Optimal Maintenance Strategies at California Gasoline Refiners Larry Harris January 8, 2013 Abstract California permits the sale of only special grades of gasoline. They are produced primarily by 9 California refiners, five of which have two refineries each that collectively account for 70% of the market. Few suppliers and low demand elasticities ensure that occasional supply disruptions at individual refineries cause prices to rise substantially. Gasoline prices spiked in the fall of 2012 when two refineries experienced production problems. This paper considers how refiners may behave strategically when budgeting for maintenance. Refiners with multiple plants may spend less on maintenance, and thus experience greater failure probabilities, than refiners in more competitive markets. For firms with multiple production lines, increased prices offset revenue losses when one production line fails. Introduction Since the winter of 1992, California law permits the sale of only certain special grades of gasoline in the state. The state requires that gasoline be specially formulated to reduce pollution. The formulations differ between the summer and winter months. Twice each year, refiners switch from producing the summer formulation to the winter formulation. The California formulations are more expensive to produce than those used in other states. The regulations governing the sale of gasoline in California effectively isolate the California wholesale gasoline market from wholesale gasoline markets in other states. During the summer, gasoline formulated for other states cannot be sold in California, and selling gasoline specially prepared for the California market in other states is cost prohibitive. The isolation of the California gasoline markets is widely thought to account for increased gasoline price volatility in the state. Gasoline prices are volatile because the both demand and supply are quite inelastic over short intervals and because the semi-annual shift from one formulation to the other makes storing gasoline very expensive if the gasoline in storage cannot be sold for six months. Figure 1 illustrates the higher volatility of the California gasoline market. The plot presents annual standard deviations of weekly price returns for retail West Coast regular-grade gasoline prices. The standard deviations for reformulated gasoline (produced primarily for the California market) are uniformly above those for conventional gasoline, which is sold in other markets. 1 Since only nine refiners produce the summer California formulations (See Table 1), supply disruptions due to production problems at individual refineries occasionally cause prices to rise substantially. California most recently experienced a substantial spike in gasoline prices in the fall of 2012 when two refineries experienced production problems. The first disruption occurred on August 6 when a fire at the Chevron Corp. Richmond refinery stopped production. The second occurred on October 1 when the ExxonMobil Torrance refinery shut down for four days due to a power problem. Figure 2 presents margin refiner margins computed as the difference between reported average wholesale gasoline prices and the price of Alaskan crude oil necessary to produce a gallon of gasoline. The second panel of the figure clearly shows the 2012 spike in prices. Refiner margins rose from $0.40/gal for the week ending August 6 to $1.23/gal for the week ending October 8. They then fell to $0.31/gal for the week ending October 22. During the eleven week period from August 6 to October 22, the refiners earned produced approximately $800M more than usual from margins that averaged $0.30/gal higher than their $0.37/gal average over the three years before August 6, 2012. When a process problem stops a production line at a refinery, that refinery cannot profit from continued production on that line. However, the resulting increase in wholesale profits may cause the company’s overall profits to rise if it has other production lines or if it had substantial finished inventory in storage. Other companies, of course, benefit substantially when prices rise unexpectedly. These considerations