Solar Energy Guides

Understanding photovoltaic (PV) systems: definition, components and types

Solar photovoltaic (PV) systems are one of the most widely used renewable energy technologies in the UK. By converting sunlight directly into electricity, they offer a practical way for homes, businesses, and even industrial facilities to cut energy costs and reduce reliance on the grid.

In this guide, we’ll cover:

What is a photovoltaic system?
Main components of a PV system
What are the advantages and disadvantages of photovoltaic systems?
Future of photovoltaic systems

What is a photovoltaic system?

A photovoltaic (PV) system is an energy-generating system that uses solar panels to convert sunlight into electricity. It typically includes photovoltaic panels, an inverter to convert the electricity into a usable form, mounting structures, as well as optional energy storage equipment.

PV systems are used in different settings: residential installations supply homes with renewable power, commercial systems help businesses reduce energy costs, and utility-scale PV projects generate large amounts of electricity for the wider grid.

Main components of a PV system

A photovoltaic (PV) system is built from several core elements that work together to generate and deliver electricity. The main components are shown below.

Solar panels

Commercial Solar panels are the most visible part of a PV system. They capture sunlight and convert it into electricity using photovoltaic cells. There are three main types:

Monocrystalline: highest efficiency and lifespan, usually the most expensive.
Polycrystalline: slightly lower efficiency, more affordable, widely used.
Thin film: lightweight and flexible, less efficient, suited for specialist projects.

Costs vary depending on panel type, size and efficiency rating.

Inverter

The inverter converts the direct current (DC) electricity produced by the panels into alternating current (AC), which is used by most appliances and the grid. Common types include:

String inverters: Cost-effective, one unit connects multiple panels.
Microinverters: Installed on each panel, efficient in shaded conditions.
Hybrid inverters: Converts power for a solar battery as well as the panels.

Mounting system

Mounting ensures panels are securely positioned and angled to maximise sunlight. Options include:

Roof-mounted: Fixed directly to the top of a building.
Ground-mounted: Suitable where roof space is limited, or for large-scale solar farms.
Tracking systems: Mobile mounts follow the sun for higher output, but added cost.

Balance of System (BOS)

BOS refers to all supporting equipment needed to connect and protect the PV system, including cabling, switches, junction boxes and surge protection. Though less visible, these parts are essential for performance and safety.

Battery storage (optional)

Solar PV batteries store surplus electricity for use at night or on cloudy days when generation is lower.. By maximising self-consumption, they allow more of the solar energy you generate to be used directly rather than exported to the grid. For more details, see our full guide to solar PV batteries.

Monitoring and control (optional)

Business energy monitoring tools track generation, performance, and system health, often via an online dashboard or app. They help optimise efficiency and highlight faults early.

Grid connection (optional)

Most PV systems in the UK are grid-connected, allowing surplus electricity to be exported and ensuring a stable supply when solar generation is low. A business energy meter records electricity consumption, and when fitted with export capability (typically through a smart meter), it measures how much power is fed into the grid.

Types of photovoltaic systems

Solar PV systems can be categorised in several ways: by property type, system size, grid connection, and even portability. Below, we break down the most common types used in the UK.

Residential PV systems

Residential solar PV systems are typically small-scale rooftop installations that supply homes with renewable power. They often interact with the grid through the Smart Export Guarantee (SEG tariff), which pays households for exporting surplus solar energy. Many homeowners also choose to add a battery or an EV charging unit to make the most of their system.

Commercial PV systems

Commercial solar PV systems are larger installations found on offices, warehouses, or factories. These systems help cut operating costs and are set up alongside business energy contracts to manage supply. Larger projects may be financed using a Corporate PPA or a leasing arrangement, to reduce upfront costs.,

Utility-scale PV systems

Utility-scale systems are large ground-mounted solar farms that generate power for the local distribution network operator. In the UK, they often participate in CfD auctions and can supply thousands of homes and businesses with renewable energy.

Grid-tied vs off-grid PV systems

Most PV systems in the UK are grid-tied, meaning they connect to the national grid to sell excess electricity and to import energy when on-site demand is higher than solar generation.

Grid-tied solar systems enable strategies like electricity arbitrage and participation in the Demand Flexibility Service. Connecting a solar PV system to the grid typically requires paying daily business energy standing charges.

Off-grid PV systems operate independently, using batteries or generators to provide power during the evening.. They offer full energy independence but come with higher costs and more complex system requirements.

Portable PV systems

Portable solar PV systems are containerised or mobile setups that can be deployed wherever temporary power is needed. They’re emerging as a cleaner alternative to diesel generators and often include integrated solar PV battery storage for added flexibility.

