Solar PV kits grid-connected

More about Solar Grid Kits

Solar kits, whether self-consumption with accumulation, that is, with solar batteries, or instantaneous self-consumption (without solar batteries), are pre-designed and optimized products with the main components (solar panels, solar inverter, mounting system, monitoring system, cables and batteries, if applicable) ready to mount in your home or ship.

The solar kits have been dimensioned based on those generation and consumption needs most common in the Spanish market. That is why the choice of the solar self-consumption kit is made much easier, without the need to choose each component separately. In the case of Tienda Solar we have for our customers the solar calculator, where you can enter your consumption data and we will recommend the solar kit for self-consumption that best suits your needs.

Additionally, the fact of acquiring the solar kits makes the price of the installation for solar self-consumption more competitive

When and how to use the solar grid connection KITS?

Self-consumption kits for grid connection are those that can be used exclusively when our home or industrial warehouse has a connection to the electrical grid. The main difference between this type of solar kits and those of the off-grid one lies in the type of solar inverter. Solar grid inverters need a frequency and voltage wave to synchronize. If they do not have a network, they cannot start or work. The rest of the elements, such as solar panels, solar batteries or mounting system are the same as those used for off-grid solar installations. However, these types of Solar Kits can be installed with or without solar batteries. Let's see when to use one or the other.

Self-consumption solar kit without solar batteries or instant self-consumption

Self-consumption solar kits without batteries allow generating solar energy to consume on the spot. That is, the energy produced by the solar panels and converted to alternating current by the solar inverter must be used in the house or industrial warehouse at that precise moment. For this reason it is important to understand at what time of day the energy is consumed and to try to overlap generation with consumption. Usually the so-called consumption curves of a home are used to size the solar installation accordingly. The most optimal instant self-consumption solar kit is one where all the energy generated throughout the day and year is instantly consumed by the home or ship in question. In this way, one kWh consumed from the photovoltaic installation saves one kWh that would have been consumed from the grid at the price that would be paid for it.

But what if I generate more than I consume at certain times of the day or year? In this case, the energy generated by the solar installation is poured directly into the electricity grid. It is important to note that the connection between solar panels-home-electrical network is bidirectional. In other words, if the solar installation does not generate enough to supply consumption, the electrical grid will be in charge of providing the necessary energy. On the contrary, if the solar generation is greater than the consumption, this excess will be injected into the grid. This process is carried out automatically and both the solar installation, home or industrial warehouse and the electrical network are self-regulating. At no time will the consumer be without electricity as the network will serve as a backup.

The next logical question would be, am I being paid for the energy generated by my solar installation that I have not consumed and poured into the grid? The answer to this question will depend on the legislation in force in each country. Particularly in Spain there is legislation that stipulates how the surpluses of a solar installation for homes and small businesses are compensated. By way of summary, the BOE stipulates that the electricity supplier with which an individual or company has the connection to the grid is obliged to pay these surpluses at a price per KWh that will be discounted at the end of each monthly billing. However, the price paid for surplus solar energy is lower than the price at which the consumer pays the consumption of energy to the grid. As an example, a private individual would pay their marketer the kWh consumed from the network at € 0.12 / kWh while the kWh injected into the network would be discounted from the monthly bill at a price of around € 0.05 / kWh .

In our blog post, and in the Official State Gazette (BOE), it is explained in more detail how the surplus energy discharged to the grid is compensated.

Solar kits with grid connection without solar batteries are currently the simplest, cheapest and most robust and with the current favorable legislation in Spain the most attractive to install in a home or industrial warehouse. The most common kits for Spanish homes are:

3000w solar kit

5000w solar kit

However, to calculate what is your ideal KIT according to your consumption and to know what savings and profitability you can achieve with your grid-connected solar installation, enter our calculator!

Self-consumption kit with solar batteries 

The solar self-consumption kits with batteries allow to generate solar energy to consume at the moment and store the surplus in the batteries. That is, the energy produced by the solar panels and converted to alternating current by the inverter is consumed as far as possible instantaneously, but in the event of excess production, it is stored for later use.

These solar kits allow optimizing solar generation and distributing it throughout the day more efficiently. With these kits, a higher self-consumption ratio is usually achieved than with those of instant self-consumption, that is, a higher percentage of the energy generated by the installation is self-consumed, reducing the amount of energy that is poured into the network. Although very high percentages of self-consumption can be achieved, there is the possibility that in situations of very low consumption and with the batteries charged 100%, there is a surplus that must be evacuated to the network.

