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Topic of Book
Smil describes natural gas as an energy source and identifies its advantages and disadvantages.
In the 1990s environmentalists were generally pro-natural gas, but since then they have changed to being very strongly anti-natural gas. This is despite the fact that natural gas is one of the most cost-effective means for lowering carbon emissions. In particular, natural gas makes it quite easy to dramatically reduce coal usage, by far the worst source of carbon emissions and pollution.
Ironically, the intermittency of solar and wind power make it very likely that natural gas will increase in usage as it is the only reliable “peaking” energy source that can turn on/off rapidly to make up for the hourly/daily changes in solar and wind production.
A switch from coal to natural gas should be priority #1 for those who are concerned about global warming, public health and air pollution.
- Natural gas has many advantages over other energy sources:
- Low cost (at least in North America)
- Spread of fracking and horizontal drilling technology should drastically lower cost in rest of world.
- Energy reserves are widely distributed geographically
- Huge energy reserves are likely to last remainder of 21st Century
- Proven energy reserves are expanding faster due to technological innovationthan they are being depleted by production.
- Low carbon emissions (CCGT emit one-third the carbon as coal)
- Very low levels of air pollution
- Unlike solar and wind, natural gas can run 24/7 or modulate based upon demand
- Easily stored and transported via pipeline
- Extremely flexible in use (industrial, heating and electricity generation)
- Can be used for both peaking and base-load electricity generation.
- Very efficient combustion
- Convenient home use
Important Quotes from Book
No energy source is perfect when judged by multiple criteria that fully appraise its value and its impacts. For fuels, the list must include not only energy density, transportability, storability, and combustion efficiency but also convenience, cleanliness, and flexibility of use; contribution to the generation of greenhouse gases; and reliability and durability of supply. When compared to its three principal fuel alternatives—wood, coal, and liquids derived from crude oil—natural gas scores poorly only on the first criterion: at ambient pressure and temperature, its specific density, and hence its energy density, is obviously lower than that of solids or liquids. On all other criteria, natural gas scores no less than very good, and on most of them, it is excellent or superior.
Moreover, pipelines transport gas at very low cost per unit of delivered energy and can do so on scales an order of magnitude higher than the transmission of electricity where technical consideration limit the maxima to 2–3 GW for single lines, while gas pipelines can have capacities of 10–25 GW
Gas turbines are now the single most efficient fuel convertors on the market and that high performance can be further boosted by combining them with steam turbines. When exiting a gas turbine, the exhaust has temperature of 480–600ÅãC, and it can be used to vaporize water, and the resulting steam runs an attached steam turbine (Kehlhofer, Rukes, and Hannemann, 2009). Such combined cycle generation (CCG, or combined cycle power plants, CCPP) can achieve overall efficiency of about 60%, the rate unsurpassed by any other mode of fuel combustion.
Little needs to be said about the convenience of use. The only chore an occupant has to do in houses heated by natural gas is to set a thermostat to desired levels (with programmable thermostats, this can be done accurately with specific day/night or weekday/weekend variations)—and make sure that the furnace is checked and cleaned once a year.
Combination of these desirable attributes—safe and reliable delivery by pipelines from fields and voluminous storages, automatic dispensation of the fuel by electronically controlled furnaces, effortless control of temperature settings for furnaces and stoves, and low environmental impact—means that natural gas is an excellent source of energy for densely populated cities that will house most of the world’s population in the twenty‐first century.
As for the cleanliness of use, electricity is the only competitor at the point of final consumption. Similarly, natural gas is a superior choice when generating electricity in large power plants.
No other form of energy has a higher flexibility of use than electricity: commercial flying is the only common final conversion that it cannot support, as it can be used for heating, lighting, cooking, and refrigeration; for supplying processing heat in many industries, powering all electronic gadgets and all stationary machinery; for propelling vehicles, trains, and ships; and for producing metals (electric arc furnaces and electrochemical processes). Natural gas shares the flying limitation with electricity—but otherwise, the fuel is remarkably flexible.
Because climate change and the future extent of global warming have become major concerns of public policy, contribution to the generation of greenhouse gases has emerged as a key criterion to assess desirability of fuels. On this score, natural gas remains unsurpassed as its combustion generates less CO2 per unit of useful energy than does the burning of coal, liquid fuels, or common biofuels (wood, charcoal, crop residues). In terms of kg CO2/GJ, the descending rates are approximately 110 for solid biofuels, 95 for coal, 77 for heavy fuel oil, 75 for diesel, 70 for gasoline, and 56 for natural gas.
Reliability of supply is perhaps best demonstrated by the fact that inhabitants of large northern cities hardly ever think about having their gas supply interrupted because such experiences are exceedingly rare.
Nor are there any great uncertainties about the reliability of international gas supply.
The best recent assessments of recoverable resources indicate that the global peak of natural gas extraction is most likely no closer than around 2050 or perhaps even after 2070. Another reassuring perspective shows that during the past three decades (between 1982 and 2012), the world gas consumption rose 2.3‐fold, but the global reserve/production ratio has remained fairly constant, fluctuating within a narrowband of 55–65 years and not signaling any imminent radical shifts.
In 50 years preceding 2010 the Latin American reserves had quintupled, Middle Eastern reserves grew more than 15‐fold, and the reserves of the countries of the former USSR grew more than 25 times. As a result, global reserves of natural gas rose from about 19 Tm3 in 1960 to 72 Tm3 in 1980, to at least 140 Tm3 in the year 2000, and to more than 177 Tm3 in 2010, more than a ninefold rise in 50 years.
