What Are The Disadvantages Of Solar Power?

Timber framed house with a photovoltaic array ...
Timber framed house with a photovoltaic array of solar panels in Buschhoven near Bonn, Germany Source: Wikipedia

Along with numerous advantages, solar power has some drawbacks. Let’s list the most important disadvantages of solar power:

1. Solar electricity might not  be economically beneficial for everyone

Our comment on this disadvantage of solar power:

Although prices of photovoltaics / solar panels are steadily going down and electricity prices rise gradually in the USA on average with 5% per year (in other countries with highest percentage), the  cost effectiveness of solar systems installation depends not only on solar panels prices but also on current electricity price at your location and hardware installation cost. The cost of a PV system can be further reduced by solar rebates and other incentives.

Therefore each case is different and needs careful evaluation. Replacing even partially your utility grid with a solar system however can be beneficial for you.

2. Variability of solar radiation

Our comment on this drawback:

Unfortunately the sun does not deliver the same amount of energy over different locations and different seasons.

In winter season energy generated by a PV system could not be enough to meet daily energy needs. This imposes use of either a large battery bank or additional power source, which brings certain drawbacks and higher costs.

3. Specific orientation of solar panels

Our comment on this drawback:

To provide maximum energy yield, roofs where solar systems are installed should face South (or North, if you live in Australia or New Zealand), and a certain elevation angle is recommended for mounting the PV panels.

Otherwise the system will not perform well and the whole investment gets pointless.

4. Site must not be shaded

Our comment:

Every shade has a negative impact on solar panels and as a consequence solar system’s performance drops dramatically. Shades and solar systems cannot coexist together.

While some manufacturers claim that their panels are shade tolerant, do have in mind that if only 1/4 of the panel cell area is shaded, the generated electrical power will be virtually nil.

5. A solar panel system produces energy in daytime only

Our comment:

Solar panels only produce energy during daytime and the amount of energy provided is different during that period. What is more a solar system can generate excessive energy during given hours when you do not need it.

The solution to such a problem is using an energy storage system (battery bank).

The solar array can be mounted on a roof. Another option which is becoming increasingly popular is building-integrated mounting where a PV array can actually be a physical replacement of the roof covering (on modern office buildings). Very often a PV array can be mounted on the top of a pole rack – as is the case of solar lamps in parks.

The PV array mounting type is 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 panel mounting mind the following:

  • Not every mounting construction is suitable for any kind of module. Furthermore certain kinds of modules are intended for a specific mounting type.
  • To ensure sufficient cooling of the PV modules, which leads to higher system efficiency, enough room is to be provided beneath them.
  • A design visa and a build permit are usually required.
  • All the necessary applicable construction regulations are to be complied with.

When designing a solar system it is very important to mount the solar array properly so that it would receive as much sunlight as possible.

As a rule solar arrays are recommended to install on roofs facing True South (for North America – USA, Canada and Europe) or True North – if you live in the Southern hemisphere, e.g. Australia, New Zealand.

Installation on roofs facing North (or South – if you live in the Southern hemisphere) is not recommended.

Solar arrays should be installed at a location which is not in shade.

Direct shadows can dramatically bring down the power yield of any PV system. Often however – and this is valid especially if you live in an urban area – it is not possible to find an unshaded place around your house.

There are two main types of solar electric systems – grid-tied and off-grid. More info about these main solar system types you can find by Clicking Here.

Here are the limitations of grid-tied systems:

  • Can generate electricity as long as your utility is on. In case of power outage, a grid-tied system cannot generate electricity regardless of whether the sun is shining or not.
  • A grid-tied system (unless it’s provided with a battery backup) can only generate electricity in daylight. A grid-tied system with battery backup however is always related with higher both initial and maintenance costs.
  • A grid-tied electric system must match various rules, regulations and standards for solar power installations. Such rules and regulations are specific for the region and the country where you live.
  • Launching a grid-tied system is always related to applying for permits and preparing lots of mandatory documents in order to meet the necessary objectives. What is more, you are dependent on your local utility grid about electricity sell/buy prices and net-metering.

Here is a list of the limitations of off-grid systems:

  • Unless your building is located too far from utility grid, it is not cost-effective to replace the utility grid with a stand-alone PV system.
  • Due to solar radiation variability a PV system does not deliver maximum performance all the year round. In winter months it is often more cost-effective to buy a hybrid system than to spend a fortune on a battery bank, relying solely on your solar system.
  • The electricity produced by the PV array can be stored in batteries for limited period only.
  • Making your home energy efficient is a must before buying a stand-alone system.
  • The battery banks used in most stand-alone systems require a separate, well-ventilated room, as well as certain maintenance.

What you should mind if you decide to buy an off-grid system:

  • During cloudy days the energy needs are to be met by the battery bank, since PV array generates insignificant amount of power.
  • The greater the energy consumption to be met, the larger battery required. ‘Larger’ means expensive, bulky and challenging to maintain.
  • In winter energy consumption is greater than in summer. In winter however, available solar radiation is much less than in summer.
  • If the PV system is designed to meet all the energy needs in winter (by throwing a fortune on a battery bank), the energy surplus will remain unused throughout the rest of the year. This makes the system quite uneconomical.
  • The longer payback period is aggravated not only by the costly battery bank, but also due to the fact that while the battery bank provides the energy required, the PV array is not operational.
  • A large battery bank is not well acceptable from an ecological point of view.

Click Here to find out how to evaluate whether solar power is good for your specific case.

 

 You also may like: Uses of Solar Energy

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Lacho Pop, MSE, holds a Master's Degree in Electronics and Automatics. He has more than 15 years of experience in the design and implementation of various sophisticated electronic, solar power, and telecommunication systems.  He authored and co-authored several practical solar books in the field of solar power and solar photovoltaics. All the books were well-received by the public. You can discover more about his bestselling solar books on Amazon on his profile page here: Lacho Pop, MSE Profile

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