Small space with a big effect – balcony and terrace as an oasis of well-being

Especially in the hustle and bustle of the city, your own little oasis of well-being is worth its weight in gold, but balconies are usually rare and space is limited. With the help of many small tricks, the transformation of a simple balcony into a very special place despite limited space is very simple. Those who are lucky enough to have a terrace can make use of many great elements to make the most of the given space and design it in the best possible way.

You do not have a balcony or terrace but a garden? No problem, because we show you how to plan and design the garden properly!

Building a stone terrace yourself – a new look for the garden

The foundation stone for any terrace is a beautiful subsoil. A patio stone is particularly suitable, as it is very easy to maintain and visually appealing. In summer, this can be walked on barefoot and a barbecue, patio furniture or a sun lounger can also find a comfortable place here. The dimensions are individually very different and can be well adapted to the circumstances. Building a stone terrace is possible on your own, but is very easy with the help of 1-2 assistants. The video explains step by step how the construction of a stone terrace becomes a success.

• A stone terrace is easy to maintain and visually appealing
• The construction is relatively simple, but time consuming.
• A stone terrace is a good way to landscape the garden and create a surface

Redesigning a city terrace – with a few simple steps to the goal

A city terrace is a true luxury, because in the city there is usually little space for green areas or terraces and balconies replace the function of these. If a city terrace is available, it is of course ideal for creating an oasis of well-being and finding some peace in the hectic city life. The design should always be adapted to the individual circumstances. In the video, experts show how the design of such places simply succeeds, which elements can be used well and how the own style can flow into the design. The modern design with matching elements helps to transform the given space into your own living oasis.

• Simple design elements create a modern living oasis in the middle of the city
• Urban terraces are becoming increasingly rare and should therefore be used to their full potential

Decorative ideas for balcony and terrace – small things with a big effect

A balcony is a basic requirement for many when looking for an apartment, and with good reason. The balcony can be an oasis of calm and offer a place to relax, especially in the summer. However, the design is very important to ensure that the small outdoor area is harmonious and coherent. Depending on the size and conditions of the balcony, a wide variety of elements can be combined to make the most of the available space. In the video, many great suggestions and ideas are given for designing a balcony. From the use of a mini herb bed to lanterns and candles to create the right mood.

• The right design of the balcony can turn the small outdoor area into a feel-good oasis
• Many elements can be realised even in a small space

Renew the wooden terrace – start the summer without splinters

Wooden terraces have a very beautiful visual aspect. Unfortunately, wooden terraces also have the property to rot with time, to become a splinter trap or to lose the beautiful visual aspect through weathering. From time to time, wooden terraces must therefore be renewed, as the function and the optical aspects are lost. When renewing, care should always be taken to know the cause of the defects so that they are not done again. The selection of the right wood is also an indicator of success and visually very crucial.

• Wood is visually very appealing, but must be renewed after a certain time
• Defects in the construction can quickly damage the wood and thus cause it to rot

Build your own privacy screen – enjoy the summer relaxed and undisturbed

A privacy screen is particularly often useful on balconies or ground-floor terraces to maintain some privacy. To ensure that the privacy screen also fits well with the design of the balcony, it should be well coordinated and visually appealing. Plants provide a great privacy screen as they echo nature and are visually striking. The video shows how a privacy screen with plants can be easily built yourself and how simple it can be used for balconies as well as for terraces in a modern way.

• A privacy screen preserves privacy on the balcony
• Visually, a privacy screen can become a design element and contribute to decoration
• Plants offer a great privacy screen and additionally pick up on nature

The best balcony tips – many ideas for small space

To take advantage of the small space on a balcony, there are many different options. From extra small tables to special flower boxes and a balcony outdoor shower. The right elements do not make the balcony look cluttered, but complement the space optimally. Barbecues, sunbathing or other activities are thus made possible and the optimal use of the space is ensured. In the video there are many different tips on how to use and design the balcony optimally.

• The right design is especially important for small areas, such as the balcony.
• Great tips and special designs help to arrange the elements on the balcony properly

Mini garden pond for balcony and terrace – the small oasis in the city apartment

A garden pond creates a great atmosphere and contributes a lot to the visual aspect of the garden. Since on a balcony or terrace the conditions for a pond are not present, there is a mini pond that is optimal for small spaces. The atmosphere of a pond is maintained and can be used in limited space. The video explains step by step how to install and build the mini pond.

• Bringing the atmosphere of a pond to the balcony or terrace
• The mini version has a great effect and enhances the spatial conditions

Small balconies new design – simple and effective ideas

Especially in spring, the balconies are basically cleaned and redesigned. New plants, new decoration and especially a new fresh look for the summer. Beautiful flowers are an important part of this process, as they herald the spring and bring new life into the room. But the right furniture and the right accessories are also important, so that in the end all elements lead to a great result. In the video, the experts explain which flowers are the right ones, how they are best transplanted and designed.

