Un sistema fotogrammetrico per il controllo di stabilità dei versanti in roccia

In document Sviluppo e Applicazioni di Tecniche di Automazione in Fotogrammetria dei Vicini (Page 163-167)

There are two problems involved in aggregating energy. First there is the inescapable quality problem; different energy carriers have different properties and simply counting their heat content does not do justice to these quality differences. An alternative way to account for energy is to express it as an economic volume (price times quantity for each energy carrier). This is done in chapter 5 and the influence on energy intensity of changed energy carrier composition is discussed. In this chapter energy is simply accounted for by its heat content.

Second there is a problem of a practical nature concerning the inclusion of electricity. Electricity is produced by means of primary energy like hydropower, coal, firewood, oil or nuclear power. If all electricity and in addition the coal, firewood and oil used for its production were included a mistake of double calculation would be made. To avoid double calculation I have excluded the share of electricity that has been produced by steam-power, fuelled with firewood, coal or oil, demonstrated in figure 3.1.

The steam ratio fell rapidly in the period 1885-1910, as hydropower increased its share of electricity production. The reason was the breakthrough of the three-phase system, which reduced transmission losses and made hydropower a viable alternative to steam. The rather constant share for steam-produced electricity between 1910 and 1974 is striking. Thereafter nuclear power expanded both at the expense of steam power and hydropower.

The aggregate energy consumption in Sweden for 1800-2000 is presented in figure 3.2.

Chapter 3

Energy intensity and CO 2 intensity

Energy intensity is the ratio between aggregate energy consumption and GDP and is measured in joule per SEK of GDP. Carbondioxide intensity is the ratio between CO2 emissions and GDP and is measured in kg CO2 per SEK of GDP.

Trends and trend breaks of the energy intensity and the CO2 intensity are presented in this chapter and the results are briefly discussed in relation to previous research.

Aggregate energy

There are two problems involved in aggregating energy. First there is the inescapable quality problem; different energy carriers have different properties and simply counting their heat content does not do justice to these quality differences. An alternative way to account for energy is to express it as an economic volume (price times quantity for each energy carrier). This is done in chapter 5 and the influence on energy intensity of changed energy carrier composition is discussed. In this chapter energy is simply accounted for by its heat content.

Second there is a problem of a practical nature concerning the inclusion of electricity. Electricity is produced by means of primary energy like hydropower, coal, firewood, oil or nuclear power. If all electricity and in addition the coal, firewood and oil used for its production were included a mistake of double calculation would be made. To avoid double calculation I have excluded the share of electricity that has been produced by steam-power, fuelled with firewood, coal or oil, demonstrated in figure 3.1.

The steam ratio fell rapidly in the period 1885-1910, as hydropower increased its share of electricity production. The reason was the breakthrough of the three-phase system, which reduced transmission losses and made hydropower a viable alternative to steam. The rather constant share for steam-produced electricity between 1910 and 1974 is striking. Thereafter nuclear power expanded both at the expense of steam power and hydropower.

The aggregate energy consumption in Sweden for 1800-2000 is presented in figure 3.2.

Figure 3.1 The steam-share of Swedish electricity 1885-2000

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

1885 1890 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Sources and method: SOS Industri 1912-2000, Hjulström, F. (1940) Sveriges elektrifiering, Uppsala, provides benchmark values for 1885 (0,82) and for 1900 (0,4) on p 34. Linear interpolations for 1885 -1900 and 1900 -1912 have been performed.

Figure 3.2 Total energy consumption in Sweden 1800-2000, in PJ.

0 500 1000 1500 2000 2500

1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000

PJ energy(S)energy(E)

Sources and methods see figures and text in chapter 2. The energy carriers of the aggregate are firewood, draught animal muscle energy, human muscle energy, coal, oil, peat, natural gas, hydro and nuclear produced electricity and spent pulping liquor. Energy (S) means that electricity is counted by its heat content, energy (E) means that electricity is counted as the heat content of the fossil fuels needed for its production, if all electricity were produced in a fossil fired plant.

