In general, both photovoltaic solar energy and, above all, thermal solar energy have a very good acceptance in society. However, it is convenient to know the advantages and disadvantages of solar energy to reinforce or contrast our opinion.
When we talk about energy sources, most people are in favor or against a certain type (solar energy, nuclear energy, wind energy, etc.). The arguments for positioning are varied: energy efficiency, pollution, safety, cost ... Therefore, we will try to analyze the advantages and disadvantages of solar energy in the most objective way possible.
Although solar thermal energy and photovoltaic solar energy are two different types of energy with different characteristics, to analyze the advantages and disadvantages of solar energy we are going to do it together.
What are the advantages of solar energy?
The advantages of solar energy depend on different factors. Depending on the characteristics of the solar installation, certain advantages will be observed compared to other energy sources.
- Solar energy is a renewable energy and, therefore, it is inexhaustible. Although the sun has a limited life, on a human scale it is considered inexhaustible.
- Low pollution and respect for the environment. The production of electrical energy in the case of photovoltaic energy or sanitary hot water in thermal solar energy is not polluting nor does it cause greenhouse gases. The use of this technology implies that the energies that use fossil fuels can be reduced. For this reason it is considered clean energy.
- Installations with a low installation cost. The cost of a solar installation compared to other types of installations such as a nuclear power plant are very low.
- Low maintenance cost. Most current solar energy systems do not require much maintenance. Residential solar panels generally only require cleaning a few times a year.
- Favorable for isolated sites. In cases where access to the electricity grid is difficult, the installation of photovoltaic panels or solar collectors is a very good option.
- Silent. In solar energy installations there are no moving parts involved. Therefore, there is no associated noise. This is a favorable point compared to other renewable technologies such as wind turbines.
- It can be used in multiple applications. Solar energy can be used for many different purposes. It can be used to generate electricity in places with no grid connection, to distill water, or even to power satellites in space.
- Good availability. Solar energy is available worldwide. Not only the countries closest to Ecuador can use solar energy: Germany, for example, has the largest solar energy capacity in the world.
- Favorable public opinion. Public opinion is mostly favorable to the use of energy produced by solar energy. The perception of the population is that it is a clean and sustainable renewable energy.
What are the disadvantages of solar energy?
Depending on the characteristics of the solar installation, the disadvantages of solar energy will be more or less important. Despite all the advantages, the disadvantages should be carefully analyzed. Certain drawbacks of solar energy may mean that a solar installation may be unfeasible. The aspects to consider are the following:
- Energy efficiency is poor compared to other energy sources. The ratio of the amount of energy received in a solar panel to the amount of electrical energy is low compared to other energy sources such as nuclear power.
- The economic cost compared to other options and especially in large solar plants. Above all in solar thermal energy, taking advantage of the properties of temperature and thermodynamics, the performance is superior to photovoltaic energy. Also the initial investment in some cases can be important.
- The performance depends on the weather. The dependence on the weather makes this energy source an unlikely option in areas where the sky is mostly cloudy.
- Limitations in solar time. Keep in mind that in certain areas the solar time is shorter. The Nordic countries, for example, during the winter days the solar hours in which the energy can be used are very few. Furthermore, the inclination of the Sun with respect to the surface varies during the different days of the year. The variation of the inclination of the radiation alone influences the performance of the solar panels.
- Limitations to store the energy generated. Because the hours when electric power can be obtained do not always coincide with the hours when it is needed, it is convenient to store the energy. For this, there are solar batteries and hot water tanks, but the efficiency is still very low.
- Environmental impact. Although solar energy is considered clean energy, it also has elements that harm the environment.
What is the environmental impact of solar energy?
The potential environmental impacts associated with solar energy (land use and habitat loss, water use, and the use of hazardous materials in manufacturing) can vary greatly by technology, which includes two broad categories: photovoltaic solar cells or plants concentration solar thermal.
- Land use. Depending on their location, larger utility-scale solar installations may raise concerns about land degradation and habitat loss.
- Water use. Solar photovoltaic cells do not use water to generate electricity. However, as in all manufacturing processes, some water is used to make photovoltaic solar components. Solar thermal concentration plants require water to cool down. In addition, these plants require keeping the reflectors clean, the water consumption is higher.
- Dangerous materials. The photovoltaic cell manufacturing process includes a number of hazardous materials, most of which are used to clean and purify the semiconductor surface. Thin-film photovoltaic cells contain a number of more toxic materials than those used in traditional silicon photovoltaic cells.
- Life cycle of global warming emissions. While there are no global warming emissions associated with the generation of electricity from solar energy, there are emissions associated with other stages of the solar life cycle, including manufacturing, transportation of materials, installation, maintenance, and decommissioning and dismantling.
What is the difference between thermal and photovoltaic solar energy?
Although both systems are powered by solar radiation, there are several differences:
- Objective: Photovoltaic generates electricity, thermal heat (although solar thermal power plants can use this heat to obtain electrical energy.
- Cost: PV panels are more expensive.
- Storage: Photovoltaic can supply energy directly or store it in batteries, while thermal can only store it in solar accumulators.
Description of solar thermal energy
Thermal solar energy (also called thermosolar energy) consists of using solar radiation to obtain thermal energy (heat). The heat obtained is used for the production of hot water for domestic consumption, either domestic hot water (DHW) or heating. Thermal solar energy can also generate electrical energy or even build solar cookers. It is, therefore, a thermodynamic mechanism in which energy is transformed.
Description of photovoltaic solar energy
On the other hand, photovoltaic solar energy also allows converting solar radiation into electricity. If thermosolar energy needs a thermodynamic process for its conversion into electrical energy, photovoltaics requires a chemical process: it consists in the transformation of solar radiation into energy through a direct electric current. This transformation is achieved thanks to the composition of semiconductor materials such as silicon and the photoelectric effect. This transformation into energy is immediate thanks to the photovoltaic modules.
Advantages and disadvantages of thermal solar energy compared to photovoltaic
The advantage of solar thermal energy, compared to photoelectric energy, is that it allows many applications (solar heating, electricity generation, etc.), while photovoltaic energy only allows the generation of electrical energy. The drawback of solar thermal energy is that it has a lower performance than that of photovoltaic solar installations.
When it comes to heating water, solar thermal energy has an advantage, since heat energy is transmitted directly to the water. Photovoltaic energy has the disadvantage that to heat water, it must first generate electricity and then heat the water with an electric heater. This system involves certain energy losses.