What is the Cost of Using Solar EnergyMARCH 15, 2014 BY SOLAR GUY

English: solar PV – Second largest Array in UK (Photo credit: Wikipedia)

A techno-economic assessment will prove the economic feasibility and

sense of buying a solar electric system.

First, let’s consider grid-tied systems.

If you are planning to buy, build yourself or have built a grid-tied system,

such an evaluation should by all means take into account expected future

price of grid electricity over the period of the guaranteed solar system

lifecycle, along with any potential income from other existing investment

options.

The evaluation of a grid-tied system will provide you with enough data to

compare the overall net income of your investment in solar PV system with

other existing alternative options to invest your money taking into account:

price of solar hardware

installation costs

annual operational expenses

generated ‘free’ solar energy offsetting these expenses.

By assessing how much money you can save from solar electricity you can

take an informed decision whether it is worth investing in solar electricity or

your money would be better invested in other financial instruments, i.e.

bank accounts or other possible investment options you can find at your

disposal.

First of all, by performing a techno-economic assessment, you are going to

find out:

What is the cost of using solar energy

How to calculate total solar power you need to use and install

How to determine how much area you need to install your PV modules

and which type of PV modules to choose taking into account:

Your solar installation area

Various types of modules available on the market

Your budget

Once you have chosen your type of PV module, you will find out how to

calculate how many PV modules you need to install and the overall cost of

your solar system.

Then you are going to find out:

How to calculate your solar energy production costs

How much you can save by a PV system over its guaranteed life cycle

The payback period of your system.

The peak photovoltaic power needed to be installed on your roof can be

calculated by the formula:

Installed solar power, Wp = Daily energy target, Wh x PSHx SLF

This formula however can be expressed otherwise:

 Daily energy target, Wh = Solar generated electricity, Wh =

= Installed solar power, Wp x PSH x SLF

Let’s assume you have an area on your roof, enough to install 30 solar

modules, of rating 150 Wp each. The installed ‘peak’ solar power of the PV

array is:

Installed solar power = 30 modules x 150 Wp each =

= 4,500 Wp or 4.5 kWp

If you assume system losses factor for your grid-tied system 0.75, and the

average annual value of PSH for your location is 4, then the 30-module

solar array will generate:

Installed solar power x PSH x SLF = 4.5 kWp x 4 x 0.75 = 13.5 kWh of

energy daily

Your possible next step can be to estimate how much money you would get

for this amount of energy.

If for electricity you export to the grid you get paid $0.08 per kWh, then

each day you will get on average:

13.5 kWh x $0.08 per kWh = $1.08,

which means that per year you will get:

365 days x $1.08 per day = $394.2

If you multiply the daily energy offset target by the electricity residential

rate, you will get the money you could save by implementing a grid-tied

solar system.

If your daily energy target is 7.7 kWh and the residential electricity price is

$0.07 per kWh, then you are going to save

7.7 kWh x $0.07 per kWh = $0.54 per day

and

$0.54 x 365 days = $197.1 per year

By comparing these two values you can estimate which option is the

preferred one for you:

Either export the whole solar energy generated to the grid, and get

paid while still using grid electricity and cashing on the difference, or

Export just the surplus of solar energy generated during some hours

of the day to the grid to offset the money you pay the grid when solar

energy is not available, i.e. at night.

It should be noted that annual electricity production might vary from year to

year due to natural variations in weather and climate.

If your utility offers net metering, you will probably get paid the full retail

price for the excess electricity produced by the PV system

Now, let’s deal with stand-alone systems.

You will find out how maintenance cost of a stand-alone system is

calculated by the example below.

Let’s have as an example the following stand-alone system:

840 Wp installed solar power,

1,012 kWh annual energy output or 2,770 Wh daily energy output,

It is able to charge a 24V-battery bank with capacity of 470 Ah.

The system will require an inverter with rated continuous power of at least

840 W.

If your stand-alone system contains an inverter, it should be replaced after

12-15 years of operation. So, if a stand-alone system has a lifespan of 25

years, the cost for inverter replacement should be included in the

maintenance cost.

If we assume inverter cost of $1 per watt, based on the needed inverter

with 840 W rated continuous power, the inverter will cost:

840 W x $1/W = $840.

Such a price distributed over 25 years of operation will result in average

inverter maintenance costs per year as follows:

$840 ? 25 years = $33.6 or about $34.

More important however are battery maintenance costs.

A lead-acid battery is to be replaced after every 5 years of operation. At the

moment a typical battery price is $1 per Ah.

So, the task is to calculate the costs for batteries during the stand-alone

system’s lifecycle.

We assume that the battery cost for the first 5 years is included in the

system cost.

If battery cost of $1 per Ah is assumed, for the next 25 year of the system

lifecycle the costs for a battery bank of 470 Ah would be:

470 Ah x (25 years / 5) x $1/Ah = $2,350.

Such a cost distributed over 25 years of operation will result in the following

average battery maintenance costs per year:

$2,350 / 25 years = $94.

Furthermore we could assume an MPPT charge controller with estimated

price of $700.

MPPT charge controllers come with a typical warranty of 5 years. We could

assume that you would need at least one additional charge controller for

replacement.

Hence, the price of the additional MPPT charge controller average annual

maintenance costs would be:

$700 x 25 years = $28

The total average annual maintenance cost of an off-grid system

comprising a battery, an inverter and a MPPT charge controller would be:

Total average annual maintenance costs =

= Average annual inverter maintenance costs + Average annual charge

controller maintenance cost + Average annual battery maintenance costs =

$34 + $94 + $28 = $156

 The next question is how to calculate the energy production costs.

For a grid-tied system without power backup, to calculate how much money

you can save by selling electricity to the grid you need to assess your costs

for producing solar electrical energy.

For a stand-alone system however, the most important is to buy a system

that matches best your daily energy consumption target. Then on the basis

of the cost of the energy generated, and on the basis of the large amount of

money saved from paying for utility interconnection, you can calculate the

money you save from being off the grid.

The energy production costs averaged over the lifespan of the off-grid solar

system are calculated as follows:

Solar electricity production costs =

[Solar system initial cost + (System lifespan x Operating costs per year)] x

(Annual solar electricity production x System lifespan)

PV system initial cost, a.k.a. CapEx, is the cost for implementing the whole

system, including: site survey, system design, construction works, obtaining

permits, equipment delivery and installation, and system commissioning

System lifespan is assumed 25 years

Operating costs, a.k.a. OpEx per year, are system maintenance costs.

