In the conventional sense, the term 'cascade' refers to a natural or artificial waterfall that runs over steps or ledges – etymologically, the term comes from the italian word cascare (to fall).

In line with this word origin, cascade use in the context of resource use is a method of utilising resources or products made from these resources in a sequence of steps, each with reduced requirements for the raw material or product properties, for as long, as often and as efficiently as possible and only then transferring them to energy use when material use is no longer possible. This involves going through various utilisation cascades, which are arranged from higher to lower levels of value creation. In this way, the aim is to keep the resources or the derived products in the system for as long as possible so that the overall level of value creation can be increased. The concept of cascade use is particularly widespread in relation to the biomass raw material wood, but also to wastewater.

Cascade use is sometimes also referred to as multiple use or multi-stage use: In the case of biomass and resources, there is generally often competition between material and energy use, as the high demand for resources is offset by a limited supply of resources. The strategy of cascade use involves multiple material use with decreasing value creation: biomass should be used as a material for as long or as much as possible over several cascade levels before being used as an energy source. Only at the end of the cascade, when material use is no longer possible, the resource is used for energetic purposes by converting it into bioenergy. This process is intended to create a link between the material sector and energy sectors, which otherwise often compete with each other.

This utilisation strategy should bring ecological and economic benefits through more efficient use of resources and represent a sustainable approach. Against the background of for land use competition, the strategy of cascade use is intended to achieve an increase in resource efficiency and thus optimise the use of limited land and correspondingly limited resources. The extension of value chains and increase in raw material productivity achieved through cascade use is intended to conserve the limited primary resource overall.

The cascade utilisation approach must be separated from two different processes or strategies:

Firstly, a differentiation must be made between cascade utilisation and coupled utilisation. The strategy of co-utilisation can take place along two strands: The first strand is the parallel, coupled generation of products (material utilisation) and energy (energy utilisation) from biomass. This means that the process waste generated during the processing of a raw material into a product is directly channelled into energy use. In the context of the second strand of co-utilisation, the 'residues' resulting from the use and processing of a main raw material are not regarded as process waste, but again as new by-products. These by-products are declared to be a new main raw material, which is then used for material purposes, possibly via several cascade stages. An example of this second strand is the processing of grain: In the food and animal feed industry, grain, i.e. the grain itself, is regarded as the main raw material and resource. In terms of this second strand of co-utilisation, however, the straw produced during the grain harvest, which is actually a 'waste product', is regarded as a new main raw material in its own right and is used as a material in the construction sector for insulation, for instance.

Cascade use must also be distinguished from the circular economy. The strategy of cascade use itself is not a true circular economy in the strict sense, as the movement of the process chain of resource utilisation is not entirely circular, but rather takes place in stages from a higher level to a lower final utilisation, i.e. energy use; however, it can be seen as an element of a broad circular economy. In general cascade use can be regarded as an intermediate form between the linear economy (waste management, in which there is a short and linear process chain of resource utilisation from biomass to product and finally to landfill or incineration without direct and consistent recycling) and the circular economy.

As with cascade use, co-utilisation and the circular economy are intended to achieve both economic and ecological benefits and reduce land use competition, as the potential of limited resources is utilised as long and efficiently as possible.