A Mathematical Programming/Economic Equilibrium Model for the Quantitative Analysis of the Stability of Japan's Energy System by Tatsuo Oyama MIT EL 86-016WP August 1986 A Mathematical Programming / Economic Equilibrium Model for the Quantitative Analysis of the Stability of Japan's Energy System Tatsuo Oyama Graduate School of Policy Sciences Saitama University, Urawa, Saitama Japan 338 A Mathematical Programming / Economic Equilibrium Model for the Quantitative Analysis of the Stability of Japan's Energy System ABSTRACT Japan's energy supply-demand system is fully dependent on the import of primary energy resources from foreign countries. So the availability of primary energy, including crude oil and coal, is a very important factor for the stability of our energy system. In order to measure our energy system's stability under an uncertain future availability of energy resources, we built a mathematical programming / economic equilibrium model based upon linear programming techniques. In the model analysis uncertain future availability of primary energy resources is expressed as random variables with a given probability distribution, and the economic equilibrium point is obtained by iterative convergent computation. From our numerical results we know an optimal energy supply-demand structure with equilibrium prices of primary energy resources at the future target year, and obtain supply stability and instability probabilities of our energy system. Furthermore, applicability of decomposition techniques to our energy model analysis and necessary and sufficient conditions stability of our energy system are discussed. for the During the years following the Arab oil of embargo 1973, there have been many energy policy debates throughout the world, including Japan. Energy policy debates concern various technical, environmental, social, economical, political and problems. Energy policy modeling efforts have not only the necessity of such also the greater availability Hoffman [1973] proposed supply-demand energy even increased interdisciplinary of high energy speed network problems, military due research, but computers. systems various Since analyses systems for analysis approaches have been developed. (See e.g. Charpentier [1974] Manne, et al [1975, 1977], [1980], and [19793 for energy models. Oyama [1980, 1980a, 1983b], Shapiro and White [1982].) Japanese electric power system (see Energy Saito and Oyama situation Also see Modiano We [19803) to see what our energy and Shapiro Group supply the [1979], and demand will be like in the year 2000. Many economic equilibrium models have also been developed which use linear and nonlinear programming techniques. (See Kennedy [1974], Hogan [1975], Griffin [1977], Hogan [1980], Daniel and Goldberg [19813. See also Takayama and and [1971] for price and resource allocation models.) Shapiro discusses decomposition techniques to show the between linear programming and econometric components planning and Shapiro investigated Study to models. interpretation Furthermore, Shapiro of the Kuhn-Tucker [1978] optimality economic equilibrium point for certain 1 e.g. Weyant Judge [1978] relationship of energy presents conditions mathematical the as an programming models. However, in most of these modeling demands and the availability of studies, primary future energy energy resources are demand and given exogenously. We believe that our future energy the availability of primary energy resources should be uncertain. In our analysis, we express the structure of our energy supply and demand system as a network as does Hoffman [1973]. then formulate a linear programming economic equilibrium in which the supply availabilities of primary energy We problem resources, such as crude oil and coal, are defined as random variables. This paper proposes an iterative convergent procedure model. compute an economic equilibrium point for our energy to The equilibrium point indicates an energy supply and demand structure for the future target year. Our mathematical programming economic equilibrium (MP/EE) model is a mathematical optimization model to find an economic equilibrium / programming point as an optimal solution of a linear programming problem. We define the probability the stability that the robability of our energy system as given linear programming feasible under the "randomized" supply availability model is constraints. In addition to these stability probabilities of our energy system of prices and demands for crude from the economic equilibrium solutions at the target year, distributions oil and coal are obtained of our energy model. policy in various We can also evaluate demand sectors by analysis with the probabilistic approach. 2 our energy combining conservation shadow price In section 1 we explain the current energy Japan. In Section 2 we outline our MP/EE energy the formulation of our energy model and situation model the their Finally, theoretical in Section analysis is 5, we summarize including computational procedure to solve it. Numerical results are given in and in described Section in Section our model and comment on 3 4. our approach. 1. Introduction Japan imports almost 90% of her total primary energy. imported energy resources are fossil fuels coal and liquefied natural gas such (LNG). as These the South Pacific region, economically unstable which arose during which contain countri es. many Considering primary energy resources. The oil impact, and created confusion engineering system. Therefore, in our whether enough primary energy resource s to meet politically and difficulties it had a country's or not future energy and is an adequate embargo oil, countries the the oil emb argo of 1973-'74, that we will not always be abl e to obtain crude primary resources are mostly imported from Middle Eastern Major probable amount very serious economic we can expected of and obtain demand concerns us greatly. The oil embargo in 1973 induced increase from $2.51/bbl in 1972 a large to $10.79/bbl 3 crude in 1974, oil price and it had serious effects on the world system. After consumption decreased ti his has economy "first oil stopped our crisi increasing The "second oil crisis", which re ted in 197 8, also caused a secon Our crucde oil imports Iranian the increase. price in 1978 to $3 by 10.7% from 1980. Total prim.ary energy consumption during the same p eriod. conservation has prevailed energy Oil from large imports decreas Through primary .8% from 1974 to 1975. Crude oil prices increased from $13.77/ in 1980. supply-demand rapidly. by 4.4% from 1973 to 1974, an revolution energy and so these 2.97/bbl 1979 decreased by "oil to 3.4% energy crises", in our indus trial demand sector. energy system has structurally changed to a system Our that does not depend heavily on crude oil. It is probable that wle will have another induced by a disruption in oil supplies due events in oil exporting quantitatively various countries. evaluate levels of our primary Therefore, energy energy "stability" of our energy system to is to be "stable" crisis" unexpected it is important supply under constraints. The Our or "unstable", upon energy to meet our "supply stability future energy probability" of demand. our By energy as probability that our mathematical programming energy model has feasible solution, the "supply stability" of 4 our energy to energy defining system the system corresponding whether or not we can have a sufficient supply of primary resources to stability dependent possibility of importing crude oil and coal. can be determined some system's fully "oil the the a system can be quantitatively investigated. 