6. ENERGY, THE ENVIRONMENT AND HEALTH
6.3. Impacts of energy production from non-renewable sources
6.3.2. Fuel combustion and air pollution
Air pollution is a side effect of energy production and end use. Energy and economic development have brought many benefits to society, but not without environmental burdens, such as air pollution in large cities. Most energy related air pollution arises from combustion of fuel for either power generation or transport.
6.3.2.1. Thermal plants and their impacts
Policies for expanding electricity generation have recently focused on hydropower or natural gas fired thermal plants. The latter were in evidence during the 2001 electricity rationing incident, which accelerated discussions on the Thermoelectric Priority Programme (PPT) [6.13].
Thermal plants utilizing natural gas emit virtually no sulphur, lead or heavy metals, which are the typical emissions of plants fuelled by coal, fuel oil and diesel. However, natural gas (as well as biomass) still results in considerable NOx emissions, which are tropospheric ozone precursors.21 Ozone is a major problem in urban areas where sunlight is abundant and local wind and rain conditions are not favourable for dispersion and abatement. This is the case for at least 25 million people living within a 100 km radius of the São Paulo city centre, in three metropolitan areas and other conurbations. An important issue under discussion is the establishment of realistic NOx emission factors for power plants and industrial processes that are appropriate for Brazilian fuels and technologies. Knowledge about baseline emissions is a fundamental prerequisite, requiring many assessments TABLE 6.2. ESTIMATED ANNUAL EMISSIONS FROM THE ENERGY SYSTEM (Mt OF CO2 EQUIVALENT) [6.56]
Year CO2 CH4a N2Ob Total GHG
1980 263.6 2.0 0.4 266.0
1985 269.5 2.5 0.3 272.3
1990 273.9 2.6 0.3 276.9
1995 288.4 2.8 0.5 291.7
2000 334.5 2.5 0.6 337.6
Note: Estimates are based on Refs [6.57, 6.58]; figures were calculated utilizing the Intergovernmental Panel on Climate Change bottom-up methodology applied in the Brazilian National Communication [6.59]. Considering non-renewable biomass burning (from deforestation) as well, these numbers are much higher than those published by the Oak Ridge National Laboratory [6.60] for CO2 emissions due to fossil fuel combustion, cement manufacture and gas flaring in Brazil in the 1980–2000 period: 46 Mt (1980), 48 Mt (1985), 55 Mt (1990), 68 Mt (1995) and 84 Mt (2000).
a Methane emissions are slightly underestimated because of the lack of emission factors for some non-major types of energy consumption.
b Because a considerable portion of emissions deriving from fossil fuels have not been included, the N2O values are under-estimates, calculated almost entirely for fossil fuel consumption under the process heat heading and for the transport sector.
20 There is still much uncertainty concerning GHG emissions from hydropower plants (see Refs [6.61, 6.62]).
However, according to the preliminary estimates, except in a very few cases, GHG emissions from hydropower plants are far lower (in fact, almost negligible) than those produced by thermoelectric power plants burning fossil fuels [6.62].
21 Other topospheric ozone precursors are CO, SO2 and non-methane volatile organic compounds (NMVOCs).
in terms of source inventories, characterization of several processes and emission monitoring.22 Figure 6.4 presents national levels and regional shares of thermal power plant emissions as communicated by the Brazilian national inventory to the Intergovern-mental Panel on Climate Change (IPCC).
A large thermal power plant (500 MW or more) is considered a commercial investment
‘anchor’ for a natural gas pipeline project. Cost effec-tiveness criteria stipulate that thermoelectric plants are to be located as close as possible to end users (saving electricity transmission and gas pipelines), that is, in densely urbanized and industrialized regions. However, location must meet certain environmental requirements, especially in large urban areas. In the light of several academic, public and institutional discussions on this matter, there is a trend in legislation towards taking into account environmental permits and local maximum allowable environmental capacity, which involves inventorying multiple source emissions, modelling atmospheric processes and predicting major impacts.
The substitution of natural gas for other fossil fuels confers environmental advantages, namely, reductions of smoke and sulphurous gases.
Depending upon plant operating conditions and air to fuel ratios, decreased emissions of HCs and incomplete combustion products also result.