The most essential part of the operating costs is related to battery and

inverter replacement. During a 25-year lifecycle the inverter should be

replaced at least once, the charger controller might be replaced at

least once, while the battery should be replaced every 5 years.

Costs for implementing an off-grid system are always higher than costs for

implementing a grid-tied system without power backup due to the higher

complexity of the former.

If system implementation cost is estimated $7 per watt-peak and the

installed solar power is 840 Wp, the initial cost of the solar system is:

$7/Wp x 840Wp = $5,880.

Furthermore if:

System lifespan is 25 years,

Yearly generated energy is 1,012 kWh under existing environment

conditions, and

OpEx is $156 as described in the section about calculating showing

the average annual maintenance costs,

the energy production costs over total lifespan of the solar system are

calculated as follows:

Solar electricity production costs =

= [Solar system initial cost + (System lifespan x Operating costs per year)]

x (Annual solar electricity production x System lifespan) =

= [$5,880+ (25 years x $156)] x(1,012 kWh x 25 years) = $0.39/kWh,

which results into annual costs incurred by solar generated electricity as

follows:

Annual solar electricity production x Energy production costs =

= 1,012 kWh x $0.39/kWh = $395

Now, it’s time to asses how much you could save from being off the grid.

Let’s say you have to pay $8,000 to get connected to your local utility grid.

Let’s also assume the current grid electricity price of $0.125, along with a

5% rate of increase thereof.

This means that for a period of 25 years the average grid electricity price is

$0.25, while at the end of those 25 years the grid electricity price will be

$0.42.

If the energy generated annually by your system is 1,012kWh, then upon

average grid electricity price of $0.25 which corresponds to current

electricity price of 0.125 raised with 5% per year, within 25 years you would

pay for grid electricity:

1,012 kWh x 25 years x $0.25/kWh = $6,325

So, the total cost for getting connected to the utility grid and use the grid

electricity to cover your daily energy needs would be:

$8,000 + $6,325 = $14,325.

The just calculated value is actually the total savings from being off the grid

during the system’s lifecycle.

Your annual spend on grid electricity would be

$14,325 / 25 years of operation = $573.

The just calculated value is actually the annual savings from being off

the grid or in other words your potential annual expenses on grid

electricity.

As a follow-up of the above example, your annual cost incurred by solar

generated electricity would be:

Solar electricity production costs x Annual solar electricity production =

$0.39/kWh x 1,012KWh = $395.

So, within a 25 year period you would save annually:

Annual spend on grid electricity – Annual costs incurred by solar generated

electricity = $573 – $395= $178.

Here comes the ultimate question: what is the payback period of an off-grid

system?

Considering the above examples, if solar system implementation costs are

$5,880, and your potential annual expenses on grid electricity are $573, the

payback period of the solar system, compared to the situation if you were

connected to the grid, would be:

System payback period, years =

[Solar system initial cost + (System lifespan x Operating costs per year)] x

Annual spend on grid electricity = ($5,880 + (25 years x $156)) ? $573 = 17

years.

If your odds to be connected to the grid however are from zero to none,

and hence calculating payback period in regard to grid does not suit you,

you might want to explore the payback period of your off-grid system with

included maintenance expenses. In such a case the payback period of your

system would be:

System payback period, years =

[Solar system initial cost + (System lifespan x Operating costs per year)] x

Annual cost incurred by solar generated electricity = ($5,880 + (25 years x

$156)) ? $395 = 25 years.

If the herein provided method for estimating feasibility of your investment in

solar energy looks kind of cumbersome, you can use our handy, simple

and fast online calculator included in the Gold Package for advanced

evaluation of off-grid systems. Click Here to Discover More about Solar

Gold Package.

You may also like:  Can Solar Panels Power A House or Do Solar Panels

Save You  Money  or  How Many Solar Panels Do I Need or Uses of Solar

Energy

 MPPT Solar Charge Controllers

MPPT solar charge controllers are used when the voltage of the solar panels is significantly greater than the required charging voltage. For example, if you wish to use a 200W grid-tie panel to charge a 12V battery, the voltage of the panel will be about 30V and 7A, but the charge voltage for the battery only 14V. In this case, if you use a standard PWM controller, when the voltage is reduced, the power production in watts also reduces (from 200W to about 100W).

MPPT controllers overcome this problem by being able to optimise the charge voltage and current, not just changing the voltage as PWM controllers do. To do this, MPPT charge controllers typically store charge within them and boost the current of the charge output as and when needed, optimising the available power input with the charging output. By doing this, they are able to increase the amount of charge current by up to 30% (dependent on the degree of voltage change required). MPPT charge controllers are, however, more expensive.

Inverters, Chargers and Backup Generators

AC-DC inverters are used to convert 12V or 24V supplies to 240V allowing you to use mains operated electrical devices on boats or in your caravan or motorhome. There is a wide range of inverters available on today's market, many of which are cheap imports which often fail quickly or cause damage to equipment. Unlike cheap imports, we only supply inverters from respected manufacturers and their inverters are guaranteed to give good service and long lifetimes.

There are two types of unit: a) modified sine wave inverters, and b) true / pure sine wave inverters. Most standard electrical devices, such as kettles and radios, can be used with the cheaper MSW type. Other devices, such as high quality audio equipment, flourescent lighting and devices with digitial timing circuits (e.g. digital microwaves and washing machines) can only be used with the TSW type. If in doubt, please ask before buying. For grid-tie solar inverters for installers and dealers, please visit our trade solar section.

Please be aware that when using an inverter, it should be connected directly to the battery bank and the battery bank must be of sufficient size to be able to cope with the potentially high current draw of the inverter. Theoretically, a current of 1A on the AC side of the inverter can become 20A on the DC side (A = V x W).

Inverter Size Typical Battery Bank Size (12V)

1000W 420Ah

1500W 540Ah

2000W 750Ah

2500W 1000Ah

24V Solar Panel Systems

Given that many people nowadays are using 24V (24 volt) solar panel systems espcailly on boats and yachts, you would expect that it would be very easy to set up a 24V solar system. However, a quick trawl of the internet quickly highlights that nearly everything written talks about 12V systems and that it is very difficult to find good information about using 24 volts.

The primary problem is that all charge controllers, whether PWM or MPPT technology, are simply not capable of significantly increasing the system voltage without losing power. Whilst thet claims of some manufacturers that their MPPT controllers can charge a 24V battery using 12V panels are true, the power loss remains untenable. The only reliable way of using solar panels with a 24V battery bank is to ensure that the solar array is at 24V or higher. In this case, the charge controllers can drop the voltage without losing significant amounts of power.

