What Is the Difference Between Active and Passive Solar Energy?

Most people are aware of the positive impacts of solar energy, which is understandable given its increasing popularity and use around the world. In the right conditions, solar energy is able to provide power to regions that are deprived of electricity, allowing them to lead a high-quality lifestyle.

While the importance of solar energy cannot be disputed, it still remains a mystery to many exactly what the difference is between active and passive solar energy. This article will explore this distinction in more detail, as well as identify where you can find the best sources of both types of solar energy.

What Is the Difference Between Active and Passive Solar Energy?

As the name would suggest, active solar energy is generally considered to be those systems that are manually controlled. This could mean that you have a panel that converts the sun’s energy directly into electricity, or it could mean that you have a series of solar-powered devices (such as solar photovoltaic panels) that work in conjunction with one another to generate electricity.

In any case, a panel-based system that is actively generating power is considered to be a form of active solar energy. By contrast, passive solar energy does not require as much direct intervention from human occupants, allowing the owners of these homes to leave their dwellings and do other things without worrying about whether or not their energy needs are being met.

Passive Solar Energy

Passive solar energy can be used to heat water for domestic use, provide electricity to areas that are disconnected from the electricity grid, or even generate a small amount of electricity that can be stored and later used when needed. While many people are familiar with the concept of passive solar energy, it is still worth distinguishing between it and other varietals of solar energy as the distinctions can be somewhat nuanced.

Passive solar energy is defined as “solar energy that is directly extracted from the environment instead of being generated by electric generation facilities or other energy-consuming devices”. This should not be confused with what are known as free-standing solar thermal power plants, which are designed to capture the heat that the sun shines upon them.

Let’s examine each of these distinctions.

Manually Controlled

As mentioned above, one of the defining characteristics of active solar energy is its direct human intervention. It is essential that the individual(s) controlling the system (typically known as “solar panelists”) are directly mindful of the tasks required to optimize their output (generating as much electricity as possible given the conditions).

In general, the more directly the solar energy system can be tied to human activity, the more effective it will be at generating electricity. An example of this would be a person walking outside and shading the panels or standing in front of them waving a sheet overhead to track the sun’s path across the sky and gather that energy.

By contrast, passive solar energy is automatically controlled by the sun itself. This means that the system will work to its fullest extent without the need for constant human intervention to keep it running smoothly. This also means that passive solar energy does not always offer the best possible experience for end users; in some cases, it might even be more difficult to use than its active counterpart.

Tied To Human Activity

Tied to human activity directly relates to the degree to which the output of a solar-powered device can be directly tied to human activity. This could mean that the device is specifically designed to collect solar energy during times of heavy human occupancy (such as when homeowners are outside during the day), or alternatively, that the device is capable of producing electricity without depending on human intervention (standby mode).

In the case of solar thermal power plants, this would mean that they are designed to operate at maximum capacity (generating as much heat as possible during the hottest times of the day) while in the case of PV solar panels, it would mean that they can generate maximum electricity even when there is no direct human presence. Simply put, with a manually controlled device, there is a lot more that the user can do to directly impact the output of the device.

The fact that these devices can operate in stand-by mode makes them even more useful in places where there is no sunlight or sufficient sunlight to generate energy during the day. In these cases, solar thermal power plants offer great value since they can still generate electricity when there is enough time for heat to accumulate during the day. This makes them ideal for use in developing countries where electricity is not readily available and the sun does not provide enough energy to keep the devices constantly active. (In fact, this last point brings us to our next distinction…)


Since we already established the fact that passive solar energy does not require direct human intervention to work, let’s discuss storage a bit. As we established above, a passive solar energy device stores the energy that it gathers from the environment and generates later when it is needed. In the case of a thermal generator, this would mean that the device is capable of storing the heat that it collects during the day in order to produce electricity at a later time. This later time could be when the device is plugged into a generator (when used in conjunction with one) or stored in some other way (such as molten salt).

In terms of efficiency, thermal generators are great for storing large quantities of energy since they are able to operate at maximum capacity for longer periods of times. This allows for more energy to be accumulated and subsequently released when needed. However, this comes at the expense of lower peak power outputs compared to other varietals of solar energy (solar photovoltaic and concentrated solar power). Additionally, thermal generators might not be the most efficient means of generating electricity when plugged directly into a device such as a laptop or mobile phone charger since these devices require high peak power outputs to operate.

On the other hand, concentrated solar power (also known as “CPV”) does not store any energy, but rather, it operates based on the principle that the sun’s energy is most effective when focused directly upon it. This could mean that you have a tower filled with hundreds of parabolic mirrors that concentrate the sun’s rays upon a single point. As a result, concentrated solar power is generally considered the most efficient means of generating electricity compared to other solar energy devices since it is not subjected to the daily fluctuations in energy that plague traditional solar panels. However, this comes at the price of requiring more complex and expensive equipment (such as the parabolic mirrors themselves) to implement. This makes concentrated solar power the most expensive form of solar energy overall.

Types Of Solar Energy

In addition to establishing the difference between active and passive solar energy, one other important distinction to make is the type of solar energy that each variety provides. As we established above, solar thermal power plants are those that are manually controlled, while the others are generally considered to be automatic. Therefore, we can say that one provides manual control over the system and the other does not.

Concentrated solar power is completely automatic, requiring nothing more than the presence of sunlight and a grid connection to operate. It does not even require that you be present to keep it functioning. In fact, the whole process of generating electricity with this form of solar energy is completely automatic and does not require direct human participation. This is why it is also often referred to as “free solar energy”. It can be used to run appliances such as stoves, coffee machines, or even light bulbs. Plus, it can generate electricity when needed even if the sun is not shining brightly enough to directly provide light.

By contrast, solar photovoltaic systems function on the same basic principle as traditional solar cells (i.e., they convert sunlight directly into electricity through the photovoltaic effect). However, while traditional solar cells only need sunlight to produce electricity, solar photovoltaic systems require additional components in order to work effectively (such as solar panels). As a result, this is often considered a hybrid form of solar energy since it provides the benefits of both types of energy – namely, it is able to operate independently (passively) as well as in conjunction with other devices and systems (actively).

Due to its additional requirements and its ability to operate independently of any other device or system, solar photovoltaic systems are often considered more complex than concentrated solar power plants. Additionally, they are generally more expensive to purchase and operate. However, they also have distinct advantages that make them an ideal solution for situations where manual intervention is undesirable.

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