• Redesigning the balcony in spring is an exciting process that heralds the new season
• Fresh flowers and a new look contribute to the design of the balcony

Solar collectors – the heart of the solar system

Without the collector, a solar system could not convert the solar energy into usable heat. The collector is therefore the heart of the solar system, which makes it possible to use the renewable energy in the home. Want to learn more about solar systems and the cost? Calculate the cost of your individual solar system with our solar system calculator! But which different models are there among the collectors and which one is the right one for my solar system?

Flat plate collector – the proven model

Flat-plate collectors were the first collectors to be used to harness solar energy. They are therefore still the most widespread model today and form a market share of a proud 70%. Their reputation is probably not entirely unconnected to this, as flat-plate collectors are considered to be very inexpensive, reliable and, above all, they offer a technology that has certainly proven itself over the years.

Structure of a flat plate collector – absorber, housing and the heat transfer fluid

A flat plate collector has two simple components. A housing and a blackened metal sheet that is located inside the housing. This metal sheet is also called an absorber, because the dark coating ensures good absorption of the incident solar radiation. The absorber also efficiently converts the incident solar energy into heat. In order for the heat to be transported, pipes run along the back of the absorber in which heat transfer fluid flows. This flows cold into the collector and leaves it hot. To protect the collector from external conditions, such as the weather, it is covered by a safety glass. This glass is very stable and at the same time highly transparent, so that as little radiation as possible bounces off it. This ensures that as much solar energy as possible reaches the absorber to be converted into heat. To ensure that the housing also contributes effectively to heat generation, it is particularly well insulated and therefore hardly loses any heat energy. The efficiency of the solar system is thus increased.

Differences in flat plate collectors – structure, shape & piping

Even if the flat plate collectors are combined into one model, there are still differences. Different flat plate collectors differ in the housing material, the different connection of the tubes and other features. Depending on the application, the different designs have their advantages and disadvantages.

• Shape of the absorber – The absorber can be made of different materials. There are absorbers made of steel, stainless steel or aluminium sheets. These can be connected in different ways, for example by spot welding or roll bonding. There are also differences in the copper pipes in which the liquid is conducted. They can be pressed in but also soldered.
• Coating of the absorber – The absorber layer has developed further and further in recent years. After all, the layer should be able to absorb as much of the solar energy as possible. Today’s technology provides for highly selective layers that have a particularly high degree of absorption. It also has a low emissivity of the long-wave thermal radiation.
• Laying the heat transfer tubes – The tubes can either be laid in a tube register, where they are parallel side by side and connected at the top and bottom, or they can be laid in a meandering pattern, which means snake-like in one piece.
• Housing material – The material of the housing can also vary depending on the model. The most common are aluminum, stainless steel but also plastic. Even wood would be an option as a housing for a solar collector.

Tube collector – the better thermal insulation ensures higher efficiency

The tube collector came after the flat plate collector and is an alternative to it. Despite different technology and less market share, this model also has its advantages.

Structure of a tube collector – vacuum, heat pipe and the glass tubes

The tube collector model differs from the flat plate collector in one particular point, namely in the insulation. While with the flat plate collector only the housing is insulated, with the tube collector every single absorber is insulated and this in a special way. Here, the absorber is encased in an evacuated glass tube, as vacuum has particularly good thermal insulation properties and allows neither losses through convection nor through heat conduction. Several of the tubes together are connected to a collector and then form a tube collector. Since this way of insulating is much more effective than that of a flat plate collector, the efficiency is much higher here, since less energy is lost. Due to the technology, this model is also called a vacuum tube collector.

Different design of tube collectors – heat pipe, CPC & direct flow

The tube collector models are additionally differentiated into different designs. On the one hand, the direct and the non-direct flow tube collectors – they are also called heat pipes. Another form are the CPC – vacuum tube collectors.

• Direct flow tube collectors – In this design, the heat transfer fluid flows directly through copper tubes into the glass tubes. Here it is heated and when it exits it is combined with the other tubes in the collector. It is then transported to the heat exchanger via the solar circuit. In the event of a defective vacuum, it is not difficult to replace one of the tubes independently of the others.
• Heat-Pipe (non-direct flow) – The heat-pipe uses a thermodynamic process for heat transfer in which a heat pipe ( head-pipe ) passes through the glass tube containing a readily vaporizing liquid, such as water or alcohol. When heated, this liquid evaporates and rises to the head of the glass tube where heat is transferred by condensation of the vapor to the heat transfer fluid passing outside the head. The rest of the liquid flows back to the bottom of the tubes and repeats the process once room temperature is reached. This is sufficient to cause the liquid to condense, as there is a negative pressure in the tubes – the vacuum.
• CPC vacuum tube collector – This design is a variation of the direct flow tube collectors. Here too, the copper tubes run through the glass tubes, but the special feature is that two glass tubes are arranged concentrically and lie in front of a parabolic mirror. The absorbent coating is applied to the inside of the glass tubes. The parabolic mirror helps to make the collector even more efficient, especially at low irradiation. The yields are therefore comparatively higher and the collector works more effectively.