The range of 24V+ solar panels designed for off-grid use is, unfortunately, not particularly wide at the more cost-effective end of the market. Sunware do manufacture 24V panels at 48W and 70W, but there is a price attached. Other manufacturers, such as Yingli and Kyocera, manufacture a wide range of 'grid-tie' panels that operate at 24V plus, but again these are more expensive products. In short, there is no easy answer and a 24V solar panel installation is always going to be more expensive. There are of course benefits, such as reduced voltage losses and cable sizes, but these may well be overshadowed by the cost penalty.

To install a 24V system using standard off grid panels, it is necessary to wire the panels in 'series pairs'. For example, wiring two 100W 17V (5.9A) panels in series will result in a solar array of 200W and 34V (still 5.9A):

Another important factor to bear in mind when looking at 24V systems is that their are different types of electrical devices, some which operate at a constant current and others with a fixed power consumption in watts. Generally, while many people do talk in amps or amp-hours, it is much more meaningful if we use watts and watt-hours in our calculations - this is a much more realistic figure for power consumption as opposed to current draw (amps).

Whilst at first glance it may seem as though a 24V system is producing less power than a 12V system with the same number of panels, the truth is that this is only really true if we are talking about current production in amps. In most instances, the combined wattage of the panels is the same regardless of system voltage. Only where a device operates at a fixed current, independent of the voltage do we start seeing changing wattages:

Constant consumption:120W@12V = 10A :: 120W @ 24V = 5A

Constant current:10A @ 12V = 120W :: 10A @ 24V = 240W

Contact us at Cleversolar for help and advice or a look at our Solar Panels Advice & FAQs to find out more about 24 volt solar panel systems.

How Many Solar Panels Do I Need?

How many solar panels do I need is one of the most frequently asked

questions by solar enthusiast.

We suppose that you have already made your home or office more energy

efficient and that you  know the different types of solar panels available in

the market .

The right choice of the solar panel type is very important.

It predetermines the number of solar panels, because every  solar panel

type shows different efficiency in  converting solar energy to DC power.

Having said that, let’s go straight to the point.

First, you should calculate your daily energy target.

You have to decide what percentage of your annual electricity bill you want

to offset to your grid tied system.

Let’s say your annual energy usage is 7,000 kWh. You want to offset 40%

of it to a grid-tied system.

This means that energy target is:

7,000 kWh x 0.40 = 2,800 kWh

Since there are 365 days in a year, your daily energy target is:

2,800 / 365 = 7.7 kWh

If you know your daily energy target and the average annual PSH (Perfect

Sun Hours) value for your area, you can calculate the amount of peak

power you need to install on your roof:

Installed ‘peak’ solar power = Daily energy target/(SLF*PSH)

SLF is the System Losses Factor, a.k.a system efficiency ,which takes into

account  system losses or system inefficiency. For a grid-tied system

system efficiency  is assessed usually between 70% and 80%. This means

that we lose (20-30)% of the energy  in the system and our panels must

have  higher installed peak power so as to compensate for those loses.For

an off-grid system the system efficiency is  somewhere between (50-65)%.

If your daily energy target is in Wh, then you obtain the peak solar power in

Wp (watts-peak). If daily energy target is in kWh, you obtain the peak solar

power in kWp (kilowatts-peak).

PSH is abbreviated from ‘Perfect Sun Hours’ and refers to the number of

hours per day during which the solar irradiance equals 1,000 W/m2. PSH

are measured in kW/m2/day and it can be found by using solar maps.

By NREL (National Renewable Energy Laboratory of the United States Department)                                                                              (http://www.nrel.gov/gis/solar.html) [Public domain], via Wikimedia CommonsIf your daily energy target offset is 7.7 kWh, the area you live has an average

annual PSH = 4.5 hours, and you assume system efficiency = 75% 0r SLF= 0.75, then the needed total peak installed power is:

7.7 kWh / (4.5 hours x 0.75) = 2.28 kWp or

This is the installed ‘peak’ solar power needed to generate the required

energy target.

At this stage it is important to assess how much area you need to install the

solar array. Based on your energy needs, you can determine whether the

area of your roof would be enough to fit all the panels needed. Here we

don’t talk about a specific panel model but rather about solar panel type –

monocrystalline, polycrystalline or thin-film.

The area required for installing the solar array, so that your PV system

would meet the energy offset target, depends on:

Peak power installed on the roof (in kWp or Wp)

The kind of modules you use (monocrystalline, polycrystalline, thin-

film).

To estimate the area you need to install the required peak power, you

should use the following table:

How to estimate the area you need to install the required solar peak power

The required roof area is calculated by the formula:

  Total area needed =

  = Installed solar power in kWp x Area needed for 1 kWp

a) If your target peak power is 2.28 kWp, and you decide to

use monocrystalline solar modules, the area you need is:

   2.28 kWp x 7 m2 = 15.96 m2 or 2.28 kWp x 75 ft2 = 171 ft2

b) In case you prefer to use polycrystalline solar modules, the area you

need is:

  2.28 kWp x 8 m2 = 18.24 m2 or 2.28 kWp x 86 ft2 = 196.08 ft2

c) Should you decide to buy thin-film solar modules, the area you need is:

  2.28 kWp x 15 m2 = 33.87 m2 or 2.28 kWp x 161 ft2 = 367.08 ft2

Finally, to find out how many solar panels you need, you should divide the

total installed power by the rated power of a single panel you are going to

buy, and round the result up to the nearest integer.

For example, if you have chosen to buy panels of 160 Wp rated power

each, the number of panels required is:

2,280 Wp / 160 = 14.25, which should be rounded up to 15.

Please, have in mind that such a number is reasonably exact for budgeting

purposes only.

The reason is that solar panel output power changes with temperature and

solar (sun) energy deviation. Such power output deviation forms the

‘operating window’ of a solar panel or solar array.

Furthermore depending on the solar power system you use, the next to the

solar panel component which can be either a charge controller or an

inverter, has its own operating input window as well.

To provide an efficient energy delivery to the loads in your home or office

over time, the operating window of the solar array formed by these solar

panels  should be always within the operating input window of either charge

controller or the inverter (depending on the solar system type) and match

the capacity of the battery bank (if any needed).

You can estimate the number of solar panels needed for your solar power

system by using our  free solar panel calculator .

You can find even more money saving solar  information and more precise

calculators helping to build or buy an affordable yet efficient solar power

system  in  our  informational Solar packages.   Click Here to learn more

about our Solar Packages Now!

