Exploring Hydrocarbon Depletion
Page added on February 21, 2012
This is Part 1 in a three-part series focusing on fossil-fuel dependence and the intersection of energy and the environment. Part 1 discusses what underpins our current dependence on fossil fuels to meet our energy needs: its unmatched efficiency as an energy source.
Developed societies have enormous energy needs, which at present can only be met by large-scale energy sources (oil, gas, coal, nuclear power, and hydro). An increased dependence on “unconventional” fossil fuels (oil from oil sands, shale gas) has been met with an increased level of concern about environmental issues surrounding these developments, including proposals for pipelines to carry oil-sands crude, and the “fracking” process required to release gas from deeply buried shales. Protesters, raising concerns about “Canada’s dirty oil,” would like to stop the oil-sands industry and cause pipeline projects to be cancelled. But our dependence on fossil fuels means we need to take a more holistic approach to these issues. At present, without fossil fuels, industrial production would be crippled, there would be no efficient transportation, and there would be little or no economic growth. Despite concerns about fossil-fuel emissions and impacts on climate, we must not lose sight of the critical importance of fossil fuels to developed society. Because of this, climate-change solutions cannot be focused only on Canada’s petroleum industry, which is making strides to reduce its carbon intensity.
There is much hopeful talk about a future “low-carbon economy” following a switch to renewable energy, but, at present, the major renewable sources – solar, wind, and biofuel power – cannot provide the necessary substitute, despite much optimistic promotion of a clean, green future. This is true even in jurisdictions where there has been heavy investment in renewables: Consider the wind farms of Denmark and Germany, which only meet five to 20 per cent of the countries’ electricity needs. Wind is too variable to provide a steady base-load capacity – coal, gas, or other traditional power sources need to be retained for this purpose. Furthermore, the scale of the needs is commonly misunderstood. A typical thermal-power plant (gas, coal, nuclear) can generate 200-2,000 MW of electricity continuously, whereas the most powerful modern wind turbines only generate three MW in the same timeframe under ideal conditions (i.e. when the wind is blowing at the right speed, which seems to only be about 30 per cent of the time). Thus, thousands of wind turbines are needed to make a real difference, and backup thermal-power plants must still be retained.
There is an increasingly urgent need to develop new and cheaper renewable-energy technologies. For one thing, the supply of petroleum is finite (something I will discuss in more detail in Part 2 of this series). For some applications – air transportation and the manufacture of plastics and other synthetic materials being among the most important – there is currently no substitute for petroleum. As a developed society, we often fail to recognize our enormous dependence on fossil fuels for these purposes.
Current renewable technologies, in addition to being of limited use, are very inefficient. In order to measure the efficiency of various energy sources, economists have created an index called the Energy Return on Energy Invested (EROEI), which considers how much energy it takes to get the useful energy out (for example, the energy required to drill a well). EROEI can help us understand which energy sources promise a good return on investment. It tells us, for instance, that petroleum has decreased in its returns over the last several decades. At the beginning of the petroleum age, and until the 1970s, the return on petroleum energy invested was about 100:1 (100 units of energy were produced per one unit of energy invested). However, the increasing need to search for reserves in remote or hostile territory, such as the deep offshore, is steadily reducing the returns to less than 20:1.
Providing insight into the returns on investment for various energy sources, EROEI gives us a sense of their value and their likelihood of use for the foreseeable future:
Based on this index, then, it looks like fossil fuels like coal, oil, and natural gas (as well as nuclear power and hydro) will remain essential to meeting electricity generation needs for many years yet. In the developed areas of the world, we are so accustomed to dependence on petroleum that we take its convenience and efficiency for granted. The compactness, flexibility, transportability, and energy density (the amount of energy per unit mass) of liquid oil and natural gas are currently unchallenged by the other sources. To continue the supply of these resources as long as possible requires drilling in more difficult areas, using more invasive technology, and expanding the infrastructure of plants and pipelines for delivery to the places it is needed. These developments raise legitimate environmental concerns, an important factor that I will discuss in the third article in this series. While it is naïve to think that our energy supply can be transformed overnight, the pressure to make this transformation is also linked to the finite nature of oil and gas, which I will explore in more detail in Part 2.