Photovoltaic (PV) technology harnesses sunlight and converts it directly into electricity using semiconductor materials. PV panels are mounted on buildings or ground-mounted to generate clean renewable power.
PV offers a sustainable solution to meet the UK’s rising electricity demand. But the variability of solar resources along with upfront costs pose challenges to widespread adoption.
This article provides an overview of how PV technology works, major types of solar panels available, and key considerations for residential or commercial PV systems.
How Do Solar Panels Generate Electricity?
PV cells contain special materials called semiconductors such as silicon, which release electrons when exposed to sunlight. As photons from sunlight strike the cells, electrons are knocked loose and flow in a single direction, creating direct electrical current (DC).
An inverter then converts the DC output into alternating current (AC) used for lighting, appliances and devices. Excess solar power can be exported to the grid.
PV panels are wired together in an array to produce system voltages and power outputs capable of real-world applications. A residential rooftop array typically ranges from 3-8 kW.
Major Solar Panel Types
Monocrystalline and Polycrystalline Silicon – Made from silicon wafers and the most common PV technologies, achieving 15-22% efficiency.
Thin Film – Utilize cadmium telluride or copper indium gallium selenide layers, requiring only 1% of silicon used in crystalline panels. Typically 13-19% efficient.
Organic – Use carbon-rich polymers and dyes on plastic backing. Lower efficiency but highly flexible. Mostly used for consumer electronics charging.
Concentrated PV (CPV) – Use lenses and curved mirrors to concentrate sunlight onto highly efficient multi-junction cells. Primarily used in large-scale installations.
Key Factors for PV System Design
Solar Resource – The amount of sunlight received determines energy generation capability. The UK’s solar resource varies by region but can fulfill a substantial portion of electricity needs.
Panel Orientation – Optimal panel tilting and azimuth orientations maximize solar capture throughout the year. South-facing at 30-40 degree tilt angles are typical in the UK.
Available Area – A sufficiently large, unshaded area is required for installing panels, whether on rooftops or ground-mounted racks.
Electricity Demand – Residential and commercial solar system sizes should be matched to actual site consumption patterns and existing supply agreements.
Benefits of Photovoltaic Solar
- Renewable, zero-emission power generation once installed
- Reduced electricity bills from onsite usage offsetting grid purchases
- Additional income from exporting surplus power to the grid
- Enhanced energy security and insulation from utility rate hikes
- Low maintenance requirements
- Decades-long lifetime with warranties up to 25 years
Challenges Facing PV Adoption
- Relatively high upfront capital investment required
- Intermittency of solar generation requires grid backup or energy storage
- Limited control over timing of peak production which may not match site demand
- Weather impacts such as snow cover and cloudy periods affect output
- Long payback periods depending on regional solar resources and electricity rates
For the UK to continue growing its solar energy capacity, robust policies and incentives aimed at improving PV’s cost-competitiveness are vital. But the fundamental environmental and long-term economic benefits make photovoltaic power a crucial sustainable energy solution going forward.