The heat transfer fluid – what needs to be considered

The heat transfer fluid stores the heat and transports it through the solar circuit to the solar storage tank. The heat is then released from the fluid and used to heat tap or heating water. The cooled fluid then flows back and starts its journey all over again. The question that arises, however, is what is suitable as a heat transfer fluid. Here the answer is relatively simple, because normal water is already perfectly suitable for this task. However, as there is a risk of frost, especially in cold months, which could cause irreparable damage to the collector or absorber pipe, the water must be mixed with an antifreeze. But the heat transfer fluid must also be able to withstand high temperatures. Especially in CPC vacuum tube collectors, temperatures of up to 350 °C can occur. To ensure that the viscosity does not suffer due to the antifreeze and such high temperatures, thus reducing the heat capacity, a mixing ratio of 40% propylene glycol and 60% water is usually aimed for. This mixture not only withstands cold temperatures as low as -25°C, but is also suitable for high temperatures. When purchasing the heat transfer fluid, pay particular attention to high temperature stability, good corrosion protection, the lowest possible viscosity, high environmental compatibility and a high heat capacity.

Photovoltaics – the prerequisites for your property

When planning a photovoltaic system, the first step is to find a suitable area for the system. A wide variety of options can be considered here. The site conditions must also allow the plant to be operated economically. The legal situation should also not be forgotten, as there are also a number of things to consider here. Builders and property owners who are interested in switching to renewable energies should deal with the topic in detail.

Photovoltaics – the installation options for the modules

When planning a photovoltaic system, the first question is usually where the system should be placed. Roofs are the most suitable, because these areas are available anyway and are usually not used for other purposes. In addition, they face the sky and the shading is usually rather low due to the positive elevation. But there are also differences in the roofs. Which roof is most suitable for the connection of the photovoltaic system?

Installation options on a pitched roof

The widespread pitched roofs offer ideal conditions for the installation of a photovoltaic system. The modules can simply be mounted parallel to the roofing. The existing roof covering is completely retained and continues to take on the function of weather and heat protection. A large-scale installation of photovoltaic modules leads to a reduction in the thermal load on the attic. Alternatively, there is also an in-roof installation, in which the photovoltaic modules are flush with the roof covering and even partially replace it.

For all builders of new buildings there is the possibility to install photovoltaic modules as a substitute for an ordinary roof. In addition to the production of electricity, these take on the function of weather protection and thus replace the usual roof covering.

Installation options on a flat roof

An ordinary flat roof also offers an ideal installation option for photovoltaic systems. Unlike pitched roofs, the inclination can be freely determined and does not have to be oriented to the inclination of the roof. The optimal alignment is simple, allowing productivity and efficiency to reach their maximum. Here, too, the installation does not negatively affect the existing roof structure.

Installation options for building-integrated photovoltaic systems

However, photovoltaic systems do not necessarily have to be installed on the roof, because there are other alternatives to use the renewable energy. One of these alternatives is the integration of the modules into the facade. For this purpose, facade components can be used, but canopies or similar are also possible. This alternative is also called building integrated photovoltaics (BIPV).

Photovoltaics – the individual site conditions for your property

Once the area for the photovoltaic system has been found, the question now arises as to whether the site conditions allow the system to be operated economically. For this, many factors must be taken into account that influence the yield and thus the economic efficiency of the system. This makes it possible to check whether the investment in a photovoltaic system is really worthwhile.

The influence of global radiation

Global radiation is one of these factors, because it indicates how much radiation falls on one square meter of horizontal receiving surface within a period of time (usually one year). It is therefore not a constant, but depends on the time of day and year as well as the location and the weather. In general, global radiation is higher in southern latitudes than in northern latitudes and greater in summer than in winter. Clouds cause the global radiation to have only a fraction of the values as in clear skies. For the planning of photovoltaic systems, this means that the distribution of global radiation in Germany varies depending on the location. In northern Germany, the average global radiation is therefore around 900-1,000 kWh/m2year, while in southern Germany it is around 1,200 kWh/m2year. A difference of about 20 % only within Germany. When planning a photovoltaic system, the global radiation at the individual location must therefore be taken into account in order to be able to estimate the efficiency of the system.