Mixing solar panels – Dos and Don’ts

Mixing solar panels of various voltage or wattage, or produced by different

manufacturers, is a frequently asked question by most DIYers.

Though mixing different solar panels is not recommended, it’s not forbidden

and things would be ok as long as each panel’s electrical parameters

(voltage, wattage, amps) are carefully considered.

When you intend to wire two panels produced by different vendors, the

vendors actually are not the problem. The problem is in different electrical

characteristics of the panels, together with different performance

degradation.

Solar modules are connected in series to obtain higher output voltage. The

maximum system voltage however must not be exceeded.

For modules connected in series total power is calculated as follows:

Mixing solar panels in series

Total connected power = 150W + 150W + 150W + 150W = 600W

However if among modules connected in series a module has rated power

lower than the other modules, due to  lower rated current of this panel

compared to the other modules belonging to this string, that module might

drag the overall system output down:

Mixing different solar panels in series

Solar modules are connected in parallel to obtain higher output current.

For PV modules connected in parallel total power is calculated as follows:

Mixing solar panels in parallel

Total connected power = 150W + 150W + 150W + 150W = 600W

Unlike connection in series, if among modules connected in parallel there is

a module of power output lower than the output of the other modules, this

might not affect seriously the total power output of the array,provided that

this module has equal to the other modules rated voltage:

Mixing different solar panels in

parallel

Maximum voltage on a string of modules must always be lower than

maximum input DC voltage of the inverter.

When connecting different solar modules, it’s not the different wattage, it’s

actually the current (for series connection) and voltage (for parallel

connection) that could drag down the performance of the solar array

composed of those modules.

Only solar panels of exact or similar current should be wired together in

series. When you connect a 3A panel to a 3.5A panel, the overall current

will be dragged down to 3A. Such a reduction in current will by all means

lead to a reduction in power output and therefore loss in system

performance.

Similarly only solar panels of exact or similar voltage should be wired

together in parallel. When you connect a 15V panel to a 24 V panel, the

overall voltage will be dragged down to 15 Volts. Such a reduction in

voltage will lead to a reduction in power output and therefore loss in system

performance.

Compared to voltage and current, wattage is not a significant concern.

When you wire together a 60W panel to a 100W panel in series, the total

connected power would be 160W, provided that the two panels are of equal

current.

Here any difference in voltages is not important, voltages with just sum up

and all you’ve got to consider is that the total voltage should fall within the

inverter voltage window.

If their current ratings are different however, you should be prepared to

expected unpleasant surprises, since the overall current would be the lower

of the two, which will means that you’re not going to obtain a total of 160W

but always less. How much less – depends on difference in rated currents.

Furthermore when you wire together a 60W panel to a 100W panel in

parallel, the total connected power would be 160W, provided that the two

panels are of equal voltage. Here any difference in currents is not

important, currents with just sum up and all you’ve got to consider is that

the total current should not exceed the maximum inverter input current.

If their voltage ratings are different however, you should be prepared to

expected unpleasant surprises, since the overall voltage would be the

lower of the two, which will means that you’re not going to obtain a total of

160W but always less.

How much less – depends on difference in rated voltages.

Why it is not recommended to connect different solar panels?

Apart from rated power, each panel has a power degrade percentage.

This means solar panels’ output degrade in a different way over time.

Moreover the stated degradation not always coincides with what is

written on a panel’s nameplate. Therefore it’s not easy to find an exact

panel match of different solar vendors. ‘Exact match’ means both

almost similar ratings and ratings degradation.

For panels connected in series, voltage is additive while current is the

same, provided however that all the panels have equal current rating.

If among the panels connected in series there is a panel with rated

current lower than the others, it will drag down the current passing

through all the remaining panels.

Therefore each of the remaining panels (with higher current rating) will

underperform which means that will produce lower current (and

power) than stated on its nameplate.

In other words if two dissimilar modules are wired in series, the

voltage is still additive, but the current will be equal to  the current

produced by the panel with the lowest current output in the series

string.

For panels connected in parallel, current is additive while voltage is

the same. If among the panels connected in parallel there is a panel

with rated voltage lower than the others, it will drag down the voltage

on all the remaining panels.

Therefore each of the remaining panels (with higher current rating) will

underperform which means that will produce lower voltage (and

power) than stated on its nameplate.

Mixing solar panels with different electrical characteristics is not

recommended if you use an MPPT charge controller. Different

wattages make impossible for the controller to find the optimal

operating voltage and current, since they are different for each panel

type.

The solution is simple: utilize panels that have similar electrical

characteristics to the original panels.

Therefore, when connecting different solar panels, to minimize the losses:

Connect only in series panels of the same brand and of the same

current

Connect only in series panels of the different brands and of the same

current-this is your second option if for whatever reason you cannot

find the same brand panels

Connect in parallel panels of the same brand and of the same voltage

Connect in parallel panels of different brands and of the same voltage-

this is your second option if for whatever reason you cannot find the

same brand panels

Connecting different solar panels with the same array is not

recommended since either the voltage or the current might get

reduced. Therefore if you are planning to use dissimilar panels, try to

pick the ones with similar voltage and current.

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Monitoring is the key to unlocking the energy production of the solar cell. It is easy to lose efficiency through the use of circuit architectures that assume

constant energy production when the solar environment is constantly changing.

The change in current-voltage properties as a solar module heats up or receives more light can be an important source of efficiency losses in solar arrays. If the inverter that generates grid-compatible electricity is not tuned to the output voltage and current conditions, it will waste more of the electricity than it should. In response, electronics companies have produced ICs that perform the maximum power-point tracking (MPPT) needed to optimize energy conversion as well as bypass electronics to prevent temporarily unproductive modules from disrupting the output of active cells.

Costly Solar Mistakes Related to Solar Site Survey

This article reveals the major solar mistakes related to performing solar site

survey and location assessment for eventual deployment  of a solar panel

system. Please read it carefully because neglecting described below

mistakes may drain down your solar budget.

Performing a site survey is the starting point of launching every

photovoltaic system.

When searching for appropriate site for installation of PV modules, the

following is to be considered:

• Orientation towards the sun

• Lack of any shading obstacles (during the whole day and throughout the

whole year!)

• Minimization of the length of the DC cables between the PV array and the

inverter

• Aesthetics

• Protection from theft and vandalism

• Easy access for installation and maintenance of the PV array

Certainly the greatest mistake is to completely neglect the need for site

survey and expecting that a solar vendor will do that for you. Yes, they

will…but why not be better prepared to:

– Abandon your solar project due to bad location,

– Learn the performance limits of the system that will be installed at your

site,

– Find out how much your solar project will cost, or

– Avoid getting ripped off by an unconscious solar vendor?

