Solar photovoltaic (PV) panels harness energy from the sun's brilliance and transform it into electricity using silicon semiconductors containing atoms. When these atoms interact with protons, a robust electric current is generated.
This current is subsequently routed through a solar inverter, a critical component responsible for converting the raw direct current (DC) into alternating current (AC), the type of electricity used to power homes and businesses.
Solar energy output is quantified in kilowatt-hours (kWh), while the maximum output of a solar array is measured in kilowatt-peak (kWp). Generally, one kilowatt-peak can be converted into an annual energy output of 1,000 kWh, but we'll delve deeper into that later.
Solar panels offer several compelling reasons for their choice. Unlike sources such as gas, oil, peat, and coal, solar energy is a renewable resource. Consequently, its utilization does not result in any carbon emissions. This not only yields numerous environmental benefits but also acts as an effective defense against the escalating costs associated with external factors.
Determining the ideal number of solar panels for your home in Ireland depends on various factors, but using kWp provides an effective method to gauge average household energy requirements.
While individual energy consumption can vary, a solar array ranging from 2 to 4 kWp is generally considered sufficient for an average four-person household in Ireland. This system size typically equates to between 6 and 15 solar panels.
As an illustration, installing eight 425-watt panels will generate a system output of approximately 3.4 kWp, resulting in nearly 3,000 kWh of annual electricity generation
To determine actual solar output, it's essential to grasp the distinction between rated power wattage and real electrical output, with factors like orientation and exposure playing crucial roles in the calculation process.
When computing solar outputs, the following formula can be a helpful reference:
Average Hours of Sunlight × Solar Panel Watts × 75% = Daily watt-hours
The 75% factor is incorporated to account for variables like orientation and exposure. While no formula can provide precise measurements at all times, this method is the most trusted and coherent way to estimate output levels.
For instance, let's consider Rory's home, which receives an average of 4.5 hours of sunlight per day, and his solar panel wattage is 425. Using Rory's example, we can calculate the following figures:
4.5 × 425 × 0.75 = 1,434 Daily watt-hours
Subsequently, this figure is divided by 1000 to express the result in kilowatt-hours. This means that Rory's array will produce 1.434 kilowatt-hours per panel. As we discussed earlier, this figure can then be converted into kWp to illustrate the maximum system output over a given period.
By now, you probably recognize that when it comes to solar energy, there's no 'one size fits all' solution. However, based on average energy consumption, a 4kW solar array should generally suffice for an average Irish family of four.
Typically, a 4kW system comprises 16 panels, each measuring 1.6 meters with a wattage of approximately 265. Considering these figures not only reveals the system's capacity but also the production per square meter of the individual panels.
The following formulas are applicable for determining output per square meter:
Number of Panels × Solar Capacity
To determine the wattage generated per meter, use:
Capacity / Total System Size (number of panels × size of individual panels)
In the case of our friend Rory, his 12 panels with 425 watts each will generate a capacity of 5,100 kWh. We can then use these figures to calculate how much Rory's solar array produces per square meter.
The issue of solar efficiency is also worth mentioning. While it would be ideal to convert 100% of harvested energy into usable electricity, no such technology currently exists. Therefore, solar manufacturers rate their efficiency, with the average panel rarely exceeding 20%. Some models with efficiency in the 30% to 40% range do exist, but they tend to be prohibitively expensive for the average consumer.
Similar to our most cherished possessions, solar panels have a finite lifespan. On average, a solar panel array experiences an annual energy output degradation rate ranging between 0.5% and 1%. While some degree of degradation is inevitable, solar panels still offer a highly worthwhile investment. Based on this rate, many can anticipate their panels operating at approximately 90% capacity even after a decade. Moreover, several panels come with warranties that provide coverage for up to 30 years!
Although degradation is an inherent aspect over time, homeowners can take proactive measures to mitigate its impact and extend efficiency. For more information on steps that can be implemented to ensure proper maintenance of solar panels and optimize their performance, please refer to Wattcharger's comprehensive guide on the subject.
Now that we've established that a 16-panel, 4 kWp system is the recommended array for a family, let's delve into the cost analysis for such a solar setup. In Ireland, solar panel prices typically range from €5,000 to €18,000. Naturally, the cost of the panels will vary depending on the desired system output size.
For a system with a peak output of 5 kW, the starting price is approximately €10,000. While this initial expense may appear daunting, several factors ensure that the returns will justify this investment.
According to Electric Ireland, homeowners in Ireland who install a three-meter array could potentially save more than 50% on their annual electricity bills. This substantial savings is achievable because much of the energy generated can be utilized independently, reducing reliance on energy providers such as Bord Gas and SSE Airtricity.
Furthermore, an emerging technology called microgeneration allows homeowners to sell surplus solar-generated electricity back to the grid in exchange for monetary compensation, known as a Clean Export Guarantee. To take advantage of the exciting microgeneration incentives available in Ireland and understand the necessary steps, please refer to Wattcharger's comprehensive guide on microgeneration.
Fortunately, the Irish Government has placed a strong emphasis on encouraging the adoption of solar energy among its residents. The Sustainable Energy Authority (SEAI) is the agency responsible for promoting and facilitating renewable energy solutions in the country. Fortunately for homeowners, the SEAI offers several schemes to alleviate the financial burden of solar panel installation.
Depending on the size of the installation, Irish homeowners can receive financial support ranging from €800 to €2,100 for a solar PV panel installation through the SEAI. Additionally, the Targeted Agricultural Support Scheme (TAMS) is designed to assist Irish farmers by providing financial support covering up to 60% of installation costs, with a maximum value of €90,000.
For a more comprehensive understanding of the various financial assistance schemes offered by the Irish government to help alleviate the costs of installation, Wattcharger's complete guide on the grants for Solar Panels serves as an invaluable resource.
As we've seen, solar panels come with a considerable price tag. However, we've also discovered that various support measures can substantially reduce these costs.
Despite this, some homeowners and business operators in Ireland opt to lease solar panels. Leasing panels operate much like leasing a vehicle, where individuals enter into an agreement with a provider but do not acquire ownership of the equipment itself. Instead, the use of the panels hinges on regular payments to the installation party, typically on a monthly basis.
While leasing may offer some short-term financial relief, it almost always represents a suboptimal choice compared to purchasing the panels outright. Firstly, permanent solar installations can significantly enhance a home's value. Furthermore, the various grant incentives are typically available only when the panels are owned by the homeowner.
Purchasing panels do come with higher initial costs and the responsibility of maintenance. Nonetheless, it's crucial to keep in mind that buying your own panels nearly always stands as the superior option when it comes to investing in your solar future.