This is half correct and half incorrect. It's the current
perception of future supply that is what primarily affects current prices
and future prices, not the actual current supply. Apparently you know nothing about the futures markets, which I have actual experience trading, and have made some decent money doing, a couple decades ago. All energy prices - crude oil, natural gas, electricity, are determined by their futures market prices, prices determined by futures markets participants, buyers and sellers, which may include users: producers and refiners, and also speculators and hedgers.
This, for example, is a one-year daily bar chart of West Texas Intermediate Crude Oil for a contract to make (as seller) or to take (as buyer) delivery in December (which is the current monthly contract with the most "open interest" - aka number of contracts to buy and to sell - each contract representing one buyer for one barrel of oil and and one seller of one barrel of oil) and you can see a recent accelerating upward trend. The price a buyer will pay for a barrel of crude oil in December will be the price at which they purchased the contract, which if they had purchased it back in July would have been about $70 a barrel, but almost $80 a barrel if they just purchased it today. There are many grades of crude oil and many producers, but WTI Crude is the "benchmark" on which they all price their products at a discount or a premium depending on what kind and how much refined products they can get out of it.
View attachment 1823
Terminating a potential source of production
does affect the
perception of what future prices will need to be to obtain supply and so, yes, terminating the pipeline does affect actual prices paid, because all delivery months get bid up by that perception of potential future short supply.