Figure 3.1 The steam-share of Swedish electricity 1885-2000

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

1885 1890 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Sources and method: SOS Industri 1912-2000, Hjulström, F. (1940) Sveriges elektrifiering, Uppsala, provides benchmark values for 1885 (0,82) and for 1900 (0,4) on p 34. Linear interpolations for 1885 -1900 and 1900 -1912 have been performed.

Figure 3.2 Total energy consumption in Sweden 1800-2000, in PJ.

0 500 1000 1500 2000 2500

1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000

PJ energy(S)energy(E)

Sources and methods see figures and text in chapter 2. The energy carriers of the aggregate are firewood, draught animal muscle energy, human muscle energy, coal, oil, peat, natural gas, hydro and nuclear produced electricity and spent pulping liquor. Energy (S) means that electricity is counted by its heat content, energy (E) means that electricity is counted as the heat content of the fossil fuels needed for its production, if all electricity were produced in a fossil fired plant.

Swedish energy consumption increased exponentially from the late 19th century until 1970, except during the War years. When electricity is calculated in the typical Swedish manner there is a stabilisation of total energy consumption after 1970, whereas it continues to increase after 1970, but at a lower rate than before, when electricity is calculated in the typical European manner. In figure 3.3 both aggregate energy and energy/capita are presented.

Figure 3.3 Aggregate energy (PJ) and energy/capita (GJ) 1800-2000.

0 200 400 600 800 1000 1200 1400 1600 1800

1800 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

PJ

0 20 40 60 80 100 120 140 160 180 200

GJ energy(S)

energy(S)/cap

Sources: see figure 3.2, Historical Statistics of Sweden , part 1: Population, SCB.

An average Swede consumed 47 GJ per year in 1800 and 167 GJ in 2000, which means that per capita energy consumption was 3.5 times larger in 2000 than in 1800. Total energy consumption was 14 times larger in 2000 than in 1800. It can thus be concluded that the population increase explains 30% of the total energy increase, while variations in energy per capita explain 70%.1 During the 19th century the entire energy increase was explained by the population increase, since in this period energy/capita actually fell. During the 20th century variations in energy per capita played an important role for the increase. The pattern is, however, not linear in relation to income, as shown in the following.

1 The population increased by a factor of 4 in the period 1800-2000. The total energy increased by a factor of 4*3.5=14. The population increase explains 4/14 of the energy increase, i. e. 30%.

Swedish energy consumption increased exponentially from the late 19th century until 1970, except during the War years. When electricity is calculated in the typical Swedish manner there is a stabilisation of total energy consumption after 1970, whereas it continues to increase after 1970, but at a lower rate than before, when electricity is calculated in the typical European manner. In figure 3.3 both aggregate energy and energy/capita are presented.

Figure 3.3 Aggregate energy (PJ) and energy/capita (GJ) 1800-2000.

0 200 400 600 800 1000 1200 1400 1600 1800

1800 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

PJ

0 20 40 60 80 100 120 140 160 180 200

GJ energy(S)

energy(S)/cap

Sources: see figure 3.2, Historical Statistics of Sweden , part 1: Population, SCB.

An average Swede consumed 47 GJ per year in 1800 and 167 GJ in 2000, which means that per capita energy consumption was 3.5 times larger in 2000 than in 1800. Total energy consumption was 14 times larger in 2000 than in 1800. It can thus be concluded that the population increase explains 30% of the total energy increase, while variations in energy per capita explain 70%.1 During the 19th century the entire energy increase was explained by the population increase, since in this period energy/capita actually fell. During the 20th century variations in energy per capita played an important role for the increase. The pattern is, however, not linear in relation to income, as shown in the following.

1 The population increased by a factor of 4 in the period 1800-2000. The total energy increased by a factor of 4*3.5=14. The population increase explains 4/14 of the energy increase, i. e. 30%.

In document Sviluppo e Applicazioni di Tecniche di Automazione in Fotogrammetria dei Vicini (Page 163-167)