Sixteen years, three prices, twelve events

One chart of everything that happened

Three prices, monthly, since 2010. is the world price — oil loaded on tankers that can sail anywhere. is the American price, set at a pipeline crossroads in Oklahoma. is Alberta's price, set at , about an hour southeast of Edmonton. The numbered lines mark the events this page walks through. Two things are worth noticing before any of the stories: the three lines almost always move together, and the orange line is always on the bottom.

Plain words · What's a benchmark price?

There is no single price of oil. Quality differs from field to field, and a barrel's location matters as much as its contents. So the market picks a few well-known blends at well-known places and quotes everything else as a premium or discount to them. Those references are benchmarks, and the prices reported in the news are benchmark prices.

The three on this chart each answer a different question. Brent sits on the water and can sail anywhere, so it reads as the world's price. WTI sits at a pipeline junction in Oklahoma, so it reads as America's price. WCS sits at Hardisty, Alberta, further from the ocean still, so it reads as Alberta's price. When the lines drift apart, the distance between them is usually telling a story about geography and plumbing.

The world price, the U.S. price, and Alberta's price

Monthly averages, US$ per barrel · January 2010 – June 2026

1.Civil war in Libya (2011-02) — About 1.5 million barrels a day of exports stop; Brent climbs above $120 within weeks.
2.OPEC declines to cut (2014-11) — Facing the U.S. supply surge, the cartel keeps pumping to defend market share. The price halves.
3.Iran's sanctions lift (2016-01) — More supply into an already flooded market. The bottom: WTI averages under $32 this month.
4.OPEC+ forms (2016-12) — Russia joins OPEC in coordinated cuts for the first time. Prices grind back toward $60.
5.U.S. leaves the Iran deal (2018-05) — Sanctions return; Iranian exports fall sharply over the following year.
6.Alberta's discount peaks (2018-11) — Not a world event — a pipeline shortage at home. The WCS gap hits $46; Alberta orders production cuts.
7.Drone attack on Abqaiq (2019-09) — Roughly 5% of world supply knocked out in one strike on Saudi Arabia — and prices recover within a month.
8.Pandemic demand collapse (2020-04) — A third of world demand vanishes. On April 20 the U.S. benchmark settles below zero.
9.Russia invades Ukraine (2022-02) — The world's second-largest exporter faces sanctions. Brent touches $139 in early March.
10.Embargo and price cap (2022-12) — Europe stops buying Russian seaborne crude; the G7 caps its price. Discounted barrels reroute to Asia.
11.Trans Mountain expansion opens (2024-05) — Alberta's first big new export pipe in decades. The chronic discount narrows.
12.Israel–Iran strikes (2025-06) — Two weeks of strikes near the world's busiest oil strait. Prices jump, then settle within the month.

2010–2014 · the surge

First, the United States more than doubled its oil production

Everything else on this page happens in the shadow of one change: American drillers learned to pull oil out of , and U.S. production went from 5.4 million a day in early 2010 to 13.0 million by the end of 2019. The world had priced oil on the assumption that America would always need to import more; that assumption quietly died.

You can see the strain arrive before any headline said so. From 2011 to 2013 the world price ran about $15 a barrel above the American price — unusual, since the two normally sit within a dollar or two. The new oil was piling up in the middle of the continent faster than pipelines could carry it to the coast. If that sounds familiar, it should: it's a preview of Alberta's entire decade, happening to Texas first.

U.S. crude oil production

Monthly, million barrels per day · 2000 – 2026

2014–2019 · the glut

OPEC stopped defending the price, and shocks stopped sticking

In November 2014, with the new American supply flooding in, met and chose not to cut production — the cartel would rather keep its customers than its price. The price of oil halved within months, and by January 2016, after on Iran lifted and one more producer rejoined the market, WTI averaged $31.68 — down from over $105 eighteen months earlier. Alberta rode the whole slide: WCS averaged $17.88 that month.

Plain words · Who OPEC and OPEC+ actually are

OPEC, the Organization of the Petroleum Exporting Countries, is a group of oil-exporting states founded in 1960, with Saudi Arabia its largest producer. Its members' governments agree on production targets, because together they supply enough of the world's oil that pumping less tends to raise the price and pumping more tends to lower it. Nothing binds a member except its own interest, and members quietly exceeding their quotas is a recurring feature.

