Ley General de Asentamientos Humanos.

McHale (1971) has shown that in the world as a whole, in 1850 wood made up 42% of total energy use, coal 27%, dung 8% and muscle energy 17%. By 1900, coal had a 46% share of total consumption, wood had declined to 33% and dung and muscle to 10 and 9% respectively. Oil contributed 2% of total consumption in 1900. Significantly, solid fuels were still the vast majority of the fuel energy consumption at that time. By 1950 coal consumption had increased to 54%, wood was reduced to 9% and oil had increased to about 30% of total consumption. In 1950 the relative consumption of dung and muscle energy against other fuels had declined to insignificance from a global perspec­ tive.

Darmstadter et al.’s (1971) research on trends in energy consumption in the world between 1925 and 1965 provide statistics which can be compared with Hong Kong trends and their findings tend to support the more generalised data presented above. It is shown that in 1950 solid fuels formed 61% of the world energy consumption and liquid fuels 27.7%. (The consideration of natural gas and hydroelectricity is not applicable to Hong Kong discussions.)

By 1968 the world consumption of solid fuels had fallen below total liquid fuel consumption, the latter forming 42.8% and the former 36.7% of the total. Within the region, considering Asia without Japan which holds considerable coal reserves, solid fuels were 57% of the configuration in 1950 and 39.6% in 1965. Similarly, liquid fuels were 39% in 1950 and 50.2% in 1965.

Table X shows the trends in Hong Kong fuel consumption by type of fuel over the period 1954 to 1971. In Fig.4 these trends are presented on a log scale. In 1954 solid fuels made up nearly 30% of consumption and liquid fuels 70%. By 1971 solid fuels were virtually insignificant constituting only 1.9% of the total, while liquid fuels form 98.1%. The major shift in solid fuel use came about though the fall in use of firewood and coal. The decline of the domestic fuel firewood seems to have been inversely proportional to the growth of the resettled or rehoused section of the urban population. It is reported by the Commissioner for Resettlement (1971) that the high density

TABLE X

Trends in co nsum ption o f energy by energy form, Hong Kong 1 9 5 4 —1971 (MJ X 1 0 8)

Selected years 1 9 5 4 - 1 9 7 1 1954 % o f total 1957 % o f total 1961 % o f total Energy Type: Firew ood 29.00 8.6 36.05 8.2 18.52 3.7 Charcoal 13.1 0 3.9 15.09 3.4 14.94 3.0 Coke 0 .48 0.1 1.68 0.4 1.18 0.2 Coal 58 .1 0 17.2 71 .3 6 16.3 6 7 .8 9 13.5 SOLID FUEL S U B T O T A L 100.6 8 29.8 1 2 4 .1 8 28.3 1 0 2 .5 3 20.4 Motor spirit 2 1.55 6.4 21.39 4.9 2 8 .7 6 5.7 Kerosene 15.61 4.6 23.55 5.4 49 .0 4 9.8

Gas oils, diesel fuels 36.8 10.9 4 6 .8 0 10.7 59 .5 5 11.9

Fuel oil 163.4 48.3 2 2 2 .0 9 50.7 2 6 2 .2 8 52.2 Liquefied petroleum gas LIQUEFIED FUELS SUB TOTAL 2 3 7 .3 6 70.2 3 1 3 .8 3 71.7 3 9 9 .6 3 7 9 .6 OV ERA LL TOTAL 338 .0 4 10 0 .0 4 3 8 .0 1 10 0 .0 5 0 2 .1 6 10 0 .0

* Figure represents imports of firewood is opposed to adjusted figure in Table IV. The import

figure has been used for comparison with previous years unadjusted figures.

Source: H.K. Yip, Trade Research Section, Census and Statistics Department, personal

com m unic ation, 1 9 7 4 .

housing environments grew rapidly from 1954, thereby placing a restriction on the use of smoky and voluminous fuels.

Coal was dispensed with as a primary fuel in two steps: first with the change to fuel oil for electricity generation and then with the shift away from coal to fuel oil for gas generation between 1958 and 1968.