The correct roof orientation and pitch

The roof pitch and roof orientation are important factors that influence the economic efficiency of a photovoltaic system. In a new building, the roof can be optimally aligned, but in existing properties, the existing conditions must be used. Here, both the compass direction and the angle of the roof are important in order to ensure the greatest possible energy generation. In the case of flat roofs, as already described above, the orientation and inclination can be completely self-determined and thus individually adapted to the correct values. Depending on the location, a different orientation is the best, as this depends individually on the area. In general, the orientation to the south is the most optimal in most cases. The angle of inclination of 30-35 degrees is usually the most effective in the German wide, but this must also be determined individually depending on the object.

Planning the individual shading

The last location factor that influences the economic efficiency of the photovoltaic system is shading. This factor is most often underestimated, because even a little shade can significantly affect the performance of the photovoltaic system. This includes especially shadows caused by trees or nearby houses, but also small shadows from chimneys or antennas can have a negative effect on the performance. In the case of larger shadows, the system must be planned precisely. For smaller permanent shadows, it makes sense to install the system in such a way that it is not installed in certain places on the roof. A small permanent shadow can reduce the performance of the entire string and thus have a major impact on the economic efficiency. When planning, you should therefore pay close attention to the individual shadows on your property and include them in the planning to avoid performance reductions.

Photovoltaics – the legal aspects

The installation of a photovoltaic system always brings with it legal aspects, because here too there are legal rules and regulations that both builders and property owners must follow. What does the law stipulate, what regulations are there and what must owners of a photovoltaic system observe?

Building permit

Photovoltaic systems must generally comply with building laws. However, these depend on the respective federal state, because building law is a matter for the federal states. Depending on the federal state, there are therefore slightly different regulations for the installation of the modules. However, most federal states do not require a building permit for photovoltaic systems that are installed on the roofs of buildings. In this case, the building owner is responsible for ensuring that the system complies with the building code. The installation is therefore not subject to any additional checks by the authorities. However, systems that are to be installed on open spaces require a building permit in most federal states. In this case, the system must not exceed a specified size, which is usually nine meters long and three meters high. Systems that are to be erected on listed buildings normally also require a building permit. Find out individually for your federal state which legal principles you are subject to when building a photovoltaic system.

Photovoltaics – the individual planning of your plant

The planning of a photovoltaic system requires many considerations. A good system depends on many factors and should be individually tailored to you. Important aspects, such as the energy requirement or the size of the system, should be discussed in advance and well thought through. Which other factors are important and what should you never forget when planning your system?

Estimate and calculate the correct energy demand and dimensioning

At the beginning of the planning there is always the question of how big the system has to be, because the financial conditions generally depend on this. First of all, you need to find out how high your average energy consumption is. The photovoltaic system is then adapted exactly to your individual energy consumption. This is quite easy to find out by looking at your last electricity bill. Based on this information, further parameters can be determined, which will later lead to the required size of the system. For the individual calculation of your electricity consumption and the resulting minimum size of the required system, use our solar panel calculator.

The registration of the photovoltaic system with the authorities

If a grid-connected photovoltaic system is installed, it must be registered with both the Federal Network Agency (BNetzA) and the relevant grid operator.

Registration with the Federal Network Agency

The Renewable Energies Act (EEG) stipulates that operators of a photovoltaic system must register it with the Federal Network Agency. This applies both to own use of the electricity produced and to the energy that is directly marketed. Extensions to existing photovoltaic systems must also be registered. The registration of new or extended plants is done via the portal of the Federal Network Agency on the Internet and since 2011 this is also the only way to register photovoltaic plants. To register the system with the Federal Network Agency, you need the following data:

• Name and address of the operator of the photovoltaic system
• Location of the plant
• Nominal power of the plant in kWp
• E-mail address
• The day on which the plant is put into operation

Register the plant before commissioning or on the same day of commissioning at the latest. Two weeks’ lead time is quite sufficient to notify the authorities of the installation.

Tip: The registration of your photovoltaic system is urgently necessary. If a system is not registered in time, the owner has no claim to the feed-in tariff!

Registration with the network operator

Grid-connected systems feed surplus electricity produced into the public grid. The Renewable Energies Act (EEG) provides for a feed-in tariff of between 10 and 13 cents per kilowatt hour for this feed-in. Before commissioning the system, the operator must therefore notify the grid operator of the photovoltaic system and submit an application for grid connection. This is a legal obligation that the operator must observe. In the case of plants that are not connected to the grid, the grid operator does not have to be informed.

Find the right offer for you

Once the decision for a photovoltaic system has been made, you only have to find the right company to accompany you on the way of planning, delivery, mounting and commissioning. For this, sufficient research on the Internet, in newspapers or in the surrounding area is a good idea, but even if you find someone, you must first check the conditions and qualifications.

Recognizing the qualifications of a good solar installer

Most system owners don’t have the expertise needed to know whether or not a solar contractor is a professional in their field. Nevertheless, in order for you to know some facts that a company should offer you when installing your system, here is a list of what a professional solar contractor should adhere to.

