04 February 2008

Dull Revolutions: HVDC Power Transmission

High voltage DC (HVDC)transmission of electricity has been around since the 1950s. Pioneered by the Swedes, the Swiss, and the Germans, HVDC is more common in Europe than North America. But given the huge advantages of HVDC over HVAC power transmission, expect to see a lot more HVDC projects in this part of the world.

Sea Breeze Power Corp is involved in a project to bring HVDC power across the San Juan de Fuca Strait. The map below shows the Siemens underground/submarine HVDC project to supply power to San Francisco.If you know anything about electricity, you know that high voltage power transmission is more efficient than lower voltage transmission. And since only AC power can be transformed from low to high voltage (for transmission) and back (for residential, commercial, and industrial use), AC has been the "power of choice" for most utilities and transmission companies. But now that power electronics technology is able to rectify and invert AC to DC and back with very high efficiency, we are able to take advantage of the many advantages of HVDC transmission (PDF).

HVDC transmission incurs less than half the I^2R transmission losses that HVAC incurs. HVDC can be more safely and reliably buried underground and laid undersea. HVDC can be used to link large HVAC grids that are not synchronous with each other. And the list goes on and on.

The addition of HT superconducting cable to HVDC would be even better, but we do not need to wait for large scale rollout of superconducting transmission cable to begin experiencing huge savings in our transmission grid. HVDC is a mature technology that can save billions of dollars for electrical utilities and grid systems.


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Blogger al fin said...

Thanks for the link, Michael. Terrawatts.com has some good pdf documents related to the blog post.

Monday, 04 February, 2008  
Blogger Fat Knowledge said...

I came across this article on HVDC a while back. Some interesting stuff in there.

I am with you, from what I read HVDC is the way to go. I think we need to upgrade the grid using this technology. What I still don't understand is why private industry was able to build the backbone for the internet, but apparently private industry isn't upgrading the power backbone in a similar fashion. I wonder what is different about the industries that leads to the different result.

Thursday, 07 February, 2008  
Blogger al fin said...

Nice article, FK, thanks.

Interconnects between asynchronous AC grids is a big use of HVDC internationally.

The infrastructure of power transmission grids is enormously expense, so rather than expecting a wholesale replacement of HVAC by HVDC, rather look to particularly high-value HVDC installations:

Interconnects in multi-grids to increase stabililty and reliability.

Underground and undersea power pipelines.

A massively interconnected HVDC grid as described in your article, would improve reliability.

But I prefer a more decentralised approach, with a few high capacity HVDC long distance pipes, a few central nodes (for nuclear power and clean coal distribution) and a lot of decentralised production and storage (like redox flow cells) for renewables.

Trying to tie everything together in one big (but redundantly reliable) bundle is too much like the over-engineered NASA approach. I like Kevin Kelly's "Out of Control" swarm self-organising approach, wherever possible.

Thursday, 07 February, 2008  

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