2. MP/EE Energy Model 2.1 Energy System and Linear Programming Model Our energy system, which involves energy flow supply regions to final sectors, demand is from and Four stockpile-transfer. hydro-nuclear, crude oil, regions, kinds coal, of and as illustrated network system in Figure 1. The supply sector consists divisions, including five supply various of a seven domestic production, primary energy LNG-natural gas of are transformed into petroleum products, coal products, and secondary energy of electricity and consists of four city categories: gas. The industry, final demand sector residential-commercial, transportation, and stockpile-transfer. A feasible future energy energy demand flow in the network under various supply physical and engineering constraints. The arcs of the network correspond to unknown and network constraints are linear has to satisfy constraints, energy flows variables equalities the and on the of the model, and inequalities using those variables. Thus the problem of finding an equilibrium energy flow can be formulated The goal is to corresponding to an obtain as a linear programming a desirable economic feasible equilibrium problem. energy point in flow our mathematical programming energy model. A desirable energy flow in 5 the network energy system of Figure 1 can be determined as a flow attaining a maximum economic surplus criterion; i.e., minimizing supply cost less demand cost. One can obtain flow by solving linear programming problems an optimal energy iteratively, until satisfying a convergence criterion. 2.2 Structure of the MP/EE Energy Model In the MP/EE variables ({xi, yj, correspond Zk, to energy the remaining demands energy model there are five kinds of endogenous wi, dij). Four kinds of them (xi,yj,zk,w}) flows, as in the network endogenous for imported primary xi, iM energies = (1,...,17) : primary indicate {dij) variables of Figure 1, while "flexible" of crude oil and coal. energy transported the from supply regions and the stockpile-transfer node yj, jN = {1,...,14} : primary energy transformed into petroleum products, coal products, or secondary energy; primary energy directly consumed in demand sector Zk, : petroleum ksK = (1,...,28} and coal products into secondary transformed energy or consumed in demand sector wl, le = {1,...,5} : secondary energy consumed in final demand sector d'j, iI = {R,L}, jJ = { ±1, ±2,..., ±6) variables indicating the perturbation of 6 primary energy resources' (R:crude oil L:coal) demand from their standard demands Using the programming above variables, model are expressed constraints in the linear as follows: (1) Availability Constraints of Primary Energy Resources In the energy network of Figure 1, primary energy enter the system through supply nodes. The amount resources of primary energy at each supply node has an upper bound determined by the physical, economical or, sometimes, political situations in the supply regions. The physical availability of each primary energy resource from each supply region is given as follows: xi b, isM. (1) (2) Flow Conservation Constraints The set of nodes in the network is divided into three groups supply nodes corresponding to supply regions, demand nodes indicating demand sectors nodes. intermediate At in-flow has to be equal = Z x Z yj = Z ieMp jsNp jeNp keKp from each p=13 to p=16, intermediate to out-flow. node and remaining p(1,...,12), Therefore, yj p=1,2,3 (2) Zk p=4,...,10 (3) p=11,12 (4) Z yj + Z Zk = Z wl jsNp k6Kp l6Lp 7 (3) Upper and Lower Bounding Capacity Constraints Upper and lower bounds are given for the variables indicating production of petroleum and coal products (Zk, and consumption constraints of electricity are written and city gas eL). These as follows: LBZk S Zk UBZk, kEK'CK (5) LBWi UBWI, E1L (6) wi where LBZk, UBZk, LBWI and UBW l are lower {Zk} ({wi, kK'CK), and {wi), respectively. constraints (5) are given and K' is a proper upper subset for some variables bounds of K, of hence of (k}. (4) Yield Constraints of Petroleum Products Refinery systems have their own restrictions regarding the yields physical of petroleum and engineering products. Each petroleum product has both lower and upper production bounds. YLjC yj YUjC C = X + X2 + X4 + X7 + Xl 3<j:6 (7) + X12 + X15 - Y2 where YLj and yuj are the lower and upper bounds petroleum product indicated of the yield by yj, and C is the total crude of oil entering the refineries. (5) Demand Requirement Constraints for Imported Primary Energy Resources Imports of primary energy resources are restricted by following constraint: Z Xi iEMk Dk + Z jEJ+ dkj - 8 Z jEJ- dk ke {R,L) (8) the where J+ and J- indicate J=(±l, ±2,..., sets of positive ±6), respectively. The inequality expresses the flow of and negative left each side primary indices of of the energy above resource from each supply region to Japan, while the right side expresses the perturbed demand of each primary from standard demand. The deleted, is illustrated corresponds dkj in Figure 0 dkj (dkj}, in Figure to the standard Each variable interval variable has an energy demand upper with 2, where Dko the the the supe:rscript the demand in bound resource k q uantity Do constr aint correspondin g (8). to the 2. Akj, k{(R,L}, jeJ. (9) (6) Final Energy Demand Requirement Constraints In the four demand residential-commercial, nodes corresponding transportation and to industry, stockpile -transfer, the following final energy demand requirement constrain ts have to be satisfied: Z yj jgNp + Z kEKp Zk + Z lcLp (10) p=13,...,16 Dp Wl (7) Objective Function The total supply defined cost of the energy as the sum of fuel costs this model, we define and system in Figure transformation the fuel cost to be the cost of 1 is costs. In obtaining the resource in each supply region and transporting it to i.e., the CIF cost. The transformation cost is defined Japan, to be the cost for transforming primary energy resources into petroleum and 9 coal products, electricity, and city gas, and consists mainly the capital cost necessary for energy fuel cost per thermal unit (010 transformation be d, jN. transformation. kcal) be ci, iM, cost per unit kcal of petroleum Let the let the and and coal products