Wp means ‘watt-peak’. The power Wp on a panel indicates the maximum power (or nominal power) the panel can produce, calibrated in test-lab conditions (solar radiation 1.000W/M2). kWh means 'kilo-watt-hour'; the energy unit which you consume, pay or produce. 1 kWh is the energy of 1.000 W (1 kW) during one hour. For example, if your electric coffee machine indicates a power of 900 W, the machine consumes 900 W per hour, or 0,9 kWh. The utility companies charge the energy per used kWh, aproximately 0,23-0,26 Euros /kWh (january 2014).
The term “Photovoltaic” means the natural process of converting light (photons) into electrical current. This is what the silicon cells in PV panels do. This is how PV panels produce electrical energy.
A thermal solar panel produces hot water which is being fed into a hot water accumulator for sanitary use or heating. A PV solar panel converts light into electrical current.
An inverter is the 'central' where all the cables of the solar panels come together. The inverter converts the electrical direct current (DC) from the solar panels into normal alternating current (AC) 230 Volt household current (or whatever the grid or main voltage is in your country). The inverter also adjusts continuously the energy from the solar panels in order to get maximum power from the panels, for example in case of partial shadows from trees or on cloudy days. This is why revosolar only uses MPPT inverters, which are more precise then normal inverters. For every panel configuration we use a specific inverter. Revosolar always searches for the optimal point between solar panels and inverter to offer the most efficient configuration.
Produce a high energy yield because of their special solar cells, which are 'cultivated' in a cylindrical silicon cristal. After being sliced in waters they normally have rounded corners. The efficiency of these panels is between 15-18%, although these figures increase every year. Monocrystaline panels are more expensive while in most European countries the additional efficiency does not justify the additional cost.
These are the most used panels today. The components for polycrystalline cells are founded in a square mold. The blue crystalline structure is formed during the cooling process. From these blocs very thin wafers are cut. Because of the square shape of the wafers or cells, the covering of the surface of the solar panel is slightly better, which compensates some of the inferior efficiency compared with mono-cells. Efficiencies of polycrystalline panels reach 14-17% nowadays, although these figures increase every year. Based on price-quality-efficiency ratios, polycrystalline solar panels are the absolute majority in the world, covering 80% of the world market.
Flexible monocrystalline panels
A variation of monocrystalline panels, used on a flexible and transparent polycarbonate laminate in stead of glass. These panels offer an excepcional flexibility and mechanical resistance, ideal for curved applications, semi-transparent applications for greenhouses, terrace covers, modern arquitecture, cars and boats.
Thin film amorphous panels
Produced by printing a thin film layer on glass or flexible compounds, with a special photovoltaic 'ink' emulsion. The production process is much faster and cost-effective, although these solar paneles have a significant lower efficiency; between 8-10%. For a specific quantity of installed solar power, thin-film panels need much more panels then mono- or polycrystalline panels. If space is not a problem (i.e. large solar fields or large industrial roofs), the lower cost compensates at large the lower efficiency, which is why these panels are widely used in large installations.
Black solar cells are generally made of mono-crystalline silicon. Blue cells are generally poly-crystalline. Lately also black polycrystalline cells are being introduced in the market (all-black-poly).
A PV solar installation consists of PV solar panels, inverter/regulator, the connection to your house (fusebox), a bidirectional meter and batteries (optional):
Solar panels convert light into electrical energy. It's that simple. The more light, the more energy is generated.
Solar panels generate direct current (DC) at 38 Volts, while the mayority of houses in Europe work with alternating current (AC) at 230Volts. The inverter converts DC into AC, and elevates the Voltage from 38 to 230V (or whatever the grid voltage in your country is). This way, the power produced by your solar installation is exactly the same as the power supplied by your power company (harmonized), only that the quality of your solar current is superior (no peaks, surges or fluctuations).
The connection of the solar installation with your house can be done simply by plugging into the power socket, if the power is under 500W. Above these values it should be connected to a separate group in your meter cupboard. Not a difficult issue for any electrician which should cost not more then €80,- and does not need any permission from the utility company.
If you have a classical 'disc-meter' this will start turning backwards when the production of solar energy is higher then the consumption. However, the utility companies are changing these meters for digital 'smart' meters which they can control remotely through a communication signal through the power cables. If there is a 'net-balance' system in your country, no doubt that they will install a double digital meter with separate input and output metering.
