-"~'::;f::J'......"".....nllllt...-Ili.......'1......L../CYC/VVIIICJIL.For exampleifTo=273 + 127=400'K ie theinputtemperature is 127°CandT =273 + 27 =300'K, ie theoutputtemperature is 27°CE = 1 - 300 =0.25,andefficiency is25%I 400In practice,dueto frictionandother losses the efficiency of thermalmachines is lowerthanthe maximum value.Second-law efficiencyThere are often different methods of performing the same task. for example. heating alivingspace. Let us assumethatthis is done by delivering anamountof heat Qtoa build-ingat 30°C by a gas furnace which has an efficiencyof 60%.The same task can be done bya heat pump (aCarnotcycle run in reverse) capable of extracting a quantity of heat Qfromthe atmosphere usingworkW delivered by a motor. The theoretical minimum energy con-sumptionW of the heat pump isTW=Q(I-To)Iftheoutdoortemperatureis SoCT =273 + S =278°K andTo=273 + 30 = 303°Kthen278 _QW = Q(I - 303) - IiUsing the furnace for the same task. the amount of heat necessary would be Q..A newefficiency can then be defined as_ theoretical minimum energy consumption for a particular taskEll - actual energy consumption for a particular taskThis is sometimes calledtheSecond LawEfficiency.ThusW W () IEll = Qo= Q Qo=12x 0.6 = 0.05Source:Goldemberg. j. Johansson. T B. Reddy.A K N and Williams. R H.Energy(oraSustainable World. john Wiley and Sons. Chichester. UK (1988).&'0Id~bzA.JChapter3Energy and DevelopmentThe aggregate monetary value of all goodsandservicesproducedin a yearfor a whole country or region is called the Gross National Product (GNP).Oftenanotherindicator isused- the Gross Domestic Product (GOP).'TheGNPpercapita is the averagemonetaryvalue of goodsandservices,ie income available to each person in a given country.GNP/'GNPcapita =populationAsitis an average,GNP/capitaglossesoverdistributions of income,which are sometimes considerable.Itis, however, an easily measured indi-catorandhas come to be widelyusedby economistsandplanners as a proxyfor development.It is for this reason that the World Bank divides countries in three aggre-gates:• high-income countries (annual GNP / capita above US$ 6000);• middle-income countries (annualGNP/ capita between US$ 651andUS$ 6000);and• low-income countries (annual GNP / capita below US$ 650).The definitions of GDP and GNP are:• Gross Domestic Product (GDP): the totaloutputof goods and services forfinal use produced by an economy, by both residents and non-residents.• Gross National Product (GNP): the total domestic and foreign value addedclaimed by residents, calculated without making deductions for depredation.It comprisesGDP plus net factor income from abroad, which is the income res-idents receive from abroad for factor services (laborandcapital), less similarpayments made to non-residents who contribute to the domestic economy."i I12Energy, EnvironmentandDevelopmentEnergyandDevelopment13,Disparities in Income DistributionDistributionof economicactivity,1991(percentage of world total)Percentageof population20406080Source: Adapted from data contained in World Bank Reports, Washington DC, US.Figure3.2Lorenz curve for income distribution'"100CIiE8.s'0~c~~Figure 3.2showsa Lorenz curve. Iftheincome distribution was uniformly equal, 25 percentoftheworld's population would have 25percentoftheincome, 50percentwouldhave 50percent, and so on. The 45° line wouldrepresentthis situation. The actual dis-tribution isshownbythecurved line, which isplottedby first indicatingthelow-incomecountryshare(L),thenaddingthemiddle-income shares (L+M),thenaddingthehigh-incomeshares(L+M+H). Clearly,theglobal distribution ofincomeis skewed. Low-incomecountries have 61percentoftheworld's populationbutonly 5percentof global income;middle-incomecountrieshave 23 and 13percent, respectively; while high-income coun-tries have 17 and 82percent, respectively.Global distribution of incomeEachhorizontal bandIrepresents an equalfifthof the world's people~~~o......"c;oua~o.....-5L..".£~~o.£~o.....'E~~o.....~:ns:u~A complete list of countries in each category is given in Appendix 3. A list ofwhich countries are considered developing (LDCs) or industrialized is givenin Appendix 4. In general, it is the high-income countries which areindus-trializedbutEast European countries, some of the Republics of the ex-SovietUnionandsome middle-income countries are also included in this category.Source:UNDP,HumanDevelopmentReport,Oxford University Press, Oxford, UK (1994).Figure3. I Global economic disparitiesGNP changes dramaticallyamongcountries asshownin Figure 3.1 inwhichcountries are divided into five categories: those comprising the poorest fifthof the population represent1.4percentof theworld'sGNPandthe countrieswhere the richest fifth live represent 84.7percent. Anotherwayof display-ing this type of information isthrougha Lorenz Curve Diagram (see Box onGlobal distribution of income).~"C'!:JY,LIlVIJU/IJIJf:::IJLUIJUUf:::Vf:::/UPflJf::lJ[Energy and uevetopment15Even more striking than such global information is the disparity of incomeinside a given country. An example is given in Figure 3.3 for Brazil in 1970:66percent of the populationhada monthly income of between 0and2 wageunits (WU),and4percent above 10 units.1266%10-;;;-8c~£~~E6-12'0...Q).0E"I Iz422%28%For the poor, developmentmeanssatisfying the basichumanneeds,including access to jobs, food, health services, education, housing,runningwater, sewage treatment, etc. The lack of access of the majority of people tosuch services is a fertilegroundfor political unrest, revolution,andthe hope-lessnessanddespair that lead to emigration to industrialized countries insearch of a better future. .Much of the energy for agriculture, transportationanddomestic activitiesin developing countries comes fromhumanbeingsanddraft animals. Othersources include biomass in the form of fuelwood, animal wastesandagri-culturalresidues. Fuelwood, in fact, is thedominantsource of energy in ruralareas,andcooking is the most energy-intensive activity. These biologicalsources of energy are often described as 'non-commercial' because they arenot the object of commercial transactions: in rural areas, thewomenandchil-dren usually gather twigsandbranches for cooking fuel instead ofbuyingwood.Figure 3.4 shows as an example ofhowenergy is consumed by differentincome/capita groups in Brazil. For families with income higher than 10WU, oil derivatives represent 65percent of total energy consumption whilefor families between 0and2 WU they represent