• The company responds flexibly to your wishes with regard to the modules and does not insist on a particular product.
• The company will look at your roof and house in person before providing a quote
• The company offers you only one offer, in which all individual positions are listed exactly and no questions remain open for you.
• The company does not put you under time pressure and takes enough time to answer all your questions in detail.
• The company shall disclose to you the wiring diagrams and provide detailed information on registration, commissioning and the deposit of permits
• The company makes realistic yield forecasts for the plant, which roughly correspond to what you have calculated yourself in advance.

Photovoltaics – the economics of solar cells

Economic efficiency is generally determined by comparing revenues and savings. This is also the case with photovoltaic systems, where a distinction is made between acquisition and operating costs in order to determine economic viability. While prices for photovoltaic systems have dropped significantly in recent years, feed-in tariffs have also become considerably lower. But what costs do you expect to incur when purchasing a photovoltaic system and what costs will you face in the coming years?

The acquisition costs for a photovoltaic system

The acquisition costs generally consist of the costs required for the installation of the system. This includes the solar modules, the inverter, the wiring and the installation itself. For builders and property owners, this aspect is probably the most important, as the level of investment required will, in case of doubt, determine whether a system is installed or not.

Costs for the solar modules

Solar modules themselves have lost enormous costs in recent years. This is due on the one hand to strong competition from low-cost Chinese suppliers and on the other hand to positive economies of scale. In general, this means that solar modules become cheaper the more of them are produced. Costs are usually compared in euros per watt peak. At the beginning of 2018, the costs were 45 – 90 cents per watt peak, depending on which model and which supplier was chosen.

Costs for the inverter

The costs for the inverter should not be underestimated. They usually account for 15 % of the investment costs. Depending on the conditions of the system and the external influencing factors, more than one inverter may be required. The costs for the inverter vary depending on the power size. For a kW inverter you can calculate with about 200 € net. Smaller inverters usually cost more than large ones, as the manufacturing costs are higher. For a 5 kW inverter a price of about 1000 € can be calculated. If your system requires two inverters, the price will double.

Costs for the cabling

The cabling also makes up a large part of the investment. The higher the cross-section of solar cables, the higher the prices. However, a high cross-section is necessary to prevent losses. The price of solar cables ranges from 1 to 5 euros for the quantity purchased, the cross-section and the cable material, with the costs of the connection cables for the inverters and the charge controllers being added to this. This entails further costs of 20 to 50 euros, depending on the supplier and quality.

Installation costs

With the costs for the assembly not only the costs for the craftsmen come on you, but also the costs for the assembly system. These are quite different depending on which system you have chosen. The prices vary depending on the quality and features, such as the snow and wind load, but also on the model of the system. On average, you can expect costs for the mounting system between 100 and 150 euros per kWp and with installation costs for the substructure with another 100 euros per kWp. It is difficult to make a blanket statement about prices, as they can vary greatly and depend on many factors, such as the individual property, the conditions, the quality and the exact products.

The operating costs for a photovoltaic system

After the investment in a photovoltaic system, the owner will still incur further costs, for example to maintain the system. These costs must also be taken into account when analysing the profitability, as they can amount to around 1% of the purchase costs per year. But what costs do owners of a photovoltaic system really face and what should they expect?

Costs for the inverter

Even though the inverter is one of the initial costs, it is not as durable as the solar modules themselves. The inverter must therefore be changed and replaced from time to time. Since the inverter is not the cheapest investment, reserves should be formed for this case. Depending on which grid operator the photovoltaic system is registered with, minimum fees of up to 10 euros per month are charged. The inverter requires electricity from the public grid for control, data logger, analogue monitoring and the like.

Maintenance costs

Of course, the system must be maintained to avoid failures and errors. Some companies offer maintenance contracts, where a contribution of about 150 euros per year is incurred and the maintenance is taken over. Such an investment is well worth it, since in the event of a failure, electricity can neither be generated nor fed into the grid. Depending on the plant, such a contract can be cheaper than charging for each maintenance job individually. In particular, such contracts are worthwhile for large plants that require more frequent maintenance.

Cleaning costs

The costs for cleaning are in comparison significantly lower than the maintenance of the system. Soiling caused by leaves, pollen, dust or the like is usually cleaned again with a rain shower. However, permanent soiling can lead to a loss of yield. Professional cleaning of the modules is normally only necessary every few years. In areas with high pollution, for example due to heavy traffic, the system should be cleaned more frequently. The average cost of professional cleaning is around 2.50 euros per square metre.

Insurance costs

Insuring the photovoltaic system can make sense for many owners. Depending on the size of the system, liability insurance and all-risk insurance can protect against failures in the feed-in tariff as well as against high repair costs and liability cases. The cost of insurance can be added annually to the operating costs, but is relatively moderate in comparison. Prices of around 50 euros per year can be incurred by owners. Depending on the circumstances and the external environment, insurance, cleaning and maintenance make more or less sense, this depends individually on your property.

