Investing in a solar power system is a decision worth careful planning. Here’s how the project progresses smoothly from planning to implementation.
1. Assessing the starting point
The first step is to determine where the solar power system will be installed and what kind of preconditions are available.
Rooftop installation
If the solar power system is to be installed on the roof, the condition of the roof must be checked. The service life of a solar power system can exceed 30 years, so if a roof renovation is planned in the coming years, bringing it forward may be a sensible choice. While the system can be dismantled and reinstalled, this will incur additional costs. It is also essential to ensure that the system can be connected to the building’s electrical system.
Ground-mounted installation
For ground-mounted installations, in addition to solar exposure, the distance to the grid connection point is crucial. The farther the system is from the electrical connection, the higher the costs will be. The site should also be chosen to minimize traffic and movement in the area, reducing the risk of damage or vandalism.
Wall-mounted installation
Wall-mounted installation is a viable option especially for winter use. Electricity prices are typically higher in winter, and the sun stays low in the sky. Wall-mounted panels do not get covered by snow, allowing them to produce energy year-round. The downside is slightly lower output during summer, when the sun is higher. Make sure the panels are not shaded by elements such as eaves, as even minor shading can significantly reduce energy production.
2. Defining objectives and proper system sizing
The sizing of a solar power system depends on your goals. Do you want to maximize energy production, or achieve the best possible financial return?
When aiming for economic profitability, it is important to examine your own electricity consumption. A solar power system only produces electricity during daylight hours, so its capacity should be sized especially to match consumption between approximately 7 a.m. and 8 p.m.
In Finland, there is little sunlight during the winter months, but from spring to autumn daylight is abundant. A system that is too small increases costs relative to production, while an oversized system may result in most of the electricity being sold to the grid instead of used on site. The optimal situation is to use as large a share of the produced electricity as possible for your own consumption.
3. Familiarizing yourself with the equipment
Once the system size is correctly defined, it’s time to take a closer look at the different system options. A solar power system mainly consists of panels, mounting structures, and inverters.
Solar panels
Panels are the heart of the system. The power ratings of new panels are typically in the range of 400–450 W. Higher-efficiency panels mean fewer panels overall and therefore a smaller initial investment.
However, price is not the only decisive factor— the manufacturer’s background and financial stability are also important. Solar panels usually come with long warranties, but if the manufacturer goes bankrupt, the warranty offers little real protection.
At Terawatt, we primarily use Tier 1–rated panels. This means the panel manufacturer is classified in the highest category in terms of financial stability.
Mounting structures
The purpose of the mounting structures is to keep the solar power system securely in place. Snow loads and storms in northern conditions place significant stress on the structures, so it is important to choose mounting systems specifically designed for our climate. Mounting structures typically come with long warranties—up to 30 years.
As with panel manufacturers, it is also worth familiarizing yourself with the background of the mounting system supplier. A smart contractor selects mounting solutions backed by a reliable and reputable manufacturer.
Inverter
The inverter converts the direct current (DC) produced by the solar panels into alternating current (AC), which is what we use in everyday life. There are two different types of inverter systems:
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A Central Inverter System
A central inverter system is currently the most common way to implement a solar power system. In this setup, the direct current produced by strings of panels is carried via cables to an inverter, which converts it into alternating current suitable for the electrical grid.
The main advantage of a central inverter is cost efficiency—typically only one inverter is needed for the entire system. The challenges are related to the design of the panel strings and the installation of DC cabling. If one panel in a string fails or becomes shaded, it reduces the output of the entire string.
The warranty period for central inverters is usually around 10 years, so over a 30-year service life the inverter will likely need to be replaced once. This should be taken into account in profitability calculations.
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A Microinverter
In a microinverter system, each inverter is connected to 1–6 panels, and the inverter is installed in close proximity to the panels. This eliminates the need for long DC cabling, which reduces fire safety risks.
Microinverters offer better monitoring at the individual panel level, allowing potential faults to be detected more quickly. Warranty periods are also typically longer than those of central inverters.
One important factor to consider is the heat tolerance of microinverters—on a sunny day, temperatures near the panels on the roof can rise significantly. A microinverter system generally requires a higher initial investment.
Terawatt installs both inverter systems. In addition, the monitoring capabilities and optimization of individual panel output in a central inverter system can be further enhanced with power optimizers.
4. Choosing a reliable contractor
Once the system has been selected, the next step is to find a suitable contractor. High-quality equipment alone is not enough if the installation and project management are not up to standard.
At Terawatt, we have been delivering solar power plants for years, and we aim to be a competitive option for your project as well. We encourage you to compare different providers’ references, experience, and financial stability. A solar power system is a long-term investment, so the reliability of your partner is crucial.
At Terawatt, our strengths lie in a stable financial foundation, experienced professionals, and carefully executed projects. Our customer feedback speaks for itself—and we believe we will still be here supporting our customers 20 years from now.
Would you like to discuss further? Get in touch!
Perttu Takkinen
Asiakkuuspäällikkö
Aurinkosähkö
044 055 1050