Solar PV Energy

Key Terms

• Photons: packets of energy from the sun.

• Photovoltaic (PV) cells: what solar panels are made up of. Solar PV cells are made up of silicon, a type of semiconductor. The silicon is "doped" in two different elements to create an electric field with a positive and negative layer, similar in concept to a battery. Specifically, phosphorus is seeded onto the top layer of silicon, adding electrons and giving that layer a negative charge. The bottom layer of silicon is completed with boron, giving it a negative charge. 

• Direct current energy (DC): an electric current where the flow of electricity is uni-directional, meaning that the current flows in only one direction. It is what most household devices and batteries used, but is too expensive for large-scale transmissions.

• Alternating current energy (AC): an electric current that is used by the majority of power plants and distribution centers because it is cheaper and has less energy loss.

How It Works

When photons hit a PV cell (a solar cell), they knock an electron loose from the atoms inside of the solar cell. This happens due to the electric field created by the differently doped silicon layers of the PV cells. Once this electron is knocked free from the atoms, then the electric field pushes the electron out of the silicon "sandwich". On the sides of the cell are conductive metal plates that capture the electrons then send them to wires, which allow the electrons to flow as usable electricity. 

How It Is Renewable Energy

The sun will never run out. Therefore, we will always have plenty of solar energy to use. Furthermore, solar panels do not release any carbon dioxide emissions, except during the manufacturing process. This is because solar panels do not require a combustion process.

Advantages and Disadvantages

Advantages

One of the first advantages of solar PV is the rapidly dropping prices. Over the last decade alone, solar PV prices per watt have dropped 70%. This drop in prices has been coupled with substantial investment. The U.S. solar industry generated $18.7 billion of investment in the American economy in 2019, providing over 250,000 jobs across 10,000 domestic companies. As a result, the solar industry is rapidly growing, with 40% of all newly added electricity in 2019 being from solar. In addition, solar is being paired with battery storage in order to provide electricity at all times of the day. Solar PV can also be installed on people's homes and commercial buildings, putting less strain on the electric grid while at the same time mitigating climate change. Furthermore, government and private programs incentivize homeowners to install solar panels by allowing them to sell excess electricity back into the grid.

Negative Impacts

Despite the many positives, large-scale solar farms use a lot of space, and solar farms can be considered hypocritical for causing deforestation. However, it is less space than that taken over by fossil fuel drilling and mining operations, and solar panels still allow green space to stay. Some also accuse solar panels of high transportation and manufacturing emissions costs, which is a legitimate concern. However, this is an important example of how climate solutions must be deployed in tandem; industrial solutions. Improving the manufacturing processes — as well as transportation — will fastly reduce the amount of greenhouse gas emissions from solar panels.

Conclusion: Our Take

Solar PV is one of the first and most important ways that the transition to renewable energy will occur. Its falling prices and increasingly important role in the economy will help its growth. Moreover, as efficiency increases, land use will decrease, and as industrial solutions are employed, manufacturing emissions can be cut down. Hence, solar PV is a vital part of the renewable energy sector.