1) Ignoring the influence of the nearby objects

The PV array should be provided with clear and unobstructed access to

sunlight between 9 a.m. and 3 p.m. every day, throughout the year. Mind

that even small shadows can affect severely the power output of the PV

array.

To achieve the maximum of your shading analysis, do the survey during a

bright and sunny day, preferably in summer when trees have their full

foliage mass.

During the site survey you should be looking for the following obstacles:

• Buildings – certainly you should be informed whether a new building is not

being planned nearby, throwing shade to your site;

• Chimneys, power lines, poles, hedges and neighboring roofs;

• Trees – if you’re performing your site survey in winter, remember than in

summer trees look different than in winter;

• Hills and other earth obstacles – mind that in winter sun is much closer to

the horizon than in summer.

A site that is unshaded during a part of the day might be partially shaded

during other time of the day. Similarly, if a site is unshaded in summer, it

might be shaded in winter since in winter sun is lower than in summer (and

close to the horizon) and casts longer shadows.

2) Underestimating the roof condition

Solar systems can be installed on any roof type.

There are two options for installing solar modules – either mounting them

on the roof or replacing the roof tiles with solar modules.

As a rule roofs with composition shingles are the easiest to work with, while

those with slate are the most difficult ones.

If solar modules are mounted on the roof, this has the following drawbacks:

• Modules must be removed upon performing any roof repair or

replacement activity;

• Installation of brackets and racks could cause roof leaks;

• Roof warranty may be affected;

• Some people might find this unattractive.

Roof-integrated installation costs amount however up to 40% more than

roof-mounted installation.

If your roof is relatively old and needs to be replaced in the near future, in

order to minimize any redundant costs a smart idea would be to replace it

at the time the PV system is being installed.

If you have a new roof, consult both your PV provider and roof repair

company how installation of a PV system will affect your roof warranty.

Certainly PV modules can be placed on the ground as well, on a fixed or

tracking mount.

3) Miscalculating the available roof area

Usually access space around the modules adds up to 20 % to the required

area for placing solar modules.

Don’t try to use every last square inch on your roof to install a solar array

because:

• The array gets difficult to install;

• The array gets hard to maintain;

• Wind loading at the edge of the roof increases;

• From a regulatory point of view you could violate some provisions for

providing available space for fire-fighters and other personal that might

need to access the roof area.

Consider the dead spaces around the array. These are the spots that are

either shaded or need to be left between the modules.

4) Choosing wrong orientation and tilt of the solar array

For grid-direct systems the orientation and tilt angle of the solar array is

usually subject of roof orientation and slope.

Use compass to check what direction your roof faces. Use a spirit level to

measure the angle of the roof from the horizontal.

If your site is located in the northern hemisphere, you should look towards

south, east and west. If your location is in the southern hemisphere, you

should look towards north, east and west. If you live near the equator, you

should look towards east and west.

The ideal roof for mounting your PV array is a roof facing south if you live in

the northern hemisphere, and facing north if you live in the southern

hemisphere.

Having chosen the right orientation, you have three options for tilting the

solar panels, certainly if your roof or installation area permits:

• For average yield throughout the year;

• For maximum yield in winter;

• For maximum yield in summer.

Solar energy differs from month to month and from season to season. This

is also true for sun’s position in the sky. That is why you have to choose in

advance between the above mentioned options.

For example, if your solar panels are tilted for maximum production in

winter, it means that the chosen tilt ensures solar rays to fall almost

perpendicularly onto solar panels only in winter.

For average yield throughout the year your solar panels should be tilted to

an angle equal to the latitude (in degrees) of your location.

For maximum yield in winter your solar panels should be tilted to an angle

equal to the latitude of your location minus 15 degrees.

For maximum yield in summer your solar panels should be tilted to an

angle equal to the latitude of your location plus 15 degrees.

How to find fast and easy the latitude of your location?

Just go to Wikipedia and search for your location. Then look at the top of

the right corner where location’s coordinates are reported. The first left

number is latitude of your location, followed by the longitude. If you cannot

find your city in Wikipedia, just find the closest big city to it.

Let’s imagine that you live in Birmingham, Alabama (USA), and you are

curious to find what tilt angels should be for the three available options:

From Wikipedia we get:

So the latitude of Birmingham is 33.525°. Therefore the three solar tilt

angles for the three above described options are as follows:

– For average yield throughout the year: -33.5°

– For maximum yield in winter: -18.5°

– For maximum yield in summer: -48.5°

6) Improperly chosen mounting of the solar array

There are four types of mounting methods:

• (Sloped-) Roof mounting,

• Flat roof/ground mounting,

• Roof-integrated mounting and

• Wall mounting

The PV array mounting type should be selected by carefully considering:

• Orientation towards the sun

• Site shading

• Weather at the location

• Roof material and bearing capacity (in case of roof mounting)

• Soil type and condition (in case of ground-mounting)

Regarding solar array mounting constructions, mind the following:

• Not every mounting construction is suitable for any kind of module, while

certain kinds of modules are intended for a specific mounting;

• It’s a good plan to ask the supplier of the PV modules to install them on

the roof;

• To ensure sufficient cooling of the PV modules, enough room should be

provided beneath them;

• A design visa and/or a build permit might be required

• All the necessary construction regulations are to be complied with.

11) Ignoring the benefits and drawbacks of solar tracking [1]

Use of solar tracker is another option for squeezing more power from the

sun. A solar tracker follows the sun position and movement in the sky and

ensures maximum collection of sun energy by solar panels.

The average efficiency of solar tracker is reported to increase the total

production yelled of 25-45%.

Although adding to the overall system costs, residential solar trackers do

not need much maintenance. More important however is that every solar

tracker is a potential point of failure. Furthermore a solar tracker consumes

extra power. What you should also have in mind is that there might be

some local regulations that prohibit the use of solar trackers.

Solar trackers are recommended especially in cases of limited space where

customer wants to achieve maximum solar array performance.

Source:

1. http://energyinformative.org/solar-panel-tracking-systems

Can Solar Panels Power a House?

What Can Solar Panels Power in My Home ?

Whether a solar electric system can entirely replace the utility grid and

meet your daily energy needs depends on your daily consumption.

If your home is already connected to the utility grid, replacing completely

the utility with a PV system might NOT be cost-effective.

Offsetting a part of your electrical bills through a solar system however

could be the best way to save money on electricity.