The transformation cost per kcal of secondary is given by e, lL. Then the total energy supply of cost energy can be written as follows: Z cxi + i6M However, djyj + leL the demand total cost for meeting (11) eiwi. jEN cost of the energy a forecast system, energy demand, approximation to the area under the nonincreasing By using a step function = g(q)dq E in Figure 2, the cost defined is given demand as as a an curve. is Pjdj (12) dj, (13) jSJQ 0 where Q = Qe + . jasJQ and JQ is a set of indices contained in the corresponding range from to the demand from (12) the constant {j} corresponding 0 to Q, in demand the and Pj j-th is a the intervals commodity interval. cost corresponding 10 to price Subtracting to the integral of the demand following from 0 to Q curve in f(q)dq = where sgn(j) we obtain the sgn(j)Pjdj Z (14) j6Ja indicates sgn(j) = the sign of index j 1 if (j+O), i.e., j>O if j<O. = -1 Thus adding (12) for each iI=(R,L), Minimize 2, sum: Qe0 be given Figure our objective function can as follows: Z cixi + ieM Z djyj jEN + eiwi lEL Z Z sgn(j)Pijdij. ieIjeJ The negative of the above objective function can as maximizing the demand be (15) interpreted cost less supply cost, while meeting the future energy demand requirements. Hence the optimization problem corresponds to finding the economic equilibrium point maximizing economic surplus. The probabilistic aspects of our energy model are as follows: many energy supplying countries are somewhat politically and economically unstable. Hence, we assume availabilities of the primary energy resources 11 that which supply correspond bi in to the right hand side values Suppose that the upper (1) are bound of the total random variables. of availability some primary energy resources from the overseas supply region to Japan follow beta denoted by b and q, whose distributions bm, and respectively. and whose Then the upper and parameters random lower bounds are p integers are b variable has the following probability density function: f(b) = (b-bm) P- (bM-b) q- , K where K is a constant. When parameters bm b b (16) p and q are integers, K is given by K = r(p)r(q) r(p+q) (p-l) ! (q-l) ! = (p+q-l)! (bM-bm)P+q- where r(-) is a Gamma function r(p) = e-xxp-dx. .0 12 1 (17) Suppose parame ters p and q satisfy p>1 and q>l, then variable b has the following mean , variance 2, the and mode m. bmq+ bp (18a) = p random + q - bm ) pq(bM 2 (18b) (p+q)2(p+q-1)2 bm(q-1)+ b(p-1) m (18c) = p+q-2 2.3 Computational Method Our energy model described in the previous formulated in a vector-matrix Minimize cx - pd subject to Aix variables form as follows: (19) A2x = b2 (20b) s a b3 + Kd (20c) d ~ b4 (20d) d (20e) 0 variable {xi, yj, Zk, w) vectors and x and d consist (dij), respectively. of (20c) are in (14), respectively. the resource Constraints availability 13 the Here, p and d are price and commodity vectors, whose elements are given by and sgn(j)dij be (20a) x, the unknown can bi A3x where section (20a), constraints, Pj (20b) and balancing equations and demand requirement constraints, respectively. (20d) indicates the bounding constraints in (9) for the demand variables (dkj). We define our resource supply cost minimization submodel as follows: c s xs Minimize subject to ASixs AS3Xs 2 bs3 (2:2c) by (19)-(20 '). imply 2 0 i=1,2 ,3, for subvectors that The of cs and the and are, corresponding subvectors supply resource xs respecti vely, Ai, b; for inal linear programming problem given submatrices our 2b) (2:2d) c and x in the orig i=1,2,3, (22a) (2 bSi submatrices and bSi AS2Xs = bS2 xs where Ai, (21) submodel consists components related to crude oil and coal only, above described rather of the than the whole suppl y model. Let the thLe shadow demand resource requirement is I be i .e ., the price, n'i. optimal dual co ns traint Then th.e equi 1 (22c) of ibrating solution, primary condition for energy for our MP/EE energgy model can be wr.i t ten as follows: t'i = gi(Di where g g(q), indicates corresponding + di'j - jE + the i-th j Ej - component di'j) of (23) the demand to the primary energy resource iI. 14 function Die and d'ij indicate the standard energy demand for the resource iI an optimal solution for the demand variable dj, respectively. The optimization problem given by (19)-(20) is surplus maximization problem. A general problem cannot always be transformed into maximization the problem. In order for e.g. Hurwicz [1971). demand function has Therefore, to be the an economic equilibrium economic surplus transformation be i.e. to integrable Jacobian symmetric, an market possible, the demand function g(q) needs to and matrix the be (see of cross the price elasticities between two different commodities must be symmetric. In our energy model, cross price elasticities commodities were assumed between different to be zero, and thus our Jacobian matrix is symmetric. Let us look at a computational economic equilibrium point in procedure our energy for obtaining model. Firstly, sequence of random numbers with a beta distribution (beta each pair of these a random numbers) are generated. Two sequences of beta random numbers generated simultaneously, and an numbers are is assigned to the corresponding right side in the constraints given by (1). Then the linear programming economic equilibrium model is solved to obtain an optimal energy flow meeting demand. The computational method in our MP/EE model future energy analysis is presented in the flow chart of Figure 3. Solving our MP/EE energy model iteratively is a principal part of our analysis. details of the solution algorithm are given in Figure 4. 15 The The correcting process at the t-th iteration, given energy prices pt primary and supply costs cs, is written as follows: 1 Pt+l =-(7r't 2 + pt) (24) cSt+i = C + cst (25) where Acst = A(x't - c), 0 A 1. (26) The convergence of this iterative computation is attained when the shadow price of each primary energy resource of crude oil and coal equals that obtained from the approximate demand curve corresponding to optimal commodity demand. 