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| Fig. 1: A schematic of the path of electricity from a centralized power plant to a residential consumer. (Courtesy of the EIA) |
In 1879, Thomas Edison submitted a patent for the lightbulb. [1] Several years later, the first centralized power plant was created, but had a limited range due to power dissipation in wires. In 1896, Nikola Tesla invented alternating current, and this significantly reduced power losses in electric transportation. [2] The ability from that point to generate energy at scale from large power plants founded for the modern-day electric grid. Because means of electric production were limited at the time, the decision to create large electrical facilities that could serve cities at a time was the most effective and efficient one. Over the following century, this system has been bolstered, but there was no significant innovation. This system has several significant limitations, from environmentally hazardous emissions to low efficiency and frequent breakdowns. With the rise of certain technologies in the energy sector, such as wind and solar power generation and electric cars, this highly centralized energy distribution system has an opportunity to be adapted into a more efficient, effective, and environmentally friendly model.
The centralized energy system has several categories of problems: those related to aging infrastructure, those related to power delivery and efficiency, and those related to emission of pollution.
The majority of the current electrical grid in the United States was built in the 50s and 60s, and it is in need of significant repair. [3] Maintenance costs to renew electrical infrastructure are in the hundreds of billions, and power outages cause tens of billions of dollars in losses. The system is hanging on by a thread, and the US averages 360 minutes of outages each year, compared to 15 minutes in Germany and 11 in Japan. [4]
Finally, the most notorious drawback of large-scale power plants is the emission of pollution and hazardous byproducts. There are four main ways in which centralized power plants are harmful to the environment. [7,8] Firstly, coal, oil, and natural gas power plants emit hazardous air pollutants, the most prominent of which are carbon dioxide, sulfur oxides, nitrogen oxides, carbon monoxide, hydrocarbons, and particulate matter. Among these emissions are carbon dioxide and methane, which are major greenhouse gases. Greenhouse gases lead to global warming, which is a cause of increases in extreme weather events, melting polar ice caps, and other adverse effects. [8] Carbon dioxide emissions by power plants contributes over 40% of the global share of carbon dioxide emission. [6] Then there are waste products such as ash and wastewater from the power generation process that contain heavy metals and sulfides and can be acidic. [7] These must be carefully disposed of as they are hazardous. For nuclear energy, hazardous waste materials are particularly hard to dispose of because of their radioactivity. [9] Furthermore, the extraction processes for coal, oil, natural gas, and uranium, as well as any potential refinement contribute further pollution of hazardous substances. [7-9]
The main novel energy sources in the past 20 years are wind and solar energy. These are different from conventional power plants in that they do not have to be centralized to produce power at similar efficiencies. An important aspect of both of these technologies is that they are starting to reach grid parity, which is the point where an alternative energy costs as much as energy from a conventional power plant. [10] Certain European countries and several US states have already reached solar grid parity. One of the greatest advantages of alternative energies is that they do not produce any hazardous emissions: the environmental impacts are limited to creation and installation of these systems as well as land use.
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| Fig. 2: A schematic of the electric grid within a distributed system. (Source: Wikimedia Commons) |
Distributed energy solutions are not strictly defined and may come in many forms. Typically, they make greater use of alternative energies and are more modular. The scale can range from a personal rooftop solar array to a wind turbine farm. The systems, however, are smaller and closer to the end consumer. This modularity makes the grid more robust and reliable, due to a higher flexibility. [11]
One of the innovations that makes a flexible grid more possible is blockchain, which allows consumers to trade solar energy or any other generated energies back to the grid and to each other. [12] Blockchain technology can provide an easy, secure, reliable, and transparent way to manage two-way flows of electricity across a smart grid. Some prototypes of a blockchain-based energy exchange system are already in place, such as one in Brooklyn, NY. [12] Ultimately, this may form a foundation for including personal electric generation such as rooftop arrays into the power grid, increasing flexibility and reliability.
A significant problem with solar and wind energy has been their variability. At peak hours, energy production can be too high, such that excess energy is generated. The current electric grid cannot store energy very well, which results in curtailment of renewable energies. Curtailment is the loss of energy that happens when electricity generated from sources such as wind or solar produce energy that is unable to be used, and is thereby wasted. [13] A possible solution comes from an ironic source: electric vehicles. Electric vehicles actually move cars closer to centralization, and away from the liquid fuel model, in which each car generates its own electricity through a combustion engine. However, each electric vehicle must contain a substantially sized battery to store electric energy. If electric vehicles are connected to the grid, any excess energy within the grid has an opportunity for storage, and when general electric usage is high, they can support the load of electric demand. [14,15] For fossil-fuel power plants, this would have the effect of facilitating a more even energy production demand throughout the day, and this would decrease the amount of generation systems that are only used during times of peak demand, which are costly and inefficient since they are not used for the majority of the time. More significantly, with wind and solar energies, which fluctuate in energy generation quantity throughout the day, electric vehicles would be able to facilitate storage of over-generated electricity during peak hours and redistribution of this energy at times when variable energy sources are in low production. This, in conjunction with smart control systems that dictate flow of electricity, would significantly alleviate the problem of energy curtailment.
Modular distributed energy systems have the power to renew our grid and make it more reliable and flexible. In addition, many distributed energy technologies reduce harmful environmental impact and have higher efficiencies. As these technologies become more widely used, the infrastructure of the electric grid will have to adapt in turn.
© Alec Arshavsky. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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