Alternate Energy Sources

Unconventional Oils

When most people think of oil, they think of the liquid which shoots out of the ground when the drill reaches it. But this is only part of the oil resource, known as conventional oil. There are other types of oil known by many names such as unconventional oil, heavy oil, tar sands, oil shale, bitumen, etc. Some of these oils exist in vast amounts, greater than the remaining conventional oil, but unfortunately they are not the answer to our needs.

AO1. Production of Heavy Oil

The chart above shows the expected contribution of heavy oil (actually tar sands since shale oil is too small for consideration) to our needs up to 2030. It shows that even in that year, it will only contribute a fairly small amount to our needs, about 17% of conventional oil's. There may be vast amounts of heavy oil around but it is the production rate which is the key factor.

Oil Shale

An "oil shale" contains neither oil nor shale; it is an ordinary petroleum source rock that has never been buried into the oil window [converted to oil]...The rock has to be mined, crushed and heated in closed containers. The leftovers after the oil is recovered fluff up to more than their original volume; the hole where the rock was mined isn't big enough to hold the waste.

Kenneth Deffeyes from "Hubbert's Peak"

There is certainly no shortage of oil shales – it is estimated that the world has over 1,600 Gb of shale oil available, 1,200 Gb of which lies in the USA. Other countries with oil shale include Canada, Australia, Estonia, Germany and Israel. With conventional oil reserves estimated at 860 Gb, it would seem to be the answer to our prayers.

Unfortunately oil shale carries serious disadvantages. First, most of it needs to be dug out in strip mining rather that drilled, a process that has high environmental problems. Once dug out, it then needs to be heated to 450-500°C, enriched with hydrogen via steam before the resulting oil is separated. We are then left with a sludge which has increased in volume by 30% through the process and needs to be disposed of.

The downsides of all this are that oil shale production creates more than four times as much greenhouse gases as conventional oil production, it uses vast quantities of water (which are not always available where the shale is), and wastes something like 40% of its initial energy in production.

Oil shale production is expensive, wasteful and environmentally hazardous. It is only now, when conventional oil prices are high, that oil shale production has become feasible. It will no doubt make a small contribution to the oil shortfall (less than one million barrels a day by 2030) in the future but it is no panacea.

Tar Sands

When erosion brings an oil field to the surface, the smaller molecules evaporate, and a nearly solid tar is left in the reservoir rock...Tarry oil is extracted by mining the sand, contacting it with hot water, and separating the oil.

Kenneth Deffeyes from "Hubbert's Peak"

Tar sands (often now called by the more attractive sounding but less accurate 'oil sands') consists of a combination of sand and clay with bitumen. It exists in even greater quantities than oil shale, about one third (1,800 Gb) in Venezuela (Orinoco), one third (1,700 Gb) in Canada (Athabasca) and the rest mainly in the Middle East. Unfortunately, like oil shale, it also carries a heavy burden.

The tar sands in Canada generally lie deep and have to be produced by damaging strip mining. Hot water is added to the result, piped to a plant and then agitated before the oil is skimmed off. What this process needs are vast amounts of water, an abundance of energy to boil that water, and plenty of space for the waste. The first two are becoming in serious short supply in Canada.

To produce a single barrel of oil means digging out four tonnes of materials and leaves you with 80 kg of greenhouse gases and 3-5 barrels of waste water as well as the sand residue. It consumes two to five barrels of fresh water, 250 cubic feet (7,000 liters) of natural gas to mine and 500 cubic feet (14,000 liters) of gas to upgrade to synthetic crude oil. This gas is enough to heat a Canadian home for 4.5 days. The tar sands industry consumes about 0.6 billion cubic feet (17 billion liters) of natural gas daily, enough to heat 3.2 million Canadian homes each day. The result also totally destroys the forests and bogs there.

Although in great supply, tar sands face even greater problems than oil shales in their production. It is unlikely that the rate of production from them will make much of a dent in the oil depletion problem. The present output from Canada is about 1.5 million barrels per day; this at a time when world consumption is over 85 Mbpd. It is thought that output could reach 2.5 Mbpd in 2030 but, with demand rising and conventional oil declining, the contribution would be small.

Like oil shales, tar sands could be compared to standing by a lake while your house is on fire and trying to put it out with a cup. The amount of water is irrelevant; it is the 'flow rate' that will decide if your house burns down or not.

Deepwater (and other types)

A third type of unconventional oil is the conventional oil that is found in difficult locations. Although it is 'flowing' oil, it is classed as unconventional because the production rates are greatly limited. As with tar sands and shale oils, there may be large amounts of the oil there but we will not be able to produce it at a high enough rate to make a substantial difference.

Deepwater oil is classed as that found at a water depth below 500m (by comparison, the main oil areas of the North Sea are up to 200m deep). There is also polar oil, and NGL (natural gas liquids) which are found in gas fields but are used as liquids.

The chart below shows the contributions of all these unconventional oils (as well as conventional oil) to world production. It shows the present totals (2007) and the expected totals in 2020 and 2030.

AO2. Contributions of Unconventional Oil

Unconventional Oils : Natural Gas : Coal : Nuclear : Renewables : Hydrogen