Spectrum: China’s Ambitious Plan to Build the World’s Biggest Supergrid

Wind rips across an isolated utility station in northwestern China’s desolate Gansu Corridor. More than 2,000 years ago, Silk Road traders from Central Asia and Europe crossed this arid, narrow plain, threading between forbidding mountains to the south and the Gobi Desert to the north, bearing precious cargo bound for Imperial Beijing. Today the corridor carries a distinctly modern commodity: gigawatts of electricity destined for the megacities of eastern China. One waypoint on that journey is this ultrahigh-voltage converter station outside the city of Jiuquan, in Gansu province.

Electricity from the region’s wind turbines, solar farms, and coal-fired power plants arrives at the station as alternating current. Two dozen 500-metric-ton transformers feed the AC into a cavernous hall, where AC-DC converter circuits hang from the 28-meter-high ceiling, emitting a penetrating, incessant buzz. Within each circuit, solid-state switches known as thyristors chew up the AC and spit it out as DC flowing at 800 kilovolts.

From here, the transmission line traverses three more provinces before terminating at a sister station in Hunan province, more than 2,300 kilometers away. There, the DC is converted back to AC, to be fed onto the regional power grid. The sheer scale of the new line and the advanced grid technology that’s been developed to support it dwarf anything going on in pretty much any other country. And yet, here in China, it’s just one of 22 such ultrahigh-voltage megaprojects that grid operators have built over the past decade.

The result is an emerging nationwide supergrid that will rectify the huge geographic mismatch between where China produces its cleanest power — in the north and west — and where power is consumed in the densely populated east. Moving energy via this supergrid will be crucial to maximizing China’s use of renewable energy and slashing reliance on coal.

Read on at IEEE Spectrum

China Crushes Transmission Records

China’s primary grid operator has energized its biggest and most powerful line yet, a 1.1-million-volt direct current (DC) behemoth that crushes world records for voltage, distance and power. The new ultra-high voltage DC (UHVDC) line built by Beijing-based State Grid Corporation of China can move enough power for 50 million Chinese households, according to a statement issued in Chinese by State Grid last week — 50 percent more than the 800-kilovolt UHVDC lines that State Grid has built over the past decade.

The new 1100-kv UHVDC line absorbs the grid’s alternating current at an AC/DC converter station near the capitol of Xinjiang—China’s vast northwestern territory—and sends DC power to a second converter station in Anhui province in eastern China. That 3,293 kilometer run extends power transmission’s distance record by over 900 kms.

State Grid dubs it the “Power Silk Road” in its statement because it follows the eponymous ancient route’s path through northwest China’s Hexi Corridor and can replace the equivalent of 25,000 coal trains’ worth of coal-fired generation in China’s heavily polluted eastern cities. In addition to battling air pollution, it could also deliver a hefty reduction in greenhouse gas emissions if State Grid prioritizes export of the northwest’s abundant solar and wind power. Continue reading “China Crushes Transmission Records”

Making Power Grids 100 Percent Renewable

nsc_20180609-152x200Just a few  decades ago many experts fretted that variable power from wind turbines and solar panels would destabilize power grids. Today they’re debating the feasibility of 100 percent renewable power, which appears to be the most likely route to decarbonized energy systems by mid-century and thus our best shot at avoiding truly extreme climate change. Two of my recent feature articles explore what running grids on 100 percent renewable energy will take. My June cover story for NewScientist assesses the big picture, identifying the changes required in consumer behavior and power supplies and the technologies available to deliver them. My feature for Scientific American, meanwhile, takes a deeper dive into power grids, and how weather smarts must be built in to make the most of weather-driven “fuel” such as winds and sunlight. Both articles are behind paywalls online. One more reason to consider subscribing to two of the world’s top science magazines!

Grid Tech Sparks Wildfires

Wind-swept fires that killed more than 40 people in California have jolted the state’s biggest utilities, Pacific Gas & Electric (PG&E) and Southern California Edison (SCE). State regulators and trial lawyers are probing the utilities’ tree trimming and line maintenance — common culprits in prior California fires. But they also examining a utility device that produces sparks by design: automatic circuit reclosers.

Continue reading “Grid Tech Sparks Wildfires”

Power Vaults a Contentious Border

Relations between the United States and Mexico are strained as President Donald Trump pushes his promised border control wall and demands a U.S.-favored rewrite of the North American Free Trade Agreement (NAFTA). But Mexico and the southwestern states that border it continue building an international agenda for electricity. The region’s power players plan to complete a first set of projects before Trump’s term is up that will make the border far more electrically-porous.

Continue reading “Power Vaults a Contentious Border”

Can Reprogrammed Renewables Stabilize Grids?

As renewable power displaces more coal, gas, and nuclear generation, electricity grids are losing the conventional power plants whose rotating masses have traditionally helped smooth over glitches in grid voltage and frequency. One solution is to keep old generators spinning in sync with the grid, even as the steam and gas turbines that once drove them are mothballed. Another emerging option will get a hearing next week at the 15th International Workshop on Large-Scale Integration of Wind Power in Vienna: creating “synthetic inertia” by reprogramming wind and solar equipment to emulate the behavior of their fossil-fired predecessors.

Continue reading “Can Reprogrammed Renewables Stabilize Grids?”

Does Electrification Really Cause Economic Growth?

Electrification is credited with delivering a seemingly endless list of social and economic goods. Nations that use more power tend to have increased income levels and educational attainment and lower risk of infant mortality, to name but a few. So I was baffled to stumble across a pair of economic analyses on electrification in India and Kenya, posted last month, that cast serious doubt on what has long assumed to be a causal link between the glow of electricity and rural development. “It is difficult to find evidence in the data that electrification is dramatically transforming rural India,” concludes Fiona Burlig, a fourth-year UC Berkeley doctoral student in agricultural and resource economics who coauthored the India study. “In the medium term, rural electrification just doesn’t appear to be a silver bullet for development.” Continue reading “Does Electrification Really Cause Economic Growth?”