CALGARY - Alberta's oil storage tanks aren't brimming with crude like their U.S. counterparts, but the business is still one of the bright spots amid the oilpatch's devastating downturn.

"Storage has been one of the few growing investments in midstreams since the downturn," said Steven Paget, an analyst at FirstEnergy Capital Corp.

Companies like Keyera Corp. and Gibson Energy are moving ahead with big expansion projects, despite the global oil price plunge.

And with long-term contracts in place, they've been buffered from the oil price shocks that have hit other parts of the oil industry, including drilling and services.

"These oil storage companies should still make money no matter what the price of oil is, assuming their long-term contracts are good," said Paget.

The smaller midstream companies - those that transport, store or market crude and refined petroleum products - have seen big investments in recent years to meet future production growth from the oilsands along with bigger players like Enbridge Inc., TransCanada Corp. and Kinder Morgan.

Dylan White, an analyst with market research firm Genscape Inc., says altogether they're currently building seven million barrels of capacity across the Alberta storage hubs of Hardisty and Edmonton, as well as in Kerrobert, Sask.

That's on top of the 17 million barrels of capacity that's been added in the last three years that brought total capacity in the region to an estimated 48 million barrels, said White.

The significant ramp-up in storage means the tanks and underground caverns in the two provinces are only currently about half full, despite being only a couple million barrels short of the record-high levels of total oil, said White.

That's in contrast to the U.S. oil hub of Cushing, Okla., where excess oil production has pushed storage levels to record levels of 65 million barrels out of a max capacity of 73 million barrels.

Those storage levels have been pushed up in part because the future price of oil is currently higher than the spot price, meaning it can pay to hold onto the oil and sell it later.

Canada has seen some of that ripple effect, said Beth Lau, manager of oil supply and transportation at the Canadian Association of Petroleum Producers.

"What we're seeing on the Canadian side is storage has been growing for the last several months as well," said Lau.

"It just makes sense if you're going to keep it in storage and then sell it for a higher price in the next month or two rather than push it into another market early on where it's going to sit in storage once again."

But nowhere near as much as in the U.S., where White says producers and traders prefer to have their oil closer to American refiners and markets.

Even if Cushing fills up as some have speculated, he said producers would still likely go to other regions in the U.S., like the Gulf Coast.

"Before people store in Canada, there are better opportunities in the U.S. that are farther downstream, and the economics might be better," said White.

But if oil prices remain persistently low, White said those hubs could fill up too.

"Hypothetically, if prices stay as low as they are - and overall U.S. inventories continue to increase at the rate of change that they've been increasing - it would only take four to five months to reach maximum utilization in the U.S. of storage."