What Are the 2 Main Disadvantages of Solar Energy? Solar Panels Cons

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The 2 Main Disadvantages to Solar Energy_post top

What are 2/3 disadvantages of solar energy?

The 2 main disadvantages of solar energy are dependence on weather conditions and the inability to store electricity. Solar energy output depends mostly on direct sunlight. A cloudy day can reduce electricity generation by more than 80%. Solar panels generate no power at night and so batteries are needed for 24 hour supply.

Page Contents

What are the main disadvantages of solar energy?

Cons of Solar Energy

    1. Dependence on the weather – clouds severely reduce output
    2. Solar panels don’t work at night
    3. Not good for the environment in the long-term – toxicity
    4. Installation cost, particularly if batteries needed
    5. Solar panels are not very efficient
    6. Solar output in watts depends on irradiance (sun’s energy) in geographic location
    7. Big area needed for large systems
    8. Solar panels get hot in full sun and output reduces
    9. Actual output about 75% of system rating due to system losses
    10. Solar PV electricity output is DC – inverters needed to convert to AC

The Pros and Cons of Solar Energy

Just a few years ago one of the main disadvantages of solar energy was cost. This is no longer the case.

The cost of producing solar panels has fallen tenfold in as many years and financial incentives make it very attractive for the homeowner.

However, solar energy does still have significant disadvantages which we should be aware of.

Main benefits and negatives of solar power

Pros and Cons of solar power

Main Advantages (benefits)

Main Disdavantages (drawbacks)

Non-polluting once installed

Pollutants released during manufacture

No moving parts (long installation life)

Contain toxic chemicals

Replaces fossil fuels - reduces emissions

Difficult and expensive to recycle

Generates jobs

Output depends on the weather

Totally renewable as long as the sun shines!

Expensive to install

Reduces over-loaded national power grids

Can't store electricity (unless batteries installed)

Advantages and 2 main disadvantages of solar energy


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Solar energy main disadvantages #1 – Dependence on the weather

I think solar energy is a miracle that should not be understated. It’s clean, there are no moving parts and it can help to clean up our planet.

However, solar panels have a massive disadvantage – if the sun doesn’t shine, no electricity is generated! This one of the biggest drawbacks of solar energy. One fundamental limitation of solar power is that the amount of power generated is hugely dependent on the strength of the sun’s rays.

If solar panels are shaded by passing clouds, power output will drop. This is one of the drawbacks compared to geothermal energy, for example, which is available all the time. However, solar still has significant advantages over fast disappearing non renewable resources.

How efficient are solar panels?

Most commercial solar panels are between 18% to 20% efficient. Some manufacturers (such as Dokio) boast up to 25% efficiency, but this is still quite low.

It means that for every 1000 watts of the sun’s energy falling onto the panel’s surface, we get about 200 watts of electrical power. The solar cell conversion process is not that efficient.

Compare that with solar water heating, which transfers the sun’s energy to water with up to 75% efficiency. The difference is that it is a thermal transfer and not a conversion process.

The effect of irradiance and location on solar energy output

Irradiance is a direct measure of the sun’s energy falling onto solar panels and varies according to location. It’s measured in kilowatt-hour per square meter per day (kWh/m2/day or year) which is also known as peak-sun-hours.

Solar irradiance (peak-sun-hours) for some US and UK cities

City

Chicago, Il

London, UK

Glasgow, UK

Houston, Tx

San Fran., Ca

Irradiance (peak-sun-hours)

4.043

2.374

1.860

4.253

5.699

Solar installers use this value to estimate how much energy a solar panel will produce. The average irradiance for the USA is 4 peak-sun-hours. For a 100 watt solar panel:

Energy generated by 100 watts solar = 100 watts x 4 peak-sun-hours = 400 watt-hours.

Some locations have high irradiance, like Nevada, and others have low irradiance, like Alaska. Alaska’s low irradiance is a big disadvantage for people considering a solar energy installation.

