World's Largest Solar Farm to Be Built in Australia - But They Won't Get The Power

davfor

Another sign renewables are worth paying attention to.....

.....the Power Link doesn't just involve building the world's largest solar farm, which will be easily visible from space. The project also anticipates construction of what will be the world's longest submarine power cable, which will export electricity all the way from outback Australia to Singapore via a 4,500-kilometre (2,800 miles) high-voltage direct current (HVDC) network.

https://sciencealert.com/world-s-largest-solar-farm-to-pipe-power-internationally-from-australia-under-the-sea

msf

4,500-kilometre (2,800 miles) high-voltage direct current (HVDC) network.

This shows how far behind the times I am. I had thought (and it used to be true) that AC was better than DC for power transmission. From National Geographic, 2012:

An updated, high-voltage version of DC, called HVDC, is being touted as the transmission method of the future because of its ability to transmit current over very long distances with fewer losses than AC. And that trend may be accelerated by a new device called a hybrid HVDC breaker, which may make it possible to use DC on large power grids without the fear of catastrophic breakdown that stymied the technology in the past. ...

[HVDC is] better suited to places where electricity must be transmitted extraordinarily long distances from power plants to urban areas. It also is more efficient for underwater electricity transmission. ...

Far-flung arrays of wind farms and solar installations could be tied together in giant networks. Because of its stability and low losses, HVDC could balance out the natural fluctuations in renewable energy in a way that AC never could.

https://www.nationalgeographic.com/news/energy/2012/12/121206-high-voltage-dc-breakthrough/

"If you have the transmission of electricity over very large distances between countries, then the flow of energy changes from liquid fuels – oil and LNG – to electrons." (Original article.)

Electrons "flow" only in DC. "The electrons in an AC circuit don’t really move along with the current flow. Instead, they sort of sit and wiggle back and forth." At least the basic laws of physics haven't changed.
https://www.dummies.com/education/science/science-electronics/electronics-basics-direct-and-alternating-current/

catch22

Nikola Tesla changed all the early theories about electron flows and AC electricity.

Mr. Thomas Edison and friends were attempting to figure how to move "dc" electricity throughout a community for electric lighting. A very costly proposition at the time and not efficient for the use of electrons.
I recall studying the early course material for electronics in the late 1960's. A fairly common question among the students revolved around electron flow in various materials, which is the basis for causing AC or DC current/voltage potentials.
The instructor suggested that one could pursue studies at a PhD level to obtain a better understanding.
I decided at my young age, for my purposes of learning and passing this early class and the more advanced classes to follow, that I would accept the fact that electrons exist and some very brilliant folks had discovered way before my time how to "manipulate" the electrons.
I also recall that several of my large text books contained the common title words of "theory of"; which for me was a "I'll take your word for it" moment. I took the authors at their word and that I needed to concentrate on how to discover (trouble-shoot) why a group of electrons started at point "A" and didn't finish their mission at point "B" or other locations.

Hole flow was interesting for our young minds, as we did not have a prior need for such pondering.

Today, of course; few seldom consider the power of electrons at their fingertips via their phones and personal computers.

Old_Joe

I've found the subject of ultra-high voltage power transmission lines to be very interesting. In the early days, as Catch22 mentions, the DC voltages involved were quite low, so to increase the deliverable power the transmission lines had to be extremely thick, expensive, and heavy. Because AC voltage can be easily increased or decreased by transformers, it became the transmission method of choice.

To greatly simplify, the effective power that can be delivered through a circuit is the product of the voltage x the amperage (current). So to deliver more power through the same set of transmission lines the voltage can be increased. If a resistive load such as an electric heater needs 1000 watts of power, that can be delivered by supplying 100 volts at 10 amps, or alternatively by 200 volts at 5 amps, etc. The 200 volt supply would be preferable from the standpoint of power transmission, as the power lines need only be 1/2 as thick, saving copper, weight, and therefore expense.

However, as AC voltage is increased to extremely high values, other complex issues come into play, causing significant losses in power transmission. Because of advances in electronic switching apparatus, it is now also possible to transmit extremely high DC voltages.

The voltage generated is still actually AC, and transformers are used to increase that voltage to extremely high values. That high voltage is then converted to DC, and sent over typically long transmission lines. At the receiving end, the DC is reconverted to AC for local distribution. The terminal equipment for the DC lines is expensive, but the transmission lines are much thinner, and the transmission losses are much smaller.

As Davfor's post illustrates, this transmission mode is especially useful for long underwater transmission lines.

If interested, good information on all of this is available at Wickipedia.

davfor

Thanks to all for the discussion about HVDC transmission.

The first major HVDC transmission line in the US has been sending renewable hydropower from Bonneville Dam to the Los Angeles area via an 846-mile long overhead line for about 50 years.



https://new.abb.com/news/detail/45972/abb-completes-upgrade-of-first-major-hvdc-link-in-us-transmission-history

Mark

Thanks OJ for all the color added.

Rbrt

This is good stuff! Thanks to all. Although not directly related, I am linking an article about “green hydrogen” electricity generation. The idea is that excess solar power would be used to create hydrogen, through electrolysis, and then that hydrogen could power a gas turbine or fuel cell to generate electricity when the sun isn’t shining.

BofA on Green Hydrogen

Wikipedia description

Old_Joe

Yes, it's going to take a while but eventually all of this stuff is going to come together and it's going to be a whole new world as far as energy use is concerned.

DrVenture

Yeah, great thread. Very informative. And in addition to "green hydrogen", battery storage solutions have been improving at a breakneck pace, mostly due to research and engineering into EVs. Merely 10 years ago a tiny subcompact like the Nissan Leaf had only a 72 mile range. Today 250 to over 300 miles of range is becoming the norm. The 2020 Tesla Model S is rated at over 400 miles. Illustrating how far battery tech has evolved in only a decade.

I must admit, I always thought of solar as a "local" power solution. If this is a feasible option, it seems like a real game changer. Imagine a continent like Africa, with all it's economic hurdles, becoming a vast exporter of energy to far-flung locations.