The installation of an efficient and high-quality photovoltaic system requires the skill and experience offered by our trained specialist installation partners.

Are you an end customer who would like to buy a HaWi system? Congratulations on your decision! You are already well on the way to saving your wallet and the environment.

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Power and heat from renewable energy resources offer a wonderful opportunity to tackle the imminent problems of scarcity of resources and global climate change. Renewable energies can make a country independent of energy imports, strengthen industrial and economic growth and provide innovations in technical developments. The amount that radiates every single day from the sun onto our planet is about 10,000 times greater than global energy consumption and does not cost us a cent. The solar energy that falls on one square metre in Germany annually corresponds to the energy content of 100 litres of oil. The available roof areas alone would be sufficient to ensure half of the total German power requirement. The power supply of the future will be a mix of regenerative energy sources of which photovoltaics will have a constantly increasing share. The prerequisite for this is first-class and durable PV installations involving high-quality products and technical know-how.

Solar panels are fastened in a stable and permanent way on a substructure and connected electrically with each other. The direct current produced by the panels is collected via the cabling and fed to the so-called inverters, which convert the direct current effectively into the alternating current usual in the public power grid (230 Volt, 50 Hertz). From here the power is fed via a meter into the public power grid. The meter documents the quantity of power supplied, which is then reimbursed by the energy provider. So-called off-grid systems are installed if there is no power grid available. The power is used personally in situ, e.g. to supply remote villages, cottage hospitals and other facilities in so-called isolated networks.

If, on a fine sunny day, the joint power output of, for example, six solar panels for one hour is exactly 1,000 W, this small photovoltaic system has produced exactly one kilowatt-hour (kWh) during this period. This amount of power is well-known as a unit of energy consumption both for power and for heat. A vacuum cleaner with a given power output of 1,000 W could be operated for one hour with this amount of power. In order to be able to compare different photovoltaic systems with different degrees of efficiency, it has been agreed on always to refer to the kilowatt-hours produced to the installed rated output. The yield unit of photovoltaic systems is therefore the kilowatt-hour per installed rated output or else kWh/kWpeak. As the PV systems produce more power in summer when there is a lot of sunlight and correspondingly less in winter, it makes sense to indicate the yields in each case for the whole year. A system consisting for example of panels with a total rated output of 4,000 Wattp (= 4 kWp) and supplying 4,160 kilowatt-hours of power in its first year of operation, according to this has a yield of 1,040 kWh/kWp/year. If you assume that the solar energy radiating onto the PV system in question does not vary much on average from year to year, you have a good indication of the yield to be expected in future. As most PV systems are currently financed via the sale of the power, knowledge about the yield to be expected over long periods is the essential component of any system planning. This simulation of future yield revenue is nowadays provided by recognised computer programs ("PV software"). It can be simulated that the yields do not depend on the system itself but on the place where it is set up and the attendant weather conditions. In this case the number of hours of sunshine with direct irradiation at the relevant location is particularly significant. In this connection, the southern regions of Germany for example Bavaria and Baden-Württemberg are at an advantage compared with the northern regions. An indication for yields to be expected is offered meanwhile by so-called solar radiation maps, which are published by various publishers and Internet sites.

As a rule of thumb, a manufacturer of solar panels can reduce its costs with each tenfold increase of the production and sales figures by about half. With the current growth forecasts and a slight increase in electricity prices from fossil energy sources (uranium is approaching scarcity), solar power will be the same price or even already cheaper than the public grid power in almost the whole of Europe by 2020. Another reason for the cost pressure on the manufacturers is the year on year reduction of the feed-in tariffs laid down in the EEC: In Germany by around 2020 you will only get between 11.2 and 15.4 cent/kWh for the new installation of a PV system. Anyone who would like to achieve high returns via the feed-in tariffs will have his system set up in the next few years; anyone who simply wants to procure clean power cheaply can look forward to a sustainably rosy future with photovoltaics.