Photovoltaics – the promotion & financing for builders and property owners

A photovoltaic system is a large investment that requires good financing. Although interested parties are lured with the feed-in tariff, these have become less and less in recent years. To successfuly finance the photovoltaic system, however, some options are still open.

The feed-in tariff for photovoltaic owners

The feed-in tariff is set out in the Renewable Energies Act. The feed-in tariff is paid to those who feed surplus energy produced by the photovoltaic system into the public grid. The amount of this remuneration depends on the location factors and is determined by the legislator.

The Renewable Energies Act (EEG)

The Renewable Energies Act (EEG) came into force on 01 April 2000. It regulates the tariffs for electricity from various sources of renewable energy. The aim of the law is to promote renewable energies, such as water and wind power, but also solar energy, biomass and landfill, sewage and mine gas. The use of environmentally harmful energy sources is to be avoided and technology in the field of regenerative energies is to be promoted. In the course of the EEG, regulations on the feed-in tariff were also made in order to make the option of having one’s own solar system on the roof more attractive for builders and property owners.

Self-consumption remuneration

It was not until 2009 that the self-consumption tariff was introduced. Since then, the entire electricity produced no longer has to be fed into the public grid and compensation is paid for the consumption of solar electricity. However, this remuneration is much lower than the feed-in tariff.

The aim of the remuneration for self-consumption

The aim of the self-consumption remuneration was, in the first sense, to save costs for grid expansion and to save costs for the remuneration of solar electricity. However, owners of photovoltaic systems also derive an advantage here. They can use the self-produced solar electricity directly without having to feed it into the public grid beforehand. The owners therefore save money, as they are no longer dependent on the public grid and get the self-consumption remuneration on top, so to speak.

Photovoltaics – solar modules and how they work

The most important component of a photovoltaic system are the solar modules. Depending on the size of the modules, solar cells are connected together here. A photovoltaic system combines several solar modules and connects them to so-called strings. The entire unit of the strings then results in the solar generator. But how exactly does a solar cell work and how is solar energy converted into electricity?

The different types of solar cells

Solar cells convert radiation energy into direct current. The phenomenon that takes place in solar cells can be explained by the physical photoelectric effect. Solar cells consist of a negative electrode, an n- and a p-doped silicon, a boundary layer and a positive electrode. The electric field created between the n- and p-layer ensures the flow of current in a closed circuit.

Polycrystalline solar cells

In polycrystalline solar cells, the semiconductor material is silicon. This is melted and doped and cast into blocks using various casting processes. The silicon becomes solid and is called ingots when solidified. After the ingot is cut into slices, the original silicon is called wafers, which are coated with an anti-reflective layer. These polycrystalline solar cells have a lower efficiency than monocrystalline solar cells, but they are cheaper to produce.

Monocrystalline solar cells

Monocrystalline solar cells also use silicon as a semiconductor material, but the manufacturing process is different from that of polycrystalline solar cells. Due to the different manufacturing process, the production is more expensive, but the energy consumption and the efficiency is very high. During production, other crystals are formed here, which creates the difference between the two solar cells.

Thin-film cells

Thin-film cells have a completely different adjustment method than mono- or polycrystalline solar cells. The semiconductor is coated with a carrier material in these solar cells, which means that this method uses very little raw material and is very easy to manufacture. Which semi-material is used, is here in a large framework. In addition to silicon, gallium arsenide, copper indium selenide, cadmium telluride or dyes can also be used as coatings. However, the efficiency of these solar cells is lower than that of crystalline cells, but they are cheap and easy to produce.

Photovoltaic system – the different variants of renewable energy generation

The system that is chosen by most is the so-called photovoltaic system that generates electricity with the help of solar energy. With such a system, the owners are independent of public grid providers and do not have to pay more for their own electricity. But also with the photovoltaic systems there are different variants, each of which has its advantages and disadvantages.

Feed-in system – earning money with your own electricity

The most commonly used variant of the photovoltaic system is the feed-in system. This produces electricity for the household and feeds the electricity that is not consumed into the public grid. As required by law, the house is connected to the public grid and feeds surplus electricity into it. For this, the Renewable Energy Sources Act (EEG) stipulates that the producer must be remunerated. The so-called feed-in tariff varies between 10 and 13 cents per kilowatt hour (kWh) depending on the nominal output of the system and is fixed for the next 20 years. To illustrate this: An average family consumes only about 30 % of the electricity generated. 70 % is fed into the public grid and remunerated. However, there is a trap here that private individuals often fall into, because selling electricity is a trade and as soon as a private individual does this, he becomes a freelancer and is self-employed. Taxes and lots of paperwork are just waiting for you. To avoid this, check out our guide on all things solar without the tax office! Through an electricity storage, the self-consumption can be increased up to 75% and the owner benefits twice from the electricity.

