Photovoltaic panels are one of the most efficient renewable energy sources on board pleasure craft.

The photovoltaic effect is at the heart of the conversion of solar energy into electricity. It exploits the unique properties of semiconductor materials, particularly silicon.

But how does light produce energy, and what are the different types of photovoltaic cells? 

The photovoltaic effect

At the heart of this process are photovoltaic cells, made up of two distinct semiconductor layers: the negative (n) and positive (p) layers.

When these two layers are superimposed, they create an electric field at their interface.
Photons, the basic constituents of light, are carriers of electromagnetic energy. When light of an appropriate wavelength strikes the photovoltaic cell, the photon energy is transferred to an electron in the semiconductor material, placing it in a higher energy state. This electron, in its new state, can then move through the semiconductor material, generating an electric current.

Various semiconductor materials can be used in photovoltaic cells, but silicon is the most commonly used with silica crystals.

Photovoltaic cells can be classified according to the crystalline structure of the silicon used, in particular into monocrystalline cells, made up of a single silicon crystal, and polycrystalline cells, made up of several of these crystals.

Edmond Becquerel's work on the photovoltaic effect (1839) paved the way for the use of solar energy as a clean, renewable source of electricity. Photovoltaic cells are a reliable and efficient method of converting sunlight directly into electricity, with no moving parts or emissions.

Monocrystalline photovoltaic cells

Monocrystalline photovoltaic cells are highly efficient. They are made from a single crystal of silicon, and offer high efficiencies of over 20%.

Their lifespan often exceeds 25 years, making them a long-term investment.
Their production cost is higher than that of polycrystalline cells.
Despite a higher initial environmental impact, their higher efficiency means that the CO2 emissions required for their construction are quickly offset.
These cells currently make up the majority of photovoltaic panels on the market.
 

Polycrystalline cells

These cheap cells owe their existence to their relatively low production cost compared with monocrystalline cells. They are made up of multiple fragments of crystalline silicon, which are fused together to form polycrystalline cells. Each polycrystalline cell can be recognised by its bluish appearance and its texture, which resembles a patchwork of silicon crystals of different sizes and orientations.

Polycrystalline cells are manufactured by melting scrap silicon, which is then cooled in a mould to form a solid block. This block is then cut into thin wafers, which are used as the photovoltaic cells in solar panels.

Their energy yield is lower than that of monocrystalline panels, generally less than 14%.

Monocrystalline photovoltaic cells

Monocrystalline photovoltaic cells are highly efficient. They are made from a single crystal of silicon, and offer high efficiencies of over 20%.

Their lifespan often exceeds 25 years, making them a long-term investment.
Their production cost is higher than that of polycrystalline cells.
Despite a higher initial environmental impact, their higher efficiency means that the CO2 emissions required for their construction are quickly offset.
These cells currently make up the majority of photovoltaic panels on the market.

Polycrystalline cells

These cheap cells owe their existence to their relatively low production cost compared with monocrystalline cells. They are made up of multiple fragments of crystalline silicon, which are fused together to form polycrystalline cells. Each polycrystalline cell can be recognised by its bluish appearance and its texture, which resembles a patchwork of silicon crystals of different sizes and orientations.

Polycrystalline cells are manufactured by melting scrap silicon, which is then cooled in a mould to form a solid block. This block is then cut into thin wafers, which are used as the photovoltaic cells in solar panels.

Their energy yield is lower than that of monocrystalline panels, generally less than 14%.