Air Transport Material Delivery

^{Created by S.J.S., BFH, on 20.06.2024}

Solar systems in alpine regions offer unique advantages over other installation regions. The intense solar radiation leads to improved utilisation of the output capacities and the remote location minimises shading factors. Modern installation techniques enable minimal disruption of the surrounding flora and fauna to the benefit of the latter, as well as a number of other positive aspects.

However, the remote location also has its obstacles. For instance, the transport of building materials and of the fragile solar modules in particular is very difficult.
Well-known transport methods include large and small lorries, temporary cable cars and specialised off-road vehicles. In addition to these, air transport as a form of short to medium distance cargo transport should not be neglected. Where helicopters are usually used nowadays, the option of transport by cargo drone is becoming increasingly interesting.

To provide an overview of the feasibility and suitability of these two methods of air transportation, this article will briefly explain how these methods work and provide a succinct overview table of relevant factors. In a fictitious transport example, the methods will be compared to transport via lorry.

Air Transport Options

Air transport provides a dynamic and individualised cargo transport solution for moving building materials and modules from a centralised loading site to an installation site or the final module field. Long distance cargo transport by helicopter or drone is as of yet not feasible. This is due to significant cost, lack of availability, air space restrictions, further authorisation processes along with other reasons.
The different use cases for separate modes of transportation require a differentiated approach in gauging the benefit and efficiency of each option at their current state of development and availability.

Helicopter

Cargo Transport via Helicopter most often involves hanging the cargo from wires on a cargo hook below the helicopter body. The helicopter model, the surrounding terrain and the weather conditions influence how the cargo is packaged. This could mean transporting a full pallet of modules at once, exactly like they were packaged by the manufacturer. Moving pre-built module tables with the modules already mounted or moving the individual modules in smaller groups are other options.

Helicopters are often used just for transport but they can also be used in aiding installation in rough terrain. This might be the case when there is not enough space to safely store the modules around the installation site prior to installing them, as the helicopter does not need to be able to land to unload the cargo.
One option for helicopter installation is transporting individual modules to be installed one by one directly from the transport wire. Another opton would be the previously mentioned installation of pre-built module tables with the modules already mounted.

One limiting factor for the use of helicopters is nonetheless the space needed. A landing space close to the work area is likely required. The best case scenario would be a landing space right where the material will be loaded. The installation site also cannot be too close to certain wildlife habitats, as to not disturb the resident fauna. Moreover, the cargo unloading point cannot be too close to a rock face since the rotors need room to spin.

Drone

Similar to transport via helicopter, drones often utilise cargo hooks positioned on the underside of the drone body. Some drones do also offer cargo containers. But as of yet there is no information regarding a cargo container with sufficient dimensions to hold a solar panel.

To affix the modules to the cargo hook, they are bundled in small groups (roughly 1-5 modules, depending on size, weight, weather conditions etc.) and placed inside a cargo net or tarpaulin. The bundle is then attached to the hook with wires, akin to how one would attach cargo to a helicopter.

A considerable difference from cargo drones to helicopters are the substantially smaller dimensions, resulting in the drone also needing far less room to operate. This simplifies certain manoeuvres and makes drones noticably more agile. Seeing as the drone is operated remotely, an added requirement is that the installation site as well as the loading site have to both be visible to the remote drone operator, affecting the workable transport distances.

Air Transport Comparison Table

* dependent on helicopter type and total weight (mass inertia ➝‬ heavier = more stable)

All information is non-binding and for illustrative purposes only.

Transport Example

To illustrate the real life application of these different transport methods, a fictitious example was developed. Keep in mind that comparing air transport to transport by lorry seldom makes sense in real life, as air transport only becomes relevant when traditional methods cannot be utilised. This example is simply meant to illustrate the differences in costs and duration for alpine projects relative to conventional PV projects.

In this example, the modules are transported directly to the module field to be installed on the module tables, for all three transport options. In reality there is also often the case of having an installation site separate from the module field where either individual parts of the final installation or complete module tables are assembled to then be transported to the module field.

The air-line distance of 5km was chosen as this is a realistic distance for both methods of air transportation. Keep in mind that both of these options will still require the use of some other form of traditional cargo transport from the module and material suppliers to the loading site, as air transport is only suitable for short to medium distances.

* one rotation is one flight from loading site to module field and back

** plus flyover flat rate (dependent on distance from home base to operation area), ~5% CO2/fuel surcharge, ~8.1% VAT

All information is non-binding and for illustrative purposes only.