Poor weather in the form of clouds has the same effect as low irradiance as the sun’s energy is blocked.

Effect of cloud cover on solar panels

All solar power systems are subject to a variety of losses which reduce the power output of solar panels.

Some losses we can impact, such as cleaning, but other we have to live with. One of these losses we can’t improve is the effect of bad weather and cloud cover.

The infographic below shows that shading losses due to poor weather can be up to 7%. For an average size solar system of 6kW this represents 420 watts, almost half a kilowatt.

Without suitable protection using suitable electronics, a 60 cell solar panel can lose up to 75% of its power output if just one cell is completely covered!

In real-life situations all of a panel’s cells are subject to reduced irradiance due to various types of cloud cover. Solar panels aren’t very efficient anyway, and added losses can be a major disadvantage.

Infographic: Solar Disadvantages – Typical solar PV losses in a home installation

Cloud cover is a major disadvantage of solar energy

One disadvantage of solar power generation is shading due to passing clouds

What kind of protection prevention is used against shading?

In the early days of home solar power system design an individual inverter was used to convert the DC generated by solar panels into the AC needed by home appliances.

This topology was efficient enough when all of the solar panels were irradiated in full sunshine.

However, if even one of the solar panels became covered, the output of the whole system would be reduced, sometimes dramatically.

The modern solution is to install micro-inverters at the panel level, or a small groups of panels. This has the effect of limiting power reduction to a small part of the solar power system.

Shading protection – compare string inverters, microinverters and power optimizers

Central Inverter $

Converts DC to AC in one location.

No local panel monitoring.

Whole system output reduced by shading

String Inverters $$

Converts DC to AC for several panels.

String can be monitored.

Only string output reduced by shading.

Micro Inverters $$$

Converts DC to AC at panels level.

Panel level monitoring and optimization.

Only individual panel output affected by shading.

String Inverter + Power Optimizer $$$$

Converts DC to AC for several panels.

Adds panel level MPP function - DC optimization at panel level.

Only individual panel output affected by shading.

Main disadvantages of solar energy #2

Solar panels don’t work at night

Although research into solar panels that work at night is ongoing, they don’t yet exist in any viable form, so it must be considered one of the main disadvantages.

Solar panels work best in full sunshine during the four or five hours around mid-day. Power output reduces rapidly in the early morning and late evening (see power output curve below.)

Soalr panels disadvantage - no generation at night

The blue curve shows solar output in the day with no solar tracking – generation at night is zero.

If power is required at night, for an off-grid solar power system for example, then batteries will be required.

The additional cost of batteries to a solar installation can be up to 30% of the overall cost, which is another primary disadvantage of solar panels.

Even for a grid-tie system it’s not ideal, as during the night power is taken from the grid. Although the home-owner is credited for solar over-production, a few cloudy days could severely reduce the savings associated with on grid solar.

One solution is to install home energy storage batteries, even if connected to the grid. In this way they will always be topped up and ready to supply power at night or during an outage.

Disadvantages of solar energy #3

Disadvantages of solar energy to the environment

The third disadvantage of solar power is very important and shouldn’t be minimized – although they are very clean in operation, solar panels are potential pollutants.

Solar panel manufactures give warranties between 25 to 30 years, guaranteeing output up to 85% to 90% after that time. Panels may continue to generate power for up to 50 years.

It seems reasonable to suppose that homeowners will opt to replace solar panels soon after the guarantee period, rather than experience declining output levels, particularly if prices keep coming down.

Hundreds of thousands, if not millions, of solar panels are being installed right now and these will be scrapped in 25 years. Where are they going to go?

Do solar panels have toxic chemicals?

The main active component of a solar cell is silicon – it’s basically a flat semi-conductor. Almost everything that goes into a panel’s construction is rich in heavy metals which are toxic to various degrees.

The question is how to deal with them when they are no longer needed?

Toxic Chemicals in Solar Panels

Material

Easily Recycled? Into What Form?