Advantages

• Reimbursement of sales tax on the purchase price of the plant
• Good price-performance ratio
• Feed-in tariff according to EEG as additional income

Disadvantages

• Registration of the plant as a trade
• Subject to the obligations of the EEG
• Increased bureaucracy

Such feed-in systems are particularly suitable for property owners who have a constant average electricity consumption and want to drastically reduce electricity costs. On the contrary, such a plant can not only reduce annual electricity costs, but also be used as a source of income.

Zero feed system – all the electricity for your own home

The second variant of the photovoltaic system is the so-called zero feed system. As the name suggests, no surplus electricity is fed into the public grid. In the best case, 100% of the electricity produced is consumed in one’s own household, so that nothing is fed into the public grid. In order to ensure this, the system must be precisely adapted to the individual needs of the owner and also have a suitable electricity storage system. The electricity production is additionally controlled by an inverter, so that the output of the system exactly matches the electricity consumed and no electricity is fed into the public grid. The owners of such a system thus forego the feed-in tariff under the Renewable Energy Sources Act (EEG), but at the same time they avoid all the obligations that the feed-in tariff entails. You do not have to register a business and you do not have to pay taxes for the electricity fed into the grid. Although the photovoltaic system is intended to generate 100% of the electricity required, the property is still connected to the public grid so that it can continue to draw normal electricity if the solar power is not enough.

Advantages

• No increased bureaucratic effort, such as business registration, etc.
• Greater independence
• No obligations under the EEG

Disadvantages

• No feed-in tariff
• No refund of sales tax

The zero-emission system is therefore particularly suitable for private individuals who have a high energy consumption. The installation of a suitable electricity storage unit is mandatory for such a system, so that the self-produced electricity can be used most effectively.

Photovoltaic island system – independent of the public power grid

The photovoltaic stand-alone system variant does without the connection to the public grid and assumes that the solar system can always supply the electricity storage system with energy. The household is therefore supplied with electricity solely from the solar modules and does not rely on electricity from the public grid in an emergency. The owner is therefore not dependent on electricity from the public grid at any time. Here we will first distinguish between two types.

Stand-alone system without mains connection

As the name suggests, this model is a system that is not connected to the public grid in any way. The house relies exclusively on energy from the photovoltaic system. The system was designed for such a case so that both solar modules and energy storage are so large that they can independently supply the entire house with electricity without resorting to another power source. The electricity in such a house is therefore produced and stored 100% by the photovoltaic system. However, this system is usually only installed when a connection to the public power grid would be too costly. This is particularly the case for remote houses, mountain huts or individual infrastructures.

Island system for backup power

Independence from public electricity can also be made possible for German homeowners. The installation of an island system for emergency power is the solution here. In the event of a failure of the power grid, the stand-alone system for emergency power can then intervene. It makes it possible for both feed-in and zero feed-in systems to become an island system in an emergency. In the event of a power failure of the public grid, this system switches to backup power within a few seconds and the house remains normally supplied with electricity. So, the household is not dependent on the public grid and does not have to worry about a power outage. Here it is ensured that there is always enough power available. During installation, the entire house is disconnected from the public grid and a backup power system is set up that can communicate with the storage system.

Advantages

• Function as a backup power system
• Maximum independence from the public power grid
• Protection against power failures

Disadvantages

• Significant additional costs
• Is rarely used
• There is hardly any economic benefit for the owners

Such an investment does not always make economic sense for the homeowner. So before you decide on this option, first check your average daily consumption, the appropriate size of the system and the design of the solar storage tank. With this, you can calculate whether an investment would be profitable for you or not. The independence that owners have with such technology from the public grid is undisputed and will change and influence the energy policy of Germany in the coming years.

Wind turbines – everything you need to know about renewable energy from wind

Most people only know wind turbines as large plants that appear again and again in the landscape, but how exactly does such a wind turbine actually work and how can usable energy be created by it?

Keyfact 1 – A modern and large wind turbine can reach an output of several megawatts.

Keyfact 2 – Wind turbines are differentiated into offshore and onshore by location

Keyfact 3 – Wind turbines have no direct impact on the value of a property or land.

The power – how much energy does a wind turbine produce?

The power generated by a wind turbine increases in proportion to the third power of the wind speed. This means that the power increases eightfold when the wind speed doubles. However, if there is too little or too much wind, the turbine cannot operate. If the wind speed falls below 2 m/s, production stops, but if the speed is too high or there are storms, the turbine must be shut down for safety reasons to prevent damage. A large and modern wind turbine can reach an output of several megawatts and thus produce a lot of energy.