OPEC+ is the larger table that formed in 2016, when OPEC began coordinating with outside exporters, Russia the most important among them. The 2014 moment on this page is the choice this group faces perpetually: cut production to defend the price, or defend market share and let the price fall. In 2014, facing the American surge, OPEC chose its customers over its price.

The strangest lesson of these years is what didn't move prices. In September 2019, drones hit the Abqaiq processing plant in Saudi Arabia and knocked out roughly five percent of world supply — the largest single-day disruption in the market's history. Brent jumped 12% in one trading day. Then Saudi repairs came in fast, and within 14 days the price was back below where it started. A market drowning in oil had learned to shrug off a missile strike.

The spike that didn't stick — Brent around the Abqaiq attack

Daily closes, US$ per barrel · August – November 2019

2018 · the discount

Alberta's worst price crisis of the decade wasn't caused by a war

Here is the gap itself — the world's events as Alberta actually felt them. The difference between WTI and WCS has a long-run median of about $15. Watch what it does in late 2018: it hits $45.93 in November — the widest month ever recorded. WTI was a healthy $57 that month. Alberta's barrel fetched $11.03. In December it averaged $5.97.

No war did this. projects finished years in the making and added supply; every pipe out of the province was already full; a big American refinery that buys heavy crude went down for repairs. The barrels had nowhere to go, and buyers knew it. Then the provincial government — a thing Alberta had not done since the 1980s — and the gap collapsed from $46 to $9.62 in three months.

Plain words · Heavy oil, light oil, and why refineries care

A refinery turns crude into things people buy, and the light products (gasoline, diesel, jet fuel) pay best. Light crude arrives already close to those products. Heavy crude, which is what the oil sands produce, is dense and carbon-heavy; a refinery needs extra processing units to break it down, and more of each barrel comes out as lower-value product. Sulphur adds a second penalty: high-sulphur “sour” crude corrodes equipment and must have its sulphur stripped out, and WCS is sour as well as heavy.

So Alberta's barrels appeal mainly to refineries that have invested in the equipment to handle them, concentrated in the American Midwest and on the Gulf Coast. Some discount for WCS is therefore permanent, honest physics. This page reads the changes in the discount, because those are what the physics alone can't explain.

The gap: WTI minus WCS

Monthly averages, US$ per barrel · 2005 – June 2026

Why was every pipe full? The regulator's own records say it plainly. When shippers want space on a pipeline, they “nominate” barrels; when there isn't room, the pipeline turns a share of them away — it's called apportionment, and it is the cleanest measure of congestion there is. Through 2018, turned away an average of 40% of the barrels nominated to it, and the about a third.

The overflow went to railcars: by February 2020 Canada was loading 411,991 barrels a day onto trains — a slower, costlier, and more accident-prone way to move oil, used at that scale for one reason: there was no room in the pipe.

Plain words · How pipeline space is rationed

Pipeline space is allocated month by month. Each shipper nominates: it tells the operator how many barrels it wants to move. If the requests fit under the pipe's capacity, everyone ships. If they don't, the operator doesn't run an auction. Under Canadian rules it scales every shipper back by the same fraction, and that scaling-back is called apportionment.

The turned-away share is the cleanest measure of congestion in the public record. And the turned-away barrels don't vanish. They wait in storage tanks, ride out on railcars, or get resold into a local market that already has too much, with sellers undercutting one another to find a buyer. That last part is the mechanism that connects a full pipe to a cheap barrel at Hardisty.

Share of nominated barrels turned away, by pipeline

Monthly apportionment at the system level · CER records, 2007 – present

Crude oil leaving Canada by train

Monthly, barrels per day · 2012 – present

2020–2022 · the whiplash

A pandemic took demand away, then a war took supply

In April 2020, with much of the world staying home, oil demand fell by something like a third — and for one afternoon the price system briefly stopped making sense. Traders holding for delivery at had nowhere to put the physical barrels; storage was full. On April 20 the U.S. benchmark settled at −$36.98 — negative — meaning sellers paid buyers to take oil off their hands. WCS averaged $3.50 for the whole month. Not per litre. Per barrel.

