Intro to AS/RS: Automated Storage and Retrieval Systems

What if your warehouse could do the heavy lifting for you—storing, picking, and moving inventory with minimal effort from your team? That’s the power of an Automated Storage and Retrieval System (AS/RS). They take care of the most repetitive, physically demanding tasks within warehouses—freeing up your staff to focus on more valuable work instead of spending hours walking the floor to locate ordered items.

Whether it’s retrieving products for order fulfillment or storing goods in high-density configurations, AS/RS replace manual effort with precision-driven automation. The result? Faster order processing, lower operating costs, and better use of space—all crucial for staying competitive.

All Automated Storage and Retrieval Systems (AS/RS) have a few things in common. They are enclosed systems designed to automatically store and retrieve goods with minimal manual intervention. Inside the system, equipment like robots, cranes, shuttles, or carousels moves items between storage racks and picking stations. Inventory enters through conveyors linked to inbound operations like receiving or repacking/decanting stations. Completed orders leave the system through conveyors connected to picking stations or outbound areas like packing, shipping, or staging zones for carrier pickup.

The entire system is managed by software that connects with the Warehouse Management System (WMS) to keep everything running smoothly and accurately.

There’s no one-size-fits-all when it comes to AS/RS. Depending on your inventory and operational needs, different types of AS/RS solutions can offer unique advantages:

• Mini-Load AS/RS: Mini-load systems use large cranes that run on rails in narrow aisles to store and retrieve lightweight items kept in totes, bins, or cartons within high-density racks. After picking an item, the crane places it onto a conveyor, which moves it to a picking station.
• Unit-Load AS/RS: Unit-load systems are similar to mini-loads but are designed to handle larger and heavier items, typically stored on pallets or in large containers. They use cranes or stacker cranes to move loads between storage locations and inbound or outbound stations, making them well-suited for bulk handling and long-term storage.
• Shuttle AS/RS: Shuttle systems use small, fast-moving shuttles that run horizontally along rails at each storage level to handle totes, trays, or cartons. A vertical lift is typically integrated to move items between levels, allowing access to multiple storage tiers. Shuttles transfer goods to conveyors or lifts, which then deliver them to picking or packing stations.
• Pallet Shuttle AS/RS: Pallet shuttle systems use powered shuttles that run on rails within racking structures to move pallets in and out of deep storage lanes. Vertical lifts may be integrated to move pallets between levels.
• Vertical Lift Modules (VLMs): VLMs are enclosed towers with inventory stored vertically on both sides of a central lift mechanism. Items are accessed via an operator window at the base as the lift retrieves the required item.
• Cube-Based AS/RS: In cube-based systems, storage bins are stacked in vertical columns within a grid structure. Robotic vehicles travel on top of the grid to access, retrieve, stack, and destack bins as needed. Retrieved bins are then delivered to picking stations located along the perimeter of the system.
• Mobile AS/RS: Mobile AS/RS use autonomous robots that can move in all directions throughout the system. These robots transport storage bins or cases between racks, picking and packing stations, and inbound or outbound areas.

Investing in an Automated Storage and Retrieval System (AS/RS) isn’t just about keeping up with industry trends—it’s about unlocking the full potential of your warehouse. By automating labor-intensive tasks, AS/RS solutions help businesses optimize operations, reduce costs, and stay competitive in today’s demanding market. Let’s explore the benefits that make AS/RS an essential tool for modern warehouses.

Increased Throughput and Efficiency

Speed is the lifeline of any fulfillment operation, and AS/RS deliver impressive gains in throughput. These systems drastically reduce processing times by automating tasks like inventory retrieval and order picking. Most AS/RS solutions can handle hundreds of small SKU picks per hour, simplifying workflows for industries like e-commerce and healthcare.

Additionally, AS/RS optimize picking routes, eliminating unnecessary movement. This leads to faster order processing and happier customers, especially in industries where same-day or next-day delivery is the standard.

Maximized Storage Capacity

Many warehouses hit a ceiling (literally) when it comes to capacity, yet an Automated Storage and Retrieval System (AS/RS) makes every cubic foot productive. By stacking inventory in 30-plus-foot racks and running robots through aisles too narrow for fork-trucks, AS/RS typically at least triples storage density versus conventional racking. That’s a straightforward win, but here’s what often gets overlooked:

Footprint reduction means you can postpone or avoid the high costs of urban rents or land purchases. That freed capital can be redirected to faster-payback initiatives. High-rise storage also provides vertical inventory buffering, giving you increased capacity without building new infrastructure. This allows you to hedge against demand spikes or supplier disruptions without bloating safety stock across the network.