An isolated solar system means it is disconnected from the mains. We distinguish three cases:
1. The house has no connection to the network (off grid), for example in remote farmhouses and cottages. In this case you will have solar panels and batteries and it will also save the cost of bringing the power line to your house.
2. The house is connected to the network, but this isn't used. In fact the network is switched off because it has solar panels during the day, and batteries for energy supply at night.
3. The house is connected to the network, but only at night when there is no solar energy; The house is isolated from the network during the day. We call this a hybrid system. In cases 2 and 3 Revosolar will supply the hybrid SOLARROUTER system.
An assisted solar installation means that the house is connected to the mains and also to a solar installation, so both sources are always connected to the house. Solar power assists in lowering the electricity bill: During the day the house consumes its own solar energy, and if not sufficient, your house will take some extra current from the mains. When the solar system produces more energy in the house than consumed, this energy is lost.
An interconnected solar installation means that the house is also connected to the mains and with a solar installation. The difference with assisited solar power is that the excess electricity produced by your solar system is fed-into the mains. In this case the house has a double input / output counter. The energy fed-in to the network can be consumed whenever you want for no cost, because it is produced by you, and so it is your property! No need to install batteries, because the power grid serves as our battery.
Thus at the end of the month, the balance between electricity consumed and injected into the network can be zero, and therefore your electricity bill also. Hence the name of NET BALANCE . This is the most convenient, efficient and universally adopted in all countries within the European Union .... except in SPAIN!
Clearly the future of Spain is to follow this model, but for now the Spanish government prefers to protect the interests of the utility corporations, above the interests of the people, despite protests from around the world, including the European Union.
If you have any question related to the best system for you, please do not hesitate to contact us. There is always a solution!
That depends of who asks the question. With a little DIY skills anyone can do it. Most connections are plug&play. The installation manual from Revosolar speaks for itself. Be aware of your safety if you install on your roof (life-line). For connecting the inverter to your house-grid you have to have some notions of electricity. If you decide for a local electrician in your area, most of them already have experience in solar. If not, revosolar can assist them.
We advise you not to change this meter, except if it is a model which is not allowed anymore. There are disc-meters which do not turn backwards. You can test this on a sunny day, producing solar energy and shutting off all consumption. The advantage of a disc-meter is that it can never go wrong because the in- and outgoing energy is compensated at the same time. If you have this type of meter it is important not to use more electricity then generated.
b. digital meter with in- and out- metering
You do not have to change this meter because it is prepared for both power consumption as for feeding back into the grid.
c. digital meter without outgoing metering
This meter is good if you have no intention in feeding back into the grid. This is for assisted solar power in which you only save the electricity produced by your solar installation and consumed during daytime.
Untill 500 Watts of solar power can be plugged directly into any socket in your house or any existing group in your meter cupboard. This is reached by 2 panels of 250W each and an inverter of 500W. If the power if higher you have to add an extra group or use a free group in your meter cupboard. The cost for such an extra group, which can be done by any electrician, is around €80,- , and does not need any permission from the utility company.
Each solar panel has two cables; one plus and one minus. For one solar panel you can plug them directly into the inverter. If the system consists of more then one panel, the panels will be connected in series or 'string'. The plus and minus of each solar panel have male/female connectors which can be connected without possible error. A 'string' or series of panels can vary from 2 to 25.
Example: if you have 3 panels, connect the + of the first panel with the - of the second, the + of the second with the - of the third. The + of the third and de - of the first panel will be connected to the inverter. Since every panel has a + and - connector it is difficult to make any mistake. Be aware that when connecting more panels in series, the Voltage adds up; 10 panel easily produce 380 Volts, which can be dangerous. Do not manipulate cables or connectors and NEVER connect the + with the - of any panel or string. The high voltage and current can easily cause meltdown of connectors or cables.
REMEMBER: Panels in series will add up the Voltage while maintains the Current. Panels in parallel will maintain the Voltage and add up the Current.