suggest that refineries may behave strategically when budgeting for maintenance. In particular, California refiners may choose to spend less on maintenance than refiners in other markets that face more competition from other refiners. Lower maintenance expenditures lead to a greater probability of failure. For firms that have multiple production lines or that normally hold substantial inventories, the resulting increase in price offsets the loss of production in the failed line, and may even more than make up for it. These considerations also suggest that refineries could benefit substantially if they could collude to decrease production. Explicit collusion would be illegal and presumably does not occur. However, the possibility of its occurrence has led to the creation of various state and federal surveillance systems to enforce anti-trust laws. The operation of these systems hopefully helps deter explicit collusion. In contrast, even if firms do not explicitly or implicitly collude with each other, each company undoubtedly considers what other companies might do when setting their maintenance budgets. As a result, they each may independently and rationally decide to undertake less maintenance than they would if they competed in more competitive markets. Assuming that no collusion occurs, such behavior is not illegal, but it would be a matter of concern to public policy makers. This short note examines a simple model of imperfect competition among a limited number of refiners, each of whom can set their maintenance budgets to maximize their overall profits. The model employs a Nash equilibrium in which refiners independently set their maintenance budgets on the assumption that other refiners are doing the same. The model assumes that no entry or exist occurs in the shortterm, presumably because capital costs and regulatory costs associated with environmental approvals are extremely high. 2 The results predict that maintenance budgets would indeed be lower when few refiners compete with each other. These results suggest that California regulators may want to regulate maintenance budgets to protect the public welfare. This model does not examine how storage strategies might interact with maintenance strategies. In particular, it could be optimal to shut a line when storage levels are high to benefit from higher prices. The shutdown could be intentional, or it could be the result of inadequate maintenance due to underfunding such as is described by the model. These results apply to any industry where few competitors compete with each other to supply products produced by multiple production lines that they sell into markets characterized by inelastic demands and supplies and expensive storage. These conditions characterize the production of gasoline for the California markets. They may also characterize production in other markets, such as for specialty plastics. The model Assume that each of π refiners has ππ production lines. A production line is a productive process for which all output stops if a single element of the process fails. If a company has two refineries, it clearly has at least two production lines. But a company may have more than one production line in each refinery. For example, a refinery might employ two crackers or two distillers that do essentially the same work at a single refinery. If one fails, output for the refinery presumably would drop by half. For simplicity, assume that each production line is identical within a firm and across firms. Let ππ represent the total production at firm π. Assume that each production line produces one unit of quantity with production probability ππ , and zero units with probability 1 − ππ . Finally, assume that the production probability is independent across lines so that total production ππ follows a (ππ , ππ ) binomial process. The expected production level and the variance of that production thus are given by Eππ = ππ ππ and var(ππ ) = ππ ππ (1 − ππ ). Assume that the production probability ππ for a given line is an increasing function of maintenance expenditure ππ on that line so that ππ = π(ππ ) and ππ′ = ππ(ππ ) > 0. πππ Assume further that 3 ππ′′ = π2 