The energy emitted by the sun has the ability to fulfill all of our planet’s energy needs. Capturing and processing the energy of these high-speed photons was made possible by the invention of the semiconductor. However, the integration of solar energy into the power grid remains a small percentage overall in the US.
The limitations facing the expansion of solar power stem from the land usage requirements, excess energy storage, and conversion efficiency. However, with the recent advancements in grid-connected systems, excess energy that might have been lost in an off-the-grid system reenters the power grid to increase efficiency and reliability.
Solar Technology Functionality
Many people wonder, “How does solar power work?” Solar panels contain photodiodes that respond specifically to the sun’s light wavelength to produce energy in the form of moving electrons. Photodiodes contain semiconductors made of highly purified silicon dioxide. Silicon dioxide’s atomic make-up responds to the sun’s light rays by excitement of electrons. Exciting an electron means that it has been given a surge of energy that moves it into higher energy levels of an atomic material.
When the electrons move between energy levels, electron density rises and falls, thus creating a pressure driven flow of electrons. Flowing electrons can also be referred to as electrical current. The power grid captures the electrical current created by the sun’s electron excitement and resulting electron flow to fulfill energy requirements using solar panels.
Solar panels contain photovoltaic cells that are composed of the silicon dioxide semiconductors, metal contacts to guide the flowing electrons and connect the semiconductor cells, anti-reflective coating to maximize absorption efficiency, and a heat-resistant back sheet. These panels, or modules, are then connected to an inverter that converts direct current (DC) into alternating current (AC). Our electrical energy appliances require AC current, thus making inverters a key component of the solar power system.
Inverter technology has advanced in recent years, thus allowing the “smart inverter” grid-connected systems to allocate energy to powering the system, storing energy, or sending electricity back into the power grid.
Current Power Grid Situation
Because national power demand and production must operate in real time to meet the needs of a hugely energy consumptive society without failure, the reliance of solar energy on uncontrollable factors such as weather posed an unacceptable risk to the power grid. If excess energy produced by solar panels could be captured and stored as a safety net, this variability might pose less of a problem.
Grid-connected systems have the possibility of acting as this safety net. When property owners use solar modules to power their homes, but end up generating more power than needed, they have the option to send this energy back into the power grid. These grid-connected systems can generate renewable energy, and decrease monthly electricity bills by selling this excess energy back to the power grid.
Implications of Advances in Battery Storage
A report by Rocky Mountain Institute (RMI) outlines the possibility of electricity load defection. Load defection refers to the possibility of customers choosing to become autonomous energy producers. The advancement of battery storage technology for solar power systems would make this possible. The consistently decreasing costs of solar modules combined with these advancements in storage could pose a threat to the grid and to lower income customers. It would also lead to a decrease in efficiency because the grid could not utilize the excess power generated by the defected customers.
However, should communities and local governments stress ideas of community renewable energy generation and keep customers grid-connected, this threat of defection could transform into a significant benefit. Should communities head down the path of an integrated grid, socioeconomic benefits would emerge as well, because lower income customers would be able to benefit from the grid system as well. When more customers contribute to the grid system, they have more opportunity to sell their excess electricity back into the grid.
As the impacts of climate change become more prevalent and the demand for clean energy increases, solar energy and wind energy have the highest potential to make a significant difference. Grid-connected solar energy systems have the capacity to accelerate the growth of solar energy production. To keep the power grid safely operational, individual customers contributing to the market in the grid would increase the efficiency and volume of solar production. Economic and social planning must happen in the optimal geographical regions to make this transformation a reality.