17-1 Evaluating Energy Resources
What Types of Energy Do We Use? Supplementing Free Solar Capital
Life on Earth is made possible by a gigantic nuclear fusion reactor safely located in space about 150 million kilometres (93 million miles) away. This direct input of solar energy also produces several other indirect forms of renewable solar energy. Examples are wind, falling and flowing water (hydro- power), and biomass (solar energy converted to chemical energy stored in chemical bonds of organic compounds in trees and other plants).
Commercial energy sold in the marketplace makes up the remaining 1% of the energy we use. Most commercial energy comes from extracting and burning nonrenewable mineral resources obtained from the Earth’s crust, primarily carbon-containing fossil fuels.
What Types of Commercial Energy Does the World Depend On? The Fossil Fuel Era
About 85% of the commercial energy consumed in the world comes from nonrenewable energy resources; the remaining coming from renewable energy sources.
Roughly half the world’s people in developing countries burn wood and charcoal to heat their dwellings and cook their food. This biomass energy is renew- able as long as wood supplies are not harvested faster than they are replenished. Most of this biomass is collected by users and not sold in the marketplace.
Why Is the Energy Future of the United States Important to Canada? Environmental and Economic Impacts
The United States is the world’s largest energy user, with the average American consuming as much energy in one day as a person in the poorest countries consumes in a year.
The United States is out of step with Canada and the rest of the world in terms of the energy resources it uses. About 93% of its commercial energy comes from nonrenewable energy resources (oil, coal, natural gas, and nuclear power), whereas the remaining 7% comes mostly from renewable biomass and hydropower. In comparison, only 73% of commercial energy used in Canada and 85% of the energy used in the world comes from nonrenewable energy resources, with renewable biomass and hydropower accounting for most of the remainder.
How Can We Decide Which Energy Resources to Use? Evaluating Alternative Resources
Energy policies must be developed with the future in mind because experience shows that it usually takes at least 50 years and huge investments to phase in new energy alternatives to the point where they provide 10–20% of total energy use. Making these decisions and converting them into energy policy involves answering the following questions for each alternative:
What is the intended use for that energy? All sources of energy do not lend themselves to the same applications.
Are other considerations, such as convenience, important? It might be a priority to secure plentiful supplies of an energy source that could easily be adapted to many products and services, or could easily be transported.
How much of the energy resource is likely to be available in the near future (the next 15–25 years) and the long term (the next 25–50 years)?
What is the net energy yield for the resource?
How much will it cost to develop, phase in, and use the resource?
What government research and development subsidies and tax breaks will be used to help develop the resource?
How will dependence on the resource affect national and global economic and military security?
How vulnerable is the resource to disruption through wars, natural disasters, economic problems, or terrorism?
How will extracting, transporting, and using the resource affect the environment, human health, and the Earth’s climate?
What Is Net Energy? An Important Consideration
It takes energy to get energy. For example, before oil is useful to us it must be found, pumped from beneath the ground or ocean floor, transferred to a refinery and converted to useful fuels (such as gasoline, diesel fuel, and heating oil), transported to users, and burned in furnaces and cars.
The usable amount of high-quality energy available from a given quantity of a resource is its net energy. It is the total amount of energy available from the resource minus the energy needed to find, extract, process, and get it to consumers.
Currently, oil has a high net energy ratio because much of it comes from large, accessible, and cheap- to-extract deposits such as those in the Middle East. When those are depleted, the net energy ratio of oil will decline and prices will rise. Conventional nuclear energy has a low net energy ratio because of the large amounts of energy needed to make it available. We have to extract and process uranium ore, convert it into nuclear fuel, build and operate nuclear power plants, dismantle the highly radioactive plants after their 15–60 years of useful life, and store the resulting highly radioactive wastes safely for 10 000–240 000 years depending on the types of radioisotopes they contain.