68 – Understanding Why Wind and Ground Solar Energy Cannot Replace Fossil Fuels

America faces two critical challenges this century. The first is responding to the uncertainty that the abnormally high and rising atmospheric carbon dioxide (CO2) level will have detrimental environmental consequences for human civilization. The second is replacing the diminishing U.S. technically recoverable fossil fuel endowment with new non-fossil fuel energy sources. Wind and ground solar energy are two the three primary non-fossil fuel terrestrial energy sources that could possibly replace fossil fuels. However, the land area required for wind and/or ground solar farms necessary to generate sufficient renewable electricity to replace fossil fuels makes both of these alternatives impractical to replace fossil fuels.

“Understanding Why Wind and Ground Solar Energy Cannot Replace Fossil Fuels” is the fourth of an Energy & Environmental Security Series of videos published on the Spacefaring Institute’s™ YouTube® channel. These videos explain why the United States should undertake an orderly transition from fossil fuels to space-based solar energy. The video includes an introduction to space solar power and illustrations of the types of spacefaring logistics capabilities that America’s aerospace industry can now design and build to become a true commercial human spacefaring nation and undertake space solar power.

This 15-minute video addresses these topics:

  • What sustainable terrestrial energy sources can replace fossil fuels?
  • How much energy will Americans need in 2100?
  • What will it take to meet this per capita energy need using non-fossil fuels?
  • Can wind and ground solar energy practically meet U.S. 2100 energy needs?
  • What can America do to transition from fossil fuels?

The script of the video follows:

Introduction

The United States faces two important challenges this century related to our use of fossil fuels. The first arises from our substantial dependence on fossil fuels which now provide 80 percent of the total energy Americans use. While the United States has a technically recoverable fossil fuel endowment of about 1,500 billion barrels of oil equivalent or BOE, the fossil fuel demands by a growing U.S. population, expected to reach 500 million by 2100, will likely exhaust this endowment before 2100. This constitutes an energy security challenge that cannot be ignored. The second challenge is reining in carbon dioxide emissions from our use of fossil fuels. The abnormally high and still rising atmospheric carbon dioxide level, now 40 percent higher than what has been seen over the last 800,000 years, creates uncertainty that this may threaten human civilization. The reasonable response to these challenges is to curtail our use of fossil fuels, in an orderly manner, by switching to new sustainable energy sources. The list of potential terrestrial alternatives to replace fossil fuels is short with wind and ground solar energy being two of the three primary alternatives. To understand the practicality of relying on these two energy sources to replace fossil fuels, this Spacefaring Institute video addresses:

  • What sustainable terrestrial energy sources can replace fossil fuels?
  • How much energy will Americans need in 2100?
  • What will it take to meet this per capita energy need using non-fossil fuels?
  • Can wind and ground solar energy practically meet U.S. 2100 energy needs?
  • And, what can America do to transition from fossil fuels?

Part A – What sustainable terrestrial energy sources can replace fossil fuels?

Replacing fossil fuels requires a means to generate electricity and produce the fuels required for transportation, industrial processing, and commercial and home uses. Geothermal-electricity, hydroelectricity, and biofuels, such as alcohol made from corn and wood, will meet some of this need, as they do now. However, these simply cannot be scaled up, especially the use of food to produce fuel when the world’s demand for food is growing. Recall that hydrogen can be liberated from water using electrolysis. Consequently, by producing electricity from non-fossil fuel sources, such as nuclear energy, both electricity and hydrogen fuel can be supplied to replace energy now provided by fossil fuels. As discussed in this other Spacefaring Institute video, conventional terrestrial nuclear energy cannot be scaled up sufficiently to replace fossil fuels for the United States. With these other alternatives not being capable of replacing fossil fuels, can wind and ground solar energy be scaled up to accomplish this? The starting point in answering this question is to establish America’s future per capita energy needs for electricity and fuels.

Part B – How much energy will Americans be needing in 2100?