Plain words · How a price can fall below zero

The WTI number in the news is the price of a futures contract: a standardized promise to deliver oil at Cushing, Oklahoma, in a particular month. Most traders never touch a barrel; they sell the promise on before it comes due. But a contract still held at expiry ends in real oil, and the holder must have somewhere at Cushing to put it.

In April 2020, demand had collapsed and Cushing's storage was effectively spoken for. Traders still holding the May contract on its final trading day faced taking delivery of barrels they could not store. Getting out of that promise was worth paying for, so the contract's price fell through zero. Oil was never worthless; storage had briefly become worth more than the oil.

Two years later the same chart ran in reverse. Russia — the world's second-largest oil exporter — invaded Ukraine, and Brent averaged $117.25 in March 2022, touching $139 intraday. Then in December 2022, Europe stopped buying Russian seaborne crude and the G7 , and something subtler happened in Alberta's numbers: Russia's discounted barrels flooded into Asia, competing with every other heavy, crude — and Alberta's discount widened to $29.30 that December, its worst month since the 2018 crisis. A sanctions policy written for the other side of the planet showed up, within weeks, in the price at Hardisty.

Plain words · Sanctions, embargoes, and the price cap

Three tools were aimed at Russian oil in late 2022, and they are easy to blur together. Sanctions restrict doing business with named countries or firms. An embargo bans purchases outright, which is what Europe applied to Russian crude arriving by sea. The price cap was the novel one: a rule from the G7 group of Western economies that Western tankers and insurers, which handle much of the world's shipping, could carry Russian oil only if it had been sold below a set price.

The cap was built to do two things at once: keep Russian barrels flowing, so the world price stayed calm, while trimming Russia's earnings on each one. The barrels rerouted to Asia at discounts and competed with the world's other heavy, sour crudes. Alberta sells into that same pool of refineries, which is how a policy aimed at Russia shows up on this page as a wider gap at Hardisty.

The day the price went negative — WTI in early 2020

Daily closes, US$ per barrel · January – June 2020

2024 · the new pipe

Then a pipeline opened, and the discount narrowed

For eighteen years the throughput line on this chart hugs the capacity line — the pipe to the Pacific ran effectively full, every month, through every price regime above. In May 2024 the Trans Mountain expansion finally opened after twelve years of planning, protest, court challenges, and a change of owner, roughly tripling the system's capacity (from about 302 to 874 thousand barrels a day). The blue line — barrels loading onto tankers at the Westridge dock in Burnaby — goes from a rounding error to several hundred thousand barrels a day within months.

The knock-on effects arrive one by one, each visible in a different dataset. Apportionment on Trans Mountain: 40% average in 2018, 0% in 2025. Crude-by-rail: back to a trickle. Exports beyond the United States: 126,511 barrels a day in 2023, 373,190 in 2025 — with the taking record volumes too. And the discount itself averaged $18.67 in 2023 but $11.76 in 2025.

The world's crises kept coming through these months — strikes near the in June 2025, a tariff scare between Ottawa and Washington that spring that mostly resolved into exemptions — and the monthly gap barely flinched at either. The quiet infrastructure change moved Alberta's number more than the loud geopolitical ones did.

Trans Mountain: eighteen years full, then room to breathe

Monthly throughput vs available capacity, thousand barrels per day · 2006 – present

Where the exported barrels go

Annual averages, barrels per day · 2010 – 2025 · destinations beyond the U.S. were near zero for decades

Reading it back

Wars moved the price for weeks. Pipelines moved Alberta's price for years.

We went into this expecting geopolitics to be the story, and it is — but not in the way we assumed. A few patterns kept repeating:

Supply shocks healed fast; demand shocks didn't. The largest supply disruption in history (Abqaiq) was fully priced away in 14 days. The demand collapse of 2020 took the better part of two years to work through.

Alberta felt world events through a narrow funnel. When the pipes had room, Alberta's price tracked the world's. When they didn't — 2018 most of all — local plumbing mattered more than global politics, and the two worst discounts on record ($46 in 2018, $29 in late 2022) came from a full pipe and a distant sanctions regime, not from any war touching a barrel of Canadian oil.

The dramatic days were rarely the expensive ones. The negative price lasted one afternoon. The 2018 blowout held the gap above $25 for six months of that year. And the full pipes underneath it all were a permanent condition, not an event — which may be why they never made the same headlines.

