Krispy's Blog

“I have never failed”

Thomas Edison

The headlines from the Dutch Newspaper NRC Handelsblad on Thursday, April 26th 2012 read:

Global player landing in Rotterdam

We would have chosen a different headline, because the global player meant is General Electric, founded by Thomas Edison. He improved the light bulb and lay the foundation for today’s electrical distribution system. His company, GE, is an important linking pin between generating and using renewable energy. That linking pin is direct current (DC). A technology that lay at the foundation of General Electric over 150 years ago and a technology that will be used in a smart grid pilot at the municipality of Haarlemmermeer that will start soon.

War of Currents
In 1879 Thomas Edison introduced his improved version of the light bulb. He soon discovered that an electrical distribution system was needed to provide power to light bulbs. Therefore he built the world’s first electricity network with a voltage of 110 Volt. It was based on direct current (DC), which worked well with incandescent lamps, which were the principal load of the day, and with motors. Direct current systems could be directly used with storage batteries, providing valuable load-leveling and backup power during interruptions of generator operation. Direct-current generators could be easily paralleled, allowing economical operation by using smaller machines during periods of light load and improving reliability. The disadvantage of direct current at that time was that power generation needed to be close to the load, because there was no efficient low-cost technology that would allow reduction of a high transmission voltage to a low utilization voltage. To overcome this disadvantage Edison choose a distributed generation system.

The alternating current system (AC) had first developed in Europe. In North America one of the believers in the new technology was George Westinghouse, one of the opponents of Edison. Westinghouse was willing to invest in the technology and hired, amongst others, Nikola Tesla to study the design of Edison and further develop the alternating current system. After vigorous campaigns by both Edison and Tesla to demonstrate the danger of using the opponents system alternating current became the dominant standard, both in Europe and the USA.

The use of alternating current gave the opportunity to increase the distance between power stations and loads. Alternating current set the stage for large scale, centralized power generation.

The silent revolution towards DC
The alternating current network dates from a time that load consisted of lamps, heaters and electric motors, but the development of technology hasn’t come to a standstill since setting the standard to AC. Direct current has been returning nearby in three different forms: electronic devices, sustainable energy and energy storage.

The invention of the “transistor” in the year 1947 forms the starting point of the silent revolution towards direct current. Transistors form the fundamental building block for the development of complex electronic equipment. Currently almost all current electronic equipment and electrical devices use DC internally. Alternating current from the grid is converted to direct current using a AC/DC transformer for internal use in electronic equipment like mobile phones, computers and led-lights.

The last decades see a shift towards sustainable energy within the European Union. The share of power generated by wind, water, solar and co-generation is rising, especially in Germany with it’s feed-in system. All those forms of sustainable energy generate direct current which has to be transformed to alternating current to feed it back in to the grid. To be able to integrate offshore wind farms the Dutch grid operator Tennet, which owns part of the German grid, wants to construct a DC network. High Voltage Direct Current is already used for bulk transmission of energy from distant generating stations or for interconnection of separate alternating-current systems.

Sustainable power generation will be rising in the Netherlands too. For example solar power is expected to grow rapidly in The Netherlands, as grid parity for consumers and small business is (almost) reached at current retail electricity prices. Some municipalities and local energy cooperatives are already pioneering with large scale solar energy systems, where people without a suitable rooftop crowd-fund the needed investment. In return they receive the electricity generated instead of a financial return.

After sustainable energy has been transformed to alternating current for transport over the grid it has to be converted back to direct current again to be used by our electronic devices and led-bulbs or to be stored in (car) batteries. That doesn’t sound very efficient does it?

This does bring us to the third form of DC we encounter close by: batteries. With the coming age of the electric car and all the fuzz about ‘range anxiety’ it might be good to know a Dutch company exists that can deliver a range of up ot 300 kilometers using a DC powertrain and replacing the AC/DC transformer with extra batteries.

Rotterdam or GE can be the connection

In the municipality of Haarlemmermeer Direct Current BV, Stichting Gelijkspanning (the direct current foundation) and their partners are working on a smart grid based on direct current. The pilot has received subsidy from the Ministry of Economic Affairs, Agriculture & Innovation. This regional grid will be operating on voltages in excess of 300 Volt. The smart grid based on direct current will link sustainable power generation with users of the electricity, for example charge stations for electric cars.

Direct current could also be used to provide shore supply of electricity to ships in the Rotterdam harbour significantly improving air quality in the Rotterdam area. If Haarlemmermeer deems to far for Rotterdam perhaps a GE executive is landing at Schiphol Airport to visit the Rotterdam plant can drop by and learn more about what Stichting Gelijkspanning, Direct Current and their partners are up to with DC, the technology used by it’s founding father Thomas Edison. That would return GE to its roots and help bridge the gap between sustainable power generation, power storage and the sustainable use of electricity. It could also make the war on currents lost by GE a lost battle.

As they say in Rotterdam:

Not words but deeds!

This contribution was originally written for and published at TEDxBinnenhof in close collaboration with Bob Zijderveld, independent Consultant DC, Conventions and member of the board at Stichting Gelijkspanning.