Matthew L. Wald

The New York Times News Service Published on Wednesday, Mar. 17, 2010 7:11AM EDT Last updated on Wednesday, Mar. 17, 2010 10:52AM EDT

Generating 20 per cent of America’s electricity with wind, as recent studies proposed, would require building up to 22,000 miles of new high-voltage transmission lines. But the huge towers and unsightly tree-cutting that these projects require have provoked intense public opposition.

Recently, though, some companies are finding a remarkably simple answer to that political problem. They are putting power lines under water, in a string of projects that has so far provoked only token opposition from environmentalists and virtually no reaction from the larger public.

“The fish don’t vote,” said Edward M. Stern, president of PowerBridge, a company that built a 65-mile offshore cable from New Jersey to Long Island and is working on two more.

The projects have even drawn cautious enthusiasm from some environmental groups, who say the new power lines serve their goal of getting the United States to use more renewable power.

…

Nearly all the submarine cables use direct current, a form of transmission favored by Thomas Edison but mostly rejected in the late 1800s in favor of alternating current, the kind of electricity now used to run most appliances. But alternating-current lines are hard to bury, because an interaction between the current and the cable casing drives up voltage to unwanted levels.

Direct-current transmission is also undergoing a modest revival on land, because over long distances, its line losses are smaller, and flows are easier to control. Two recent proposals for a centrally planned overhaul of the North American electric grid called for heavy use of direct current.

New technology offered by two European companies, Siemens and ABB, has lowered the cost for some direct current projects, and shrunk the size of the terminals where alternating current is converted to direct current and back, a crucial consideration in urban projects.

Developers and power companies are recognizing that the expense of underwater lines may be worth it if it helps them overcome political opposition.

physburn writes “Somewhere in a triangle between Roswell (UFO) NM, Albuquerque (Left Turn) NM, and Amarillo (Do you know the way?) TX, a 22.5 square mile triangle of High Temperature Superconductor pipeline is to be built. Each leg of the triangle can carry 5GW of electricity. The purpose to load-balance and sell electricity between America’s three power grids. Previously the Eastern Grid, Western Grid and Texan Grid have been separate, preventing cheap electricity being sold from one end of America to the other. The Tres Amiga Superstation, as it is to be called, will finally connect the three grids. The superstation is also designed to link renewable solar and wind power in the grids, and is to use HTS wire from American Superconductor. Some 23 years after its invention, today HTS comes of age. “

Apr 30th 2009 | CHICAGO
From The Economist print edition
Creating windpower transmission in the Midwest

FRANKLIN ROOSEVELT helped bring electricity beyond America’s cities to its most distant farms. Barack Obama hopes the countryside will return the favour. Much of this challenge rests in the gusty upper Midwest. In recent years Interstates 29 and 80, highways of America’s heartland, have teemed with lorries bringing wind blades to new plants. Efforts to build transmission have moved more slowly. There are 300,000 megawatts of proposed wind projects waiting to connect to the electricity grid, says the American Wind Energy Association. Of these, 70,000 megawatts are in the upper Midwest.

Now action is at last replacing talk. Firms are proposing ambitious transmission lines across the plains. The region’s governors and regulators are mulling ways to help them. The federal government is playing its part. In February the stimulus package allotted $11 billion to modernise the grid. Since then members of Congress have proposed an array of bills to develop transmission. Jeff Bingaman, chairman of the Senate energy committee, intends to start marking up transmission plans next week—though debate over other parts of the energy bill may delay progress.

America’s grid is complex: 3,000 utilities, 500 transmission owners and 164,000 miles (264,000km) of high-voltage transmission lines are stretched across three “interconnections” in the east, west and Texas. If wind is to generate 20% of electricity by 2030, as in one scenario from the Department of Energy, about $60 billion must be spent on new transmission. Just as important, regulations must change.

Planning for “peak load” is a transmission lie. Utilities have incentive to overstate “need” when they build for peaks. The higher the peak they build for (with peak occurring only several times annually), the deeper the off-peak valley and the more electricity they can sell on the market when generation is available but not “needed.” Conservation and peak-shaving is against their interest because it lowers peak and lessens the valley of market sales.