Charcoal has also declined because of the switch in restaurant and domestic cooking use to the more clean and efficient liquid and gaseous fuels. Charcoal remains important, however, in the preparation of roast meats and the brewing of Chinese medicines. Coke has actually increased slightly in volume over the period, while remaining a small percentage of total consumption. Its use as a smokeless fuel for restaurants and as a smelting fuel maintains its popularity.

Of the liquid fuels, gasoils and diesel fuels are the most rapidly increasing in volume. Their widespread use for transport and in restaurants has ensured a growth in their consumption in line with the respective demands for those services. Motor spirit has increased steadily in absolute terms but has declined relative to the total fuel consumption. A report on Air Pollution in Hong Kong

1 9 6 4 % o f 1 9 6 7 % o f 1 9 7 1 % o f A n n u a l rate t o t a l t o t a l t o t a l o f c h a n g e 1 9 5 4 - 1 9 7 1 5 . 3 0 . 9 2 . 8 3 0 . 3 1 . 5 3 0 . 1 - 2 9 % 1 2 . 0 6 2 . 0 7 . 1 0 0 . 9 7 . 8 3 0 . 6 - 1 1 . 6 % 1 . 8 6 0 . 3 1 . 6 2 0 . 2 2 . 6 2 0 . 2 4 . 2 % 4 9 . 2 8 8 . 1 3 3 . 2 3 4 . 0 9 . 3 0 0 . 7 - 2 0 . 7 % 6 8 . 5 0 1 1 . 3 4 4 . 7 8 5 . 4 2 1 . 2 8 1 . 6 - 1 8 . 8 % 3 0 . 8 4 5 . 1 3 8 . 6 2 4 . 6 5 1 . 7 6 4 . 2 - 2 . 5 % 5 9 . 7 6 9 . 8 8 1 . 6 6 9 . 8 7 7 . 6 0 6 . 3 1.9 % 7 1 . 6 5 1 1 . 8 1 0 5 . 6 1 2 . 7 2 6 7 . 6 6 2 1 . 6 4 . 1 % 3 7 5 . 2 9 6 1 . 7 5 5 6 . 5 6 6 6 . 7 8 0 0 . 6 9 6 4 . 5 1 .7 % 2 . 1 2 0 . 3 6 . 6 4 0 . 8 2 2 . 2 0 1 . 8 1 1 . 1 % 5 3 9 . 6 6 8 8 . 7 7 8 9 . 0 8 9 4 . 6 1 2 1 9 . 9 1 9 8 . 4 2 .0 % 6 0 8 . 1 6 1 0 0 . 0 8 3 3 . 8 6 1 0 0 . 0 1 2 4 1 . 1 9 * 1 0 0 . 0

(1969) made recommendation to restrict the use of the more visibly polluting gasoils and diesel fuels. If implemented, this change will cause an increase in the motor spirit share of the transport market. Fuel oil increased both relatively and absolutely until 1964, but since then has levelled out relative to other fuel consumption. This fact tends to obscure the importance of fuel oil which has by far the largest share of consumption in volume terms, and must be consid­ ered the key fuel in the local economy.

Kerosene has decreased both relatively and absolutely over the past 7 years, following a rapid growth rate in consumption in the 1950’s. Liquefied petro­ leum gas introduced in negligible proportions in 1960 as an experimental fuel has quickly encroached on the kerosene market as its major competitor as a domestic fuel. It has the fastest growth rate of all fuels in Hong Kong, at 11.6% per annum since its introduction.

Table XI shows Hong Kong’s solid and liquid fuel trends against those of selected regions of the world over the period 1950—1965. Hong Kong’s rapid shift away from solid fuels during that period is greater than any of the regions

T O N N E S 1,0 0 0, 00 0 G o s O i I i , D t e s e I F u e T b A v i" o t i o K e r o s e M o t o 100,000 l . P . G o s C h o r c o o I 10,000 , / \ C o t e F i r e w o o d A v i a t i o n S p r i t 1,000 YEAR

Fig.4. Trends in energy consumption by type of energy for the 17-year period 1954—1971. The vertical axis is a log scale.