However, increased fugitive HC (from gas transfer operations) and CO and NOx emissions are likely to occur, although these would be lower than those from other fossil and biomass fuels.
In the southern States of Santa Catarina and Rio Grande do Sul, there are a few coal fired power plants (taking advantage of local coal availability).
These plants are significant polluters, since Brazilian coal has high contents of ash (20–55%) and sulphur (0.8–6.5%). Because these plants operate at lower boiler temperatures, their NOx emissions are relatively low compared with those of natural gas fired plants. An assessment of four plants — Charqueadas, Candiota, Jorge Lacerda and Cambuí — showed emission levels of 1300-5175 kg of SO2 per terajoule, 100–233 kg of NOx per terajoule and 0.5–1.1 kg of N2O per terajoule. Calorific values for the most commonly used coal ranged between 13 and 19 TJ/kt [6.64].
It is expected that the recently discovered offshore natural gas resources in São Paulo, combined with gas imports and gas consumption incentive policies, will lead to more emissions of global and local pollutants. This problem could intensify air pollution in populated areas, forcing the adoption of stronger enforcement policies and actions. A future challenge is the control of ozone, mainly caused by emissions of NOx and volatile organic compounds (VOCs). As in developed countries, emission offset policies will have to be instituted, forcing older facilities to be upgraded and new ones (seeking environmental permits) to adopt pollution abatement measures.23
There are few studies of local pollution emissions from sugar cane bagasse fired boilers in Brazil. Coelho [6.29] provides an estimate of 0.6 kg of NOx — and the same amount of PM — per tonne of bagasse burned. In many cases, particularly in São Paulo State, different kinds of air pollution control equipment (baghouses, electrostatic precipi-tators) are used for PM abatement, especially in the pulp and paper and sugar cane–alcohol sectors.
Furthermore, combustion of biomass and biomass derived fuels still generates air pollutants, including CO, NOx and PM such as soot and ash.
The amount of pollution emitted per unit of energy generated varies widely according to the technology used, but wood burning in traditional stoves is generally the worst offender, since the pollution occurs indoors. More advanced technologies with appropriate control devices generate far fewer emissions [6.65].
22 As natural gas fired power plants have high fuel consumption rates, local emissions have to be modelled to avoid excessive concentration of pollutants in certain areas.
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
CO2 (1.63 Tg as C) CH4 (0.29 Gg) N2O (0.15 Gg) NOx (35.31 Gg) CO (2.49 Gg) S (0.30 Tg)
North Northeast Midwest Southeast South
FIG. 6.4. Thermal power plant emissions, total and shares by region for 1997 [6.63].
23 São Paulo State has already issued a law (2004 Decree No. 48 523) implementing an air pollution emissions offset scheme, where new enterprises have to balance their emissions with those of existing firms.
6.3.2.2. Transport related emissions
Automotive fuels have shown considerable improvement since the introduction of ethanol in 1975, especially since the late 1980s with the continuous removal of lead and sulphur. In general, automotive emissions have been reduced by blending all gasoline with 20–26% ethanol. The improvement of fuel quality has brought about a substantial reduction in CO, HC and GHG emissions from new vehicles. The addition of ethanol to gasoline at a percentage regulated by law has also helped Brazilian refineries to ban the use of tetraethyl lead, thus eliminating an extremely hazardous emission [6.66].
Ethanol use as an automotive fuel yields considerable GHG abatement benefits. Yet, an ethanol or natural gas fuelled automobile may emit more NOx, for example. Other problems include the inadequate conversion of gasoline engines to natural gas fuelled engines; the use, by some automobile owners, of excessive quantities of ethanol in their fuel mix to minimize costs; and the use of fake, illegally obtained catalytic converters. It is expected that, in the future, Brazil’s vehicle inspection and maintenance programme will adequately address these concerns.
In 1986 the National Vehicle Emission Control Programme (PROCONVE) was instituted.
It has since become a benchmark in terms of improvements in vehicle technology. Since 1992, two-way catalytic converters (oxidizing both CO and HC) have been installed in new Brazilian light vehicles. Since 1997, vehicles have been equipped with both three-way units (oxidizing CO and HC, while also reducing NOx emissions) and electroni-cally controlled fuel injection and ignition systems, which have contributed towards more efficient engines that are more tolerant of fuel composition fluctuations.
