ABB and Siemens Power Ahead in Smart Grid Technology
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The debate over which electric transmission technology to use -- either AC (alternating current) or DC (direct current) -- goes back to the time of Thomas Edison, a proponent of DC.
AC seemed to have won the debate since it is the method that is widely used to bring power into our homes and businesses. But surprisingly, the debate is not settled. In a smart grid world, DC is making a comeback.
The latest DC technology, high voltage direct current (HVDC), has been called the backbone of plans for smart grids or supergrids.
This technology allows the transmitting of electricity at higher voltages and over longer distances with minimal power loss when compared to current transmission technology.
Transmission losses and other inefficiencies due to the use of AC power is of some consequence in the developed world since semiconductors need DC power. Just think about all the electronics and appliances in homes that have semiconductors in them. These devices have to convert AC power into DC power, generating heat and wasting energy.
In the emerging world, it is of even greater importance. Rapid economic growth has given rise to surging demand for electricity. However, many end users are far away from the actual power sources making power losses incurred over transmission lines a vital issue.
Therefore, HVDC has become a growth industry. Both Siemens and ABB estimate that HVDC will be a $10 billion business in the next five years.
The companies forecast installation of new HVDC transmission lines by 2020 with a total capacity of 250 gigawatts. This is a dramatic increase since in the last 40 years there has been just 100 gigawatts worth of HVDC transmission lines installed.
One factor holding back this technology to date is the fact that such systems have lacked flexibility, allowing only one power source and end user. The users of such systems, electric utilities, would like to make multiple connections to these power lines allowing them to switch on or off individual sections of the line. This a must for power grids in the developed countries.
But there is a problem. Companies like ABB and Siemens have yet to develop effective circuit breakers to handle the DC voltages involved. The difficulty is that the technology involves more than simply breaking a physical connection between two pieces of metal, as with AC switch technology.
Instead, researchers at the companies are trying to adapt the advanced semiconductors used by both firms in the 'converter stations' of their HVDC lines, where AC and DC power are converted back and forth. At the moment, no breakthrough seems imminent, but is inevitable.
In the years ahead, as energy research firm Pike Research said, “the role of DC will increase, and AC will decrease.”
This makes sense if only from the standpoint that power generated from renewable sources such as wind and solar produce DC power. And DC power transmission lines to get this power to end users is certain to increase.
HVDC and the companies leading the way in this technology will definitely be worth watching for those investors interested in the smart grid technology space.
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