Because AS/RS can fit into smaller sites—even within mezzanines—it opens the door to hyper-local fulfillment strategies. You can place automated nodes closer to customers, reducing last-mile delivery costs and improving service levels, which are often more impactful levers on your P&L than warehouse savings alone.

Finally, a smaller building envelope often brings long-term benefits like lower energy consumption and reduced property tax exposure. These aren’t always included in upfront ROI models, but over a 10-year horizon, they can add several points to your operating margin.

Cost Reduction

One of the most compelling reasons to adopt AS/RS is their ability to reduce costs across the board. Storing and retrieving goods is the most labor-intensive and expensive aspect of warehouse operations. Due to the physically demanding nature of the work, it’s also one of the hardest roles to staff.

By automating these tasks, AS/RS minimize reliance on manual labor, lowering hiring, training, and turnover costs. Automation also delivers near-perfect accuracy in picking and inventory management, significantly reducing errors and returns.

Improved Safety and Ergonomics

Workplace safety is a top priority in warehouses, and AS/RS are necessary to create a safer environment. By automating repetitive and physically demanding tasks—like heavy lifting and high-reach picking—these systems reduce the risk of workplace injuries.

AS/RS also eliminates the need for workers to walk long distances, search for items, or work near potentially dangerous equipment like forklifts. Instead, goods are brought directly to ergonomic workstations, allowing employees to stay in safe, comfortable positions while they work.

With fewer employees needed for tiring picking, labor can be shifted to more value-added roles like quality control or custom packaging. 

Automation excels in integration with warehouse management systems (WMS). Combining the precision of AS/RS with the intelligence of a WMS creates a fully optimized operation where inventory moves smoothly, orders are fulfilled accurately, and workflows are streamlined.

How AS/RS Works with WMS

A Warehouse Management System (WMS) and an AS/RS work hand-in-hand in automated warehouses. While the WMS manages inventory and high-level tasks, the AS/RS relies on its own software—usually called a Warehouse Control System (WCS)—to handle the real-time movement of goods.

Inbound: When goods arrive, the WMS records receipt data and updates inventory records. It communicates high-level directives, such as what the product is and that it needs to be stored, to the WCS. From there, the WCS, which directly interfaces with the AS/RS, takes over. It determines where items should be stored within the AS/RS and commands the system to move goods from receiving to those locations.

Storage: The WMS maintains a global inventory view and integrates with upstream systems like ERP and order management. However, it typically does not manage specific storage slotting within the AS/RS. That responsibility belongs to the WCS, which makes real-time decisions about storage locations, balancing load distribution, item accessibility, and throughput optimization to keep the system running efficiently.

Retrieval: When an order is initiated, the WMS identifies which items are needed and sends the request to the WCS. The WCS then orchestrates the AS/RS to retrieve those items and deliver them to ergonomic pick stations or packing areas. This approach eliminates unnecessary walking, improves safety, and accelerates fulfillment times.

In this integrated setup, the WMS handles the strategic layer—managing what needs to be done and why, while the WCS handles execution, controlling how and when tasks are carried out within the warehouse. The WCS is often the system directly driving the AS/RS, ensuring real-time coordination, system performance, and improved communication with the WMS. Together, they turn automation into a powerful competitive advantage.

Automated storage and retrieval systems (AS/RS) aren’t just for tech demos—they solve real problems in high-pressure environments. Take E.Leclerc Seclin, a busy drive-through grocery hub, where growing order volume and SKU complexity were straining operations.

Case Study: E.Leclerc Seclin Doubles Drive-Through Capacity Without Expanding Footprint

E.Leclerc processes nearly 1,000 curbside delivery orders at their grocery store in Seclin per day. Space was tight, and manual processes couldn’t keep up with demand. To fix this, the team installed the Exotec Skypod system inside their 6,000 m² warehouse.

What Changed:

• More Orders, Same Space: With 57 Skypod robots and 10 Workstations, the site doubled its order prep capacity—no additional square meters needed.
• Denser Storage: The system added 70,000 storage bins using vertical racking that 5x storage density. Instead of expanding out, they built up.
• Faster, Safer Picking: Robots retrieve bins and deliver them directly to workers. That cut out long walks and reduced the physical strain of manual picking.
• No More Staging Areas: Integrated buffering and sequencing meant bins arrived at the right time, in the right order, ready to pack and ship.

