Primetime Debate: Will an Ultra-High Voltage Transmission Supergrid Solve China's Air Pollution Crisis?
- Apr 23, 2014 7:00 pm GMTJul 7, 2018 8:40 pm GMT
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CCTV-2, the Chinese state-run “finance” channel (that’s only sometimes focused on finance), aired an interesting hour-long debate recently on the future of electricity transmission in China. It’s hard to imagine primetime coverage of electricity transmission policy here in the U.S., and the stark contrast with Chinese television’s serious treatment of these issues demonstrates how public concerns over air pollution and renewable energy are being injected into a nearly decade-old discussion on the relationship between the grid and the state. (More background here in a commentary I authored on the institutional bottlenecks to addressing renewable integration through transmission [pdf]).
Notable organizations in attendance included Heilongjiang Grid (one of the hot spots of wind curtailment), several State Grid reps, renewable energy companies (Mingyang, Yingli, Hareon), and a video message from big AC detractor Meng Dingzhong.
Most stakeholders agree that long-distance and higher capacity transmission is necessary for sustained electricity growth. China’s energy resources are widely geographically distributed, often far from load centers. Concerns over air pollution, railway congestion from coal shipments, and providing adequate supply to support electricity demand growth of over 10% annually shift central planners’ gaze to the less developed central, north and western regions as growing electricity production centers.
As early as 2004, State Grid advocated a large, interconnected ultra-high voltage (UHV) 1000 kV AC grid that would criss-cross the country to connect centers of electricity production to demand centers in the east. There was opposition to this vision, however, as some engineers claimed that UHV-AC was too expensive (possibly more expensive than shipping coal by rail to power plants closer to eastern cities) and still technically unproven. (Here’s a longer Chinese piece on this debate.)
A nation-spanning UHV-AC grid also raises the risk of a large-scale blackout. While DC interconnects are asynchronous, AC systems must be fully synchronized, and the wider the area covered by the interconnected AC grid, the higher the risk for cascading failures (to illustrate this point, the studio even turned off the lights for a few minutes as panelists talked about what an electricity outage feels like). Distributed generation was raised as a potential option to keep the lights on, but it still took a back seat to the broader push to build a large-scale, interconnected and centralized power system for China.
Unrelated to technology, another latent concern was the natural concentration of operation that comes from a synchronous grid. Currently, six regional grids and the provinces below them have considerable autonomy in dispatch and planning, which creates more opportunities for local influence on grid operation (though, under this system transmission projects may be underutilized). While a synchronized UHV-AC grid could lead to more centralized control of the national power system, an asynchronous UHV-DC grid need not disturb the current setup significantly and is seen as a hedge against greater monopolization.
Like most other energy programs in China these days, the motivation behind plans for a long-distance UHV grid (whether AC or DC) is framed as the overriding public concern over intense air pollution in China’s large eastern cities. UHV transmission is promoted as a key lever to address this, by (1) allowing larger amounts of renewable energy to get on the grid and (2) slow down or reverse coal plant builds in eastern cities. The CCTV program ran a long opening sequence (with a background score more reminiscent of Jerry Bruckheimer than 60 minutes) profiling the pressing challenge of curtailed wind, and even the possibility for curtailed solar, which is partially related to transmission bottlenecks.
Integrating renewables through transmission effectively requires some changes in grid operation, to address the dispatch issues above, but also more importantly to ensure that the lines are not being built primarily to transmit coal-fired electricity from a growing number of “mine-mouth” plants.
More familiar to a Western audience might be delays in the approval of new transmission lines and the vexing issue of transmission siting. One complaint targeted China’s central policy planner, the NDRC, for failing to approve all of State Grid’s plans. On the other side, a rep from the major transmission component manufacturer Nanrui pointed to rising land costs and right-of-way as key roadblocks on the UHV “super-highway.” NIMBYism, as anywhere, leads to delays in China – even as panelists talked about the “greater social good” of these large projects.
Today, China’s power system is moving toward greater consolidation (horizontal and vertical) and centralization. And these goals are increasingly being reformulated in terms of addressing concerns over air pollution. Most recently, last year’s air pollution plan called for special “air pollution control transmission corridors”: 12 west-east lines that can reduce coal-fired electricity production in the eastern population centers. “Air pollution control” lines in the south primarily connect hydro, while northern lines are frequently referred to as “wind-coal bundling” as they originate in areas of rapid development of both energy sources.
Shifting electricity production to the other end of the line would certainly reduce pollution in major cities, but the percentage of utilization of those lines by clean sources matters for environmental impacts in western cities as well as for CO2 emissions, as was raised in the debate. The growing number of coal caps in Chinese provinces could address this leakage issue, but these are undercut by increases in emissions-intensive coal-to-gas projects and the lack of stringent control measures in some of the large coal provinces like Inner Mongolia. Going forward, the benefits of future transmission plans in China will likely stay in the spotlight as a means of addressing pollution, but as usual with China’s energy policies the devil is in the details.