Is it toxic?

Silicon

Medium - melted and re-formed into silicon slugs

No

Glass

Easy - reformed into glass for other products

No

Aluminium

Easy - remelted and extruded into new frames

Medium

Copper

Easy - melted and reformed into wires and contacts

Low

Silver

Easy - melted and reformed into electrical connectors

Very low

Lead

Easy, if in metallic form (very small amount in panels)

Yes, over time, cumulative

Cadmium Telluride

Difficult

Yes

Copper Indium Selenide

Difficult

Yes

Cadmium Gallium (di)Selenide

Difficult

Yes

Copper Indium Gallium (di)Selenide

Medium

Yes

Polyvinyl Fluoride

Difficult

Yes

Silcon Tetracholoride

No - Production stage by-product

Yes

Much research is being carried out with a view to recycling them back into usable panels but there are major problems. At the current time it seems as though the easiest (and worst) solution will be to bury them in landfills.

Over time the heavy metals will leach out into the environment so this is not a good long-term solution. It’s considered that this disadvantage is more than outweighed by the environmental impact of replacing non renewable energies in the form of fossil fuels.

Complete recycling is possible but the issue is cost. It costs 3 times more to recycle solar panels than to simply bury them. The story is ongoing …

Pros and cons of solar panels on my roof

There aren’t too many problems with solar panels. They are generally a great way to generate electricity from a renewable resource but on of the cons of solar panels for home use is that your roof:

  • may not face the sun in a good orientation to maximize solar output
  • could be too small to mount sufficient solar panels area for your needs
  • your roof may be shaded by trees or other buildings

Facts about solar energy

Some negative facts about solar energy include environmental issues regarding their toxicity, solar panels are very inefficient (about 18% energy conversion rate), and their output depends on weather conditions and the amount of the sun’s energy in any location.

5 facts about solar energy

  1. Solar panels are only about 18% efficient
  2. Solar system output is only 75% of rated output due to system losses
  3. Monocrystalline panels are more efficient than polycrystalline, but more expensive
  4. Solar PV systems need an inverter to convert DC electricity to AC
  5. Solar panels life is between 25 to 30 years

Other Questions Frequently Asked:

What is a major disadvantage of using solar power?

Perhaps the biggest drawback of solar power is that it’s very dependent on the weather. If clouds cover the sun, the solar energy output is severely limited.

As a general rule, a cloudy and rainy day can reduce panel output by up to 90%, you need to think hard about installing a system in  a location with low irradiance (peak-sun-hours) – see this site to check solar irradiance for your location.

What are 2 pros and 2 cons of solar energy?

A ‘pro’ is a benefit and a ‘con’ is a drawback, from the Latin pro et contra, meaning ‘for and against’.

2 Main pros for solar

  1. Main pro #1: Once installed, energy is completely free as long as the sun shines.
  2. Main pro #2: Solar installation are quiet, reliable and require almost no maintenance.

2 main cons for solar

  1. Main con #1: Dependent on the weather.
  2. Main con #2: Installation costs are high, although reducing all the time.

Do you really save money with solar panels?

Solar panels really do save money, and also make money as they can increase the value of your home.

The calculation below shows the savings and payback period for a solar panels installation in Houston, Texas:

  • City: Houston, Texas
  • Average size of system: 5kW
  • Cost of solar = $13700 – 22% federal tax credit = $10686
  • Irradiance in Houston, Tx = 1552
  • Electricity produced = 1552 x 5kw = 7760 kWhrs
  • Cost of electricity = 10.98 cents/kWh
  • Amount saving per year = solar production x electricity cost = 7760 x 10.98 = $852
  • Time to payback = cost of solar system / yearly savings = 10686/852 = 12.5 years

In addition, Zillow found that a solar installation adds around 4% to the value of the average American home.

What are 2/3 disadvantages of solar energy?