Because of the extremely complex process for manufacturing the high-purity silicon required and the associated production plants, photovoltaics is a very cost-intensive technology. The solar power generated is still one of the most expensive types of power. In contrast, because of its sustainability, ecological compatibility and ubiquitous availability, this form of energy has turned out to be so beneficial that many countries, especially Germany and Europe, have decided in favour of the development and expansion of PV systems through political guidelines on financial subsidies. The decisive cornerstone here was the introduction of feed-in laws that guarantee the generator of power from renewable energies the long-term purchase of his power on attractive terms. This decision, initiated in Germany and later worldwide, led to a real boom in photovoltaics, as it became immediately profitable to invest in a PV system. In 2004 a large number of PV systems were installed, which, with returns of more than 12 %, represented the most lucrative form of investment of recent years. In the meantime due to an annual reduction of the feed-in tariffs the reimbursement for solar power has sunk so low that "normal" returns of between 3 % and 8 % are aimed for and also achieved. In the process, the participating financial institutions, for example banks, have recognised that investments in solar power systems are very secure. In order that a solar power system also remains cost-effective in future, the prices of the components needed must at least sink to the same degree as the reimbursement of the solar power. Because of the worldwide growth of the PV sector, with the cost-reducing effect of the mass production of solar panels, this trend can also be identified.

As a guide, you can assume that a solar power system will have paid for itself after about fifteen years, depending on the financing model as much as three years earlier. The power will be purchased for twenty years on fixed terms. Even after that,the right to feed in remains, even if it is then at usual market energy prices. Further options for increasing cost-effectiveness are created through special loans for renewable energy offered throughout Germany (e.g. by the KfW) or through regional subsidy programmes that give tax or other inducements to investment in solar energy. No two solar power systems are the same. The individual, professional costing and simulation of your cost-effectiveness is just as necessary as your professional, individual design and planning.

According to a study of the European Photovoltaic Industry Association (EPIA), in 2030 the output of photovoltaic systems installed worldwide will be 912 gigawatts and produce over 1,200 terawatt-hours of solar power. The quantity of CO2 emissions saved in this way, compared with fossil energy sources, would then be 775 billion tonnes annually, corresponding to the emissions of over 200 coal-fired power stations*. In 2010 the saving of CO2 compared with the then power mix was 525 g CO2 per kWh of solar power. The total avoidance through solar power was approx. 6.4 million tonnes**. Using the currently existing emission trading correctly, the influence of renewable energies can have an enormously positive effect on the CO2 proportion in the atmosphere overall. After about 1 to 4 years (depending on the state of technology) a solar power system has already earned back the energy requirement needed for its manufacture, whereby in particular the thin film panels of the future will have achieved this value in even less than one year. According to details of BSW-Solar in 2010 the PV systems in Germany produced approx. 12 TWh**.

Old or broken solar panels can be recycled. Up to 95% of the material can be recycled and used for the production of new solar panels. This conserves the environment by saving energy in production and high-quality components, such as glass, aluminium and semiconductor materials, are preserved.

As a certified PV CYCLE collection point HaWi accepts old and broken solar panels from end customers and fitters free of charge.

A good PV system is characterised by its meeting a multitude of quality requirements. Ultimately a PV system will only in retrospect show how well it has been planned and installed. For at least the whole period in which it feeds power into the grid for its own financing – in this country therefore usually more than twenty years – it must earn the initially costed yield. The more this yield exceeds the expected yield the better the system has been designed and/or the higher is the quality of the components used. The requirements essentially fall into three groups: Good planning, first-class installation and high quality of the solar panels.

Good planning involves at least the following aspects:
Climate data, location conditions (irradiation, temperatures, snow)
Shading (also future)
Characteristics of the set-up site/area (base, fitting)
Alignment and gradient of the panels
Financing, yield simulation, anticipated yield losses
Incentives
Customer requirements (also for off-grid systems)
Energy provider (nearest feed-in point, etc.)
Delivery times and supply to the installation site
Choice of supplier
Planning reliability
Insurance, theft protection
Financial reserves for maintaining function (e.g. exchange inverter)
Maintenance and operating costs

Good installation involves at least the following aspects:
Electrical parameters (V, I, etc.) of panels and inverters
Panels per string, strings per inverter
Optimum configuration of the available area
Aesthetics
Rear ventilation of the solar panels
Performance ratio of PV generator to inverter
String or central inverter
Inverter technology and efficiency
Place of installation of inverter
Panel technology
Safety: overvoltage, reverse current, lightning protection, potential equalisation, earthing
Long-term stability
Optimum cabling design

High quality of the solar modules involves at least the following aspects:
Solar cell (origin, properties, technology)
Durability (UV and weather resistance, snow and wind load)
Laminating (holds the various layers together, mostly EVA)
Face plate (transparency, stability, light capture, thickness, weight)
Reverse (glass, film)
Frame (material, stability, protection, fitting)
Cables (UV protection, length)
Connectors (compatibility, ease of use, UV resistance, weather resistance)
Junction box (weather resistance, bypass diode, tensile strength)