By Dr. Rajendra Singh
Professor of Electrical and Computer Engineering, Clemson University
To further spur economic growth in South Carolina, we need to focus on sustainable renewable energy. As a manufacturing state, the availability of clean renewable energy will bring additional manufacturers to our state. Currently, decarbonization, decentralization of energy production, and vehicle electrification are the three major market forces dominating the future of energy industry: solar energy.
Solar energy is emerging as a sustainable, resilient, and ultra-low cost source of power. Initially, the use of photovoltaics (PV) for terrestrial electrical power generation was driven by decarbonization. Today, the growth of PV is driven by cost and economics.
The major driving force behind a push toward solar energy is that low cost and environmental benefits are part of sound business practices. With the advancements in technology and volume manufacturing, the cost of PV power generation has reached to as low as 1.78¢/kWh (kilowatt hour) and represents the lowest cost of electric power generation on the planet.
The global demand for photovoltaics will reach the 100 GW level for the first time in 2017, a growth of more than 30 percent compared to the 2016 level, which was 76.6 GW. A combined photovoltaics/thermal (PV/T) system can be used for generating electrical power and thermal power. The power output of a typical PV/T system is 300-400 W/m2. Thus, solar energy can meet the electrical power and thermal power needs for all applications.
For storing electric power, the lithium battery cost reduction is following the pattern of photovoltaics module cost reduction. By doubling the cumulative production, the cost of a lithium battery pack is reduced by about 22 percent. Capital costs as low as $112/kWh has been reported by Audi. Reduced cost of batteries is driven by exponential rise of the electric vehicle market. In the next 10 years, the lithium ion battery demand for electronics, electric vehicles, and stationary storage is expected to be 1200 GWh.
Similar to the Tesla gigawatt factory, there are many gigawatt factories under construction by Chinese, South Korean, and Japanese companies in different parts of the world. Thus, very soon, power storage costs of batteries will be lower than any other electrical power storage techniques. Existing low costs of PV-generated electric power coupled with potential low cost of electric power storage will provide a nearly free source of power to mankind.
Besides some inductive loads, today all our loads are direct current (DC) loads. The alternating current (AC) power distributed by the bulk electric power system is converted internally into DC power and feeds our laptops, smart phones, refrigerators, air conditioners, etc. In the process of AC power generation, transmission, and distribution, we lose more than 30 percent power.
The concept of nanogrid and clusters of nanogrids involves power generation, power storage, power sharing (two-way power transfer), and power use by an individual entity or a combination of entities. A nanogrid can be a single house or factory or a combination of several homes of a subdivision, various shops of a single mall, etc. Power generated by photovoltaics is DC power. The batteries store DC power. Thus, the new electricity infrastructure should use DC power nanogrids based on PV and batteries. Currently, utilities use about 1.6-watt DC power to generate 1-watt AC power. Thus, a significant amount of PV power is wasted.
The electrification of the transportation sector (cars, buses, smart and large trucks, etc.) require DC power, and a PV- and battery-based nanogrid is the most effective answer to generate electric vehicle’s charging stations throughout the country. Nanogrids based on PV and batteries are also resilient against solar storms and high altitude nuclear explosion.
The vehicle electrification is providing a unique growth opportunity of photovoltaics and batteries. Total gasoline consumption for transportation in 2016 for the U.S. was 277 million gallons per day, which translates to 138 billion gallons per year. At the price of $2 per gallon of gasoline, there is an opportunity to replace $275 billion in the gasoline market by the electricity infrastructure of PV and batteries. Since fast charging of EVs requires DC power, nanogrids based on PV and batteries is the ideal choice for creating EV charging electricity infrastructure.
The triangular relationship of photovoltaics, batteries, and electric vehicles is providing tremendous economic growth opportunities to our state. Unlike the past mistakes of pushing nuclear energy, our policy makers and regulators at all levels must work with the utilities to expand the solar energy to its full potential. The utilities will work with the state policy makers and regulators if they demand maximum use of solar energy. As an example, in Florida, Duke Energy killed the plan to build a nuclear reactor and is going to invest $6 billion on photovoltaics and battery based electricity infrastructure.
Dr. Rajendra Singh is a professor of electrical and computer engineering at Clemson University. He is a leading semiconductor and photovoltaic (PV) expert with more 35 years of industrial and academic experience of photovoltaic and semiconductor industries. He is also a leading advocate of the advancement of solar energy in South Carolina.