Solar photovoltaic systems are valued for their capacity to produce energy with a free input, sunlight, while producing no greenhouse gas emissions during operation. However, there is another overlooked benefit that has helped the technology succeed: the modular design of photovoltaic panels.
Regardless of how big or small a solar power system is, its basic building blocks are the same: photovoltaic panels. For example, assume a 300-watt module is being used:
Other electricity generation systems do not have this kind of flexibility. For example, megawatt-scale wind turbines offer a very low kWh cost, even lower than that of solar power in some cases. However, the cost per kW of installed generation capacity increases dramatically as the scale of wind turbines is reduced.
Conventional power plants fired by coal are affected more dramatically by economies of scale, and their cost would be prohibitive if reduced to a residential scale. Their dependence on coal as an input is also a limitation, since it would have to be delivered individually. On the other hand, sunlight is delivered for free to anyone with a rooftop.
Commercial solar power systems offer a design flexibility that allows the optimal capacity for each building. The electricity consumption profile of a building can be measured, along with the available solar radiation and rooftop area, to specify the total kW capacity that works best. Keep in mind that overproduction is not always practical, since Australian feed-in tariffs are low compared with retail kWh prices.
The modular design of solar power systems also means that the array can adapt to almost any rooftop shape, as long as the underlying structure is suitable for the weight of photovoltaic panels. It is only important to avoid installing solar panels under concentrated shadows, since they are highly detrimental for energy production.
Batteries are very promising as a complement for solar power, since they also offer scale flexibility. Just like a normal commercial solar array, a combined photovoltaic and energy storage system can be sized to match the unique consumption profile of each home or business.
Another advantage of modular installations such as commercial solar power systems is that capacity must not necessarily be concentrated in the same place. Using information technologies, it is possible to manage many generation and storage systems across multiple homes and businesses like a single system. This concept is called a virtual power plant, and it offers enhanced efficiency because generation is located at the point of use, minimising energy transmission losses. Instead of delivering all the energy produced, the network only handles energy that is not consumed where it is generated.