This kind of technology constitutes the basis for flex-fuel vehicles, capable of automatically analysing fuel alcohol to gasoline composition ratios and adapting the ignition system accordingly. Flex-fuel vehicles can run on gasoline, alcohol or any kind of ‘gasohol’ blend. Besides allowing users to choose their fuel based on the prevailing fuelling and pricing conditions, such vehicles may bring considerable environmental gains if they stimulate the use of ethanol fuel. Figure 6.5 illustrates the air emission abatement levels obtained for light vehicles with the implementation of PROCONVE.
Sulphur emissions (as well as sulphate emissions, emitted as PM) from diesel vehicles are very high. According to CETESB, the inhalable particle emissions from the light vehicle fleet in the São Paulo metropolitan region amount to 51% of total emissions, including stationary sources. The much smaller diesel powered fleet, composed predominantly of heavy duty vehicles, is responsible for 30%.24 Moreover, the Government has recently required the diesel fuelled fleet to use a lower sulphur diesel fuel, called ‘metropolitan diesel’, for urban areas.25 Government policies are systemati-cally reducing the sulphur content in gasoline as well.26 Even with the increased consumption, total emissions are decreasing more intensively, as shown in Table 6.3. In addition to reducing emissions, this lower sulphur content permits compliance with particle emission standards that are a tenth of the current standards, and it is less damaging to engine components.
Several experimental vehicle pollution abatement programmes can also be cited, such as the introduction of hybrid diesel–electric buses,27 biodiesel use28 and research into the potential use of hydrogen fuel derived from sugar cane ethanol.29 Biodiesel is a promising energy option, but the pros and cons are still not balanced in the environmental dimension: there are the advantages of reduced carbon and pollutant emissions,30 but the risks include the potential for agricultural expansion, especially the expansion of soybeans in Amazonia.31 Proper management of emissions from mobile sources also requires an integrated inspection and
24 New models of automobiles are not allowed to be fuelled by diesel, a subsidized fuel for use in cargo and public transport.
25 The 2004 levels of sulphur in diesel were 3500 ppm in regular diesel and 2000 ppm in metropolitan diesel.
Petrobras expects to reduce such levels to 500 ppm by 2006 and, if economically feasible, to 50 ppm by 2009.
26 The maximum allowable level of sulphur in gasoline is 1000 ppm (400 ppm gasoline can be found in filling stations); the target for 2008 is 80 ppm.
27 Supported by the William and Flora Hewlett Foundation [6.67].
28 PROBIODIESEL, the National Biodiesel Pro-gramme, was launched in 2002 [6.68].
29 For more information, see Ref. [6.69].
30 Biodiesel fuel has led to a significant emission reduction — 23% less black smoke — compared with the same amount of regular diesel fuel [6.70].
31 See discussion in Section 6.2; for more information, see Ref. [6.71].
maintenance programme32 and the management of fugitive emissions of non-methane volatile organic
compounds (NMVOCs), for example, at gasoline pumps and storage tanks.
6.3.2.3. Impacts and their costs
Air pollutants include CO, tropospheric ozone, SO2, NOx and PM. These pollutants are primarily the result of fossil fuel combustion, mainly in vehicles and industrial processes. Ambient air in most urban areas typically contains a mixture of
Aldehydes
0.015 g/km 0.15 g/km
0.03 g/km 0.00
0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20
0891erP 1891 3891 5891 7891 9891 1991 3991 5991 7991 9991
mk/g
Hydrocarbons
0.26 g/km 0.16 g/km 2.1 g/km
1.2 g/km 0.3 g/km 0.0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
0891erP 1891 3891 5891 7891 9891 1991 3991 5991 7991 9991
mk/g
CO
2 g/km 24 g/km
12 g/km 2 g/km 0
10 20 30 40 50 60
0891erP 1891 3891 5891 7891 9891 1991 3991 5991 7991 9991
mk/g
h
Gasoline Gasohol Ethanol Limit USA Limit Brazil NOx
0.62 g/km
0.25 g/km 2.0 g/km
1.4 g/km
0.6 g/km
0.0 0.5 1.0 1.5 2.0 2.5
0891erP 1891 3891 5891 7891 9891 1991 3991 5991 7991 9991
mk/g
FIG. 6.5. Average emission evolution for new Brazilian light vehicles [6.43].