3. Numerical Results 3.1 Assumptions We define and Input Data the year 1983 as the base year, and then the year 1990 as our future target. Firstly, average annual growth rates of final energy we demand look assume industry, residential-commercial, transportation transfer, respectively. Final energy demands given in Table I. Supplies of primary base year and the target year are energy shown in and 2.0% the for stockpile- in 1983 and 1990 are resources Table II. Table, Other Middle East Region denotes the oil-exporting 16 that between base year and the target year are 2.0%, 3.0%, 2.0% and at in the In the Middle East countries excluding Saudi Arabia, i.e., Iran, Iraq, Bahrein, Kuwait, Neutral Region, Qatar, Oman and the United Arab Emirates. The South Region consists mainly of Southern such as Indonesia, Brunei and Australia. crude oil includes African Algeria and Nigeria. The Pacific The Other oil-exporting coal-exporting countries Region countries Other for such Region as includes South Africa, China, and Soviet Union. Upper bound availabilities of primary 1990 are estimated as follows. The import from the Middle East increase 1990. In of 4.0% between estimating is upper based energy bound upon resources for an average the base year 1983 and the upper bounds for crude coal oil annual target import in year from the Southern Region, North-South America and Other Region, an average annual increase 4.0% is assumed. Estimates for supplies from the Other Middle East Region, crude oil and LNG North-South America Region, crude the Other oil from of LNG from the Region, domestic crude oil, coal, natural gas and stockpile-transfer all based on the average annual increase rates 2.0 - 4.0% are from 1983 to 1990. The upper bound availability of hydro-nuclear power is estimated according to an average annual increase of 4.0 - 5.0 % from the base year. CIF prices of primary energy resources from various regions in 1983 and their estimates for the year 1990 supply are in Table III. Crude oil prices in 1983 indicate 'average' given prices in oil-exporting countries in the region. For example, the oil price in Saudi Arabia is that of Arabian 17 light, and the crude oil price in Other Middle East Region is based Emirates Murban. Prices in the on Southern Crude oil price estimates except Sumatra respectively. for the target year 1990 that the increase Arab North-South Indonesian Blend, from 1983 data by assuming an average annual 4.0%, United Region, America Region and Other Region are those of Light, Mexican Isthmus and Algerian Sahara the are price obtained increase rate is 5.0% for Other Middle as East Region. Coal prices in 1983 are the weighted mean of s team coal material coal from each supply region. Coal prices in Region and North- South America Australian Region's Chinese and the coal pri ce United is Region the Natural on an average mean weighted annual gas and LNG prices on The coal incr ease of 5.0% in 1983 are those and North-Sou th South those Sout]h of for fut ure LNG for the Middl e East Region, Brunei South Region, and Alaskan for based r espectively. States, and Russi an coals. Estimates 1990 are based are the and of Other African, prices in f:rom 1983. Abu of Indonesia n America Dhabi for the R,egion. LNG price estimates for the target year 1990 are obtained from 1983 data by assuming an average annual incre ase of 4.0%. Transformati on costs for petroleum and secondary Table energy IV. Costs (electricity and for fuel oil, products, coal products, city gas) are given kerosi ne-gas oil, and gasoline- naphtha are weighted mea ns minus fuel costs . in The other petroleum products' transformation cost is basi cal ly the LPG price, and the coke transformation cost is the coke 18 price minus the material coal price. Electricity transformation costs for both industry and transportation are the capital costs in the electricity for industry, and those for residential-commercial are rate also the capital costs in the rate for residences. City gas transformation costs are the capital costs in the industrial and residential* commercial city gas rates. Upper and lower bounds for respect to variables constraints (5) and wi, are presented Zk and (6) in Tables V and VI. Lower bounds for petroleum and coal products are either those whose consumption is relatively small, either the consumption of the base year or a 50% for 0.0 or the amount base year's consumption when they are large. The upper with of the bound increase added when they are relatively small. The average annual increase is assumed from 1983 to large. Lower bounds 1990 for for those electricity whose and 4.0% consumption city gas is is are the consumption in the base year. Upper bounds are obtained from the base year's consumption by assuming an average annual increase of 5.0%. The upper and lower bounds for given petroleum in Table VII are based on the assumptions products' that yields demand light petroleum products such as kerosine, gas oil, gasoline naphtha will increase in the future, while demand for for and heavy petroleum products such as heavy fuel oil will decrease. The main sources of Japanese energy data used in our model analysis are Energy Statistics [1985], Handbook of Electric Power Industry [1985], Industrial Statistics 19 Table [1984], and Petroleum Statistics [1984]. bm and b Parameters minimum and estimates maximum, the beta p and q are determined to the expected future distribution respectively, for the future availability Parameters equal the for are indicating of crude oil so that mean values availability of extreme and are these the coal. nearly resources. These parameters are presented in Table VIII. Beta random numbers are generated by transformation method to uniformly applying distributed the random inverse numbers. Random numbers following uniform distribution between 0 and 1 are generated by using the square method. (For more information on random number generation, see e.g. Fishman [1973], Bratley, et al [1983].) Approximate demand curves for imported crude are based upon their own and cross price elasticity decrease () ij, price coal data. The represents the of commodity i's demand corresponding to a unit % of to analysis in Oyama [1983c], own and cross primary energy resources in 1980 are 7 4 LL=-0. and elasticity i,je(R:crude oil, L:coal), commodity j's price increase. According 0.69, oil . the price RR=-0.07, translog model elasticities ERL=0.04, Hence from the above data on eij's we of LR= can say that in Japan crude oil is rather price insensitive compared with coal, and these resources are substitutes positivity of RL and LR. 20 each other from the 3.2 Supply Stability Probability and Equilibrium Prices We wrote a FORTRAN computer program to The program consists of nearly 3800 our analyze most statements, model. of which (around 80%) comprise the product form simplex method for solving the linear programming problem. Others relate generation, figures, iterative histgrams procedures, and slack 17 xi's, variables) output random formatting 5 wi's, 14 yj's, 28 Zk', and 51 contains constraints 24 121 a second requiring about of CPU time on 140 pivots the if simplex technique. In order d'j's and (excluding we obtained IBM 3033 computer system, start from phase of obtain to an 1 necessary to solve 4 - 6 linear programming problems Since is rathe r simple about of the CPU total equilibrium problems are solved in 12 CPU mi nutes by the IBM 3033 system. As shown cases. problems. 