And one open question we're still watching: the gap has drifted wider again this year — $15.88 average so far in 2026, against $11.76 last year — while the pipes report spare room. Heavy crude is 76% of Canada's export barrel now, refinery outages come and go, and has been unwinding its cuts into a well-supplied market. We don't yet know which of those is the reason. When the data makes it clear, this page will say so.

Show the work

Method and sources

Prices. WTI, WCS, and the are monthly averages published by (2005 onward for WCS; WTI back to 1986). Brent monthly averages and the two daily windows (Brent around September 2019, WTI in spring 2020) come from the 's published series. Note one seam: starting February 2025, Treasury's WCS figure is derived from exchange-traded futures rather than the previous price assessor — the series is continuous but not identical in method. Monthly averages also smooth over drama: the famous −$37.63 settlement of April 20, 2020 appears here as a daily close of −$36.98 in the EIA series and an April average of $16.55.

Pipelines and rail. Throughput, capacity, and apportionment come from the 's published monthly key-point data. Trans Mountain throughput is the sum of its three delivery points (Burnaby, Sumas, Westridge); capacity is the CER's reported available mainline capacity. Where the regulator publishes nominations but not an apportionment percentage, we derive it as the turned-away share of original nominations. Volumes arrive in cubic metres and are converted at 6.2898 barrels per cubic metre. Crude-by-rail and export-destination volumes are CER monthly and annual series respectively.

U.S. production. EIA monthly field production of crude oil, shown from 2000.

What the gap is not. The WTI−WCS differential is not a scorecard of fairness. WCS is a heavier, more sulphurous blend that yields less gasoline per barrel and costs real money to refine and to transport — a gap near the long-run median of $15 mostly reflects that physics. This page reads the changes in the gap, not its existence.

What this page doesn't do. It doesn't forecast prices, and it doesn't assign motives — why OPEC chose what it chose, or whether any policy was wise, is argued plenty of other places. We're reading the measurements. Events are dated to the month they land in the monthly series; the event notes state widely reported mechanisms, and the price responses shown are computed from the data on this page.

Data: Alberta Treasury Board and Finance (oil prices, Open Government Licence – Alberta); U.S. Energy Information Administration (spot prices and production, U.S. public domain); Canada Energy Regulator (pipeline throughput and capacity, apportionment, crude-by-rail, exports by type and destination, Open Government Licence – Canada). Data fetched 2026-08-17; the page is refreshed as new months are published.