TABLE 6.3. SULPHUR REDUCTION IN FUELS AND CORRESPONDING ESTIMATED EMISSIONS
Year
Diesel Gasoline
S contenta (ppm) Consumption (106 m3)
S emissionsb S contenta (ppm)
Consumption (106 m3)
S emissionsb
Regular Metropolitanc kt/year kg/m3 kt/year kg/m3
1990 13 000 — 25 276 11.1 2 500 11.5 21 1.8
2002 3 500 2 000 36 107 3.0 1 000 22 16 0.7
2004d 2 000 500 38 65 1.7 400 25 7 0.3
2008d 500 50 43 18 0.4 80 30 2 0.1
Note: Diesel density is 0.85 t/m3 and gasoline density is 0.72 t/m3.
a The sulphur content reported here is the maximum in the given year.
b Sulphur emissions are represented as S, but in reality are sulphate (SO4–2) and mainly SO2.
c The volume of metropolitan diesel/gasoline was considered to be half the volume of regular diesel/gasoline.
d Scenarios for 2004 and 2008 are based on annual growth rates of 3.1% for diesel and 5.6% for gasoline.
32 The city of Rio de Janeiro has started such a scheme, but it is still in the initial phase. Although the Federal Government plans to establish a national inspec-tion programme, a legislative deadlock has been delaying the implementation of an inspection and maintenance programme at the State level [6.72].
pollutants, each of which may increase a person’s vulnerability to the effects of the others (a synergistic effect). Exposure to CO lowers reflexes and causes drowsiness, since CO molecules constitute an unbreakable bind to haemoglobin, reducing the amount of oxygen carried by red blood cells. NOx may aggravate the effects of asthma and reduce the lung’s gaseous exchange performance, as well as make a person’s airways more sensitive to allergens. Ozone also causes lung inflammation and reduces lung function and exercise capacity. Fine inhalable particles, especially those with a diameter of 10 mm or smaller (PM10), may become lodged in the lung’s alveolar sacs. Most hospitalizations due to respiratory diseases are associated with exposure to PM, as are increased mortality rates due to respiratory and cardiovascular maladies. The ozone and particulate levels commonly present in large cities increase death rates, the number of hospitali-zations and medical visits, the complications of asthma and bronchitis, and the number of days of work lost and work restrictions, and may cause lung damage [6.43].
According to Weaver [6.73], in São Paulo about 10% of all hospitalizations of children, as well as 8% of fatalities among the elderly, are due to respiratory diseases related to high PM levels.
Estimates from IPEA/ANTP [6.74] report that emissions from the São Paulo metropolitan region’s transport system cause yearly average economic losses of 340 million Brazilian reals, mainly due to delays, excessive fuel consumption, air pollution and the need for excessive road repairs. Table 6.4 summarizes the health costs associated with air pollution in the São Paulo metropolitan region, calculated using different
methods. As a reference, in 2001, 65.3 kt of PM were emitted in the region [6.40], where 308 inventoried industries accounted for 31.1 kt of PM, diesel vehicles for 19.7 kt of PM and gasoline automobiles for 5.1 kt of PM.
Evaluations have been conducted in Brazil concerning the economic values of mortality and morbidity cases, as well as the benefits of air pollution abatement. In the São Paulo metropolitan region, with a population of 18 million, studies have found significant harmful pollutant effects, especially for babies, children and elderly people.
Fine inhalable particles were the pollutants most frequently related to respiratory and cardiovascular damage. Records indicate that, during the most polluted days in São Paulo, child morbidity in hospitals increases by 30%, the mortality of elderly people increases by 15% and cardiovascular problems increase by 10%. Such studies supported by epidemiological findings have shown that current air quality standards are inadequate to protect those population groups most sensitive to pollution.
Associated health costs would decrease by half if international air quality standards were attained in the region [6.76, 6.77].