These types of solar kits are optimal to carry out what is called the peak shaving consisting of flattening the peak of household consumption in the later hours of the day by using the energy stored in the batteries that it has been generated during the day and during hours of less consumption. Solar kits with grid connection and with batteries are a suitable option when the surplus discharges to the grid are not compensated economically or at a very low price that makes the use of batteries more attractive. They are also a good option when you want to minimize the energy consumed from the conventional network as much as possible and generate as much of our own energy as possible.

These types of kits are very attractive when:

• The surpluses discharged to the network are not compensated by our marketer (in this case we could always choose to change to a marketer that did compensate us).
• When the surpluses are paid at a very low price compared to the price of consuming the network. In this case, the additional cost of the batteries could make their installation economically attractive since the stored kWh (energy) is still cheaper than buying from the grid.
• We have a lot of space on the roof to install the solar panels and we want to have a self-consumption ratio as large as possible.

Currently and with the legislation in force in Spain at Tienda Solar we believe that both Solar Kits for self-consumption without batteries and Solar Kits for self-consumption with batteries can be economically attractive. The choice of one or the other will depend on the objective sought, in the terms explained above. 

What do the solar grid connection KITS include?

Next, we explain the main components that our kits include according to their Typology.

Solar grid connection kits without batteries:

Solar Panels: Solar panels for grid connection kits tend to be high wattages, greater than 260Wp in order to reduce the cost of installation and maximize the mounting system. The panels for this type of application are usually with voltages higher than 24V with aluminum frames in order to better withstand structural loads. As far as possible and always depending on the cost of these and the space available on the roof, we recommend the use of the largest size of solar panel.

Solar Inverter: The solar inverter, as explained above, is the device that converts the direct current from the solar panels to alternating current, which is what the devices and household appliances in our house or industrial warehouse work with. Solar inverters are discriminated according to their nominal power in alternating watts, although temporarily they may give higher power peaks. The connection of panels is usually oversized in power to maximize the production of the inverter in the alternating part, which is its limiting factor. This is the reason why the solar kits install a peak power (from solar panels) higher than the nominal power determined by the inverter.

In grid-connected solar inverters, it is common, and increasingly essential, that they have a monitoring system that allows the system to be controlled at all times. Since these solar inverters are installed in residences or industrial buildings with an internet connection, many, if not most, of these devices upload the information to a cloud so that data can be accessed remotely in real time.

Mounting system: The metallic grid system allows the panels to be mounted on the roof or surface intended to support the solar panels. It can be coplanar, following and taking advantage of the same plane of the roof or inclined with an additional structure of rails that gives it the angle that we want to be able to optimize the solar capture. These systems are usually made of aluminum since they are light, easily machinable and resistant to corrosion.

Solar grid connection kits with batteries:

In addition to the elements described in Solar kits for grid connection without batteries, the self-consumption kits with batteries include, as their name indicates:

Batteries: These are the elements that store the energy generated by the panels for a short period (1-2 days) and then use it for household or industrial warehouse loads. The batteries, depending on the off-grid solar kit, can be of different technology (lithium or lead-acid base or other). It is crucial that depending on the type of solar battery used, the solar kit and the consumption needs are designed correctly. Lithium batteries work well at Depths of Discharge (DOD) of up to 80% while lead-acid technology does not go beyond 50%. It is worth mentioning that the use of batteries in our solar installation will force us to carry out some maintenance activities throughout its useful life. The type of maintenance and the replacement time of the solar batteries will depend on the chosen solar battery technology, as well as the frequency of use thereof (number of charge-discharge cycles)

Inverter charger: unlike the systems connected to the grid without batteries, the self-consumption kits with the use of batteries require an inverter slightly different from those described above. Despite fulfilling the same function (converting direct current into alternating current) they must manage the charge of the batteries. It is for this reason that they are called inverter-chargers. Additionally, this type of solar inverter has a solar charge regulator that is responsible for ensuring that the parameters of voltage, current and frequency are adequate to avoid damaging the batteries. Inverter-chargers are usually more expensive than grid inverters without this type of functionality.