Efficiency – the measure of energy

The efficiency of a rotor describes the ratio between the incoming wind energy and the electrical power generated from it. This key figure is also referred to as the power coefficient. The theoretical upper limit of the achievable efficiency is 59.3 percent, while in practice the best wind turbines have an efficiency of up to 50 percent. In practice, these figures mean that the physically possible has almost been reached and optimisation measures are mainly in the area of increasing the spectrum of wind speed. However, research in this area continues to progress and expand the potential that wind turbines and wind farms have. The resulting renewable energy thus offers a great alternative to prevailing environmentally harmful energy generation, such as nuclear power or energy from coal-fired power plants.

The different shapes – what are the differences between wind turbines

The best known are probably the horizontal wind turbines with a three-bladed rotor. The blade profiles of the rotor blades are aerodynamically optimized to achieve higher efficiency and reduce noise emissions. The diameter of the rotors varies depending on the model. The large wind turbines have a rotor diameter of more than 100 metres. With these dimensions, they deliver an efficiency of 50 percent and outputs of several megawatts. Older models often require a mechanical gearbox to keep the generator running at a sufficient speed. However, these gearboxes cause wear and friction losses, which is why a wind turbine without a gearbox is more advantageous, has less energy loss and requires less maintenance.

In addition, there is another form of wind turbine, and that is the wind turbines with vertical axes of rotation. The most common are probably the Savonius or Darrieus rotors, but compared to wind turbines with horizontal axis and three-blade rotor, these achieve a much lower efficiency and are therefore much less effective.

Offshore and onshore – the location decides

Wind turbines are also differentiated in another category. Offshore turbines are mainly built in the coastal foreland of the seas. Their construction requires a higher construction effort than that of onshore turbines. Details: property construction. These are mainly built on the mainland and require less construction work. Offshore plants have a significantly higher number of full load hours than onshore plants on the mainland.

Loss of value due to wind power – why property owners are against renewable energy

Renewable energy from wind power is giving a huge boost to the energy transition in Germany. In 2016 alone, a total of 1,624 new turbines were installed in Germany, 24 percent more than in the previous year. Most of these wind turbines are located in wind farms, but they are also slowly establishing themselves in rural areas. Homeowners often have mixed feelings about this change, as they fear that they will have to accept a loss in the value of their property. Is the concern of property owners justified or do wind farms enhance the quality of life of the residents living in the vicinity?

The fear – Harmful to health & lowering value

Property owners fear that wind farms in the vicinity of residential areas will have a negative impact not only on the quality of life, but also on land prices and property values. This concern is well-founded, as there are several arguments against renewable energy from wind: wind turbines are suspected of being harmful to health. Exposure to audible and low-frequency noise, shadows, light reflection, ice throw and light emission is said to cause sleep and concentration disorders as well as depression. In addition, wind turbines disturb the landscape. The concern, therefore, is that wind turbines close to towns and villages will lead to falling property prices and a decline in new construction. Property owners who regard their property as a retirement provision now fear the value of their investment. Experts confirm that losses of 20 to 30 percent are conceivable. A study by the Agency for Renewable Energies (AEE) has shown that the acceptance of power plants in the residential environment varies greatly. 37 percent of 1000 respondents stated that they had no objections to the erection of a wind turbine in the local environment, while 63 percent of 1000 respondents had no objections to the erection of a solar park. It can therefore be concluded that wind farms enjoy a significantly worse image than solar farms and that renewable energies from wind power are less popular.

The opposite side – what speaks against the fear of property owners?

The proponents of wind turbines see the whole thing a little differently, however, and see no reason for concern. The legal situation offers some regulations that help to keep the loss of value as low as possible. Whether it is the construction of roads, industrial estates or wind turbines, the law not only prescribes a protective distance, but also guarantees noise protection for residents. These regulations ensure that changes to the landscape have minimal impact on property values. The quality of life or value is not affected if the minimum distances and immission values are correctly observed. Another argument from the opposing side states that land prices and property values are affected by many different factors and are therefore constantly subject to change. Whether decreasing values can be directly related to the construction of a wind farm is therefore unclear and cannot be determined.

Conclusion – land value, advantages and disadvantages & the selling price

Whether for or against a wind turbine, the topic undoubtedly holds a lot of potential for discussion. But what does land value really depend on, and do wind farms have anything to do with it? One fact is that the presence of wind farms in the immediate vicinity of the property reduces the potential group of buyers, as there will always be people who do not want to move near such a park. However, a smaller group of buyers does not automatically result in a lower purchase price. The value of the property is influenced by many factors and ultimately results from the interaction of these. So even with an existing wind farm near the property, a good sales price can be achieved if the owner knows his target group and knows how to highlight the advantages of the property. The presence of a wind farm has of course its advantages and disadvantages, but it cannot be said that the presence of such a wind farm is detrimental to the locality.