Rapid population increase without corre-sponding infrastructure development to support it has caused serious traffic jams and air pollution incidents in São Paulo. In 1989, 50% of the city’s smog resulted from fixed sources, while 50% came from motor vehicle emissions. By 1999, these rates had been altered to 10% and 90%, respectively [6.77].
Another study evaluated air pollution costs incurred as a result of fine inhalable PM (PM2.5).
Air pollution health costs were estimated by
TABLE 6.4. HEALTH COSTS ASSOCIATED WITH FINE PARTICULATE MATTER (PM2.5) AIR POLLUTION IN THE SÃO PAULO METROPOLITAN REGION (103 US$ (1997)) [6.75]
Age
Morbidity Mortality
R C R, C (SPM) R (HPM) C (HPM) R (TSLV) C (TSLV)
0–13 1.1 n.a. 0.0 n.a. n.a. n.a. n.a.
14–65 2.0 7.3 73.1–197.7 0.04–0.12 0.05–0.13 3.1–13.1 3.6–14.9
65+ 2.3 7.6 9.3–11.0 0.02–0.06 n.a. 1.6–6.6 n.a.
Note: n.a. = not available; R = respiratory; C = cardiovascular; SPM = sacrificed production method, or the human capital for future production lost due to disease; HPM = hedonic prices method, a comparison of two real goods differing only by the environmental characteristic that the analyst seeks to evaluate; TSLV = transfer of statistical life value method, or the will-ingness to pay for the risk of death from a given activity.
summing up total hospitalization costs (per age group and pollution occurrence), taking into consid-eration the number of days of work lost due to disease and average regional wages. Total annual costs associated with atmospheric pollution by fine particles in the São Paulo metropolitan area average US $100 million (1997 value) in terms of heart and respiratory diseases alone. Preventive costs were not quantified as disease costs in this particular study [6.75].
6.3.2.4. Water pollution
With regard to thermal power plants, one important issue is their high water consumption for gas turbine cooling. These demands tend to compound the existing problems of meeting demands for multiple watercourse uses — such as residential, commercial and industrial supply;
wastewater discharges; irrigation; navigation; and energy generation — and could cause shortages downstream. In São Paulo State, six natural gas fired plants — amounting to a total capacity of 3600 MW — are to be installed in the already overexploited Capivari, Piracicaba and Jundiaí watersheds. It is estimated these plants will take out 4100 m3 of water per hour (enough to supply 400 000 inhabitants), of which two thirds will evaporate [6.78]. Dry cooling towers and closed cycle units are technological options that, although more expensive, would help in tackling such problems, as shown in Fig. 6.6.33
6.3.2.5. Pollution prevention and control strategies Solutions for the problem of urban air pollution are not difficult to identify. Improved air pollution regulations and enforcement as well as improved technologies as described above can go a long way to improving the situation and are reasonably influenced by legislation and economic incentives. More difficult to impose are lifestyle changes. Individuals could reduce automobile use by bicycling, walking and using public transport;
they could also make use of more fuel efficient automobiles.34 Urban planning commissions and
regional governments could redirect transportation funding towards public transport options: light rail, heavy rail or express buses. Zoning laws and other regulatory tools could be used to encourage higher density development, which is more conducive to increased public transport usage.
In 1995, a pollution control programme was instituted in São Paulo involving an automobile rotation scheme, whereby drivers were obliged to leave their vehicles at home one day a week. This system has contributed to reducing traffic volume and daily main pollutant emissions (see Chapter 9).
However, after a few years, some drivers simply bought additional automobiles — sometimes older and more polluting models — to get around the regulation. Current Government initiatives to improve local environmental conditions include building a bypass around the metropolitan area (expected to reduce city traffic by 20%) and addi-tional subway lines, and making improvements to the rail system. Other measures include progressive reductions in the sulphur content of all diesel fuel used within the metropolitan area and establishing a vehicle inspection and maintenance programme.
The city of Curitiba has adopted urban planning approaches to mitigate adverse environ-mental effects. The main goal is to reduce the
33 Since there currently are few operational natural gas fired thermal power plants in Brazil, assessments commonly utilize emission factors provided by equipment suppliers. Literature sources, such as those of the US EPA [6.42], provide theoretical results for the local situation.
34 Policies are proposed and discussed in more
34 Policies are proposed and discussed in more