Are you thinking about how to reduce your electricity bill and would like to become a prosumer? The professional association “EnergiaTa” has prepared a guide with advice on how to choose solar panels, what power will be optimal for your roof and how much such equipment costs.

The first step is to see how much energy you’re using. Take a look at your energy bills for the past year and see who is the biggest consumer in the house.

Optimize consumption. This will not only reduce the investment required for PV panels, but also reduce your monthly bill. LED lighting and more energy-efficient appliances can pay for the investment quickly.

Find out what your roof’s solar potential is (see below), choose the kit that suits your needs, and make sure the panels are installed at the correct angle and orientation.

Buy them from an authorized supplier, with an invoice and a long warranty. Also arrange an annual maintenance package with the same company that does the installation.

There are different types of photovoltaic panel construction technologies:

• monocrystalline (high efficiency in direct sunlight);
• polycrystalline (as a rule, the best price/quality ratio);
• amorphous (high efficiency in the case of indirect solar radiation, requires a larger area for the same installed power).

The service life of the panels is at least 25 years.

The performance of photovoltaic panels is affected by:

• Orientation – south or east-west orientation is preferred.
• Tilt – the optimal angle will be latitude minus 10 degrees (34-35 degrees for Romania). An angle that is too small can cause snow to settle and reduce the ability to generate electricity. Since Romania is located in the middle of the northern hemisphere, the optimal angle at which the panels should be positioned in relation to the position of the sun is affected by the seasons.
• Shading caused by other structural elements or trees – with a significant decrease in the performance characteristics of the panels.
• Temperature – High temperature means a significant reduction in performance.

How much does it cost to install a photovoltaic panel?

As an example, the authors of the guide chose a house with an area of ​​100 square meters, with an annual consumption of 3400 kWh.

For this house, the amortization of the investment in the system with an installed capacity of 3 kW/p is carried out in seven years due to the reduction of electricity bills, as well as due to the increase in the market value of the building where they are located.

So, at the moment we know that our house, the roof of 50 square meters faces south at an angle of 34 degrees:

• Annually consumes 3400 kWh
• This requires an instantaneous power of 5 kW
• It can produce 3,720 kWh per year
• Has installed power supply from 3kW panels
• The price of the system that facilitates the above is approximately 29,500 lei, including design, installation and testing costs.

In terms of cost, there are five things to consider:

• Equipment cost: 3kWp – 23,000 lei
• Cost of design, installation and testing: 6,500 lei
• Cost of authorization: over 2,000 lei
• Maintenance fee: 1000 lei/year
• Percentage of own consumption: 30%.

How much is a battery pack for photovoltaics

If we want the degree of dependence on the network to be reduced, it is necessary to consider the possibility of purchasing batteries.

For example, a 12 kWh VRLA GEL battery pack costs about 8,000 lei, measures about 60x60x30 cm and weighs 300 kg. At 50% discharge, the useful capacity will be 6 kWh, and for a daily charge/discharge cycle, the life of this set will be approximately two years.

The price of a 7.2 kWh LiFePO4 battery pack is approximately 23,000 lei, weight 80 kg, dimensions 50x40x50 cm. With DoD 80%, the useful capacity will be 6 kWh, and for a daily charge/discharge cycle, the lifetime of this pack will be more than 15 years.

Five tips for maintaining photovoltaic panels

• Clean them periodically. Dust or dirt can significantly reduce the efficiency of the panel. Cleaning with warm water and detergent is recommended in the morning, especially in dry periods.
• Be careful not to shade them. Trees, antennas or chimneys can significantly reduce the production of photovoltaic panels.
• Make sure they are ventilated. The system of fixing the panels on the roof must have free space to ensure air circulation and ventilation of the panels. Overheating of panels reduces their efficiency.
• Pay attention to the angle at which the panels are attached, it should contribute to the fall of snow in winter and dust or dirt during rains.
• Watch for birds that can nest under the panel structure and damage the electrical system.

There are over 100,000 prosumers in Romania. More specifically, the latest figures published by the Energy Regulatory Authority show that there were 101,605 consumers at the end of October.

Photo source: Dreamstime