Solar System Typical and Minimum Site Requirements

A solar panel and behind the sun as a symbol for solar system requirements

Solar power is an exciting and rapidly growing alternative to traditional energy sources, which are not as clean and certainly not sustainable. However, before considering embarking on a potential solar installation, it is essential to ensure that the proposed system meets the minimum requirements, from legal, safety and environmental perspectives, starting in the planning phase.

Although rigorous, these requirements do not diminish the attractiveness and long-term benefits of solar power, delivered through modern solar systems.

Minimum Sunlight Requirements for Solar Systems

It used to be assumed by most people that solar power was only a viable option in parts of the world that were largely sunny. However, modern solar systems are increasingly efficient, which opens up solar power to parts of the world (e.g. Northern Europe, and all of the continental United States) that would not be obvious at first glance. So what are the actual minimum sunlight requirements for a solar installation?

This determination depends on the actual amount of available sunlight – both direct and scattered – and how that figure compares to the electricity required from the proposed installation. To help make this determination, solar systems output is typically measured in kilowatt-hours per square meter (kWh/m2) or watts per square meter (W/m2). It is also vital to note that PV panels can vary in their efficiency, so the specific efficiency needs to be factored in when comparing potential configurations and other solution considerations.

The bottom line is, even scattered sunlight can provide solar power. The key question then, become:

  1. How much surface area will be required in order to generate the desired amount of power?
  2. Will that be available within the proposed solar system site?
  3. Will a system of the required surface are be financially viable, to cover the costs initially and to recoup that investment over time?

Solar specialist advice is essential to work through these parameters. Often, there will be similar projects that can be used as benchmarks, both for current estimates and potentially, historical performance in terms of power generation and financial returns.

Planning Permissions and Inspections

An authorization stamp on paper

There are two fundamental issues to be addressed here at high level:

  • the allowed use of the building (whether domestic, commercial or public) and
  • any specific restrictions (e.g. if the building is protected due to its historical significance, or if the local area is designated as a conservation area and has building restrictions in place, including visual impact of structures).

Every jurisdiction will vary, but the principle to bear in mind is need to meet local and wider regulations and laws regarding building use, generation of alternative power and the conduct of the actual work required to install the proposed solar system.

The following list is representative of the areas where requirements will need to be satisfied:

  • Structural and mechanical stability
  • Fire safety
  • Environment requirements (hygiene, health and the environment)
  • Safety in use
  • Noise levels and protection against noise (if only during installation)
  • Energy economy and heat retention
  • Sustainable use of natural resources

Typically, plans will need to be submitted and approved before any installation work can proceed. While this can and does often trip people up, these approval processes are a fact of life, so the best policy is to determine the most efficient way to comply smoothly with the requirements. That usually will entail seeking specialist advice and perhaps hiring experts to assist in this process. Either way, the first step is to determine the local and wider regulations, laws and processes that apply, and begin the process of understanding whether your project is likely to meet those requirements, and if so, the work required to obtain the necessary permissions.

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Often, inspections are required, not just when the work is completed, but at various stages along the way, to ensure the work has been carried out in compliance with regulations and in line with the agreed plans and permissions. It is worth pointing out that it is very common to underestimate the time (and to a lesser degree, the cost) of navigating these planning and inspection processes.

Solar System Required Components

At the simplest level, a solar system requires:

  • a collection of photovoltaic (PV) panels (grouped together in what is known as an array or a string, depending on the required and optimum configuration), mounted in an approved configuration that is assessed to be safe for ongoing operations
  • power inverters, to convert the direct current (DC) generated by the PV panels into alternating current (AC)
  • cabling that is matched to the voltages carried throughout the system, and other environmental factors (weather, exposure etc.)
  • monitoring equipment
  • connections to the local power grid (unless the solar system is off-grid)

Connecting to Your Local Power Grid

There will also be specific requirements for connecting a proposed solar system to the local power grid. These can include the type of components, processes for connecting (and staying connected to) the grid, and available tariffs (including the rates paid for any excess power returned to the grid).

Solar System Typical Requirements

Given the wide variety of solar systems, which are growing at a rapid rate, there are many possible configuration types, each of which have sliding scales in terms of size, complexity and output.

Therefore, for the purposes of general guidance, a typical domestic rooftop system consists of:

  • A single PV string or array, mounted in accordance with best practice
  • A single inverter
  • Connections into the local grid, via a dedicated protective device
  • A generating meter
  • A solar controller to regulate the electricity passing through the system
  • Cabling of sufficient rating for power levels etc.

As a starting point, a typical 3.5kW domestic solar installation would normally use approximately 12 panels. On the other hand, a smaller 1kW domestic system is likely to use only 2 panels. This is a simplified list, and more extensive and complex systems, including any commercial or public installations, would require far more rigorous requirements to be met.

Specialist solar advice is essential therefore to getting a more specific appreciation of how these principles and requirements would apply to specific projects. The good news is, solar power is now a well-established, financially viable and rapidly growing alternative to traditional power generation. Solar systems offer an exciting, clean and sustainable route to tapping into renewable energy, and there is a wealth of support available for new projects.

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