Local opposition to overhead powerlines is often vigorous. Should we be prepared to place them underground despite the additional cost?

This type of debate has been going on for almost the last 15 years. The folks that want better resiliency, reliability, less environmental impact, etc., always sing the praises of underground transmission. The reality is, the people that support putting it underground for various reasons never want to foot the bill. When you're looking at 5 to 10 times the cost to put facilities underground, the utilities have to pass that cost on to the consumers. Consumers just don't want to pay. So, while the debate keeps rolling along, no one is ever going to seriously consider massive underground transmission expansion until the monetary issues are addressed.

I have a strong aesthetic preference for underground utilities of all sorts -- power, telecom, water, sewage, district heating and cooling, package delivery -- not just for power.

A way to avoid the high cost of fault repair for underground lines is not to bury them in dirt-filled trenches, but to run them through tunnels. Tunnels can accommodate even high voltage AC or DC power lines, and the conductors can be heavier with higher capacities than what can feasibly be strung between towers. Shallow roofed tunnels in the median strips of divided highways shouldn't cost too much to construct and would avoid the more difficult permitting and ROW issues. Use undersea cable technologies through sections of the tunnels that might be prone to flooding.

These types of questions always involve trade offs.  Taking question 5 first, the trade off is between cost and visual preference. There are some resilience benefits to underground lines, but the cost of repair to those lines would be much higher.  Imagine, for example, a leak in the conduit containing the power lines and a subsequent short circuit.  On the other hand, there would be fewer outages from tree limbs bringing down power lines.  The first cost is roughly 3 times higher than above ground lines and more than 5 times higher as the location comes near big cities.  At some point, the cost of maintenance may outweigh the higher first cost, but that does not currently appear to be the case.  Furthermore, the industry is already lacking proper incentives to build more power lines that will be needed as the grid becomes dominated by more renewables with intermittent generation.  This is not an easy problem to solve.  It is easy to claim that the lines should be buried, but, in the final analysis, that will significantly raise consumer prices for electricity.  In Connecticut, the regulated cost of transmission and distribution is nearly twice the cost of generating the energy.  Putting the power lines underground at great expense will not necessarily be well received.

Thanks for this question Andrew Blakers. And yes, especially in urban areas where people have the transmission lines in sight, I would really support placing them underground. I am actually involved, as civilian, in a project in my municipality Oegstgeest in the Netherlands to place the cables underground. The transmission lines are very close to my back yard, roughly 100 meters. In the energy transition, the public opinion is of increasing importance. In Western Europe the public opinion can make or break a project, and I'm sure that in the States it is also an important factor to take into account. It is crucial that the public opinion stays positive on the energy transition if we want it to succeed. As the electrification trend will translate into more transmission lines, local community support for such projects is of utmost importance and therefore paying extra for getting that support should be taking in the business case calculation.

If you cannot route and permit a transmission line, you cannot build it.  Therefore, a higher capital cost for an underground line might be justified.  But, when looking at the “total cost of ownership” over the life of the underground asset, the cost is lower!   Just look at the FERC 1 reports filed by IOU’s and at the decades of UG experience at public power utilities in Anaheim, Colorado Springs and Ft. Collins to name a few.  

Engineers and planners need to evaluate these costs because intervenors most certainly are.  

Thanks.  Mike

Andrew, Absolutely!  in the situation you are describing, not only would you have difficulty getting the necessary permitting against vocal opposition, but it won't stop there.   Opposition would likely continue, as it has elsewhere, creating a potential PR nightmare.  Moreover, we have seen that overhead power lines create significant wildfire risk in arid climates in the US;  I suspect this would be the same in Australia.  So overhead power lines come with a significant liability in terms of the potential and death and destruction that can result if the power lines are subject to a traumatic weather event they are not designed for or if they are not well/frequently maintained.