A Global High Voltage DC (HVDC) Supergrid - IEEE Spectrum article

[gary]

In the August 2015 edition of the Institute of Electrical and Electronic Engineering (IEEE)
Spectrum Magazine, Clark W. Gellings, a Fellow at the Electric Power Research Institute and an
IEEE Life Fellow, describes in an article the idea of a global power grid.

As Gellings says, "With a little DC wizardry and a lot of cash, we could
swap power across continents".

Originally Posted by Clark W. Gellings, IEEE Spectrum

.. the technology now exists to transmit massive amounts of electricity over long distances without significant losses, thereby allowing operators to balance consumption and generation across an entire continent—or, potentially, the globe. If an outage occurs in one country, the sudden change in line voltage and frequency could trigger a generator thousands of kilometers away to compensate for the shortfall. Similarly, if the wind in a normally wind-dependent area dies, electricity from its neighbors could quickly fill in. Or if one region is experiencing heavy rainfall, hydroelectric dams there could capture the energy, to send elsewhere as needed. A supergrid would ensure that all or nearly all the electricity that’s generated would get consumed, thus avoiding such wasteful practices as paying wind-farm operators to curtail production or dumping energy that’s not immediately needed. (To be sure, storing excess energy would also help avoid such problems, but large-scale economical energy storage is still not widely available.)

In general, a global supergrid would allow power to be generated far from population centers. For instance, some of the world’s best sunlight can be found in the sparsely populated region south of Darwin, Australia, where it’s estimated that all of that country’s energy needs could be supplied from a solar farm the size of a cattle station. With an undersea link to Southeast Asia, that electricity could also be dispatched to countries like Indonesia, Papua New Guinea, and Singapore. And with a supergrid in place, operators could significantly scale back their spinning reserves—backup capacity that they can tap if demand spikes but in practice is rarely used.

Originally Posted by Clark W. Gellings, IEEE Spectrum

So what would it take to build a global supergrid? Technologically, it would hinge on a globe-encircling network of high-voltage direct-current (HVDC) transmission systems, most of the components of which already exist.

Originally Posted by Clark W. Gellings, IEEE Spectrum

The roots of the global supergrid stretch back to the dawn of the power industry, when the “war of the currents” raged between the era’s two great inventors: Thomas Edison and Nikola Tesla. In 1882, Edison demonstrated the first commercial electric power plant, which was based on direct current. But it was Tesla’s alternating current that would rule the day.

...

The key to AC’s triumph was that power could be transformed to higher voltages by use of magnetic induction and then sent over long distances at low currents, minimizing the losses due to resistance; at the destination, the system would reduce the voltage for local distribution. At the time, there was no way to do the same with DC. But power engineers also knew that a DC system operating at high voltage would be superior to AC for the same task, because the amount of electricity lost during DC transmission would be far less than with AC.

How much less? Let’s say you’re transmitting a given amount of power by high-voltage DC: When you double the voltage, you need only half the current of a comparable AC system, thus reducing your line losses by a factor of four. You also need a lot less wire, because DC current penetrates the entire conductor of a power line, whereas AC current remains largely near the surface. Put another way, for the same conductor size, the effective resistance is greater with AC, and more power is lost as heat. In practice, that means the overall transmission infrastructure for AC far exceeds that for DC. To transmit 6,000 megawatts using a 765-kilovolt AC system, for instance, you’d need three separate single-circuit transmission lines, which would cut a right-of-way path about 180 meters wide. Compare that with an 800-kV DC system, which would require just one 80-meter-wide path.

Article here -
http://spectrum.ieee.org/energy/the-...bal-power-grid


In a related item, Peter Fairley wrote on 28th Aug 2015 on the IEEE Spectrum web site an article entitled "Fear of Russia Drives High-Voltage Power Projects in the Baltics".

Originally Posted by Peter Fairly, IEEE Spectrum

One of the world’s longest undersea HVDC cables and other new transmission links will end reliance on Russian energy.

Former Soviet Union satellites such as Ukraine, Georgia, and the three Baltic states—Lithuania, Latvia, and Estonia—rely heavily on Russian energy, a dependence that colors the ongoing geopolitical tussle among the Russian Federation, the European Union, and NATO. But new energy infrastructure is beginning to free the Baltics from this drama, including two high-voltage direct current links to Lithuania nearing completion: the 500-megawatt LitPol Link with Poland and the 700-MW NordBalt cable to Sweden, which is among the world’s longest subsea power links.

The links will give the Baltics the ability to get 100 percent of their imported power from non-Russian sources.

Article here -
http://spectrum.ieee.org/energy/poli...in-the-baltics

Gary Kopff
IEEE Member 37 years

[xelasnave]

Thanks Gary
I had no idea
What a task

[Shiraz (Ray)]

thanks for the heads up Gary.

Interesting that two methods for making better use of renewables seem to be either - to build a huge grid - or - concentrate on local storage in the household. Slight dichotomy there.

one also has to wonder how overjoyed the Russian will be if they lose their stranglehold on supplying energy to middle Europe....

[AussieTrooper (Ben)]

At present, the trend is away from that sort of thing. Demand from the grid is falling as more local generation is added. Capital investment is dying right off. This stuff may have good applications overseas, but I can’t see it going ahead here.