ch an g e in period

1 9 5 0 1955 196 0 1 9 6 5

Solid Liquid Solid Liquid Solid Liquid Solid Liquid Solid Liquid

Selected are a World 6 1.0 27.7 54.1 32.5 47.6 35.7 4 1 .8 39.4 - 2 . 6 2.4 U.S.A. 4 2.3 37.7 30.6 43.4 24.6 43.7 2 4 .3 4 2 .9 - 3 . 8 0.9 O cean ia 7 2 .0 26.1 64.1 33.7 59.7 37.6 51.7 44.7 - 2 . 2 3.7 Asia 68.4 24.8 55.2 37.3 47.8 43.3 3 7.6 54.2 - 4 . 1 5.4 J a p a n 83.2 6.1 68.4 22.1 54.1 38.3 3 5 .5 58.4 - 5 . 8 16.3 O th e r Asia 57.0 39.0 46.0 48.0 42.7 47.4 3 9 .6 50.2 - 2 . 5 1.7 H ong Kong* 35.0 6 5 .0 29.0 71.0 20.0 80.0 10.0 9 0.0 - 8 . 7 2.2 * b y e x t r a p o l a t i o n fr o m Table X.

shown, and its continued growth in liquid fuel consumption is greater than the regional trend, outside Japan, and is roughly comparable to the world trend in the time period considered. The trend towards liquid fuels will level out as the solid fuels are almost negligible in comparison with liquid fuels at the present time.

Hong Kong’s rapid shift to liquid fuels partly reflects its non-energy producing status. Liquid fuels are preferred for importation over solid fuels because of their decreased volume for equivalent calorific value and conve­ nience of handling. Hence a totally importing country would be likely to use liquid fuels as soon as it becomes a competitive proposition in the world market.

The fact that wood was a significant fuel in the early 1950’s is worthy of comment. Cottrell (1969) has suggested that the village communities of China were essentially ‘low energy communities’ and were traditionally conservative in moving from a traditional to a modern energy form. Luten (1971) has pointed to this feature in the European and North American communities in the nineteenth century. Through changes in living conditions in Hong Kong, the 10-year period 1957—1967 marked a transition from the prominent use to the exceptional use of firewood for domestic purposes and, within a gen­ eration, from its universal consumption to its virtual extinction. It is only in the remaining squatter areas and the New Territories villages that wood is found in use as a domestic fuel today.

If Hong Kong is to utilise alternative sources of energy, then those likely to be introduced in the immediate future will be more sophisticated liquid and gaseous fuels. Nuclear energy may be in use in Hong Kong during the late 1980’s.

There are numerous possibilities for the installation of recently developed solar energy collectors for water and space heating which are already in use in some parts of the world (C.S.I.R.O., 1964; Davey, 1966; Close et al., 1968; Morse, 1970; Hammond, 1974). Recent research supported by U.S. Depart­ ment of Commerce (1972) on alternative uses of solar energy presents pre­ liminary findings which are of interest to the Hong Kong situation and which, if implemented, could contribute significantly to Hong Kong’s energy supply.

Given that research in progress solves some of the technical problems of moisture removal and sulphur oxide scrubbing, pyrolysis might be attractive. Hong Kong has major animal sewage and urban refuse disposal problems, all of which will require expensive and energy-intensive solutions in the near future. According to the Civil Engineering Office (1971), the urban area generates 2 561 tonnes of refuse per day, with a potential 16 000 MJ per tonne, giving a possible energy source of 150 X 108 MJ per year, or about 12% of present requirements. However, the moisture removal can often be quite demanding of energy making net energy production minimal.

More attractive is the application of new bioconversion techniques to use organic wastes from urban refuse and animal sewage to generate methane. Agriculture and Fisheries (1973) have estimated that there are about 1 770 tonnes of animal sewage generated per day in a relatively small area which is concentrated enough to allow convenient collection. The techniques do not

require energy-expensive drying processes. By fermentation to methane, this sewage could generate up to 14 000 MJ per tonne or, allowing for 50% mois­ ture content, 45 X 10s MJ per annum, which is 3.5% of current energy demands. Given the availability of suitable technology, both urban organic wastes,

animal sewage wastes and some human sewage could be used to generate more than 10% of Hong Kong’s power requirements and at the same time reduce an aggravating solid waste disposal problem. Solar air conditioning, drying, space heating and water heating could also contribute at least 5% of total energy requirements. It is therefore clear that through direct and indirect consumption of solar energy, a significant contribution can be made to the total energy budget of Hong Kong.