Julien Pirson, site director at Seclin, put it plainly: “We’ve completely changed the way we prepare orders. It’s faster, more accurate, and fits the space we have.” For grocery operations handling thousands of orders a day, this kind of system isn’t a nice-to-have—it’s the difference between keeping up and falling behind.

Explore More Success Stories
Want to see how AS/RS has helped other companies redefine their operations? Read our collection of case studies.

Selecting the right AS/RS for your warehouse starts with understanding the type of inventory you handle and how it moves through your operation.

• Each-handling AS/RS is ideal for operations that pick individual items (eaches), such as e-commerce, pharma, or retail fulfillment centers with high order volume and SKU variety. Inventory is first removed from its original packaging and placed into bins. These bins are then stored in the AS/RS. The system retrieves ordered goods and sends them to picking stations, where pickers build the custom orders.
• Case-handling AS/RS is best when you store and retrieve full cartons. Because goods are stored and retrieved in their original cartons, there’s no need to decant items into separate bins, reducing handling steps and speeding up operations. However, this approach offers less flexibility and customization compared to dedicated each-picking systems. In some cases, each picking can be done directly from these cartons if they are cut open and accessible. 
• Unit-load AS/RS is designed to handle full pallets or heavy bulk items. This type is ideal for manufacturing or industrial environments where fewer, larger movements are required.

Ultimately, the right AS/RS depends on your dominant handling unit—each case, or load—as well as your throughput demands and space constraints. Flexible systems like the Skypod system offer the advantage of supporting both each and case picking within a single solution, allowing operations to adapt quickly to shifting order profiles and customer needs.

For supply chain leaders, selecting an AS/RS shouldn’t just be about how much product a system can move. It’s about how much it can move within the space you actually have. The key is evaluating throughput per occupied square foot (TPOSF)—a metric that combines storage density, system throughput, and space efficiency into a single performance indicator. This approach allows you to objectively compare technologies like shuttle systems, cube-based AS/RS, and mobile AS/RS on an apples-to-apples basis.

Establishing Throughput Requirements

Start by defining your warehouse’s peak flow windows. Look beyond average volumes and map your inbound and outbound demand during peak hours and seasons. This includes pallets per hour, cases per hour, or order lines per hour. These figures help establish the minimum throughput your AS/RS must consistently handle without creating backlogs or delays. Simulate 95th-percentile demand using historical WMS data and seasonal surges to build an accurate baseline.

Calculating Storage Needs

Next, calculate your true storage requirement—including the total number of SKUs, expected max on-hand quantities, and any buffer for safety stock. Avoid oversizing the system by comparing your gross available cubic volume to actual usable cube that can be used for storing inventory. Many AS/RS technologies offer 85% or higher cube utilization vs traditional racking systems. 

Measuring Performance with TPOSF

Once you’ve established throughput and storage needs, assess the TPOSF for each system being considered. This is calculated by dividing the number of units the system can move per hour by its total physical footprint. This step is essential in environments where real estate is constrained or expensive, such as urban fulfillment centers. Be cautious of systems that require large mezzanines, oversized pick aisles, or dedicated staging space that diminishes overall performance density.

Matching SKU Characteristics to Storage Strategy

It’s also important to align SKU velocity and product characteristics with the right storage and picking methods—not everything belongs in the AS/RS. In many operations, it makes sense for high-velocity SKUs to be stored outside of the automated system and picked manually. These items move so frequently that the time and system resources spent retrieving them from automation can actually reduce overall efficiency. Keeping them in forward-pick areas allows for faster access and frees up the AS/RS to focus on medium and slow-movers where automation adds the most value.

Additionally, oversized or irregularly shaped items may not be suitable for AS/RS storage at all. If they don’t fit within standard totes, cartons, or pallet dimensions, they’re better handled through manual processes. Designing a hybrid storage strategy that segments inventory by velocity, size, and handling requirements ensures your AS/RS is used where it performs best, while maintaining speed, flexibility, and system longevity across your broader operation.

Planning for Scalability

Another factor often overlooked is future scalability. Your AS/RS should support at least 25–30% growth in both throughput and storage without requiring major facility changes. For instance, throughput and storage can be scaled incrementally and independently with mobile AS/RS like the Skypod system, with the ability to add robots within minutes, picking stations within a weekend, and storage racks within a few short weeks with minimal disruption to ongoing operations. In contrast, systems based on pallet cranes or shuttle aisles often require fixed infrastructure that limits flexibility unless prebuilt expansion zones are included.