π(ππ ) <0 πππ2 so that the rate at which additional expenditures on maintenance increase reliability is decreasing. Finally, assume that each refiner spends the same amount on maintenance for each line that it runs. Each refiner chooses maintenance per line expenditure ππ to maximize expected profits: max Eπ = E((π − πΆ)ππ − ππ ππ ) ππ where π is the total price of all quantity produced by a functioning production line and πΆ is the total variable cost of the production. Production under Perfect Competition Under perfect competition, each refiner takes the price π as given and independent of its production levels. Under these assumptions, the objective function is max πΈπ = E(π − πΆ)Eππ − ππ ππ = E(π − πΆ)ππ ππ − ππ ππ ππ so that the first order condition is E(π − πΆ)ππ ππ′ − ππ = 0 or E(π − πΆ)ππ′ = 1 The second order condition is negative as it should be for maximization: E(π − πΆ)ππ ππ′′ < 0. The first order expression indicates that expenditure on maintenance will increase when the expected price increases because ππ′′ < 0. This result can be seen by examining the total differential of the first order condition: ππ′ π(Eπ) + E(π − πΆ)ππ′′ πππ = 0 Rearranging terms yields: πππ ππ′ =− >0 πEπ E(π − πΆ)ππ′′ The Perfect Competition Equilibrium To obtain the competitive market equilibrium, assume a linear demand function as a local approximation to the actual demand function and set it equal to the total market supply: 4 N ππ· = πΌ − π½π = ππ = ∑ ππ i=0 where πΌ > 0 and π½ > 0. Inverting this expression gives the price function N πΌ 1 π = − ∑ ππ π½ π½ i=0 so that the expected price is given by N πΌ 1 Eπ = − ∑ ππ ππ π½ π½ i=0 For the purpose of illustration, assume that ππ = ππ = π for all π, π so that ππ = ππ = π. This assumption allows us to express the optimal production probability π in terms of π′ . Under this assumption Eπ = πΌ πππ − π½ π½ so that the first order condition is πΌ πππ ( − − πΆ) π′ = 1 π½ π½ Solving this expression for π gives πΌ − π½πΆ − ππΆπππ = π½ ′ ππΆπππ ππ where the superscript “Comp” refers to the competitive equilibrium. Production under Imperfect Competition Now consider the refiners’ optimization problem assuming that the refiner knows that it has market power. The optimization problem is now given by max Eπ = E((π − πΆ)ππ ) − ππ ππ ππ The expectation can be evaluated by assuming the same linear demand function presented above. N πΌ 1 πΈ((π − πΆ)ππ ) = E ((( − ∑ ππ ) − πΆ) ππ ) π½ π½ i=0 5 N πΌ 1 ππ = πΈ (( − πΆ − ∑ ππ − ) ππ ) π½ π½ π½ j≠i N πΌ 1 πΈππ2 = ( − πΆ − ∑ πΈππ ) πΈππ − π½ π½ π½ j≠i N πΌ 1 ππ ππ + ππ (ππ − 1)ππ2 = ( − πΆ − ∑ ππ ππ ) ππ ππ − π½ π½ π½ j≠i Substituting this expression into the objective function and differentiating gives the imperfect competition first order condition: N πΌ 1 ππ ππ′ + 2ππ (ππ − 1)ππ ππ′ ′ ( − πΆ − ∑ ππ ππ ) ππ ππ − − ππ = 0 π½ π½ π½ j≠i The second order condition is N πΌ 1 ππ ππ′′ 2ππ (ππ − 1)ππ ππ′′ 2ππ (ππ − 1)ππ′ ′′ ( − πΆ − ∑ ππ ππ ) ππ ππ − − − π½ π½ π½ π½ π½ 2 j≠i N πΌ 1 ππ ππ′ 2ππ (ππ − 1)ππ ππ′ ππ′′ 2ππ (ππ − 1)ππ′ − (( − πΆ − ∑ ππ ππ ) ππ ππ′ − ) ′− π½ π½ π½ π½ ππ π½ j≠i 2 ππ ππ′′ 2ππ (ππ − 1)ππ′ − <0 ππ′ π½ as it should be for maximization. For ππ = 1 the first order condition reduces to N πΌ 1 ππ′ ( − πΆ − ∑ ππ ππ ) ππ′ − − 1 = 0 π½ π½ π½ j≠i or N πΌ 1 ( − (∑ ππ ππ + 1) − πΆ) ππ′ = 1 π½ π½ j≠i 6 2 When one unit of production is small relative to total expected production, the quantity in the large parentheses is essentially expected price, so that this problem has essentially the same first order condition as the competitive solution. Manipulating the first order condition gives: N πΌ 1 ππ′ + 2(ππ − 1)ππ ππ′ ( − πΆ − ∑ ππ ππ ) ππ′ − =1 π½ π½ π½ j≠i N πΌ 1 −ππ ππ ππ′ + ππ′ + 2(ππ − 1)ππ ππ′ ( − πΆ − ∑ ππ ππ ) ππ′ − =1 π½ π½ π½ j=1 E(π − πΆ)ππ′ − (1 + (ππ − 2)ππ )ππ′ =1 π½ E(π − πΆ)ππ′ = 1 + (1 + (ππ − 2)ππ )ππ′ >1 π½ Since the expression on the right is greater than one, for given price expectations Eπ, the maintenance budget under imperfect competition will be less than the maintenance budget for a price taker. The Imperfect Competition Nash Equilibrium If we assume again for illustration that ππ = ππ = π for all π, π so that ππ = ππ = π, we can obtain an implicit equation for the Nash equilibrium under the assumption that all refiners expect everyone else to behave the same as they do. To obtain the equilibrium optimal π as a function of π′ , solve the following expression derived from the first order condition for π: πΌ πππ ′ (1 + (π − 2)π)π′ ( −πΆ − )π − =1 π½ π½ π½ (πΌ − π½πΆ − πππ)π′ − (1 + (π − 2)π)π′ = π½ (πΌ − π½πΆ − πππ) − (1 + (π − 2)π) = (−ππ − π + 2)π + πΌ − π½πΆ − 1 = πΌ − π½πΆ − 1 − ππππ β = π½ ′ ππππ β (π + 1)π − 2 where the superscript “Nash” now refers to the Nash equilibrium. 