## Multispecies Swarm Electrification for Rural Areas of the Developing World
Even if the business model is chosen by the investor--usually a pay-as-you-go implementation--there is still the difficult decision to make on whether to go for a microgrid or solar home systems. Swarm behavior is a collective behavior exhibited by entities, particularly animals, of similar size which aggregate together, perhaps milling about the same spot or perhaps moving en masse or migrating in some direction [10]. In biology, during the past years, research is taking place in multispecies swarms. It has been observed that microorganisms use collective migration to cross barriers and reach new habitats, and the ability to form motile swarms, a fact which presents a competitive advantage. Microorganisms can facilitate other species' dispersal by forming multispecies swarms, with mutual benefits creating, in essence, a moving ecosystem [11]. Taking inspiration from this, we envision a Multispecies Swarm Electrification approach that is able to meet the real-world needs of the developing world in terms of electrification (see Figure 1). In detail, three types of solar home systems (species) can be used on their own or interconnected independently to provide higher power/energy for dispersed loads. At the same time, they can be interconnected in a low voltage AC microgrid in the cases it makes economic sense to invest in grid infrastructure. The core concept of swarm electrification in a rural electrification context is based on the use of a solar home system technology, where each solar home system implementation is able _\"out of the box\"_ to be interconnected with more thus forming, in the end, a low-voltage microgrid, without the use of any extra power electronics equipment. This is an ideal solution for rural and remote areas where high dispersion of households and loads is observed. Swarm electrification can allow the deployment of a single technology system in a given area, where some of the solar home systems that are closer together are interconnected from the start to form a microgrid and the rest have the ability  
Figure 1: Multispecies Swarm Electrification Ecosystem. to be interconnected to the microgrid in the future when more loads/households appear, making the investment in a microgrid extension viable. Swarm electrification was first proposed for microgrids in the developed world as a more advanced microgrid approach where interconnections with the existing grid would be easier and it would provide more freedom to the people to build their own communities. In particular, in Germany, there were lots of groups from the beginning of the 2000s that wanted more autonomy in relation to their electrification from the main grid. In this fashion microgrids was their technology of choice. In 2009 there was a paper where swarm grids were first mentioned. It was a paper presenting research results from a German power company (LichtBlack) using also technology by Volkswagen [12]. This is now commercialized [13]. A research group (now called Microenergy systems research group) from the Technical University Berlin was the first to start investigating swarm electrification for the developing world. Their research started in the beginning of the 10s. Some of the initial researchers have now formed Micro Energy International which includes a research think tank, a consulting company, a research laboratory, and a spin-off company from the university that is selling such systems in Bangladesh. Their technology is solely direct current (DC) based. Most research papers published by this group focus mostly on investigating the socioeconomic impacts in relation to the technology and not the actual technology [14; 15; 16; 17]. The DC approach used is indeed fitting to the realities of South-East Asia where large urban and peri-urban populations who, due to their poverty, cannot connect with a grid but can buy solar home systems. Due to the dispersed nature of most populations in rural sub-Saharan Africa, this approach is not applicable.