Evaluating Our Choices
Valuing energy is not just a scientific or technical endeavor, as social, political, legal, and ethical attributes are also important. However, science and technology set constraints and provide a mechanism for quantifying value. The economy, governmental policy, and even human inventiveness must operate within the constraints of what is scientifically and technically possible.
Romer (1976), in his 1978 book, Energy: An Introduction to Physics, stated three facts about the use of energy that remain quite relevant today:
- 1. The energy we use has to come from somewhere
- 2. The energy we use has to go somewhere after we use it
- 3. Every energy conversion has side effects that may be undesirable and that may not have been anticipated
Let us look at these points a little more closely. Almost all of the energy that we convert and use on Earth can be directly (or indirectly) attributed to the sun. Direct solar radiation, wind, and biomass (including fossil fuels) are all solar energy and solar energy derivatives. Fossil fuels in particular are merely ancient stores of the chemical energy of plants, now being unlocked after millions of years. What distinguishes these resources is the manner in which we process them. Most biomass is burned directly, without processing—but very polluting. The fossil fuels have been processed by nature for millions of years and actually burn cleaner because of it. Major efforts have been underway to transform biomass into higher quality fuels. A significant amount of biomass is being converted to ethanol, primarily as a transportation system, which often incurs massive toll on land, water, and food systems, for very little net energy produced. Waste streams generally avoid these negative consequences.
Solar, wind, hydropower, and geothermal energies are generally converted to electricity for large-scale commercial applications. That has benefits to the consumer, providing very versatile energy forms, with minimal impacts at the point of end use, but do not be misled to believe that means that the systems are without impacts. The impacts are moved upstream to the manufacture of the devices and facilities, rather than at the end use. We ultimately want to—need to—optimize total systems to produce the most and highest quality energy, with the least overall costs.
As such, humanity is beginning to take on the gargantuan task of placing appropriate costs and benefits to maintaining our modern, energy-heavy society and using ever cleaner resources and technologies to do so. New alternatives to fossil fuels must be able to meet current energy use practices such as transporting people and goods, heating and cooling spaces, lighting, and cooking. The list goes on.
Fossil fuels, while perceived as dirty fuels, in actuality can be quite clean, especially when compared with the combustion of raw biomass. In poor regions across the globe, biomass consumption by far outpaces the consumption of any other energy source. This is by necessity, not by choice. Firewood dependence is dangerous, dirty, and limits development.
Within the subset of the fossil fuels, coal is surely the most polluting, and natural gas is by far the least polluting, which is why such an emphasis has been placed on exploiting the shales. The fossil fuels are often viewed collectively in very negative terms, which can obscure the values that they have brought society, and the costs that would have been associated with any of the other alternatives existing at the time. The transition from firewood to coal represented an advance. The transition to petroleum dominance was another gain. The growth of natural gas offers potential for even more improvement—gains that can proceed at a greater pace than seems likely for any of the nonthermal sources.
In trying to maximize the value added by our energy systems, we need to be able to evaluate and to compare the costs and benefits across the various components of the various energy systems. We need to develop viable, robust metrics to compare the costs and benefits across and within the various energy systems. There are a number of metrics that can be drawn upon. From life cycle assessment, to net energy value, to exergy, these metrics provide a basis for evaluating environmental impacts through the stages of production of any product good or service. They look at energy from the acquisition of energy, through its transport, storage, conversion, and end use. This is a significant development in evaluating resources at a systems level. However, they do not really address the benefits or values offered and none of them fully capture the range of costs and benefits. Particularly, we suggest that it is imperative to develop metrics that account for the values offered relative to a range of needs and how values change over time and development contexts.
We cannot expect to find the perfect resources, nor the perfect applications. We can seek to improve the balance of benefits relative to the costs. To do so, we must assess those costs and benefits as realistically, honestly, and fully as possible. In so doing, we must consider energy systems in their totality: the sources, the conversion, storage, and transport of energy. We must work to assess the value of current energy systems and what changes can enhance the total values, over what time frames.
We contend that the economic, social, and environmental impact of human activity is most accurately measured by our consumption of energy, both in terms of type and quantity. Since shortly after World War II, we have seen an amazing transformation of the global economy. Public awareness of the impacts of human population growth and large-scale energy use, especially in the last 30 years, has caused attitudes to change over how to deal with environmental protection and social responsibility, placing value on our behaviors with respect to energy consumption and its impact on our surroundings.
-  There are also nonenergy by-products associated with most energy sources, but theby-products of petroleum production are particularly important and valuable. Inmodern societies, we are quite literally surrounded by petroleum products: clothing,cars, furniture, dishes, paints, lubricants, toys, food additives, and pharmaceuticals.Even if energy production from petroleum ended, its value as an organic chemicalfeedstock will probably continue for many years.