Plain-words glossary — every term on this page, in one place

Alberta Treasury Board and Finance.: The provincial ministry whose published economic statistics include the monthly WTI and WCS prices used on this page.
Apportionment.: What a pipeline does when shippers request more space than exists: it scales every request down by the same fraction. The share turned away is the apportionment percentage, and it is the plainest available measure of a congested pipe.
Barrel.: The oil industry's unit of volume, about 159 litres. Canadian pipeline records arrive in cubic metres; this page converts them at 6.2898 barrels per cubic metre.
Benchmark.: A reference price the market quotes everything else against. Rather than price every cargo from scratch, buyers and sellers agree on a discount or premium to a well-known blend at a well-known place. Brent, WTI, and WCS are all benchmarks.
Brent.: The world's reference oil price. It tracks light crude loaded onto tankers from the North Sea. Because those cargoes can sail to any buyer, Brent responds to supply and demand everywhere.
CER.: The Canada Energy Regulator, the federal regulator of pipelines that cross provincial or national borders. Its monthly records supply this page's throughput, capacity, apportionment, rail, and export figures.
Crude by rail.: Shipping crude in railway tank cars. It works anywhere the tracks go, but it is slower, costlier, and more accident-prone than a pipeline, so heavy use of it is a sign the pipes are full.
Curtailment.: A government order capping how much oil producers may pump. Alberta issued one in response to the 2018 price collapse, its first such order in decades.
Cushing.: A pipeline crossroads and tank farm in Cushing, Oklahoma: the place where WTI is priced and where its futures contracts are physically delivered. When American oil storage “fills up” in a headline, Cushing's tanks are usually the ones meant.
Differential.: The gap between two prices. On this page it means WTI minus WCS: how far Alberta's barrel sold below the American benchmark in a given month.
EIA.: The U.S. Energy Information Administration, the statistical agency of the U.S. Department of Energy. Its published series supply this page's American prices and production figures.
Enbridge Mainline.: The largest pipeline system out of Alberta, running east across the Prairies into the U.S. Midwest. More Canadian crude leaves by the Mainline than by any other route.
Futures contract.: A standardized promise to deliver oil at a set place and price in a set future month. Most oil trading is the trading of these promises. Whoever holds one at expiry must actually take the barrels.
G7.: The Group of Seven, a forum of large Western economies: Canada, France, Germany, Italy, Japan, the United Kingdom, and the United States, with the European Union alongside. It set the price cap on Russian oil.
Hardisty.: A small town southeast of Edmonton where Alberta's export pipelines and a large tank farm meet. It is where WCS is bought and sold, which makes it the spot on the map where Alberta's oil price is set.
Heavy and light crude.: Light crude is thin and yields a lot of gasoline and diesel. Heavy crude, like Alberta's, is thick, takes more processing, and yields more low-value product, so it sells for less.
Nomination.: A shipper's request for space on a pipeline for the coming month: how many barrels it would like to move.
Oil sands.: The deposits in northern Alberta where the crude, called bitumen, is too thick to flow on its own. It is mined or steamed out of the ground, then diluted or upgraded so it can travel by pipeline. Most of Alberta's oil comes from the oil sands.
OPEC.: The Organization of the Petroleum Exporting Countries: a group of large oil-exporting states, Saudi Arabia foremost, whose governments coordinate how much their industries produce. Its choices about output move world prices.
OPEC+.: OPEC plus a group of outside exporters, most importantly Russia, that have coordinated production levels with the cartel since 2016.
PADD.: One of the districts the United States uses to report its oil statistics; the abbreviation stands for Petroleum Administration for Defense District. The West Coast is PADD 5, the traditional destination for barrels leaving Westridge.
Price cap.: The G7 rule of December 2022 that Western ships and insurers may handle Russian oil only if it sold below a set price. It was designed to keep the oil flowing while shrinking what Russia earns from it.
Sanctions and embargoes.: Sanctions are government restrictions on doing business with a country or its firms. An embargo goes further and bans the purchases outright. In 2022 Europe embargoed seaborne Russian crude, while the G7 price cap kept it moving to other buyers.
Shale (tight oil).: Rock whose oil sits in pores too tight for an ordinary well. Drilling sideways through the rock and cracking it with pressurized fluid, known as fracking, releases the oil. This is the technique behind the American production surge.
Sour and sweet crude.: Sour crude carries a lot of sulphur, which refineries must strip out; sweet crude carries little. Sour therefore sells below sweet. WCS is both heavy and sour.
Spot price.: The price of oil for immediate delivery, as opposed to a price locked in today for delivery in a future month.
Strait of Hormuz.: The narrow sea passage between the Persian Gulf and the open ocean. A large share of the world's tanker-borne oil passes through it, so any threat there is read as a threat to world supply.
Trans Mountain.: The one pipeline carrying Alberta oil to the Pacific, running from near Edmonton to Burnaby, British Columbia. Bought by the federal government in 2018; its long-delayed expansion opened in May 2024 and roughly tripled its capacity.
WCS.: Western Canadian Select, Alberta's benchmark export blend: heavy, sour crude priced at Hardisty, Alberta. It is costlier to refine than the light benchmarks and starts far from any coast, so it always sells below WTI. This page is about why that discount changes size.
Westridge.: The tanker dock in Burnaby, British Columbia, at the end of the Trans Mountain pipeline. It is the only place Alberta's oil can board a ship without first crossing the United States.
WTI.: West Texas Intermediate, the American reference price. It is set at Cushing, Oklahoma, a pipeline junction deep inside the continent, so it also reflects how easily oil can move around North America.

Where to go next. The Canada Energy Regulator publishes all of its pipeline and export data openly at cer-rec.gc.ca, and Alberta's economic indicators live at economicdashboard.alberta.ca. If you want the same period read through the climate record instead of the price record, that page is here.

Built by Tamrack — the stories Alberta's data tells. See all of Tamrack's reports.

What the world does to the price of Alberta's oil