Environmental Impacts of Solar Photovoltaic System - Smart Solar Nepal

Environmental Impacts of Solar Photovoltaic System



The annual increases in global energy consumption, along with its environmental issues and concerns, are playing significant roles in the massive sustainable and renewable global transmission of energy. Solar energy systems have been grabbing most attention among all the other renewable energy systems throughout the last decade.

Since PV technology generates electricity directly from solar energy, it is free from fossil fuel consumption and greenhouse gases (GHG) emission during its operations. Thus, it seems to be completely clean and have no environmental impacts. However, during its life cycle, it actually consumes some energy and emits GHG during some stages such as solar cells manufacturing processes, PV module assembly, Balance of System (BOS) production, material transportation, PV system installation and retrofitting, and system disposal or recycling. These are the stages where solar actually has an environmental impact.

Life cycle assessment (LCA) is usually conducted to accurately investigate the environmental performance of PV systems. LCA is a methodology for assessing environmental impacts associated with all the stages of the life-cycle of a commercial product, process, or service. The following table shows the breakdown of lifecycle greenhouse gas emissions for PV in total percentages.

Table 1: Breakdown of lifecycle GHG emissions for solar PV and wind energy (% of total)

Energy  SourceFabricationConstructionOperationDecommissioning
Solar PV71.3%19%13%-3.3%
Wind71.5%24%23.9%-19.4%

It is evident from the table that fabrication is responsible for the largest share of emissions, followed by construction and operation.

The following figure shows the life cycle CO2 emissions of conventional energy supplying technologies and some renewable energy sources and compares them to the Mono-Si, P\\Si, and r-Si PV technologies.

Life Cycle CO2 emissions comparison between PV technologies and other energy supplying technologies
(Alsema and deWild, 2005).

EPBT (Energy Payback Time) is regarded as a perfect evaluation indicator for sustainability through which we can clearly determine whether the specific PV system can bring a net gain of energy for the user during its lifetime and if so to what extent. The EPBT indicator is defined as the years required for a PV system to generate a certain amount of energy (converted into equivalent primary energy) for compensation of the energy consumption over its life cycle, including energy requirements in PV modules’ manufacturing, assembly, transportation, system installation, operation and maintenance, and system decommissioning or recycling.

In 1970, the average energy payback time for solar panels was 40 years. By 2010, that number had dropped to just six months. With technological advancements, solar panels are being more efficient which means that solar’s EPBT will continue to decrease.

Impacts to air

The impact of PV energy on air quality and climate change is significantly lower than any other traditional power generation system. Hence, it can assist in eliminating numerous environmental issues that resulted from utilizing fossil fuels. PV systems have zero emissions of carbon dioxide (CO2), methane(CH4), sulfur oxides(SOX), and nitrogen oxides(NOX) during operation with negligible effects on air pollution and global warming.

It is also estimated that the use of PV systems can lead, by the year 2030, to a reduction of CO2, SO2 and NOX emissions by around 69–100 million tons, 126,000–184,000 tons and 68,000–99,000 tons, respectively. These reductions in emissions are projected to lead to a significant drop in several dangerous diseases such as heart attacks and asthma that are expected to decrease by 490–720 and 320–470 annually, respectively.

Land use

Typically, the land requirements for solar projects are larger than conventional fossil fuels’ projects. Utility-scale solar power plant requires large areas for energy production. Due to this, the facilities may interfere with existing land uses and can impact through material exploration, extraction, manufacturing and disposal. Several reports and studies show that solar power systems (PV and Concentrated solar power (CSP)) have the highest energy land use intensity compared to other energy technologies. Table 2: Land requirement for various sizes of solar and wind technologies.

