Underground construction costs less than originally thought and is much safer in extreme weather

As the importance of coal was understood, other countries started discovering their deposits and China, US, India, Australia and Russia all took advantage of their significant coal deposits.

Oil is similar. In the late 19th century, it was realised that oil could be a convenient source of energy and the discovery of oil transformed economies and geopolitics.

Reserves discovered in the Middle East in the early 20th century shifted the economic balance and now you see countries such as Saudi Arabia, USA, Russia and Iraq, rely heavily on their oil reserves.

As we move forward with the new economy, deposits of oil and coal beneath the ground will be of less importance. What sits above the ground in terms of wind and solar generation of power and storage of energy will be much more important.

There is a major difference between the new and the old economies.

Oil and coal are convenient forms of energy that are easy to transport and store. Electricity - not so much.

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What some may see as a disadvantage I see as an advantage. When you mine coal, you must transport it. If you build an electrical cable between two points, the electricity can flow automatically.

The minor issue here is the building of the cable. We have all seen overhead high voltage transmission lines. In Australia they are typically 500kV or 330kV for long transmissions.

We typically use overhead power lines for several reasons. Firstly, the power losses are mostly realised as heat. Overhead power lines allow cooling by the natural flow of air. Secondly, the cables themselves don't need sheathed insulation. Air is used as an insulator.

As we have more need to move electricity, underground high voltage power cables are being further explored.

Work has started on a 546km 400kV DC underground power cable to take 1.25GW of renewable power from Canada to New York City. From start to end you will never see the cable above ground. Larger conductors are required due to the heat problem and the cable needs to be insulated, plus the burying of cables. The end result is a cost of $6 billion.

With the interruption to farming communities and the community angst, an independent report for a 190km planned power line in Victoria shows that the underground construction is not as expensive as originally thought and is much safer in the face of bushfires and other extreme weather events.

As we learn how to operate in this new economy, we may need to challenge some of our accepted practices.