Breakthrough

By Helen Aki, Breakthrough Generation Fellow

Once upon a time in New York, Thomas Edison created an electrical system run on direct current. This early form of electricity captured the interest of the Northeast, but was more of a scientific curiosity than a utility: Edison's direct current lines were the only known way to make a light bulb glow, but they provided barely enough energy to illuminate a room.

Enter Nikola Tesla, with a better idea...


In 1884, Tesla arrived at Edison's lab in New Jersey with an alternative: alternating current. Highly critical of Edison's system, Tesla proposed that a current that flowed in multiple waves, changing direction, could be much more powerful and efficient. Over the next four years, he developed a system of generators, motors and transformers. George Westinghouse, struck with the vision of supplying America with useful, everyday electricity, purchased the patents from Tesla.

This enraged Edison, who was not about to sacrifice years of hard work to the (superior) idea of his own employee. But, Tesla possessed a higher understanding of mathematics and physics, the comprehension of which was necessary to advance the ideas of AC current. Edison had arrived at his idea through brute experimentation (having discovered 999 ways how not to make a lightbulb). Despite a hefty campaign to discourage the use of AC transmission, Edison lost the "war of the currents," and Tesla's invention is still used to connect energy sources and power our homes. (The Tesla Coil, above, is still used in modern electronic applications.)

Today, we face a pivotal energy challenge. As we increasingly recognize the need to divorce ourselves from fossil fuels, we turn to alternative sources of energy. Most of these alternatives are most easily expressed in the form of electricity, but they are also largely decentralized (the best examples being solar and wind farms). In order to make the transition to clean electricity, we need massive deployment of improved electrical transmission lines and grid technology. We have much of the technology we need to begin plugging America in to clean electricity solutions. High Voltage Direct Current (HVDC) transmission lines will play a key role in distributing clean electricity. Edison may finally get his victory!

The easiest way to move usable energy from one place to another is in the form of electricity. Electrical power is defined in terms of two components: electric potential, or voltage; and current, or amperage. High voltage transmission lines are used to transport large amounts of energy over long distances, since high power is necessary to overcome the resistance of conductors to electrical flow. Today, both AC and DC technologies are used to transport electricity, though AC is the most common.

AC won the "war of the currents" because of how easily its power can be adapted: AC transmissions can be easily converted to a lower voltage, adapted from a long-distance power line to city power lines to a standard 110V household outlet. This was very useful in 19th century New York, where greater voltage was necessary for electricity to become commonly useful. But when it comes to connecting and conveying erratic or disparate sources of electricity, such as wind turbines, AC lines have a fatal flaw: they can only connect to lines which oscillate at the same frequency and in phase. The standard oscillation in the U.S. is 60 cycles/sec (60 Hz). (It's 50 Hz in Europe, which is why you need to purchase an adapter to use your hairdryer overseas!)

This works fine if you have a continuous source of electricity. But if you want to network a wind farm with dozens or hundreds of turbines, AC's need for consistency renders it ineffective. AC transmissions also tend to lose energy when conveyed over long distances.

DC technologies, which do not oscillate but flow continuously in the same direction, have improved since Edison's unsuccessful experiment. HVDC transmission lines, invented in the 1930s, are much more effective at carrying electrical current with minimal losses over long distances.

Recent advances in HVDC technology have inspired speculation about solar farms in the Sahara, which could provide electricity to all of Europe. The EU is currently working on a scheme to pool electricity resources throughout Europe via a massive supergrid, which will cost an estimated 45 billion euros ($71 billion) by 2050.

In a recent article for the Guardian, Alok Jha reports that

He [Arnulf Jaeger-Walden for the European commission's Institute for Energy] said that the proposed grid was a way to balance out the intermittencies of renewable energy: "If you can connect the grid to hydro power, you've got that as a backup battery, and in addition there's wind. It's not a single source that's providing the energy but a combination of the different renewable energies."

A supergrid for connecting decentralized, low-intensity, renewable power sources is absolutely essential for scaling up regional energy sources, such as solar, wind and hydropower. The great thing about solar power is that it is most intense and abundant during hours of peak demand (between 11am and 1pm), but hydropower and wind can serve as backups when the sun goes down. Improved electrical grid connectivity means that every home can benefit from a plethora of electricity options, even if they lack proximity to them.

The EU supergrid vision stems from a recognition that large-scale transformations of the energy system don't emerge spontaneously, or at the behest of a few motivated individuals--instead, collaboration, communication and central investment is necessary to build the foundation for a switch to clean energy.

Writes Jha:

The vision for the renewable energy grid comes as the European Commission's Joint Research Centre (JRC) published its strategic energy technology plan, highlighting solar PV as one of eight technologies that need to be championed for the short to medium term future.

"It recognises something extraordinary - if we don't put together resources and findings across Europe and we let go the several sectors of energy, we will never reach these targets. We need a coordination of research applied to different fields," said Giovanni de Santi, director of the JRC, also speaking in Barcelona.

Though expensive and labor-intensive, the EU-North Africa solar connection could eventually generate 100 GW, more than all the electricity produced in the UK.

The vastness of America holds within it the potential for many different clean sources of electricity. If we invest in creating a HVDC supergrid, we can connect everyone in America to these resources: solar from the Mojave desert, wind turbine power from Texas, geothermal from the West. Let's take the initiative to make America connected, clean and electric!