“It’s for renewable generation” is a lie. The massive transmission infrastructure expansion proposed is not “for renewables” because transmission may not discriminate by generation type. Federal regulations prohibit discrimination among generators — it’s first come, first ready, first served. There are tens of thousands of megawatts of coal projects, with transmission studies complete or in progress, waiting for interconnection, and whatever generation is ready will be connected. Another side of this lie is when wind advocates support transmission, claiming “it’s for renewables,” and ignore the impacts of transmission on the communities it traverses. Rather than make this convoluted “it’s for renewables” claim, there’s a better way: if renewable energy mandates were directly linked with shut down of fossil generation, and if renewable generators were thoughtfully sited, both the electricity market and transmission infrastructure would be open and available.

“Long distance transmission” is a lie. Transmission is inherently inefficient over long distances. Transmission physics entails high levels of line loss, and the longer the line, the higher the line loss. To avoid this fact of physics, the electric industry has shifted its line loss analysis for new projects to a “system wide” loss, so the numbers look low. But consider actual numbers of megawatts of line loss, and look at “coal plant equivalents” to make up that loss — for every 500-600 MW of line loss, a coal plant or more would have to be built! Line losses are charged in Federal Energy Regulatory Commission rates, but this is not considered directly in the market transactions. Line loss is an afterthought add-on to the customer’s bill after transmission service is provided. Consider too the capital cost of transmission, starting at about $1.5 million per mile for 345kV lines and upward from there

Without a radically expanded and smarter electrical grid, wind and solar will remain niche power sources.

By David Talbot

“Push through a bulletproof revolving door in a nondescript building in a dreary patch of the former East Berlin and you enter the control center for Vattenfall Europe Transmission, the company that controls northeastern Germany’s electrical grid. A monitor displaying a diagram of that grid takes up most of one wall. A series of smaller screens show the real-time output of regional wind turbines and the output that had been predicted the previous day. Germany is the world’s largest user of wind energy, with enough turbines to produce 22,250 megawatts of electricity. That’s roughly the equivalent of the output from 22 coal plants–enough to meet about 6 percent of Germany’s needs. And because Vattenfall’s service area produces 41 percent of German wind energy, the control room is a critical proving ground for the grid’s ability to handle renewable power.

Like all electrical grids, the one that Vattenfall manages must continually match power production to demand from homes, offices, and factories. The challenge is to maintain a stable power supply while incorporating elec­tricity from a source as erratic as wind. If there’s too little wind-generated power, the company’s engineers might have to start up fossil-fueled power plants on short notice, an inefficient process. If there’s too much, it could overload the system, causing blackouts or forcing plants to shut down.”

Critics state that renewable energies are intermittent—the sun isn’t always shining and the winds don’t always blow—and we need reliable electricity every second. The critical infrastructure that solves this is high-voltage transmission. The interconnected grid acts as the freeway for electricity from generator to user, and it is already built throughout the developed world. Today, bulk transmission can deliver power far beyond political boundaries, with over 100 nations trading electricity for mutual benefit. Interconnected grids enable load levelling, economic exchange of power, system reliability and emergency back-up options. Long-distance transmission allows us to tap remote renewable energy resources, sometimes located in neighbouring nations, and to feed clean electricity throughout the network.

Bigger means transcontinental, at least for people like Vinod Khosla. His analogy is America’s interstate highway system, built after the second world war. The new grids would use direct, rather than alternating, current. AC was adopted as standard over a century ago, when the electrical world was rather different. But DC is better suited to transporting power over long distances. Less power is lost, even on land. And DC cables can also be laid on the seabed (the presence of all that water would dissipate an AC current very quickly). In the right geographical circumstances that eliminates both the difficulty of obtaining wayleaves to cross private land and the not-in-my-backyard objections that power lines are ugly. Indeed, there is already a plan to use underwater cables to ship wind power from Maine to Boston in this way.