250 pairs of beta random numbers. So, a of 250 cases of these economic is it can be so ived quickly. Hence, solving the MP/EE energy model takes up most time. We generated it alternating el e nergy model and the supply submod, the latter mo del the equilibrium economic availability constra ints, the MP/EE 33 bounding point for each pair of resource between for variables constraints). An optimal solution for each iteration is within number and so on. The linear programming MP/EE model (including to i n Figure 3, we For some combination s be infeasible insufficient s olved of N(=250) beta random numbers the model may since either crude oil to meet our future our MP/EE model for or coal supplies final energy demand. 21 may be Figure 5 shows model feasibility results for beta random numbers. In Figure 5, the each vertical pair of coordinate indicates the availability of imported coal, while the horizontal coordinate indicates the availability of imported crude oil. each combination of these energy resources' I indicates whether Let the number Ni. Then we define the model is feasible of infeasible availability, an F or or infeasible. cases among the "supply stability For total N probability" energy system by the ratio of the feasible cases cases be (Ps) of our to the total number of cases. Ps = N - NI (27) N Our energy system can be probability understood Ps and "unstable" Ps and 1-Ps as stability and to be "stable" with the probability instability with 1-Ps. We probabilities the call of our stability and energy system, respectively. Our numerical experiments show that the instability probabilities of Japan's energy system in the year 1990 can be presented 205 Ps 250 = 0.82, target as follows: 45 1-Ps = --250 0.18. We should consider the instability probability as an 22 (28) implication that an extremely probability di fficult of 0.18 unl ess si tuation e nergy our changed. An infeasibili ty result may occur system is m ay be changed with structurally into a "feasible" case by adding more infrastructure to our energy system, transforming our energy system into a more flexibl e one it can meet variable substitution among primiatry Figure Figure 6 is obtain ed and by infeasible by t hat prom ot ing secondary energy resources. the feasibi lity resul ts in 5 with the equil i brium prices' results of feasible and or so by demands c ombining oil and coal. The figur e first divided energy final the divides area.s. the Then into nine parts depend ing on equilibrium prices PR and PL. Note the the that imported whol e this into region regio n feasi ble crude crude oil and di vision is coal of the feasible region is not very accuratee , since the eq uilibrium price of each primary availability energy resource can vary depending on the of the ot her. However, know approximately how much each this partition energy ing resource' s price will be changed by the degrees of supply s upply helps us to equilibrium avai lability. 4. Theoretical Analysis 4.1 Application of Decomposition Techniques Decomposition techniques, which were originally proposed for solving multi-stage block diagonal linear programming have recently been applied to energy policy analysis revised forms. Shapiro [1978] has 23 given an idea problems, in for various using decomposition submodels techniques with a to linear creating a complete energy combine econometric programming planning forecasting optimization model. Shapiro [1982] have applied decomposition techniques to the integration and optimization of coal supply submodel, and and White constructive demand models. The decomposition technique is not an efficient way to solve the energy model, are but its interpretation and economic implication significant in many model analyses. In our MP/EE model we show the possibility of applying the decomposition analysis, techniques to solve a market equilibrium problem. We can rewrite our MP/EE problem (19)-(20) as follows: Minimize cx - pd subject to Ax - Kd Bx (29) qi (30a) 2 q2 (30b) -Id a -q3 0 x, d We define polyhedra X = ( x D = Let x, points { d 2 -qa, d and d, of the above polyhedra of extreme bounded) as follows: 0 ) q2, x iI=(1,2,...,nx) nd are numbers (30d) X and D (assumed Bx | -Id (30c) (31) 0 ) jJ=(1,2,...,nd) X and D, respectively, points (32) be and in X and D, respectively. the price directive master problem for (29)-(30) can be extreme nx and Then, written as follows: Minimize Z cAix i iEI Z pjd jEJ 24 j (33) subject Z AAix to - isI Z j Kjd Ai (34a) q1 jEJ = 1 (34b) = (34c) isI Z aj jeJ Ai, Denoting the constraints problem dual variables by 7, 7ql + nx + respectively, dual nx nd, and for d (35) i nd - Kd j cx i I (36a) jsJ (36b) i -pdi O. (36c) in III=IJ=O from above prices) Ax 2 If we start the (shadow nx + to (34d) can be wri tten as: to the above problem subject i I , jeJ. 0 gaj (34a)-(34c) Maximize 1 iteration we add new extreme points xi ( ini using the optimal dual solution (35 )-(36), dj each at then in the following tial ly way: solve 7r=nx=7rd=O), we the following problems: zx = min.(c - A)x (37a) subject to xX. K)d (38a) subject to dD. (38b) Zd = min.(-p Suppose (37b) + zxznx and Zd7rd; in the dual problem add a new extreme then the s olution (35)-(36). (n, x, 7d) is ptimal If n ot, i.e., zx<rx or Zd <d , point solution to generate a new form 25 column in then the CX r AX r -pdr Kd r or 1 0 1 xr and d r are extreme where respectively. Then, we point solutions return (33)-(34). Thus, an optimal to the solution to to problem the (29)-(30) can be obtained by using an optimal 'j (37) a nd of (38), the problem original solution form A'i and for (33)-(34) as follows: = d' Now, = isI A' ixi (39) j (40) Z ujd j6J the key to solving our MP/EE problem using decomposition technique is that the problem (38a)-(38b) is the very easy to solve since the polyhedron D is just a hypercube. Hence, one can solve the problem analytically, without applying simplex methods. This problem is still easy to solve even when the matrix K contains both nonzero own and cross also when demand variable vector d is price elasticities, given many elements and by defining more endogenous demand variables. Incidentally, applying the resource directive master decomposition technique does not problem help much, approach since in we the cannot obtain a simple, analytically solvable linear programming problem as in (38a)-(38b). 26 4.2 Analysis on Instability Probability In our MP/EE model analysis, the instability probability our energy system was defined to be the probability of that the Figure 6, the dividing line between feasible and infeasible regions may be energy model results are infeasible. As we can see in expressed by a straight line. From equation of the dividing our line in Figure numerical results, the 6 can be approximated as follows: u + v = 3.16x10 5 where u and v indicate the (41) supply crude oil and coal, respectively. availabilities We can expect (u,v) is feasible if u+vZ3.16x1O5 . It is that line since to zero. This is because of various an can lower bounding point otherwise. be neither of these two variables imported the infeasible However, the above equation given by (41) cannot dividing of 'exact' be close constraints on some of the decision variables in our energy model. Let X and Y be random variables following beta distributions with aisX:bi and a25Y:b2, respectively. Then we can illustrate an "approximate" infeasible region as in a shaded area in Figure Suppose the equation of the boundary line between feasible 7. and infeasible regions in Figure 7 is expressed by pX + qY = r , Then the infeasible region p, q, r: constants. of the shaded area (42) is the set of points (X,Y) satisfying pX + qY s r p>O, q>O, ai~Xsb, (43a) a2SYsb2. 