Which are the types of photovoltaic solar systems? – greenenergy®
1.Photovoltaic system interconnected to the general distribution network (on-grid) – this is a system of interconnected generation, synced with the public electric network in a way that the user consumes most of the energy directly from the solar panels, but because it is connected to the public network, it also has the opportunity to complete his or her energy generation with the energy from the public network to supply its energy demand entirely. The client or consumer becomes a solar energy producer, and if at any moment during the day the system is generating more energy than the one it is consuming, then it is exported and stored in the public network. For example, if you have solar energy at home but you are away during the day, then the unused energy is sent to the public network and you can then use it during nigh time. In Costa Rica, importing the stored energy has a cost (25% of regular rate). To achieve this, a two-way meter is needed in order to quantify the amount of energy exported and consumed. When the monthly bill arrives, the Simple Net Measurement is done and the consumer pays what corresponds. This type of system does not require the use of batteries to storage the energy since the remaining energy is injected to the public network. This makes it a much more economical solution and requires less maintenance. It is recommended for users that have access to the public network and mainly for urban areas.
2. Photovoltaic independent system (off grid) – It is known for the use of batteries. The consumer will use 100% of the energy produced by the solar panels, without being interconnected to the public network, and will use batteries to store and manage the energy. This type of systems allows an energy self-sufficiency since they don’t depend on a third party (or electric network) to function, which make users in small “energy islands”. It is recommended in areas where the access to the public network is zero or very expensive due to the investments needed to take the power lines to those areas. An off-grid user must know that it is subjected to a specific amount of energy. The batteries are the intermediaries between the generation and the usage that allows to establish an energy reserve for contingencies, occasional failures or unexpected generation lows. Therefore, to cover the consumption, there must be a good design and usage of the stored energy from the off-grid user. This is the best option for those users that seek energy independence.
3. Hybrid Photovoltaic System (network and batteries) – It is the mix of both systems, the user remains connected to the network, uses an interconnected system to generate energy, but also has a storage and management equipment to generate and manage energy and backup certain energy charges or all of the consumption. It provides the peace of mind of having the network as backup, but at the same time it allows not to depend 100% on the network to maintain on permanent functioning the important consumptions and charges. It is an automated system in a way that it is programmed so that the stored energy is used to cover the demand during blackouts (working as a power plant) or to discharge battery power during moments of high consumption in order to decrease the consumption from the network or during peak moments. Looking at it as a chain, the user will first use the generated energy, then the energy stored in the batteries and finally the energy from the public network.
4. Microgrids: A microgrid is an energy generation and distribution system of low tension that uses a generation source, in this case photovoltaic solar modules, storage batteries and a software to manage the generated electricity and deliver it to the consumption site. It can be controlled as a single entity and operate in parallel with the grid or in an intentional isolation mode. To learn more about microgrids click here.