Because reserves are determined by our technical abilities and economic possibilities, what appears unattainable today can become a matter of routine recovery in a few years or decades: recent rapid expansion of natural gas production from American shales is a perfect example of this reality as a combination of newly affordable horizontal drilling and improved hydraulic fracturing transformed a significant share of a previously untapped resource into highly economical reserve of gaseous fuel.
But the great pioneering era of oil extraction during the late nineteenth century had no counterpart in large‐scale development of gas industry. Three main factors explain this absence: ready supply of cheap coal and newly abundant refined liquid fuels; technical limits, above all the absence of inexpensive seamless pipes able to withstand higher pressure and reliable compressors to propel the gas over long distances (and hence decades of comments about large volumes of stranded gas and discovered but undeveloped resource because of no access to markets); and ubiquitous availability of coal (town) gas in all major and medium‐sized cities.
The United States was the only country where a sizable natural gas industry began to be developed during the 1920s.
The greatest period of expansion came only after WWII. The industry was driven by the need to supply natural gas for expanding cities (and suburbia) and industries as natural gas became an essential energizer of new economic prosperity. The US natural gas production grew 2.3 times during the first postwar decade, and then it doubled between 1955 and 1970.
Pre‐WWII extraction of natural gas was an overwhelmingly American affair: in 1900, the US production accounted for all but a tiny fraction (<2%) of the global output; by 1950, the share was 75%; and it was still 60% by 1970. Then came the rapid rise of Soviet gas extraction (it had more than quadrupled in two decades between 1970 and 1990), European output (mainly Groningen and the North Sea gas from Norwegian and British waters) doubled during the 1970s before it stabilized, and the Saudi production had tripled during the 1990s. This brought the US share of the global output down to 25% by 1990.
Traditionally, by far, the most important use of natural gas as fuel was to generate heat or steam required for a large variety of industrial processes, from heavy metallurgy to fine manufacturing. Emergence of this market during the closing decades of the nineteenth century was followed by the adoption of natural gas as a leading fuel for space heating and cooking in households as well as in many commercial and institutional facilities, and since the 1980s, the last two sectors have also used natural gas for central cooling. Another major market for gas as a fuel came with the growth of cleaner electricity generation as methane replaced coal, and also fuel oil, in large centralized power and created new possibilities for more decentralized power based on gas turbines.
No other stationary prime movers combine so many advantages as do modern natural gas‐fueled turbines: they have the most compact size and hence the smallest footprint of all electricity generators and hence can be easily installed within the boundaries of existing thermal power plants or industrial establishments; they can be inexpensively transported to those sites by trucks, barges, or ships; they are exceptionally reliable and relatively easy to maintain; their service is almost instantly available: they can reach full load within a few minutes and hence are perfect for covering peak load or other sudden fluctuations in demand; because they are air cooled, they (unlike steam turbogenerators) do not require any arrangements for water cooling; they are relatively quiet as silencers keep their noise below 60 dBA at the distance of 100; and in combined cycle arrangements, they have unrivaled efficiencies and hence also the lowest specific CO2 emissions.
The sudden emergence of fracking has led to three remarkable developments: to an impressive decline in North American gas prices, to an unprecedented decoupling of US oil and gas prices, and not just to cancellation of LNG imports plans but to plans for US LNG exports.
Gas‐bearing shales underlie large areas on all continents, but, so far, only the United States has developed this resource on a large scale.
This leaves plenty of other countries with the opportunity to develop a new energy resource because hydrocarbon‐bearing shales (with organic content of 2% and more) are among the world’s most commonly encountered formations. Besides the United States, other large nations with extensive shale formations include Canada, Brazil, Argentina, Russia (in Western and Central Siberia), Algeria, South Africa, Pakistan, China, and Australia.
In contrast, even when affordable, solar or wind electricity generation cannot guarantee constant availability—unless backed up by other forms of on‐demand generation (gas turbines being one of the best choices!) or by requisitely large storage—but the storage option is practical only on a relatively small scale as we have no means (save for relatively rare and inevitably energy‐losing pumped hydro facilities) of storing electricity to meet demand on the scale of hundreds of MW or a few GW (power flows required by today’s large cities). Consequently, all carbon‐free renewable alternatives will have limited impact for the foreseeable future.
The verdict is clear: rising consumption of natural gas has been a key cause of decarbonizing the global TPES, but the recent growth of gas supply could neither prevent further growth of carbon emissions nor slow down their growth to such an extent that the world would avoid going above 450ppm of CO2 in decades to come.
Natural gas is an excellent fossil fuel whose many inherent advantages guarantee its increasing use; much like all other energy sources, its greater use also has its share of drawbacks and complications, be they technical, financial, or environmental. And in the game played by the rules of dynamic global energy market, it is still, and in foreseeable future it will remain, nothing more than one of several key cards. This means that a more accurate characterization of the coming decades of changes in global fossil fuel composition would be not the age of gas but the era of rising natural gas importance.
- “Energy and Civilization: A History” by Vaclav Smil
- “Energy Transitions” by Vaclav Smil
- “A Question of Power: Electricity and the Wealth of Nations” by Robert Bryce
- “The Prize: The Epic Quest for Oil…” by Daniel Yergin
- “Prime Movers of Globalization: The History of Diesel Engines and Gas Turbines” by Vaclav Smil
- “Foragers, Farmers and Fossil Fuels” by Ian Morris
- “Power to the People: Energy in Europe over the Last Five Centuries” by Kander et al