Technology TypeSize (acres/MW)
PV <10 kW3.2
PV 10100 kW5.5
PV 1001,000 kW5.5
PV 110 MW6.1
Small PV (>1 MW, <20 MW)5.9
Fixed5.5
1-axis6.3
2-axis flat panel9.4
2-axis Concentrator photovoltaics (CPV)6.9
Large PV (> 20 MW)7.9
Fixed5.8
1-axis9.0
2-axis flat CPV6.1
Small and large PV installations2.2–12.2
Small and large CSP installations2.0–13.9
PV panels installed in parallel6.1
PV parks8.1
Wind <10 kW30
Wind 10 100 kW30
Wind 100- 1000 kW30
Wind 1 10 MW44.7

However, certain technologies have been developed to reduce land use without compromising the efficiency of solar system such as a dual-angle solar harvest system a two tilt angle solar array. To avoid the conflict with agricultural land, PV systems can be installed in degraded areas, deserts and no cropping land. Land use can be also reduced by employing floating PV (FPV) systems. In FPV systems, the PV panels are laid on top of a structure that floats in a water body. FPV systems are found to be more efficient than inland PV systems because of the continuous cooling caused by water evaporation at the back of FPV panels. Another advantage of using FPV is decreasing the water losses from freshwater bodies.

Water usage

The water consumption in PV systems during operation is insignificant. During operation, water is used mainly for panels cooling and cleaning. The water consumption during the manufacturing and recycling processes is considerably higher than the water consumption during operation.

Other technologies such as nuclear, natural gas, coal-fired facilities, all require massive amounts of water for cooling purposes. Solar energy imposes no risk to local water resources, nor their operation strains local supplies by competing with agriculture, drinking systems and other vital water needs.

The results showed that photovoltaics has the lowest footprint in water usage compared to other renewable technologies as depicted in Table 3.

Table 3: Median of water consumption in a full life cycle for different energy generation technologies.

Energy TechnologyMedian of Water Consumption
(L/MWh)
Biomass85,100
Hydropower85,100
Oil3,220
Nuclear2,290
Coal2,220
CSP1,250
Geothermal1,022
Natural Gas596
PV330
Wind43

Noise

PV modules do not contain moving or rotating parts, hence, there is no significant noise pollution produced during their operation. However, during the construction phase, many heavy machinery and vehicles operate on the site which causes noise pollution for residences, travelers, and wildlife.

PV systems not only impose zero noise pollution to the environment but also can be used as noise barriers (NB) which helps in mitigating noise. These are usually top-mounted near highways and provide the dual combination of combating noise while providing electricity. Configurations are shown in the figure below.

Different possible PVNB configurations

Hence we can conclude that the environmental impact of solar energy is net positive and have minimal impact compared to other energy generation technologies. PV in general emits no GHG during its operation. Electricity generation with solar energy instead of coal and other sources can significantly reduce greenhouse gas emissions resulting a better and cleaner environment. Although it emits some GHG during some stages of its life cycle, the total GHG emitted during its whole life cycle is the least compared to other sources of energy. Further, researchers are investigating many improvement approaches to lower the PV carbon footprint. This can be achieved by adopting best practices in design and deployment phases that lead to better performance and reduce the overall emissions. Some attributes such as: increase lifespan; increase system capacity; increase irradiance (desert); use of renewable energy mixes and thin-film (CdTe) or cadmium selenide (CdSe) quantum dot PVs, should be taken in consideration to reach the lowest gases emission levels.

References

M. Tawalbeh, A. Al-Othman, F. Kafiah, et al., Environmental
 impacts of solar photovoltaic systems: A critical review of recent progress and future
 outlook, Science of the Total Environment (2020)
 Malek Kamal Hussien Rabaia, et al., Environmental impacts of solar energy systems: A review, Science of the Total Environment (2021)
 https://news.energysage.com/what-is-the-environmental-impact-of-solar-energy/

More from Us

RENEWABLE ENERGY

Renewable energy, also called alternative energy, usable from replenishable sources such as the sun (solar energy), wind(wind energy)river(hydroelectric energy), hot…

PROMOTING DIVERSITY AND INCLUSION IN THE ENERGY SECTOR OF NEPAL

Significant energy disparities exist in the world, both between and within individual states as well as between affluent and poor…

Solar PV in Nepal: A Bright Future For Clean Energy 

Around 20% of Nepal's total energy consumption is made up of modern energy sources including electricity, petroleum, and renewables, and…