The top 3 disadvantages of solar energy are:

  1. Can be severely affected by the weather (clouds and rain reduces irradiance)
  2. Cannot generate power at night (batteries are required for off-grid systems)
  3. Potentially toxic and difficult to recycle (heavy metals can leach from landfills)

How long do solar panels last?

Manufacturer’s warranties vary from 25 to 30 years, with a guarantee of 90% production after that period.

Solar panels can continue to generate power for up to 50 years, with reducing output of 0.8% per year.

Do solar panels need servicing?

The actual panels don’t need servicing unless the output reduces. In that case, simple tests can be carried out to see which panel is at fault.

The only regular maintenance recommended is a twice-yearly cleaning to remove any dust and debris. Dust and dirt can result in a 2% loss in output power.

What are other drawbacks to solar energy? Recap

The main drawbacks to solar energy are:

  • reduced power output in cloudy weather
  • zero output at night
  • solar panels can’t store electricity
  • solar energy is direct current and needs converting for a.c. appliances
  • solar panels are inefficient, 20% maximum

Are solar panels worth it economically?

As a general rule, solar panels are worth it largely due to a application of the Federal Tax Rebate (USA wide tax refund), Net Metering rates for buying-back surplus energy, and other incentives that vary from State to State,including sales tax and tax exemptions for improving your home.

Key takeaways of solar panel system disadvantages

Solar energy systems are a particularly good way of using an abundant renewable energy source: the sun! Government and state tax credits help homeowners to reduce their carbon footprint and their electric bill.

There is a big push for clean energy in the United States, both from the point of view of climate change and the continually rising energy bill. Solar arrays are one of the keys to affordable energy and in the long run solar farms may someday provide all the excess energy we need to run homes and factories.

Is the solar industry sustainable?

Fossil-based fuels such as natural gas emit carbon dioxide and are also expensive, driving up your electricity bill. Any homeowner can get energy independence with a reasonable upfront cost, freedom from utility bills and reduce greenhouse gases by simply using solar cells and abundant solar radiation. It can even increase your home value!

Solar companies apply the latest solar energy technology to their business and work hand in hand with your utility company to create viable solar solutions with enough energy to run your home. The solar energy industry is no longer in it’s infancy and global warming will not go away!

Do solar energy disadvantages outweigh the advantages?

In my opinion, the disadvantages of solar power are insignificant when compared with the benefits of this source of energy. While it’s true that photovoltaic cells are difficult to recycle, they can produce useful power with low maintenance costs for up to 30 years, easily paying back the initial investment.

Care needs to be taken when scrapping solar panels as they contain hazardous materials and the federal government has strict legislation dealing with recycling. More and more, solar technologies include methods for safely scrapping a PV cell.

Will solar panel installation costs ever come down?

All solar energy work will tend to have a high initial cost, but tax incentives can reduce this substantially, particularly in recent years, over the past decade. The upfront costs are well worth it when considering reduced greenhouse gas emissions.

On the plus side, homeowners can get a solar investment tax credit to further bring down the cost of their energy needs. The cost of electrical energy is particularly steep and more is being used every year.

Once installed, little maintenance is needed so additional costs are minimal and in the summer months excess power is almost assured. Installing solar batteries with a solar array would also give some autonomy and protect against power outage while saving on energy costs.

How do other power sources compare with solar energy?

Solar power is a good candidate as it feeds directly into the electrical grid. Other renewable sources are more problematic as they need conversion before utility companies can use them in their original form.

One of the worst things about solar is that output can be very low on rainy days, sometimes not delivering enough power to fully run a home. In this case, and in the winter months, the power grid is used, which would push up the average cost of solar electricity.

Other resources relating to solar disadvantages:

Solar Energy Pros And Cons: The Top Benefits/Drawbacks

Advantages & Disadvantages of Solar Energy | GreenMatch

16 Advantages & 10 Disadvantages Of Solar Panels In 2022

The Cost of Solar Panels – and Are They Worth It? – US News

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