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Question

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

Andrew Blakers's picture
Professor of Engineering Australian National university

Andrew Blakers is Professor of Engineering at the Australian National University. He founded the solar PV research group at ANU. In the 1980s and 1990s he was responsible for the design and...

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Strong interstate transmission is important for a solar & wind dominated electricity system to smooth out local weather. However, local opposition to overhead powerlines is often vigorous. Should we be prepared to place them underground despite the additional cost?

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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.

Agree, Heather. We should build upon the grids we have, with nuclear power plants at the hubs and spokes radiating outwards. Why? Grids of branching fractals*, like tree branches with water, transmit the most electricity, to the most people, most efficiently. *Attempts by distributed energy fanatics to associate branching fractals with disconnected microgrids ("fractalgrids") have no basis in physics nor math.

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.

I hope we consider more nuclear in addition to "trying to even out intermittency" of renewables. Let's repeal California's nuclear moratorium so we can be poised to build SMRs specifically in locations where we have a need to reliable electricity.
Andrew Blakers's picture
Andrew Blakers on Feb 17, 2022

Nuclear also needs strong transmission and storage to smooth out local demand and to move energy from site into the cities.

According to the World Nuclear Association, nuclear went backwards in the last decade in terms of actual electricity generation - because it is so expensive compared with solar & wind.

Bob Meinetz's picture
Bob Meinetz on Feb 23, 2022

"Nuclear also needs strong transmission and storage to smooth out local demand..."

Nuclear has never had storage - nor needed it. And how does transmission and storage smooth out local demand, which is instantaneous?

"...and to move energy from site into the cities."

I assume it requires strong transmission to move wind energy 240km from Hornsdale to Adelaide, no?

Please provide a link to support your contention that "nuclear went backwards in the last decade...because it is so expensive compared with solar & wind." Thanks.

"Strong interstate transmission is important for a solar & wind dominated electricity system to smooth out local weather." Strong interstate transmission can't smooth out local weather enough to power an electricity system, Andrew. You should instead be prepared to accept nuclear power as an alternative to solar & wind. It's inevitable.
Andrew Blakers's picture
Andrew Blakers on Feb 17, 2022

According to the World Nuclear Association, nuclear went backwards in the last decade in terms of actual electricity generation - because it is so expensive compared with solar & wind

Australia is demonstrating that strong interstate transmission is very effective in reducing storage requirements for wind and solar. The state of South Australia had an average wind & solar fraction of 89% for the first week of February. The electricity price was the lowest in the country. As more and more solar & wind gets built, South Australia breaks records again and again, showing that its straightforward and cheap to get to very high levels of solar & wind. There is no nuclear or hydro or any other renewables in South Australia.

Bob Meinetz's picture
Bob Meinetz on Feb 17, 2022

"The state of South Australia had an average wind & solar fraction of 89% for the first week of February." I agree, Andrew, that's quite an achievement. It's not good enough, however. Not even close.

Grid managers in the U.S. require electricity system uptime to be at a reliability of "four nines" - 99.99%. If you had transmission circling the globe you would never be able to power it with intermittent solar and wind power at that level of reliability, much less in South Australia.

So you're forced to rely on coal, or natural gas. You might have seen a recent post of mine, 6 of the 10 most expensive energy projects in the world are in Australia, and consider devoting some of your efforts to ending Australia's obsession with profiting, at the expense of global environmental health, on the sale of natural gas. It would be of much greater environmental value than promoting boutique sources of energy that are only available to the world's wealthiest citizens.

Andrew Blakers's picture
Andrew Blakers on Feb 18, 2022

Australia indeed has large export projects for fossil gas and coal. More fool the customers and shame on the company executives. I don't know how they look their kids in the eye.

At the same time, Australia has more solar per capita than any other country and also is a top-10 wind country. Only 5% of electricity generation is from fossil gas. Australia is demonstating that high levels of solar & wind produce a highly stable grid with low wholesale electricity costs.

Strong interstate transmission is really important to get to high levels of solar & wind, so smooth out local eather & demand.

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.

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