Ans:
Oil supply in the 1970s/1980s was used mainly for transportation and the operation of machines.
In the 1970s, since there is an oil embargo proclaimed by the OAPEC (Organisation of Arab Petroleum Exporting Countries), the price of oil therefore increases.
In the 1970s, there is also an energy crisis, hence issues related to petroleum supply was escalating which in turn led to the increase in prices of oil as the production (input) of oil increases lead to the increase in quantity demanded of oil and when supply of oil cannot match up with the demand, price of oil therefore increases.
Price elasticity of demand (PED) measures the degree of responsiveness of quantity demanded of a good to a change in the price of a good itself, ceteris paribus.
On the other hand, since there is an economic recession in the 1980s, there will be an expectation of decrease in income for the people which makes people to spend less proportion of their income. This in turn, will lead to a decrease in demand of petrol since people who are driving will switch to other cheaper alternatives (means of transport) as they would not be willing to spend a large portion of their incomes on petrol as the price of oil was soaring at that point of time.
Price elasticity of supply (PES) measures the degree of responsiveness of quantity supplied of a good to a change in the price of a good itself, ceteris paribus.
When there is an increase in prices of oil, it will be difficult to raise outputs immediately, and with the economic recession going on, it is not feasible to get people to spend their money on petrol in the long run.
However, the high price of oil didn't maintain through the 1980s because the 1970 energy crisis causes the production to slow down and people to practice energy conservation due to high fuel prices.
Figure 1: Equilibrium Price and Quantity of Oil
At Figure 1, initial equilibrium of E0, equilibrium price is P0 and equilibrium quantity is Q0. Supply curve shifts to the right from S0 to S1 due to a decrease in supply. At P0, quantity supplied exceeds quantity demanded, hence there is a surplus leading to a downward pressure on price. As price decreases, there will be a downward movement along the demand curve (D0) as quantity demanded increases to meet the excess supply and quantity supplied to fall to remove excess supply.
Since there is a surplus of oil due to the decrease of demand for oil, the price of oil has to drop in the long run in order to reduce the surplus of oil.
Income elasticity of demand (YED) measures the degree of responsiveness of demand for a good to a change in income, ceteris paribus.
Oil is considered as a luxury good but demand for luxury good during an economic recession (lower income for an individual) will not be high which in turn results in the loss of revenue if oil prices continue to soar, hence, prices of oil has to decrease in order to reduce the loss of revenue.
Cross elasticity of demand (XED) measures the degree of responsiveness of demand for a good A to a change in the price of another good B, ceteris paribus.
Since there is no close substitute for oil back then, producing oil as the only source for petrol will be very expensive since it is a raw material, thus, industry for producing oil will have to reduce its production in order to continue on its production. Hence, as petrol and cars are complements of each other, prices of oil has to drop in order to increase the demand for oil, as people will then be willing and able to afford the petrol for cars. Also, with the drop in prices of oil, the loss of revenue will then be reduced in an economic recession.
As a result, the high prices of oil cannot be maintained through the 1980s.
Credits to sources from the Internet:
http://en.wikipedia.org/wiki/1970s_energy_crisis
http://en.wikipedia.org/wiki/Early_1980s_recession