7 π½ π′ π½ π′ Comparison of the Two Equilibria For when ππ = ππ = π for all π, π, showing that the production probability in the Nash equilibrium is smaller than or at most equal to the probability in the competitive equilibrium is fairly easy: The competitive equilibrium is described by πΌ ππππ ′ ( −πΆ− ) ππ = 1 π½ π½ while the Nash equilibrium is described by πΌ ππππ ′ (1 + (π − 2)ππ )ππ′ ( −πΆ− ) ππ − =1 π½ π½ π½ Note that the second term of this equation is positive for π ≥ 2 so that πΌ ππππ ′ ( −πΆ− ) ππ > 1 π½ π½ Note that also that πΌ ππππ ( −πΆ− )>0 π½ π½ and πΌ ππππ ( −πΆ − )>0 π½ π½ since ππ′ > 0 and ππ′ > 0. Now suppose ππ < ππ . That would imply πΌ ππππ πΌ ππππ ( −πΆ− )<( −πΆ− ) π½ π½ π½ π½ It also implies ππ′ > ππ′ so that πΌ ππππ ′ πΌ ππππ ′ ( −πΆ − ) ππ < ( − πΆ − ) ππ = 1 π½ π½ π½ π½ But we already established that πΌ ππππ ′ ( −πΆ− ) ππ > 1 π½ π½ so the assumption that ππ < ππ cannot be true. Instead, ππ ≥ ππ . 8 The Nash equilibrium production probability can be expressed in terms of the competitive equilibrium production probability when ππ = ππ = π for all π, π: πΌ − π½πΆ − 1 − ππππ β = π½ ′ ππππ β (π + 1)π − 2 πΌ − π½πΆ − ππΆπππ = π½ ′ ππΆπππ ππ ′ ππΆπππ π½ ′ − 1 + 1) πΆπππ ′ π ππππ β (π + 1)π − 2 πΌ − π½πΆ − 1 − ( ππππ β = πΌ − π½πΆ − = (πΌ − π½πΆ − = π½ π ′ ππΆπππ π½ ′ − 1) πΆπππ ′ π ππππ β (π + 1)π − 2 −1−( πΆπππ ′ ′ ππ ππΆπππ π½ − 1 − ) ( ′ ′ − 1) πΆπππ ′ ππΆπππ ππ π ππππ β (π + 1)π − 2 π½ ′ ππΆπππ π½ ′ − 1) πΆπππ ′ π ππππ β (π + 1)π − 2 ππΆπππ ππ − 1 − ( = ′ = ππΆπππ 1 − 1 2 1+ − π ππ ( ππΆπππ π½ ′ − 1) πΆπππ ′ 1 π ππππ β − (π + 1)π − 2 (π + 1)π − 2 Note that the two production probabilities converge as π gets large. If four refiners are in the market (π = 4) and each has two processes (π = 2) then ππππ β > ππΆπππ ( 1 1 1 )− = ππΆπππ − 1 2 (4 + 1)2 − 2 8 1+4−4×2 The inequality arises because the second of the three terms above is negative. Calibration Suppose that π refiners each have π lines. When all lines are running, total production is π = ππ. Suppose that occurs where price is ππππ . Suppose further that the absolute value of the demand curve elasticity is π. Finally, assume constant elasticity demand 9 ππ· = ππ−π These conditions imply π= ππ −π ππππ Linearization of the demand curve at π = ππππ yields: ππ· = ππ −π ππ −π −π ππππ − −π πππππ (π − ππππ ) ππππ ππππ = ππ − πππ(π − ππππ ) = πΌ − π½π where πΌ = ππ(1 + πππππ ) π½ = πππ Now assume that π = 1 − exp(−πΏπ) Assume that if all lines are running, price will be $3.50. Assume further that the variable costs are also $3.50 so that nobody is profiting. Finally, assume that demand elasticity is 0.2. ππππ = $3.50 πΆ = $3.50 π = 0.2 For π = 4 and π = 3 a value of πΏ = 20 (the calibration variable) produces the following results: Variable P M Expected price Expected profit Competitive Equilibrium 0.9 0.115129 Nash Equilibrium 0.8 0.080472 $4.00 $1.2375 $4.50 2.20 10 The expected profit under the Nash equilibrium has price at $4.50, which is about the average price of gasoline including occasional spikes due to shutdowns. As expected, less maintenance is done than if the refiners were operating in perfectly competitive markets. Conclusion The simple model developed in this paper shows that refiners who have multiple production lines may spend less on maintenance when they have market power than when they compete in competitive markets. This result was developed under the Nash assumption that the refiners do not actively collude with each other, but rather simply assume that each refiner will take the other refiners’ behavior as given. These results suggest that California energy