In order to assess how many panels you can connect, observe the main fuse in you meter cupboard. Typically it is 1 x 25A, 35A, 40A or for example 3 x 25A (3-phase power). The value of each group has to be a factor 1,6 inferior to the main fuse. This is to assure that the main fuse does not blowout. If your main fuse is 40A, any group must be less then 25A. In a 25A group you can connect an inverter of 5.5 kW, which is enough for 22 panels of 250W each. This configuration will produce more then 5.500 kWh per year in Northern Europe (+7.000 kWh in Spain), more then enough for an average household for the whole year (5.000 kWh/yr).
In the toolbox of this web you can see the solar radiation maps of Europe and some specific countries, expressed in Watts/m2. This radiation is the sum of all solar radiation; direct radiation (blue sky, no clouds) and diffused radiation (cloudy days). Solar panels also generate power at cloudy days although substantially less (less then 50%).
Yes, solar panels also work on cloudy days, although substancially less! Really dark days in the wintertime will only generate 20% of the maximum power.
This depends on your energy consumption, which you can see in your utility bills. For a fast calculation you can divide your annual consumption in kWh with 0.9 (North European latitudes) or 1.4 (South European latitudes). The result is the total installed power in Watts you would need to reach your annual consumption.
This again depends on the lattitude you are; In Spain where the sun is higher, the optimal angle is 20 degrees in the summer and 35-40 in the winter. For grid connected solar you should use summer angles and for isolated solar your should install for winter angles. In North European latitudes you should take 30 degrees in summer position (grid connection) and 45-60 degrees in winter position (isolated solar). These angles are important but not critical; Roofs between 15-50 degrees will still give an acceptable energy production of 90%. The panels should also be positioned as much as possible towards South. Again, S-West or S-East also give acceptable production results although slightly less.
In general, today's mono- and poly-crystalline solar panels produce around 100W/m2 in Northern Europe, 150W/m2 in Spain. This means that a 250Wp solar panel with a surface of 1.65m2 produces an average of 225 kWh per year in Northern Europe, 350kWh in Spain.
In 2013 the total amount of solar panels installed in the world has reached 100 GigaWatts, the equivalent of 100 Nuclear Power Plants. The world market is growing at a pace of 20-30% per year. 70% of this volume has been installed in Europe. Today many european markets are in full swing (UK, Holland, Germany, France, etc.).
Untill 2008 Spain was the first market in volume although mostly in large scale power plants. This has completely changed since the right-wing government has drawn back the compensation scheme, while still not allowing net-balance connections for private households.
The future plans within the EU are to decentralize power production to where the energy is needed, demanding that in 2030 all European households contribute in the generation of their own power.
In the meantime China has announced plans to unfold large scale PV power within China, to limit the tremendous air pollution problem in this country.
Solar power is further developing fast in the US, S-America, Africa, Middle East, India and Australia.
Except for special ancient or historial buildings (monument protection), in general in Europe no permits are needed for solar installations.
In Spain only isolated solar does not need permits. For grid connected solar you need permission from the ministry of Industry and from the Power Companies.
The produced electricity of solar panels is converted by the inverter into pure harmonical current, exactly the same as produced by your power company. Solar energy is even better, more pure, without peaks or surges. All appliances including computers and delicate electronic devices will work perfect. There is no difference in the power produced by your solar installation or the power delivered by the power company. You will not experiment any difference, except in your utility bills!
Revosolar is manufacturer and distributor at world level and moves large volumes of solar panels and inverters. Besides this advantage of economies of scale, the philosophy of the founders of revosolar has always been to lower the threshold for solar as much as possible to increase the adoption of solar systems. We do this by increasing company efficiency and reducing commercial margins, without giving in an inch on quality! All revosolar clients will benefit from this policy.
Of course we are in business, but since our main goal is to change the world into a better place, being entrepreneurs with responsability is the most important thing for us. Our goal is win-win-win: which means that in every transaction all three have to win: the client, the world, and as a compensation, we also. But only in this order!
All revosolar products have been tested and certified by the most important quality assesment organisations, such as TÜV, CE, ISO, MCS, etc. which include the highest demands in terms of mechanical and electrical safety. Also the installation of the solar panels in your house must be executed following the local safety standards and certifications. This way you can obtain 30 years of problem-free comfort. Solar panels are even safer then any electrical appliance in your home!
Additionally, revosolar offers a 25 year warranty on energy production efficiency and 10 years on workmanship. On top of all, revosolar offers a 14 day money back guarantee, no questions asked!
