ABB engineers test high-voltage direct current at a company test site. The automation company has designed the first circuit breaker for HVDC, paving the way for uninterrupted power flow over longer distances. (Source: ABB)
The new high voltage circuit breaker is indeed be a valuable and needed element in the DC distribution network, but there are other considerations. DC does indeed provide a mode that does not suffer from all of those capacitive and inductive losses, which does allow for much closer conductor spacing. But that is only half of the picture.
High voltage transport over relatively longer distances needs to use as high a voltage as possible in order to minimize the current relative to the transmitted power. That part is obvious and beyond argument. The downside is that at the user end of the transmission we need a much lower voltage, after all, even 16kV requires a lot of extra effort in order to distribute and control it. For AC power, transformers have been doing a very good job for many years, and getting better all the time. But the details of converting 30kV DC down to something to run our lights and laptops is a bit more complex. Even taking it down to 480 volts, 3 phases, is a task that is quite challenging. Therein lies the very bigg problem, which is mostly the step down for distribution process. The hardware to do the stepdown is presently far more complex than a large transformer, and quite a bit more expensive, as well. That has been, and probably still remains as, the chief obstacle in the path of HVDC power transport. Even more daunting is the fact that the conversion system will need to be more efficient, end to end, than the present transformer technology.
Unfortunately there don't seem to be a lot of sources for this hardware, not because it is not needed, but because it is just plain a hard thing to do. So while the circuit breaker is a needed element in the system, it is not the maajor part of the solution. So the real game changer will be the 98% efficient step-down inverter.
This is a great achievement and can offer large energy savings in the transportation of power from renewable energy sources. In the infancy of energy distribution, controlling the power was everything, because some people realized there was huge money to be made by a giant grid of power, keeping everyone reliant on the utility for power and enslaved to a utility bill. DC did not work for this model, because of the long distance transmission problem. While this is very exiting, in order to be really energy independant and efficient, we need to concentrate on making more DC power devices for our homes to couple with the renewable power generators at hand, focusing on more of localized energy creation than trying to fix the flawed and antiquated power grid we have now in this country. The grid makes us vulnerable to terrorist attacks and widespread outages that we can not control, not to mention keeping us enslaved to a utility bill and power generaration from sources we can not control. This invention will certainly save a lot of power and increase the financial feasablility of renewable energy sources.
Wow, this is fantastic, and an incredible breakthrough. The applications are self-evident. What's not so obvious is why ABB managed to achieve this, and how. Elizabeth, what did they say about the technology that made this possible?
It is exciting, but it is also historically interesting. The first electric generation and distribution systems were DC. These were developed by Thomas A. Edison. They were considered inefficient compared to Nikola Tesla's AC system, specifically for long distance transmission. To be able to transmit over long distances you need to operate at high voltages (otherwise the wire required is too large). On the other hand, most of the applications we have are DC. We then use transformers to get DC to power, for example, the laptop I am using right now.
The other issue is still storage. I don't think that DC helps there.
This is the kind of technology that really excites me in terms of making renewable energy more viable for large-scale deployment, and helping people become less dependent on the traditional grid. It also shows companies really thinking about the problem and trying to solve barriers that have existed to this type of energy for years. That is really forward-thinking, and that is good news for energy production.