Specialised PV systems

In addition to the main categories above, there are more advanced setups that offer greater flexibility:

Solar PV roof tiles provide a discreet alternative where traditional panels are unsuitable, such as on listed buildings.
Agrivoltaic farms combine solar generation with agricultural land use, allowing crops or livestock to share space with panels.
Solar-powered greenhouses and solar-powered seawater greenhouses integrate PV generation with greenhouse systems, optimising land and energy use.

What are the advantages and disadvantages of photovoltaic systems?

Like any energy technology, solar technology comes with both benefits and limitations.

Understanding these will help you decide whether a PV system is the right choice for your home or business.

Advantages of PV systems

PV systems offer several clear benefits that make them attractive for both households and businesses:

Lower electricity costs: Solar PV systems reduce reliance on the grid, helping to cut bills for households and businesses.
Clean energy: Solar power produces no emissions during operation, supporting green energy targets.
Scalable: PV systems are modular and can be expanded to suit different needs, from a few panels on a home to large arrays powering warehouses or entire solar farms.
Grid income potential: Smaller systems can benefit from payments through the Smart Export Guarantee (SEG tariff), while larger projects can secure Corporate PPAs.
Low maintenance: With no moving parts, PV systems typically require little upkeep beyond occasional cleaning and inspections. Find out more in our guide to solar maintenance.
Flexibility: Optional features such as battery storage, EV charging units, or solar PV roof tiles can be added to match specific needs.

Disadvantages of PV systems

Despite the benefits, there are also some drawbacks to consider before investing in solar:

Upfront cost: Solar installation costs can be high, though support such as business energy grants and financing options can reduce the impact.
Variable output: Solar generation depends on weather and daylight hours, so output is intermittent.
Space requirements: Large PV systems, particularly utility-scale systems, need significant land or a large roof area.
Grid dependence: Most PV systems remain tied to the grid, which means ongoing costs like a business energy standing charge. Off-grid systems are possible but require expensive storage and backup.
Payback period: While savings are long-term, it can take several years before installation costs are recovered.

Future of photovoltaic systems

The role of photovoltaic systems in the UK is expected to grow rapidly in the coming years. Advances in technology, lower costs, and better integration with the grid are shaping how PV will be deployed across residential, commercial, and utility-scale projects.

Falling costs

The cost of solar panels and associated equipment continues to decline. Global supply chains and improved manufacturing techniques are reducing prices, making PV systems more affordable for homes and businesses.

Scaling and LCOE trends

As systems get larger, the levelised cost of electricity (LCOE) from PV continues to fall. Utility-scale solar is now one of the cheapest forms of new electricity generation, and economies of scale are also making commercial rooftop projects increasingly competitive.

Next-generation PV technologies

Research into perovskite and tandem solar cells promises higher efficiency at lower cost, while advances in battery storage will improve reliability and make it easier to balance supply and demand. These innovations could significantly boost the performance of both residential and utility-scale systems.

Grid flexibility

Solar power is intermittent, but flexibility services are helping smooth integration into the electricity system. Mechanisms such as Demand Flexibility Services allow PV owners to adjust usage or storage to support grid stability during peak times.

Grid connection challenges

One of the main barriers to new projects is gridlock on connection applications. The queue for large-scale PV projects in the UK has grown significantly, delaying deployment despite strong demand from investors and developers.

CfD pipeline

The government’s Contracts for Difference (CfD) scheme remains the main route for utility-scale solar projects to secure long-term revenues. Recent auction rounds have attracted record levels of solar, and future rounds will play a key role in scaling PV capacity further.

FAQs about PV systems

Thinking about installing a photovoltaic system, but still have questions? Our experts answer some of the most common queries about solar PV in the UK.

How effective are solar PV systems?

Solar PV panels in the UK have a capacity factor of around 10–12%, meaning they generate about one-tenth of their maximum possible output over the course of a year. While efficiency depends on panel type and installation, well-positioned systems can generate enough power to significantly cut household or business energy bills.

How many homes have a PV system?

As of 2024, there are more than 1.3 million residential solar PV installations in the UK, with some estimates placing the figure closer to 1.5 million homes. The number is rising each year as installation costs fall and more households look to cut bills and reduce carbon emissions.

What’s the difference between solar thermal and solar PV?

Solar PV uses photovoltaic panels to generate electricity, while solar thermal systems use collectors to heat water. PV is more common in the UK because it provides versatile electricity for appliances, heating, and even EV charging.