27 (43b) The infeasible region given above can be transformed into the case of the standard beta distribution, with random numbers x and y distributed 0 between and 1. Therefore the instability probability for our energy system is approximated as follows: ax+byc TI 1 B(p,q)B(r,s) xp- (l-x)q-lyr-1(1-y)5ldxdy 0&x I 0 yl1 I (1-x) q - I XP x) b yr-l(1-y)s-ldydx 0 0 11 XP -1(1-x),Q-'F(x)dx (44) 0 The last expression in the above formula can be numerical integral since we have a detailed table given of by values a of beta functions. Now let us look at our instability The necessary and sufficient condition prob abi 1 i ty more closely. for the problem (19)-(20) to be feasible are given a s Farkas' lemma (see e.g. Shapiro [1979], fo p28) linear llows in program by a using slightly modified form. zy (45) O 0 where zy = max.( - ybi subject to + Y2b2 + y3b3 - y4b4 ) - yiAi + y2A2 + y3A3 yi, y3, 28 (46a) (46b) - y3K - y4I (46c) 0 (46d) y4 If zySO for all the random variable components of bi, then the model given by (19)-(20) can always be feasible, i.e., Ps=l.0. We can give a sufficient (20) to be feasible. condition Since the problem's objective function is for our MP/EE model general convex and respect to the right hand side values, corresponding problem the to the inf.(infimum) programming nondecreasing the should have the greatest lower bound of values, linear objective function of the vector bi. Let (47) for all random variable and no bi' such that b'5b variable components subject 1 bi'~bi be defined + y2b2 + y3b3 - MP/EE variable vector bi. Note that for vector all bi random (48a) 5 0 (48b) - y3K - y4I ~ 0 (48c) y4 is feasible the a y4b4 } y3, model of by - yiAi + y2A2 + y3A3 to yi, Then, if zySO0, our components satisfies of bi. Let z zOy = max { - yib0 with (46a)-(46d) bB1 = inf. bi i.e., bibi (19)- above 0 (48d) for sufficient any random condition guarantees the feasibility of the MP/EE model by solving a single linear programming problem, while the necessary and sufficient condition given by (45)-(46) for the model's feasibility requires that (45) holds for all possible bi. 5. Summary In this analysis, we have 29 investigated the effects of primary energy resources' supply constraints on system. a It is generally true that when Japan's energy primary resource's availability is high, its commodity price and vice versa. However, since we have considered energy goes two down kinds of primary energy resources simultaneously, and furthermore price elasticities are the price effects of more complex to resources supply analyse. Through very different, constraints our MP/EE are a model little we obtain an their economic equilibrium point for each energy resource as shown in Figure However, the regions splitting based on of the commodity feasible prices, as region in into the complicated because the equilibrium points may be 6. smaller figure, is dependent on the computational method and its convergence criteria. Our computational technique is fundamentally similar to PIES model Ahn (see e.g. Hogan [1975], and Hogan, [1979], and Ahn and Hogan for special cases) in its [1982] main for et al [19 78); also arguments convergence framework, the except that the iterative procedures and some assumptions about supply and demand functions are different. In the PIES model, the was assumed to be continuously differentiable, demand and the supply mapping was a point-to-set mapping, while we function (inverse) assumed for our model that both supply and demand functions were po int-to-set mappings. The assumptions of the PIES model guarantee existence and the uniqueness of an equilibrium MP/EE the model assumes only existence solution. 30 point, of an both the while our equilibrium Our iterative computational method worked very well, and could obtain an equilibrium point after all feasible cases. Although the several convergence iterations for proof for our believe the computational method is not given in this paper, we convergence is guaranteed by showing the fact that the shadow price of the demand requirement constraint (25c) is expressed the approximate demand function value we corresponding to by the optimal resource demand. We are presently working on this proof. Approximating a demand function is another problem. In paper we assumed the existence of nonzero own price for primary energy resources only, neglecting this elasticities cross price elasticities between two distinct primary energy resources. Both own and cross price elasticities can be simultaneously considered in our model matrix price K analysis of by incorporating (20c). elasticities The does this information consideration not make of solving into nonzero the the cross problem more difficult, but rather changes the problem formulation slightly by adding more nonzero elements in the coefficient matrix. Applying decomposition techniques should also be very effective in solving our MP/EE model in this case. The stability probability was defined to be the that the MP/EE model was feasible. random numbers obtained the as our stability import and We tried a single supply instability probability sequence availability, and probabilities of of then our energy system. We know that if the substitutability between crude oil and coal increases, then the stability 31 probability will also increase, since there are more ways to meet the forecast energy demand. We can conclude that the Japanese energy system needs to more flexible, so that it can structurally primary energy supply availability. For adjust example, (from 1979 to 1980). of variations the Japanese cement industry changed almost totally from fuel oil to one year be In another good example, coal our in power industry is introducing mixed fuel thermal power plants consuming fuel oil, coal and LNG. If our energy system were well coal, it will greatly heighten organized the stability primary energy supply, and also lower cost. We would the to consume probability total not have to depend so heavily more of energy the system on crude oil, which has higher supply uncertainty and instability. We must note coal transportation and storage infrastructure and countermeasures for SOx and NOx emissions and very important in the case where we consume environmental burned a that great are ashes of amount coal. Thus, the substitutability among primary energy resources is a very important factor in our energy system's stability. In order to further elucidate the relationship between the stability