While you take your connection to the local utility grid for granted, solar

produced electricity is more expensive because your costs for solar

electricity production are higher than the costs of your utility grid for

producing electricity.

Therefore before implementing a solar system you should try to reduce

your daily electrical consumption. You should start with increasing energy

efficiency of your home or office. Achieving energy efficiency means

reducing electrical consumption and your monthly electricity bills

respectively.

Yes, saving energy is less expensive than producing energy. By improving

energy efficiency the cost of the photovoltaic system you are going to install

will be reduced.

Electrical heating appliances (dishwashers, washing machines, electrical

boilers, tumble driers) are not recommended to be powered by photovoltaic

systems.

For each heating appliance you should find a proper both energy-efficient

and cost-effective alternative. As a matter of fact, heat is always an

expensive source.

Actually you could power all those devices by solar electricity. You will

rarely see anyone do that however since heating devices are known as

‘power-hungry’. This means that powering heating devices by photovoltaics

turns out to be very expensive.

Calculating your daily consumption

Calculating your daily electricity consumption is a step to both reaching

energy efficiency and implementing a solar electric system.

Since an off-grid is not connected to the grid, it is irrelevant to talk about

offsetting a part of your energy consumption to the PV system. The PV

system should be able to meet all of your daily energy needs.

Calculating your daily electrical consumption means performing a load

analysis – determining your daily electrical energy consumption in Wh (or

kWh).

Performing a load analysis is very important since your PV system should

be neither oversized (=waste of time and money) nor undersized (=useless

for you).

To calculate your total average daily load you need to determine the

amount of energy (in kWh) consumed by each AC load. Therefore you

need to know the rated power of each load, the amount of time it is used

each day and the number of day this device is used each week.

You can find the power rating of each device on its label. If only current (in

Amps) is stated, multiply it by the voltage to get the power consumed. You

get the energy needed for every device by multiplying the power by the

number of hours the device is on.

By looking at the list of devices and consumed energy, you will get the idea

which of them consume the most energy and either think about ways for

reducing the consumption or discuss possible alternatives.

Example: AC loads table for a summer house:

solar daily consumption estimation

 

Total power = Rating x Qty

Average daily use = (Total power x Hours use per day x Days of use per

week) ? 7 days per week

If we assume a value of 0.92 for inverter efficiency, and the total average

daily load is 0 (i.e. no DC devices are used), the daily energy target is

calculated by the formula: Daily energy target = = (Total average AC load ?

Inverter efficiency) + Total average DC load = = (1,646 ? 0.92) + 0 = 1,789

Wh = 1.789 kWh

Instead of doing these calculations this manually, you could automate the

process by our Load Analysis Tool.  Click Here to Learn More About this

Tool

The Load Analysis Tool performs all the above calculations. Thus you can

directly use the values obtained in off-grid system basic evaluation.

What to do if your daily consumption is too high?

If your daily consumption of electricity is more than 2.5 kWh or if you live in

a region with poor sunlight for long periods, a purely photovoltaic off-grid

system cannot meet your energy needs. In such a case hybrid systems are

recommended.

A backup power generator modifies a stand-alone (that is, purely

photovoltaic) system into a hybrid one.

You could actually do without a backup generator in a photovoltaic-only

system but at higher cost – by oversizing your stand-alone PV system and

choosing a battery bank with very large capacity.

Such a strategy however is highly impractical for two reasons:

• Extremely high initial cost on batteries

• Such a system will work with maximum performance just a few months a

year (probably in winter) while in the rest of the time it will work far below its

maximum efficiency. Therefore the value of the electricity produced will be

probably not enough to cover the expenses needed for maintenance

support of the battery bank.

A hybrid system is a combination of photovoltaic generator and alternative

power generator operating by wind or fuel. Such a generator charges the

batteries upon lack of sunlight and is used either as backup or in case the

PV system alone cannot meet specific energy demands.

Here is a simplified view of a hybrid system:

Here are the advantages of a hybrid system:

Electricity is available at an acceptable cost during long periods of

cloudy/rainy weather or in winter

You can power some of the power-hungry devices (not all however!)

in your house

You could buy smaller (less expensive) battery bank and inverter

What about the disadvantages of a hybrid system:

Additional costs required for fuel and maintenance

Higher costs for buying fuel generator and bigger battery charger

So, when you should buy a hybrid system rather that a purely solar electric

one:

When sun is not enough during some months of the year, so a PV

system cannot cope alone with your energy needs

When you want to lower your initial costs

When the access to your house is difficult and/or expensive

When maintenance costs are not a problem

When you demand that electricity must be available all the time

 Click here to discover how to get more   details about hybrid systems.

So, if you live away enough from a utility grid, and you consider buying a stand-alone PV system,

first of all you should answer the following questions:

What applications do I need to power?

Above all you should mind that a PV system is not economically beneficial

to be used for powering heating appliances. Therefore you should find a

good alternative solution for heating, cooking and refrigeration.

 

Have I already made your building energy-efficient? Are my loads as

efficient as possible?

Do I live in my house during all the year, or just during certain

seasons?

If you live in your building in winter and your energy consumption is as

much as in summer, a more cost-effective solution would be a hybrid

system.

It will reduce your initial costs on batteries and, most probably, PV

modules.

 Solar Power Systems For Your Home Or BusinessMAY 23, 2013 BY SOLAR GUY LEAVE A COMMENT

  

Solar electric (photovoltaic) systems generate electricity from solar energy.

The solar generated electricity can be used in your home/office and/or

exported to the utility grid. Therefore solar power systems are divided in

two main types – connected to the grid, or ‘grid-tied’, and disconnected to

the grid, also known as ‘off-grid’.

The main components of grid-tied systems are solar panels and inverter.

Grid-tied systems only operate when utility grid is on. In case of utility grid

failure a grid-tied system stops cannot generate electricity unless it is

provided with power backup. Grid-tied systems are less expensive than off-

grid system and require less maintenance.

Apart from solar panels most off-grid solar electric systems contain a

battery and a battery managing device called charge controller. Inverter is

not needed if an off-grid system has to provide power to DC loads only.

Typically off-grid solar systems are more expensive – both as initial cost

and maintenance costs.

If an off-grid system does not contain any other power generators, it is

called ‘stand-alone’. Stand-alone systems are used when daily electricity

needs of a household or office are up to 2.5 kW. If daily needs exceed

2.5kW, a purely photovoltaic system is usually not cost effective, and hybrid

system is a better option to go for. A hybrid system contains at least one

more power generator apart from the solar array – this might be a wind

generator or a diesel generator.