A standard barrel of oil contains 42 U.S. gallons. The thermal energy content of 42 gallons of oil is referred to as a barrel of oil equivalent or BOE. In 2007, just prior to the start of the current recession, Americans consumed the equivalent of 17.4 billion BOE from all energy sources. The equivalent of 6.5 billion BOE was used to generate electrical energy and 10.9 billion BOE was used directly as fuel. In 2007, with a U.S. population of just over 300 million, the per capita energy use that year was nearly 58 BOE. Breaking this down, the energy used per capita was nearly 14,000 kilowatt-hours of dispatched electrical energy and just over 36 BOE of fuel. Improving energy efficiencies may be expected to reduce the per capita energy use from 58 to roughly 50 BOE per year by 2100. Thus, by 2100, Americans would need about 12,000 kWh (11,932) of dispatched electrical energy and 31 BOE (31.3) of fuel to have a prosperous lifestyle.

Part C – What will it take to meet this per capita energy need using non-fossil fuels?

A kilowatt-hour is the unit of electrical energy typically used to measure home electricity use. For example, a 1000 watt or 1 kW microwave oven operating for one hour would use 1 kWh of energy. Using electrolysis to produce one BOE of hydrogen fuel, for such uses as ground transportation, will require nearly 2400 kWh – sufficient to run the microwave oven continuously for 100 days. The total electrical energy needed to produce the 31 BOE of hydrogen fuel needed in 2100 is about 74,000 kWh. In total, by 2100 each American will annually require about 86,000 kilowatt-hours to meet their annual energy needs – sufficient to run about 10 microwave ovens continuously for the year.

Part D – Can wind and ground solar energy practically meet U.S. 2100 energy needs?

Because of the variability of wind and sunlight, wind turbines and ground solar arrays do not generate electricity continuously as does, for example, a nuclear power plant. However, when they are generating renewable electricity, this can be used directly to electrolyze water to produce and store hydrogen fuel. When electricity is needed by consumers – referred to as dispatched electricity – the stored hydrogen fuel is used in place of fossil fuels to generate electricity. To account for this extra step in generating dispatched electricity, the total annual per capita electricity needed in 2100 climbs from about 86,000 kWh, if supplied by nuclear energy, to 99,000 kWh when supplied by variable wind and ground solar energy. Commercial wind farms, using 500-ft tall wind turbines, are expected to generate, on average, about 19 million kWh of variable wind-electricity per square mile per year. Thus, each square mile of these wind farms would be capable of meeting the annual energy needs of about 200 Americans. Using U.S. Census Bureau projections, America’s population is expected to grow to, at least, 500 million by 2100. To replace fossil fuels for 500 million Americans would require about 2 million sq. mi. of wind farms covering two-thirds of the continental United States – obviously, an impractical solution. Ground solar farms in the Southwest are capable of generating about 150 million kWh of variable solar-electricity each year per square mile. This would supply the energy needs of about 1,500 Americans per square mile of solar farm. To replace fossil fuels for 500 million Americans would require about 260,000 sq. mi. of generally flat land in the sunny Southwest be cleared to build solar farms. Taking into account the actual terrain of the Southwest, this would require that nearly all of the flat land in the entire Southwest be covered in solar farms – also an impractical solution.

Part E – What can America do to transition from fossil fuels?

While wind and ground solar energy are generally viewed as the likely replacement energy sources for fossil fuels, scaling these up to meet 2100 energy needs is not practical. With terrestrial nuclear energy, biofuel, and other renewables, such as hydroelectricity, also not being scalable, the United States will need to turn to the one remaining viable sustainable energy source – space solar power. In geostationary Earth orbit, or GEO, sunlight is available almost the entire year. Large space solar power platforms located in GEO can capture sunlight, convert this into electrical power, and transmit this almost continuously to ground receiving stations that would supply dispatched electrical power to customers and produce hydrogen fuel. Over the last two centuries, America has moved from wood to coal, and, then, to oil, natural gas, hydroelectricity, nuclear energy, and wind and ground solar energy to meet its increasing energy needs. The final step in this technological progression to space-based solar energy is now inevitable, due to serious energy and environmental security challenges that cannot be avoided. This next step will require that the United States become a true commercial human spacefaring nation tapping the energy and natural resources of the solar system, to obtain the non-fossil fuel energy our children and grandchildren will need. This bright and exciting spacefaring future – long an American dream – is now at hand.

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