Sizing Solar PV Systems

Sizing a solar PV array to fulfill your building energy needs

Determining the appropriate size for a solar PV array involves more than just calculating the roof dimensions and installing panels. With continuous advancements in panel efficiencies, fluctuating site energy demands and potentially overloaded distribution networks, a comprehensive assessment is essential for designing an optimal solar PV system.

Our approach

At CRS, we understand the importance of designing a solar PV system that meets your specific needs. Our consultative approach considers factors beyond just roof capacity, focusing on optimising self-consumption, reducing CO2 emissions and ensuring long-term investment viability.

By analysing 12 months of historical half-hourly metering data, our engineers accurately model the solar PV array using advanced software, delivering precise projections for energy yields and self-consumption. When working with us, you can trust in reliable, data-driven solutions that maximise performance and value.

Our expertise

In an evolving market, we frequently encounter inflated self-consumption estimates, which often mislead both contractors and clients. Such inaccuracies can lead to skewed figures and inadequate decision-making information.

Additionally, it’s becoming more common for Distribution Network Operators (DNOs) to demand costly sums for network upgrades, if feasible at all.

By analysing site energy profiles, we can tailor solar PV array designs to align with DNO capacity requirements. If site consumption allows, we can implement export limitation systems to regulate generation and comply with DNO restrictions.

Our meticulous design approach ensures that PV arrays minimise or eliminate export, mitigating the need for costly DNO upgrades. Regardless of project size, we maintain consistency in delivering accurate designs and figures for your assessment. Below, we outline our design process, aimed at providing optimal value while fulfilling design obligations.

Step 1 - Assess Site Consumption – kWh/Year

The key information required revolves around consumption data. For accurate results, we suggest utilising 12 months of historical half-hourly data, which can be obtained from your energy provider.

Step 2 - Summarise the data

We process the raw data, filtering out irrelevant information and summarising the annual consumption.

Step 3 - Calculate the minimum and maximum demand

Now, we can identify both peak and off-peak demands. This provides insight into site operations and allows you to ensure your energy usage aligns with the appropriate times of day, month or year.

Step 4 - Compare the site consumption to solar energy generation

After processing the half-hourly data, we transfer it into our design software. Here, we align the site’s consumption profile with the potential annual solar yield.

The software then compares site consumption to solar energy generation every 30 minutes over 12 months. The graph below is an example representation of these data.

The DARK BLUE line represents the site’s electrical consumption over 12 months.

The GREEN line illustrates the adjusted grid-supplied electricity following the installation of solar PV.

The LIGHT BLUE line depicts the quantity of solar energy generated, also spanning a 12-month period.

The GREY line illustrates the quantity of electricity exported to the grid.

Conclusion

Based on our calculations, a 557.28 kWp PV system would achieve approximately 92.1% self-consumption.

PV generator output: 557.28 kWp Performance Ratio (PR): 90.71% PV

Generator energy (AC grid): 457,724 kWh/year grid export: 36,054

kWh/year own power consumption: 92.1%

We can run various scenarios to assess the most cost-effective solution to meet your requirements, considering panel selection, inverter compatibility, mounting and space planning.

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