What are the pros and cons of solar energy?


Advantages of Solar Energy

1. Marginal cost of generation is zero

For most American home owners the most significant attraction to solar power is that once the capital cost of installing it is paid off the energy is free. This means the only real question is whether the payback period on the capital investment is better than the returns they would get from investing their money in other ways.

You may be surprised that we now list this as the leading advantage of solar energy. The reason we do this is that most home owners are now more interested in the financial aspects of installing solar rather than the environmental benefits.

2. Insurance against rising power prices

Installing a solar power system on your home means you can lock in a price of energy for at least the 25 year life of the solar panels. You know how much energy the solar panels will produce so that once you get an accurate price quote you know exactly how much each kilowatt hour of energy will cost you over the next 25 years. Many consumers are now able to get a levelized cost of energy of $0.10 per kilowatt hour. When you compare this to the average amount you will pay to your utility for power over the next 25 years, the average consumer with a $150 per month power bill can see savings in the range $30,000 over the life of a solar system. The monthly savings don't start out being huge, perhaps only $50 per month but in the 25th year it can reach savings of $300 per month. You can use this solar savings calculator to check what your savings will be based on usage and utility rates.

pvwatts.nrel.gov
www.solar-estimate.org

3. Renewable

Solar energy is a renewable energy source:
NASA estimates that the sun will shine for another 6.5 billion years. Most of us aren't too concerned out that far.

Solar energy is abundant:
The surface of the earth receives 120,000 terawatts of solar radiation (sunlight) – 20,000 times more power than what is needed to supply the entire world.[2]

4. Environmentally Friendly

Harnessing solar energy does not generally cause pollution. Whilst there are some emissions associated with the production and installation of solar energy equipment these emissions are minimal when compared to generating electricity from fossil fuels. The CSIRO, an Australian government research body estimates that the energy payback is 1.5 years. That is, it takes a solar panel 1.5 years to generate the amount of power it took to make it. This statistic was from 2009 and is likely to be a quicker payback now. Given solar panels are warranted to last 25 years this is quite good.

5. Geographically widely available

The level of solar irradiation that falls upon the earth varies with the geography of the planet. Generally, the closer to the equator the more solar energy but what most don't realize is that solar energy can be used anywhere. For example, in the sunniest parts of America a solar system will produce on average 4.7 kWh of power per 1 kilowatt of solar panels but in the least sunny areas, such as the mountains and north east, it wills till produce 2.9 kilowatt hours per kilowatt, per day. So although some areas are better than others for solar power it is still viable in almost all locations.

6. Reduces Electricity Costs

With the introduction of net metering and feed-in tariff (FIT) schemes, homeowners can now "sell" excess electricity, or receive bill credits, during times when they produce more electricity than what they actually consume. This means that homeowners can reduce their overall electricity expenses by going solar. Data from www.solar-estimate.org reveals that adding solar panels to your home can bring in annual savings of well above $1000 per year in many states. In California, residents save on average $28,000 after 20 years! The availability of solar finance options in the form of Solar PPA agreements and various zero down loan facilities has meant solar is now more affordable and more available than ever before.

If you want to see the average cost of solar panels installed in your county and calculate savings you could expect from installing solar on your home visit cost of solar panels.

7. Community Solar can be used to overcome installation issues

Because of shading, insufficient space and ownership issues many American homes are simply unfit for solar panels. With the introduction of shared solar, homeowners can subscribe to "community solar gardens", and generate solar electricity without actually having solar panels on their own rooftops. The advantage of this is that installation costs can be cheaper if large numbers of panels are installed on vacant land. Legislation is required to enable community solar in each state and whilst this has existed from some time in some smaller states it is only just coming into play in key states such as California and New York.

8. No moving Parts means no noise and little maintenance

Because there are no moving parts involved in solar power systems there is no noise associated with photovoltaics. This compares favorably to other renewable technologies such as wind turbines. Also, because there are no moving parts there is no noise pollution from solar technologies.

9. Financial Support from Government/State

In December 2015 the US Senate passed an extension to the 30% Renewable Tax Credit, extending this tax credit for a further 8 years. In addition to this Federal incentive there are also rebates available in some jurisdictions at either the state, county or utility company level. If you use the solar panel calculator here you can see what rebates, tax credits and other incentives your house is entitled to based on its location and the utility company you are with.

10. Technology is Improving

Technological advancements are constantly being made in the design and manufacture of solar power equipment. As the cells in solar panels become more efficient at turning solar energy into electricity the amount of space required to generate a specific amount of solar power will fall. However, do expect dramatic advances, in recent years gains in efficiency have been only modest and incremental rather than revolutionary.


 

Disadvantages of Solar Energy

1. High Capital Cost

Is solar power really expensive? This is probably the most debatable aspect on the entire solar energy pros and cons list. The driving forces behind the development of solar energy are rooted in politics. Solar power received government subsidies but the oil and coal industries have also been subsidized. In 2010, coal received $1,189 billion in federal subsidies and support for electricity production while solar is not far behind at $968 billion.[4]

Nowadays, the best solar panels can in many situations be cheaper than buying electricity from the utility.

2. Solar energy is an intermittent energy source

There are three aspects of the intermittent nature of solar power;

  • Firstly the sun doesn't shine at night and so solar panels don't generate power at night.
  • Secondly the sun shines with different intensity and different times or year and different times of each day; and
  • Cloud cover can have a significant affect on the amount of energy produced by solar panels

All of these factors have meant that to date the prevailing wisdom is that solar power can not be relied on for base load or for mission critical applications.

However, this is changing and the announcement last year by Tesla Motors that it intends to sell a Lithium Ion batter solution suitable to allow consumers to cost effectively store solar power is a sign that this may not be a limitation on solar power for long.

3. Energy Storage is Expensive

Energy storage systems such as batteries will help smoothen out demand and load, making solar power more stable, but these technologies are also expensive.

Luckily, there's a good correspondence between our access to solar energy and human energy demand. Our electricity demand peaks in the middle of the day, which also happens to be the same time there's a lot of sunlight!

4. Associated with Pollution

While solar power certainly is less polluting than fossil fuels, some problems do exist. Some manufacturing processes are associated with greenhouse gas emissions. Nitrogen trifluoride and sulfur hexafluoride has been traced back to the production of solar panels. These are some of the most potent greenhouse gases and have many thousand times the impact on global warming compared to carbon dioxide. Transportation and installation of solar power systems can also indirectly cause pollution.

The bottom line is this: There’s nothing that’s completely risk-free in the energy world, but solar power compares very favorably with all other technologies.

5. Exotic Materials

Certain solar cells require materials that are expensive and rare in nature. This is especially true for thin-film solar cells that are based on either cadmium telluride (CdTe) or copper indium gallium selenide (CIGS).

6. Requires Space

Power density, or watt per square meter (W/m2), is essential when looking at how much power can be derived from a certain area of real estate of an energy source. Low power density indicates that too much real estate is required to provide the power we demand at reasonably prices. The global mean power density for solar radiation is 170 W/m².[5] This is more than any other renewable energy source, but not comparable to oil, gas and nuclear power.

7. Solar doesn't move house

One of the disadvantages with installing solar panels on your home is that it is expensive to move them should you decide to move. The net metering agreement with your utility is fixed to the property. However, in practice solar panels add value to a home and so even if you do move you are likely to see the value of your investment in solar panels reflected in higher sale price. It is much easier if your purchase the solar panels outright if you do move because with a lease or PPA you need to the new owner to agree to take over the agreement.

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