HVDC

There is a slogan for electric transmission that it is not about how much power you generate. It is about how much you deliver. There is a lot of truth to that. It was the innovations of electric transmission well over 100 years ago that enabled the modern electric system by bringing remote generation to the load.

Today a robust transmission grid is a prerequisite to economically and reliably balance generation and load. With more variable generation resources on the system, wind and solar, transmission is again the enabler. However, regardless how strong the rational for strengthening the transmission grid may be, the opposition against building new transmission can be equally strong or stronger. At few places it is more evident than in Germany.

Picture credit: picture.alliance/dpa/SwenPfoertner.


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In 2014 there were 3634 outages in the US electric system according to the Eaton Blackout Tracker. It affected in total over 14 million people. On average close to 4000 people were affected per outage, which on average lasted 43 minutes. 30 % of the outages were caused by weather and trees. 28 % were caused by faulty equipment and/or human error.

Almost all outages were at the distribution system level, Outages at the transmission level are very rare, but when they happen the consequences are bigger, affect more people and take longer time to restore. The Northeast Blackout in August 2003 hit 55 million people in United States and Canada. One month later the Italy Blackout had also about 55 million people in Italy, Switzerland, Austria, Slovenia and Croatia losing power. As recent as in March this year 90 % of Turkey with 70 million people lost their power. The largest blackout so far was in July 2012 affecting half of India and 620 million people. In fact the grid collapsed for a second time in two days.

2003 Northeast Blackout. Satellite pictures before and after the blackout. National Geophysical Data Center (NOAA/DMSP).

2003 Northeast Blackout. Satellite pictures before and after the blackout. National Geophysical Data Center (NOAA/DMSP).

 



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blasjo-reservoir

 

 

 

 

 

 

 

 

 

 

 

 

 

Lake Blåsjö, Norway.

 

Hydro storage is basically a renewable battery. Lake Blåsjö (“Blue Lake”) in Norway with a capacity of 7.8 terrawatthours (TWh) has become a symbol of Norway’s potential to become a “Blue Battery” for Northern Europe. To put the number in perspective 7.8 TWh would cover the electric consumption of over 750 000 residential homes. To accumulate the same amount of energy with lithium ion batteries it would take over 200 years of full production at Tesla’s planned Gigafactory.



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Sunday August 18 Germany set a new renewable record. That day at 2 pm generation from renewable energy sources provided 75 % of all power needed to satisfy the total demand of electric energy.

Less noticed was that Burlington Electric Department, Vermont, in September with the purchase of a 7.4 MW hydroelectric facility achieved its goal of reaching 100 % from renewable energy.

While Germany’s August 18 record was a peak, Burlington’s 100 % is basically on a continuous basis.

What makes Burlington Electric’s achievement additionally impressive is that retail electricity rates in Burlington are less than half of the rates in Germany, 13.7 cents/kWh (time of use rate 2014) versus 36.25 cents/kWh (average 2013).



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