probability and the energy resources substitutability, we need more numerical experiments, trying different values for lower and upper bounds of certain energy flows, and varying the yields and efficiencies of petroleum and coal products. The model described in Section 2 is a single 32 period static a part of the right hand side model. Letting optimization linear programming model be a random we variable, in could the apply probabilistic and stochastic analyses, obtaining supply stability and instability probabilities. We can and increasing the number of periods probability in the more distant dynamic add estimating future. In analysis the this stability case, following difficulties occur: uncertainty with respect to primary energy variations of prices and final energy supply availability, forecast and to obtain an economic equilibrium availability another difficulty. Therefore we believe representing the next 10 - techniques of two or will three 15 years will be the largest and the necessary efficiently point future solutions, reliability of data. Obtaining the large scale structure linear programming model and computational the subsequent optimal justification of probability distribution, and by be stages, time span we can deal with reasonably. We believe that the approach introduced in this paper can be useful to quantitatively analyse the energy system countries like Japan which depend heavily on stability imported primary energy resources. We are considering further modification of energy systems approach by incorporating dynamic terms modeling of national economic structures. 33 of and our more Acknowledgements This research was initiated when the author was Researcher at the Economic Research Institute of a Visiting the Economic Planning Agency in Japan in 1983, then was finished while he was a the Postdoctoral Fellow at the Energy Laboratory Massachusetts Institute of Technology in the U.S.A. 1985 to July, 1986. Shapiro Massachusetts from of the Institute Wood of the Energy Laboratory Operations of Research Technology for Center their very Institute Research of grateful Tokyo Institute and in to Doctors M. Japan S. Ishikawa for their computational aspects of this research. 34 Mori of of at and the invaluable suggestions, comments and their sincere cooperation. is also June, The author would like to express his sincere thanks to Professors David O. Jeremy F. in The the Science Electronics assistance author Device with the TABLE I. Final Energy Demand (1010 kcal ) Sectors 1983 1990 211858 243358 Residential-Commercial Transportation 99465 122329 56869 65324 Stockpile-Transfer 45844 52660 Industry TABLE III. Energy Prices by Supply Region (106 yen/100l Energy Crude Oil Coal Natural Gas LNG Supply Region 1983 Data kcal) 1990 Price Saudi Arabia 45.996 60.488 Other Middle East 47.437 66.749 South Region North-South America 48.964 47.398 64.433 62.373 Other Region 50.729 66.756 South Region 22.712 31.958 North-South America 19.184 26.994 Other Region 17.761 24.992 Middle East 48.072 63.259 South Region North-South America 45.219 59.505 46.042 60.588 1 TABLE II. Primary Energy Resources by Supply Region (1010 kcal) Energy Crude Oil Supply Region 1983 Data Saudi Arabia 59904 74100 Other Middle East 91649 113368 South Region 38882 48096 9196 11375 13213 16344 447 588 Stockpile-Transfer South Region 28531 37545 26890 35385 North-South America 21312 28045 Other Region Domestic 8834 11173 11625 Stockpile-Transfer 7197 8851 Middle East 2411 2965 23655 29093 1389 1708 North-South America Other Region Domestic Coal Natural 1990 Supply Availability South Region America 12834 Gas North-South LNG Domestic 2154 2474 Stockpile-Transfer 1335 1642 2 TABLE IV. Transformation Costs of Secondary Energy Resources (1010 yen/ Energy Resources 1 0 10 kcal) Transformation costs Fuel Oil 2.01 Kerosine-Gas Oil Naphtha-Gasoline 32.96 Other Petroleum Products 49.85 24.85 Coke 19.29 Coke Gas-Blast Furnace Gas Electricity (Industry, Transport) 31.39 Electricity (Residential) 215.52 City Gas (Industry) 284.42 71.95 City Gas (Residential) 106.57 TABLE VI. Upper and Lower Bounds for Secondary Energy (1010 kcal) Secondary Energy Energy Lower Bound Use Industry Electricity Upper Bound 101,500 120,500 60,000 70,000 Transportation 4,000 5,500 Industry 2,400 Residential 9,500 3,500 13,500 Residential City Gas 3 TABLE V. Upper and Lower Bounds for Petroleum and Coal Products (10'1 Products Energy Crude Oil Lower Bound Use Electricity Stockpile 18,600 41,000 32,000 37,000 41,200 49,400 Residential Transportation Industry 0.0 0.0 0.0 12,600 Residential Transportation 25,000 7,000 12,000 33,000 13,500 17,600 Industry 22,000 29,000 0.0 1,400 35,000 41,500 2,600 3,500 12,500 0.0 16,500 9,500 2,000 3,500 2,000 2,900 32,000 42,500 0.0 50 Stockpile 1,300 1,800 City Gas 2,000 2,900 4,200 10,300 5,600 14,500 Fuel Oil Gas Oil Naphtha Gasoline City Gas Transportation Electricity Petroleum Products Industry Residential Transportation City Gas Industry Coke Coke Gas Upper Bound 0.0 32,000 Electricity Industry Kerosine kcal) Residential Electricity Industry 4 TABLE VII. Upper and Lower Bounds for Petroleum Products Yields Lower Bounds Petroleum Products Upper Bounds Fuel Oil 0.40 0.55 Kerosine-Gas Oil Naphtha-Gasoline 0.10 0.30 0.20 0.30 Other Petroleum Products 0.0 0.15 TABLE VIII. Parameters for Beta Distribution Parameters Energy Resource b p q 200,000 300,000 4.0 2.0 45,000 135,000 2.0 4.0 b m Crude Coal Oil 5 co II CL 1-1 L) -Z cq II v ,, Qa) - L 0a)C oC a) _0 C c= Qa C. C/) Q) Olo L. a) c Lz.3 w L. w LL- II P-2 P0 Pl P2 P3 d-3 Figure 2. d-2 d-i Do di d2 Approximate demand function and supply functions |START I Generate two sequences of beta random numbers Bl(i), B2(i), i=l,...,N. For each pair of Bl(i), B2(i), i=l,...,N, solve the MP/EE model and obtain an economic equilibrium solution. I Obtain the probability of supply stability and distributions of total energy system cost, primary energy prices and their quantities. I END Figure 3. Computational procedure for the model analysis I START | I I II -- Initial p, pe=Q(q0). t=O. q, Solve the MP/EE model and supply submodel. Optimal solution t. X+t, yt, - 3L I - t-f t E? Yes .1 "Converged". Equilibrium point obtained. l- i -- No t+l - t. Cs t=Cs+Acs t Figure 4. pt=(r't+pt-1)/2. 1 I END Algorithm for solving the MP/EE model - -- - I U) 0X 0 * . . . . . . *9 Li. I oI S 9 9 9 9e * . U. . ~Li.~ I o .U I . U. .. 9 . . . . . . . . . . . . . . . . . . . . I . * * L L. L. 9 . . . . . · eL i · 9 . UL. U. I'.I. LL.Li . U. . II. U. I U.L L. L. L ·. A. eLL i LA. I. L.UL. U. LLL · 0 UL; tU. LL U. LA. IA. U. L. II * 1LL. . * U*. L *LI Hi lL LL . .. .:. LA. Li l. . l5 :IeL U; e·· Li. L. L .9 . 9 UL . U. * LL . .. U. U. _ c .. U LL I 4J I · LI. L. *U.U. UL U · LiU. UL. U. U. .UI L · U. · U. . L +u. L. LL . U. : LL LU. L I U. lL * . U U. U. . . . . LiS. * . . . . ... . . A U . . ® * 9. 9. . e. . . I U. I H .