Comparing Long-Term Costs

Finally, normalize your cost analysis. A high-density AS/RS might carry a higher upfront cost per square foot but deliver a lower cost per unit moved over time. Factor in labor savings, rent escalation, and throughput expansion when comparing ROI. Be sure to ask vendors to show this TPOSF metric at both Year 1 and projected Year 5 volumes.

Implementing an Automated Storage and Retrieval System (AS/RS) can revolutionize warehouse operations, but it’s not without challenges. Understanding these potential hurdles and planning accordingly ensures a smoother integration process.

Warehouse Layout Adjustments

When selecting an AS/RS, businesses should look for modular systems that can adapt to the existing layout of their facility without requiring major structural changes. For instance, mobile AS/RS offers the flexibility to fit into a wide range of environments, even those with irregular features. For example, if ceiling heights vary due to low-hanging obstacles or overhead utilities, storage rack heights can be adjusted accordingly to maximize available vertical space without requiring a uniform clear height.

The most modular systems can also be configured around fixed obstructions like support columns, and in some cases, can even operate across multiple rooms or zones within a facility. This level of adaptability makes it possible to deploy automation in complex or constrained environments, enabling businesses to increase efficiency and storage capacity without investing in major renovations.

System Compatibility

Integrating AS/RS with your Warehouse Management System (WMS) or Enterprise Resource Planning (ERP) software is critical for achieving full operational efficiency. However, ensuring compatibility between systems can be a challenge.

Solutions include:

• Leveraging middleware or integration platforms that act as a bridge between the AS/RS and your WMS/ERP, allowing for efficient data exchange without custom coding. These platforms translate commands, synchronize inventory data, and manage task workflows across systems.
• Selecting AS/RS providers with open API architecture makes connecting to existing WMS or ERP solutions easier. Open APIs allow for faster implementation, better data transparency, and easier updates down the road.
• Involving integration specialists early in the planning phase to map business processes, define data handoffs, and ensure the system is configured for real-time performance. A well-planned integration minimizes the risk of errors, latency, and operational bottlenecks.
• Conducting end-to-end testing in simulation environments to validate how the WMS, WCS (Warehouse Control System), and AS/RS interact under various scenarios, including peak loads, exception handling, and system downtime.

Employee Training and Upskilling

Successful AS/RS implementation requires more than just system deployment—it demands a workforce capable of operating, maintaining, and optimizing the technology. Training should go beyond basic usage to include skills like exception handling, system troubleshooting, and performance monitoring through HMIs and dashboards. Cross-training on manual and automated workflows builds flexibility during ramp-up and maintenance periods.

Automation also creates upward mobility, shifting roles from manual labor to tech-enabled positions like inventory control, system oversight, and data analysis. Clearly mapping out these career paths and providing structured upskilling programs helps reduce resistance, improve retention, and ensure long-term ROI. Investing in people is just as critical as investing in the technology itself.

If you’re looking to reduce energy use and optimize space, how you automate matters. Not all AS/RS are designed with sustainability in mind, but some features can make a real difference.

• Lightweight, Low-Energy Robotics: Think about how heavy the system’s moving parts are and how often they operate. Designing efficient travel paths helps reduce energy use throughout each shift.
• Regenerative Braking: Look for systems that use regenerative braking. Advanced robotic systems capture energy each time a robot slows down and feeds it back into the system. It’s a simple but effective feature that can significantly reduce energy waste over time.
• Smaller Facilities, Less Energy Use: Vertical racking reduces the need for sprawling footprints, which means fewer lights, less HVAC, and lower building energy requirements.

Not only do these features improve operational performance, but they can also help shrink the energy profile of your warehouse.

Fewer Materials, Less Waste

Compact automation systems also reduce the need for additional construction or excessive racking. When you can store more in less space, you use fewer materials and avoid building out unnecessarily. Precision automation also minimizes picking errors and damaged goods, so less goes to waste.

Aligning with Green Logistics Goals

Efficient systems reduce idle travel and simplify fulfillment paths, helping you burn fewer emissions inside the warehouse and during last-mile prep. For operations working toward ESG goals or net-zero targets, choosing automation that supports these workflows is a practical step in the right direction.

Bottom line: You don’t need to sacrifice performance to make better environmental choices—you just need automation that’s built smarter from the start.

Automated Storage and Retrieval Systems (AS/RS) are no longer just a futuristic concept—they’re a practical, proven solution for warehouses aiming to improve efficiency, accuracy, and adaptability. Whether you’re scaling operations, optimizing space, or addressing labor challenges, AS/RS offer the flexibility and performance modern supply chains demand. With the right strategy and system design, automation can become a long-term advantage that grows with your business.

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