrictions simultaneously. Goal conflicts are no longer weighed manually but resolved systematically.
This changes the quality of the decisions. Instead of approximations, it leads to robust, transparent solutions that consider the overall system. This is particularly relevant for what-if scenarios. Different options can be quickly compared regarding their impact on the entire system. This not only makes planning more efficient but, above all, significantly more well-founded.
So, has Excel become obsolete for planning, or will it continue to play a role?
Excel will not disappear, nor should it. It is a good tool for many tasks: data preparation, smaller analyses, or as a supporting frontend.
The crucial question isn't whether Excel is used, but for what. As soon as it comes to complex, dynamic, and interconnected planning tasks, Excel reaches clear limits. Then, solutions specifically developed for these requirements are needed.
In the future, Excel will therefore play a supportive role but should no longer be the central planning tool. Then, solutions that were specifically developed for this purpose and consider the relationships within the overall system will be needed.
Thank you for the conversation and your perspective on how planning must change in an increasingly complex world.