Photovoltaics Clean electricity from sunlight
Producing light from light sounds strange at first. But solar luminaires, even in moderate climates, make perfect sense.
Our sun is without a doubt the most important source of energy for all life on earth: its light warms the atmosphere, and enables the photosynthesis of algae and plants, it drives the water cycle, our weather and the wind. What could be more natural than to use this inexhaustible and free source of energy in technical solutions? It takes the sun just a few minutes to transmit as much energy to the earth as all of humanity consumes in an entire year. Solar energy thus offers a promising option to cover our civilisation’s energy needs in a solution that is in harmony with the environment and nature.
The challenge lies in capturing this energy, exploiting it technically and storing it, because the fluctuation in light intensity during the course of the day is out of kilter with man’s energy requirements. The best example of this is artificial lighting that is needed at night, precisely when the sun doesn’t shine.
Sustainability in a nutshell. Aesthetic and efficient
Southern Europe is part of the “solar belt”: The regions that are ideally suited for solar energy due to their abundance of sunshine. Selux solar luminaires, which are already established in Southern Europe, are also ideally suited for the use in Northern and Central Europe thanks to their effectiveness and intelligence as more energy is usually generated than is required. Our solar luminaires have an intelligent control system for light and battery. In the months with less sunlight, a microcontroller’s algorithm ensures optimum energy management.
Selux solar luminaires have a modular design and can be operated completely independently: electricity and development costs are eliminated and installation is quick and hassle-free for the surrounding area. This makes the new luminaires particularly suitable for applications where there is no power grid and environments that are sensitive to interventions – such as parks, cycle paths and hiking trails, remote bus stops or car parks, nature reserves, projects with an ecological role model character, temporary areas of use and for municipalities that want to become climate-neutral.
Lukida 4000–P200-160 Solar light columnSeries Overview
Lukida 4000–P100-160 Solar light columnSeries Overview
Antares 4000-P100-160 Solar pole luminaireSeries Overview
Antares 4000-P200-215 Solar pole luminaireSeries Overview
Antares 8000-P200-215 Solar pole luminaire doubleSeries Overview
How do photovoltaics work?
Solar cells are based on the photoelectric effect that was discovered by the French physicist Alexandre Edmond Becquerel in 1839, which interested many other great researchers including Heinrich Hertz, his student Wilhelm Hallwachs and even Albert Einstein. In 1907, Einstein submitted a quantum theory explanation as to why light generates electrical charges in certain materials. But it wasn’t until the 1950s that American laboratories produced the first solar cells made from the semi-conductor silicon with an electrical output that could be used in a technical application. In this case, the emerging aerospace industry, but also as a decentralised power supply for telephone amplifiers, for example. The same electricity that solar cells generate can be used immediately, stored in batteries or transformed into alternating current and fed into the grid.
Silicon as base material
Silicon, the material used in most of today’s solar cells, is a semi-conductor. This raw material is common in the earth’s crust in the form of silicon dioxide (quartz, sand), making it available in almost unlimited quantities. Monocrystalline, polycrystalline and amorphous silicon can be produced from high purity silicon. These base materials are in turn used to produce solar cells with varying properties. Solar cells made from amorphous silicon offer low efficiency at a correspondingly low cost; solar cells made from monocrystalline silicon may be more costly, but they are also more efficient. The right cell type depends on the specific application. Luminaires with a decentralised power supply require a compact design and high efficiency, which is why hei solar luminaires from Selux use highly efficient solar cells generally made from monocrystalline silicon.
Nominal power and yield
The nominal power of photovoltaic installations is measured in Wp (Watt-peak). Wp refers to the performance under test conditions that approximate the maximum solar radiation in Germany. These standard test conditions (STC), used to compare different solar modules, are defined as a cell temperature of 25°C, radiation of 1000W/m² and an air mass of 1.5. A typical PV-installation on the roof of a family home (with 40m²) yields around 4 – 5kWp; the PV cells on a hei-solar luminaire from Selux have nominal power ratings in the range of 100 to 250Wp. Photovoltaics are ideally suited to regions within what we call the solar belt, where there are high levels of solar radiation irrespective of the season. These include southern areas of Europe and North America, Central and South America, Africa, Asia and Australia. Photovoltaics are also a cost-efficient alternative in neighbouring regions such as Central Europe, as has been demonstrated in recent decades. Several cities and regions in Germany and elsewhere are recording photovoltaic yields in solar land registers.
Solar power is not only sustainable from an ecological point of view, it is now also financially competitive. Over recent decades, technical advances have improved the performance of solar cells, as well as other system components such as inverters, control and charging electronics and battery storage. At the same time, the economics of scaling production mean costs have fallen considerably: solar cell prices today are 90% lower than in 2010. In many regions with corresponding light intensity, photovoltaics are already considered the cheapest way to generate electricity. In applications such as making road or path lighting self-sufficient (»off-grid«), additional factors positively impact economic efficiency and the ecological balance sheet: not only are there no electricity costs per se, neither are there any line charges or wiring installation costs.