regulators may want to mandate maintenance expenditures through a regulatory process to ensure that refiners do not exploit their market positions to the disadvantage of gasoline consumers. Game theorists recognize that strategic behavior among firms engaged in imperfect competition can take many forms. The Nash equilibrium examined here represents only one possible equilibrium in which each refiner takes as given the behavior of all other refiners, and each refiner assumes that all other refiners will do the same. Other equilibrium concepts such as tick-for-tat can lead to more profitable implicit collusions. The possibility of even more harmful equilibria further suggests that regulators should pay close attention to these markets. This model does not examine the incentives to shut down or defer maintenance when a refiner has substantial finished product inventory in stock. Regulators also should be sensitive to these issues. Finally, this model does not consider the startup costs that a refinery incurs following a shutdown or whether continual preventative maintenance is substantially cheaper than the cost of remedial maintenance following a shutdown. Both issues favor continuous plant maintenance, but neither issue eliminates the benefits that multi-plant refiners obtain from their other plants when one plant is shut down. However, if shutdown costs or remedial maintenance costs are sufficiently high, efforts to avoid them may completely dominate these benefits so that maintenance decisions by all refiners will be the same regardless of how many plants they run. 11 Possible further extensions: Calibrate the model using the actual numbers of refiners and the number and sizes of their production lines and information about demand. Show how the results depend on demand elasticity. Show that California prices have been more volatile than other prices. Show that maintenance expenditures for gasoline production lines are lower and reliability is lower at California refineries as compared at refiners in other states. <<Getting data will be hard or impossible.>> Extend the model to include storage. Show the shutdowns occur more often when finished product in shortage at that refinery is high. <<Getting data will be hard or impossible.>> 12 Table 1: California Refineries that Produce CARB Gasoline Barrels per Day (1,000) Refinery ALON USA, Bakersfield Refinery ALON USA (Paramount Petroleum Corporation), Paramount Refinery BP West Coast Products LLC, Carson Refinery Chevron U.S.A. Inc., El Segundo Refinery Chevron U.S.A. Inc., Richmond Refinery ConocoPhillips, Rodeo San Francisco Refinery ConocoPhillips, Wilmington Refinery ExxonMobil Refining & Supply Company, Torrance Refinery Kern Oil & Refining Company, Bakersfield Refinery Shell Oil Products US, Martinez Refinery Tesoro Refining & Marketing Company, Golden Eagle (Avon/Rodeo) Tesoro Refining & Marketing Company, Wilmington Refinery Valero Benicia Refinery Valero Wilmington Refinery Totals Multi-refinery Producers 66 66 50 50 240 276 245 78 139 276 245 78 139 150 26 156 166 166 104 104 132 78 132 78 1,906 1,334 70% Source: California Energy Commission Almanac at energyalmanac.ca.gov/petroleum/refineries.html 13 16% 14% 12% 10% 8% Conventional 6% Reformulated 4% 2% 0% 1990 1995 2000 2005 2010 2015 Figure 1: Yearly West Coast Weekly Retail Regular-Grade Gasoline Price Return Standard Deviations. Reformulated gasoline is produced primarily for the California market while conventional gasoline is sold in other markets. Source: U.S. Energy Information Administration at www.eia.gov/oil_gas/petroleum/data_publications/wrgp/mogas_history.html. 14 $1.40 $1.20 $1.00 $0.80 $0.60 $0.40 $0.20 $0.00 1997 ($0.20) 1999 2001 2003 2005 2007 2009 2011 2013 2012 $1.40 $1.20 $1.00 $0.80 $0.60 $0.40 $0.20 $0.00 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 2: California Refiner Margins (for unbranded refiners). The margin is the difference between reported average wholesale gasoline prices and the price per gallon of Alaskan crude oil (no adjustments is made for other refined products). Source: California Energy Commission Almanac at energyalmanac.ca.gov/gasoline/margins/index.php. 15