There are many inverter brands today. Revosolar only delivers reliable and high efficiency inverters with 5/10/15 or 20 years warranty.
Besides brands, there are different types of inverters; mono-phase, three-phase, with/without galvanic separation, micro-inverters, electronic inverters, inverters with transformers, etc. You can also choose for inverters with a remote monitoring device to control the settings and general functioning over the internet or smartphone. Very useful when you are on holidays or for second residences.
This issue has been thoroughly researched in the past and the result is that the installation of solar panels does not increase the risc of lightning impacts. The most sensitive part of the installation - the inverter, which contains sophisticated electronics - is protected against power surges due to induction. In any case, as with consumer electronics in your house, your home insurance will cover if anything goes wrong due to lightning impacts.
Revosolar also delivers 'all-black' panels which can be aesthetically better for your roof. These can be either mono- or poly-crystalline and are slightly more expensive then blue poly-panels. The efficiency of all black panels is the same.
PV solar panels are duly fixed on your roof with a strong aluminum profile estructure which comply all the EU building standards, capable to resist the most severe conditions. The panels are made of tempered glass, resistant against rain, snow, hail and storms. No extra protection is needed.
Since there are no mobile parts and are mainly made of tempered glass, solar panels do not need any maintenance and have a 'life' of over 30 years. When placed under an angle (tilt), they have a 'self-cleaning' effect, since the rain washes the dust deposits off the panel. However, the cleaner the panels, the more energy they produce. It could be wise to clean them every year as if it were glass windows. The electrical parts do not need any maintenance. If you have solar batteries, the AGM or Gel types are also maintenance-free. Lead-acid batteries do need control of the water levels.
PV solar panels have a useful live of more then 30 years. The panels delivered by revosolar come with a workmanship guarantee of 10 years against production defects plus a guarantee of 80% of the production efficiency after 25 years. Although little can go wrong with good quality panels, it is standard that the Photovoltaic efficiency (converting light into electrical current) will diminish at a rate of 0,8% per year. This means that even after 30 years the panels still deliver 76% of their maximum power!
In the last years the diferences in quality between the different brands have been reduced to almost imperceptible details. As well as the price differences. This is true for most quality panel brands. However there still are B-brands on the market - specially from China - which could have been produced by hand (not with fully automated production lines), using less quality silicon wafers, or which present micro-cracks in the cells which are not visible with the plain eye. Revosolar only delivers 100% certified error-free triple-A-grade solar panels, tested by us thorugh flash tests and Infrared cameras, before entering into our warehouses.
Revosolar has an agreement with the sustainable bank TRIODOS to finance the purchase of a solar installation over 6 years through monthly payments. Through the savings of the monthly energy bills, the installments of the credit payments are compensated, which means that a solar installation does not have to be an extra charge on your budget! Of course you are free to ask your own banker to finance the purchase. Many banks offer special low interest rates for sustainable investments.
Thast depends on the country you live in. Contributing to sustainability through private investments in general allows tax benefits in many countries in Europe. Please consult your local tax expert. There is also an indirect tax benefit if you save on your energy bills, since you pay less taxes when you pay less energy bills. Around 30% of your energy bills is tax money. This can easily add up to 500 Euro per year!.
Untill recently in most EU countries special subsidies have been given for investing in solar. In the Netherlands for example untill last year 15% of the solar installation was subsidized by the Government to a maximum amount of €650,-.
Since prices of solar panels are much lower now and solar energy generates huge savings by itself, these subsidy programs are being eliminated. Solar energy does not need subsidies in order to be attractive; generating energy for free brings the pay-back of your investment down to 5-6 years in most countries; 3-4 years in Southern Europe. This means a Return of Investment (ROI) of more then 15%, which is more then most investments, plus at zero risc! No need for extra subsidies.
Investing in solar panels costs money, but not investing costs more! With solar panels you gain independence of the energy prices which are raising every year. You can eliminate your energy bills, generating a Return of Investment (ROI) of more then 15% per year. The risc of the investment is zero; solar panels are on the roof of your house and the sun goes up every day! Compare the profitability and risc of investing in solar panels on your roof, against the interest rates of your savings account (2-3%) or on the stock market. And we all know that even banks can dissappear!
Let's put it this way; 'put your savings on your roof in stead of in your bank!'