Grid-tied systems are used to reduce your monthly electricity bills. Off-grid

solar system are built in areas where getting connected to a utility grid is

either impossible or not cost-effective. A solar system has a lifecycle of

between 25 and 30 years and it appears a good investment to meet your

future energy needs in a long-term period.

The problem however is that initial cost of photovoltaic systems and their

components are still relatively high. You have your daily energy needs and

you want to buy a solar system meeting them as cost-effectively as

possible. Apart from your budget available however, there are some other

limitations. You have a limited roof area and you don’t know how beneficial

is the sun at your location for investing a large sum of money into a solar

system. Last but not least – your site might turn out to be not suitable for

installing a solar system.

An option is to call a vendor and having all the things evaluated. But how to

select the right solar vendor? How to avoid all those unfair guys who are

eager to take advantage of your lack of solar knowledge and do your

down? How to be prepared to distinguish a good offer from a bad one and

be aware of what would best match your needs and budget?

 Free Solar Panel Calculator and Solar Power Calculator

Welcome To Our Free Solar Panel Calculator And Solar Power

Calculator.

 Please scroll down to read the Help file showing you how to use this

free solar calculator. To use our solar power calculator you need to

have Adobe Flash Player installed. Therefore, If you are using

Iphone/Android you may have difficulties in viewing our solar

calculator.

 Using the On-grid systems solar panel calculator

 Here is a quick guide how to use the calculator.

 Disclaimer: Provided calculator is for informational and educational

purposes only. By using this calculator you acknowledge that we can’t be

held responsible for any damages as a result of using this calculator

1. How many KiloWatts-Hours (kWh) do you use per month?

You are asked to quote your monthly consumption according to your

monthly electricity bill.

2. What percentage of this power will be used by renewable solar

energy?

If your home is connected to a utility grid, it is rather uncommon to offset all

of your consumption to a solar electric system. A fair percentage is usually

30 to 40, you are free however to choose a lower or a higher percentage

value.

3. Average Sun Hours per day?

You can find below information how  to find  Average Sun Hours  per day

also known as  Perfect Sun Hours/PSH/  for location in USA, Europe,

Australia and New Zealand,  and rest of the world:

3.1 You can take this value  for USA by clicking on the following link:

http://maps.nrel.gov/pvdaq ,

expand the ‘Solar Resources’ folder on the left and tick the ‘Avg. Annual Tilt

at Lat’ checkbox. After that you will see a map of the United States with

Average Sun Hours plotted on. Then by clicking on the little black arrow

right to the checkbox, you can expand the legend and see the value of

Average Sun Hours for your location after zooming in the map as much as

you need to find the place where you live.

Eventually you get the minimum and the recommended size (in Watts) of

the solar system you need. ‘System size’ means the total power of the solar

panels that need to be installed on your roof to meet the electricity

consumption target you want to offset to the solar system.

3.2 You can find the Average Sun Hours per day value for Europe  by

clicking on following link:

http://re.jrc.ec.europa.eu/pvgis/countries/europe/EU-

Glob_opta_publications.png

Please don’t forget to divide the value of yearly sum of global irradiation in

KWh/m2 by 365 to obtain the value for average Sun Hours per day.

3.3  For Australia and New Zealand:

solarpanelsvenue.com/out/australia_sunshine_hours.JPG

3.4 If you live outside USA and Europe you can find the Average Sun

Hours per day value for your country by using the World map of direct

normal irradiance, which means that these values are applicable for  the

solar panel held perpendicular to the sun rays. In other words, the tilt of

your solar panels is equal to the latitude of your place.

http://www.dlr.de/tt/Portaldata/41/Resources/dokumente/institut/system/

projects/reaccess/ssedni60.jpg

Please don’t forget to divide the value of yearly sum of direct normal

irradiance in KWh/m2/y  by 365 to obtain the value for average Sun Hours

per day for your location

On Grid  Solar Calculator Assumptions: Recommended System Size 

assumes 85% solar system efficiency or in other words 15% total system

losses.

How to calculate number of solar panels needed for your solar

system?

Number of solar panels needed= Recommended System Size in

Wats/Chosen Panel in  Watts. Round up the calculated value

For example you have calculated that you need Recommended System

Size 5000Watts.

You have chosen your system voltage to be 12V and your solar panel to be

240Watt for 12V solar system.

Then number of solar panels that you need is:

Number of solar panels needed=5000/240=20.8 solar panels. After

rounding it up we receive that you need to buy 21 solar panels.

Please, use the update button below the calculator body to update the

calculated results if those results are not updating automatically.

Using the off-grid system solar panel calculator

1. What is the total Watts (W) you electronics will consume?

You need to sum the wattages of all the electrical devices you use and

therefore you want your off-grid solar system to support. Each device has

its wattage on its back label.

2. For how long are you planning to run these devices?

You should decide for how long you have all these devices plugged in, so

that the solar system will be able to power them. Here you need the

average hours of operation rather than the maximum ones.

3. Charge Controller efficiency (PWM: 80%, MPPT: 92%)

Charge controller is a device that manages the battery of a solar system.

PWM charge controllers is less expensive than MPPT charge controllers

but they are also less efficient.

4. Average Sun Hours per day?

As it has been explained above for the off-grid solar system

 Off-grid system calculator assumptions

1. Calculated battery size provides:

-up to 2 days autonomous work with no additional charge of battery

due to bad weather or system failure at 100% battery discharge, which

is not recommended and may destroy your batteries. 

-up to 1.65  days autonomous work with 80% battery discharge

-up to 1 day autonomous work with 50% battery discharge.

 2. Minimum system size takes into account 3% cable losses and 80%

efficiency of battery bank. As you know batteries have losses due to

temperature influence and discharge rate. Generally,

lower temperatures, especially negative ones, and higher discharge

rates in Amperes may drastically reduce the battery bank efficiency.

3. Recommended system size takes into account charge controller

efficiency being inputted.

How to calculate number of solar panels needed for your solar

system?

Number of solar panels needed= Recommended System Size in

Wats/Chosen Panel in  Watts. Round up the calculated value

For example you have calculated that you need Recommended System

Size 5000Watts.

You have chosen your system voltage to be 12V and your solar panel to be

240Watt for 12V solar system.

Then number of solar panels that you need is:

Number of solar panels needed=5000/240=20.8 solar panels. After

rounding it up we receive that you need to buy 21 solar panels.

Please, use the update button below the calculator body to update the

calculated results if those results are not updating automatically.

What is a charge controller?