· _· - I * * - L. U. * L U- 9. i. I I Ie *f 9 *0 . . U. L. . L U U. L1U U. iLLi. L.. . 44 U. * UL . . ~~~~~~ I II~~llllll: · r···r~~~··· e U.. * . .e.e.e. . . .e . .o . - I : . . . . O 9 9 99 . . . . . 9 9 9 S 9 · ~~····rr··~ · I I. I · I · e· I .. · ., e·. Li.· L . l L. l. .9. r. ll· rr q·ir U. ..9 0 .· · I m . ! 0 · U. U.- U. . el U. UU . * t . e I I * l. · ·· r· · r· ·I~~~ . U. . illlelllei L U. I C, . LI U. II.. U. · . 9 . L. LL U. i. ·. II t . U. LL. *. A eL Li. UL. * UO . * ,iL e ) . , u. L. NI S a L.U. * L - . IL ULi . 0U) . 0 U. .. 9 ele e e r·o· · · I··· oe '. · · ,·r···r·~~ eoolleeeer · · ·· · · · ~~~·· H, N I ~ C 0 0 . C) Ln _ _ X 0 o0 0 U' U, _ _ 0 0 00 .0 (I _ a__ 0 0Q ru 0C:3 C 00 00 00 co O 0. 0 00O a, 0l C 0 0 0 -4 o0 0r.-4 C 0 09 la eV 0C 0U -4 m 34 V A.. vii vll m O) x Ln Cv vii Pc vi P4 I 0 4 U I UL. LL U. LL , LL. A.U,~ tLA U.. i, U) 'U. I * . . * I LL.L T U, LU. Cc U) 5-oo + LA.*. . S * LL. LL LL LU.LL . U. U 9 * * * U. U. U. e*i eL A. . rUA U* * L U. I UA. U. UL u. L. L. * · U. LA. U . U. t LL · · · .. LLA *· · Lo. *eA. U LU. . L. U. U. 4 r- · · Ur· L · r U. LLU. 4- · . * . LL . . . * U- . * LL. LL I . . . . LL LL. U- .4. Q I Ii. UI. LL. LL U.U. 0 w . |~~~~~~~~~~~. r r r r r L . LL LLU. tU .. * ·- . .. U. U. I U. * I A. L. * . U. U. LL. LL. . . L. LA.· *. *U 9 U. 0U) l . U. LL * LL. L' LL. LL . . U I LA.LA. LU . U. A. u.u. . L L.. S LLU U, .a . U. . Lu. LL . LA.U. . LL LL. LL. L. . , U.. .LL 0 . LL -·· * U. . . . . . . .Q U) 9-..I II H N*\ u I+ L( a9 . . . * . e^ II 0 U) Va .* _e " . . · ·. .>t * . UA. U- * . . U. L . LL U. U.9* Y · I- U.·A. L 'U U. ··O *e~jI I U. U. U. U) · U * " vii U. L-. -1C U. LLU. V PA v 11 0:) Ln -- u. (NI 1 LA. , *· U. · L. · ·U I U@. - U U. Mn · LA.. *· ·* ,-e -* · · ,11 i · · . * S 0 O * * * 9 * a S 9 *I r@@ I PI vi 5 * CN a .9 Q O * -9 9 l 0 * 9 * 5 * · I + _ 9 · · · · * * @ * 5 9 * * 5 9 ** . * * * * * * * 9@ 5 · · · * · * · * · 0 0 0 .* 0 . · ·S·· * * * * * I * : * * * * X · * O . · * U% 9 * · 9. _ LA * * * 0 00 * * · 9 * ** 0 3* · 5 S. * I I * 0 0 00 N I.- 0 0 00 0cgoo 0 0 0 0 0 0oo OW (3' 0 J 0 o 0 O O, e.. o0 0 0p- 00C ,o -4 0 0 en -4 Figure 7. Y Illustration of an infeasible (general case) region d b2 a2 I I I t i I t i X REFERENCES Ahn, B.H. 1979. Analysis: The of Computation Project Independence for Policy System [PIES] Equilibria Market Evaluation Approach, Gorland Publishing, Inc., New York & London. Ahn, B.H. and W.W. Hogan. 1982. On Convergence of the PIES Algorithm for Computing Equilibria, Operations Research, Vol.30, No.2, pp.281-300. Bratley, P., B.L. Fox and L.E. Schrage. 1983. A Guide to Simulation, Springer-Verlag, New York. Charpentier, J.P. 1974. A review of energy models: No.1, RR-74-10 International Institute for Applied Systems Analysis, Schloss Laxenburg, Austria. Energy Daniel, T.E. and H.M. Goldberg. 1981. Dynamic Equilibrium Modeling: The Canadian Balance Model, Operations Research, Vol. 29, pp.829-852. Dantzig, G.B. and A. Wolfe. 1960. Decomposition principle for linear programs, Operations Research, Vol.8, pp.101-111. Energy Study Group. 1979. A long-range demand of energy Research Institute and outlook electricity, Research for supply Report, and Central of Electric Power Industry, Tokyo, Japan (in Japanese). Federation of Electric Power Industry. 1984. Handbook of Electric Power Industry, Ministry of International Trade and Industry Tokyo, Japan (in Japanese). Federation of Petroleum Industry. 1984. Petroleum Statistics, Petroleum Industry League, Tokyo, Japan (in Japanese). Fishman, G.S. 1973. Concepts and methods in discrete event digital simulLation, John Wiley & Sons, U.S.A. Griffin, J.M. 1977. Long-run production modeling with pseudo data: electric power generation, The Bell Journal of Economics, Vol.8, No.1, pp.112-127. Hoffman, K. 1973. A unified framework for energy system planning, in Energy Modeling, M. Searl(ed.), Resources for the Future, Washington, D.C., U.S.A. Hogan, W.W. 1975. Energy Policy Models for Project Independence, Computers and OPerations Research, Vol.2, pp.251-271. Hogan, W.W., J.L. Sweeney and M.H. Wagner. Models in the National Energy Outlook, 1978. TIMS Energy Studies Policy in the Management Sciences, Vol.10, pp.37-62. Hogan, W.W. Discussion and J.P. Paper Weyant. E-80-02, 1980. Energy Combined and energy models, Environmental Policy Center, Harvard University, Cambridge, Mass., U.S.A. Hurwicz, L. 1971. On the problem of integrability of demand functions, in the Preferences, Utility and Demand, J.S. Chipman, L. Hurwicz, M.K. Richter and H.F. Sonnenschein (eds.), Harcourt Brace Jovanovich, Inc;, pp.174-214. Kennedy, M. 1974. An economic model of the world oil market, Bell Journal of Economics and Management Sciences, Vol.5, pp.540-577. Manne, A.S., R.G. Richels Policy Modeling: A survey, and J.P. Oerations Weyant. Research, 1979. Energy Vol.27, No.1, pp.1-36. Modiano, E.M. and J.F. Shapiro. 1980. A dynamic optimization model of depletable resources, The Bell Economics, of Journal Vol.11, No.1, pp.212-236. Oyama, T. 1980. Model analyses of energy policy debates, Research Power Report, Central Research Institute of Electric Industry, Tokyo, Japan (in Japanese). A Oyama, T. 1983a. Energy policy modeling: survey, Simulation, Vol.2, No.2, pp.77-87 (in Japanese). Oyama, T. 1983b. On the stability of Japan's energy system the primary Institute Research Series, Economic Research Economic constraints, supply energy Planning under Agency, Japan, No.40, pp.117-162 (in Japanese). Oyama, T. 1983c. Primary energy consumption and related technical A translog model analysis, Economic Research change in Japan Institute Research Series, Economic Planning Agency, Japan, No.40, pp.232-263 (in Japanese). Resources and Energy Agency. 1985. Energy Statistics, Ministry of International Trade and Industry, Tokyo, Japan (in Japanese). Research and Statistics Division. Table (Items), Ministry of 1984. International Statistics Industrial Trade and Industry, Tokyo, Japan (in Japanese). Saito, T. and T. Oyama. Research Memorandum, 1980. Outline Central of the Energy Research Institute Model DEM-1, of Electric Power Industry, Tokyo, Japan. Shapiro, J.F. 1975. OR Models for Energy Planning, Computers and Operations Research, Vol.2, pp.145-152. Shapiro, J.F. 1978. Decomposition methods for mathematical planning programming/economic equilibrium energy models, TIMS Studies in the Management Sciences, Vol.10, pp.63-76. Shapiro, J.F. 1979. Mathematical Programming: Structures and Algorithms, John Wiley & Sons, New York. Shapiro, J.F., D.E. White and D.O. Wood. 1977. Sensitivity analysis of the Brookhaven energy system optimization model, MIT Operations Research Center Working Paper OR 060-77. Shapiro, J.F. and D.E. White. 1982. A hybrid decomposition method for integrating coal supply and demand models, Operations Research, Vol.30, No.5, pp.887-906. Takayama, T. and G.G. Judge. 1971. Spatial and Temporal Price and Allocation Models, North-Holland, Amsterdam.