Charge controllers – important battery managers

Charge controller is a device preventing batteries from overcharging and

overdischarging. One of the most common problems of batteries is that

they cannot be discharged excessively or recharged too often. A charge

controller controls the charge by managing properly the battery voltage and

current.

Charge controllers are intended to protect the battery and to deliver it as

longer life as possible, while keeping the photovoltaic  system efficiency. It

should be noted that charge controllers only control DC loads. AC loads are

to be controlled (and disconnected, if needed) by an inverter.

The key functions of charge controllers are:

Protecting the battery from overcharging by limiting the charging

voltage

Protecting the battery from deep and/or unwanted discharging. The

charge controller automatically disconnects the loads from the battery

when battery voltage falls below a certain depth of discharge value

Preventing the reverse current through PV modules at night

Providing information about battery state of charge

The main charge controller types available today are PWM (Pulse Width

Modulation) and MPPT (Maximum Power Point Tracking) ones. MPPT

charge controllers are more expensive but they can boost the performance

of the solar array. PWM charge controllers are less expensive but they can

extend battery bank’s lifecycle at the expense of solar panels performing

lower than in case of MPPT controller. Similar to inverters, charge

controllers have a lifespan of about 15 years.

A charge controller costs between $500 and $1,000. This is not a fortune

but not choosing the proper charge controller for your system might results

in series of problems. Your solar system might either underperform or not

work at all. The worst however is that other system components might get

damaged. Therefore selecting charge controller should not be

underestimated. What kind of charge controller to choose depends on the

specific case and is a tradeoff between getting more power from solar

panels and extending battery life. To get an idea what controller you need

for your system you need neither dig into heavy science nor be a solar

guru. You just have to know some basic info such as:

–      Which type of charge controller is recommended for a given solar

system type

–      What maintenance a charge controller needs and how much are its

annual maintenance costs

–      When you need a couple of charge controllers rather than a single one

–      Which charge controller type is recommended for hot climates

–      What controller to select for a small solar system

–      What controller you need to connect a 48V-solar array to a 24V-

battery bank

Click Here to discover more about  how the charge controller can boost the

performance of your solar system even more.

Solar Batteries

What kind of solar battery you need for your solar electric system?

By watching  video below  you will discover:

basics of solar batteries and their application in solar power systems

the most important battery features,

what kinds of batteries are used in solar power systems

how to connect them  and what to avoid to have an efficient and

healthy solar  battery bank

Solar batteries are devices capable to produce and store DC electricity.

Batteries are commonly used in solar electric systems as substitute of solar

panels at night or during cloudy days. In such situations the needed

electricity is drawn from batteries instead from the solar array which cannot

act as a generator due to insufficient sunlight.

Battery, however, is not an indispensable part of a photovoltaic system.

When a solar electric system is connected to the utility grid, it typically does

not contain batteries unless a power backup is needed for certain special

electric devices. Most solar systems disconnected from the grid contain

batteries, along with charge controllers – devices who manage battery

charging and discharging. In a solar electric system batteries are usually

combined in a battery bank to get the desired voltage and capacity.

A battery is made of cells which can be either wet or dry ones.

Wet cell batteries are more common than dry cells due to their high

performance, cost efficiency and reliability.

Their drawbacks, however, are low mobility and need for regular

maintenance, as well as for a separate room. Such drawbacks are

eliminated by dry cell batteries which are more expensive and have shorter

lifecycle.

No matter what kind of battery is used, solar battery cost makes a

substantial part of the cost of any solar system.

As a rule, cost of the battery bank is 25% and 50% of total system cost. It is

very important if not to be able to choose the right battery bank for your

solar system, to be able to evaluate what you are offered by a solar system

vendor.

A battery with less capacity than needed will not be able to meet your daily

energy needs and the whole solar system gets pointless. A battery of

capacity greater than needed will not only cost much higher, but will also

degrade severely the performance of your system.

Moreover, such a battery will cost you much more in view of regular

maintenance and, last but not least, is tougher to get recycled.

If you’d  like to discover more how to size  your battery bank Click Here to

get our new book ” The Ultimate Solar Power Design Guide: Less Theory

More Practice” 

What is A Solar Inverter ?

 

Solar Inverter: Image by

Lauren Wellicome on Flickr, used under the Creative Commons license

Solar Inverter is a device capable to convert DC into AC electricity.

Inverters are typical components of solar electric systems since solar

panels generate DC electricity and most devices used in homes or offices

operate on AC voltage.

There are two main types of solar system – connected to the grid (grid-tied)

and disconnected from the grid (off-grid).

Although inverter’s main function is always the same – converting DC into

AC electricity – these two kinds of systems use different kinds of inverters.

Grid-tied inverter is the heart of any grid-tied solar system since a grid-tied

system must contain an inverter.

A grid-tied inverter converts the DC voltage from the solar array into AC

voltage that can be either used right away or exported to the utility grid.

A grid-tied inverter must strictly comply with utility grid’s requirements and

regulations. For example grid-tied inverters must generate AC voltage of a

strictly sinusoidal form.

One of the main features of a grid-tied inverter is that it stops operating in

case of a grid failure. Thus technicians doing any repair works on utility

network are prevented from getting an electric shock.

Off-grid inverters are different from grid-tied inverters.

An off-grid solar system might not contain an inverter if DC loads only are

to be powered.

Since off-grid systems are disconnected from utility grid, off-grid inverters

need not to match utility grid requirements and regulations.

Depending on its size a photovoltaic system could comprise either a single

inverter or multiple ones.

Each of these two concepts has its benefits and drawbacks. Most of the

modern inverters are provided with a Maximum Power Point Tracking

feature enabling generation of solar electricity at maximum solar panel

performance.

Inverters are expensive and often bulky devices especially the ones for

high power solar systems.

Nevertheless inverters are neither mysterious nor that difficult to

understand.

To be in clear what inverter you need for your solar system, you just need

to know a couple of basic things.

That info would help you not only in selecting the right kind of inverter but

will also make you confident upon receiving an offer from a solar vendor or

installer. In other words, your background about inverters can help select

the right solar offer matching best your energy needs and available budget.

As a potential solar buyer you are supposed to know the following basics:

What kind of maintenance an inverter needs and how much is such

maintenance per year

How to estimate ‘AC power rating’ – the key parameter of any inverter

What to be careful about when selecting an inverter with MPPT

feature

In which cases a single inverter is not enough

How a microinverter can increase system performance even if your solar

array is shaded

Click Here to Discover How the Solar Inverter Can Boost the Performance

of Your Solar Power system