中国的三峡大坝

中国的空气污染问题（尤其是冬季）众所周知。2013年1月北京严重的雾霾令“空气末日”一词变得流行。不过，最近的测量结果显示2017年情况有所改善，目标地区的污染指数更低，红色预警天数也有所减少。科学家还需要时间来区分有多少改善是因为排放减少，有多少是因为有利的气象条件。不过，政府升级的举措无疑已经减少了污染。

然而进一步改善空气质量将更具有挑战性。更大范围的改善将因机构、经济和政治的约束而减缓。随着治理从单纯的技术解决方案向改革能源领域和调整经济结构的长期战略转型（这些战略对治理、商业和政策都有重要影响），这些阻碍变得更加棘手。事实上，中国三大城市区域近期备受关注的改善空气质量计划之所以在这些地区产生效果，部分是通过将重工业转移到了中国其他地区。不出所料，目标区域之外的空气质量没有取得类似改善，因此从全国来看这些计划的成效并不完整。

除了空气质量挑战外，政府还承诺了温室气体减排，在电力行业引入全国性的二氧化碳排放交易系统（ETS），目前计划在2020年启动。发电去碳意味着从煤炭向可再生能源、核电和天然气的转型。这种转型将减少二氧化硫、氮氧化物，以及导致恶劣空气质量的颗粒物的排放。

在落实ETS等严峻政策任务时，还有另一大任务：电力行业改革。这和改革执行得好或帮助改善，执行不当则可能阻碍改善。在一个长期以来被规划当局紧密控制的行业，2015年“第9号公告”所启动的改革原则上可使市场导向的污染减排更加有效。改革庞大的电力系统——目前占中国煤炭使用量的45%——是政府面临的最复杂任务之一。虽然电力行业的污染排放控制比其他燃煤行业要严格得多，但考虑到其庞大规模，电力行业仍是空气污染的主要来源。

电力部一致控制着电力系统，直到1996年转型为国家电力公司。私人发电厂被允许帮助缓解当时常见的电力短缺问题。2002年，发电资产被分割成五大国有企业，并成立了国家电网和南方电网来管理能源传输。在这段时间，短缺被产能过剩所取代，一个按计划分配发电时间的系统应运而生，以确保将总需求“公平”分配给各发电厂。因此，一个不优先考虑效率或成本的调度系统被创设出来。而在一个更加合理的市场导向的系统内，最低效（通常也是最脏的）电厂将会被最后调度。2007年以来，引入更环保系统的种种努力（如“节能发电调度办法”）均成果有限，“公平调度”系统仍基本得到延续。

中国已加大力度开发可再生电力。如今中国在风力、太阳能和水力发电能力方面都居世界领先地位。不过，可再生电力仍必须在“公平调度”系统内运行，在该系统中燃煤发电厂尽管边际成本更高，但却依然保有其集中规划的发电小时份额。并且，对地方政府来说国有燃煤发电厂也是就业和收入的重要来源，这导致省政府倾向于保护它们的市场份额并抵制来自其他省份的可再生电力。这些因素连同其他原因导致了清洁和廉价电力的大量浪费，例如2016年上半年风电发电量就被削减了21%。甚至连水力发电也被减少了，因为水电地理上集中在西南，远离负荷中心。

这些显而易见的低效问题正是“第9号公告”改革的目标之一。改革计划包括建立现货市场和电力交易中心，并允许零售竞争。电力现货市场是一个短时间段的市场（如一小时），发电厂提交具体说明价格和发电量的报价，然后交易中心经理找到能满足该时间段需求的最低价格。需求来自于企业和家庭，而它们面对的价格通常是被管制的。这种现货市场要求一个先进的交易系统和老练的市场参与者，因此在中国具有中央计划源头的行业要发展这样的市场需要很长时间。

在一个典型的现货市场，高峰时段需求会非常接近于发电能力，最高边际成本的发电厂将能卖掉其电力。在美国，最高边际成本的发电机通常是能快速关闭和启动的燃气轮机。在中国，目前燃气发电机很少，最高边际成本电厂很可能是最低效的燃煤电厂。在非高峰时段，市场系统会减少这类电厂的产量。风力和太阳能本质上是零边际成本，无论是高峰还是非高峰时段，只要能发电就会被使用。这种系统和目前的安排完全不同，在目前安排下大部分发电小时数是按照集中规划来分配。如果这种市场系统能够成功，燃煤电厂发电量将降低而可再生电力将卖得更多，其对减少空气污染和碳排放的贡献将是实质性的。

此外，如果二氧化碳配额系统（ETS）能够有效被执行，将令二氧化碳价格被计入燃煤成本，这将提高燃煤发电厂在现货市场的报价。这会进一步使低碳发电方式获得优势。

考虑到这些系统的复杂性、政治权势很大的燃煤发电厂的抵制，以及政府在2018年面临的其他经济挑战，上述两个“如果”面临着巨大的不确定性。

最后，2010年代中期对投资的放松导致燃煤发电厂严重过度建设。这种产能过剩已导致燃煤电厂利用率的大幅下跌，令它们在2017年超过一半时间内被闲置。2015年，据估计“搁浅”的煤电资产超过5000亿美元。并且，虽然燃煤电厂的建设许可被暂停了，但最近的卫星证据仍显示新增了更多的燃煤电厂，这进一步恶化了产能过剩问题。

处理搁浅资产和实施挑战既得利益的电力行业改革，很可能是能源政策制定者的头等大事，这会分散他们实施二氧化碳ETS和电力行业减排的注意力。但是，如果中国向清洁电力的重大转型想获得真正的推动力（同时也是为了令ETS的碳定价如预期那样发挥作用），那么首先要做的就是必须正确实施电力行业改革。

The Three-Gorges Dam in China (Picture Credit: Marshall Segal)

The scale of air pollution problems in China, particularly in winter, is well known. The term “airpocalypse” was popularized by the severe haze episodes in Beijing in January 2013. However, more recent measurements indicate improved conditions in 2017, with lower pollution readings in targeted regions and fewer red-alert days. It will take time for scientists to disentangle how much of the improvement is due to reduced emissions and how much to favorable meteorological conditions, but there is no doubt that stepped-up efforts by the government have reduced pollution.

Further improvement in air quality, however, will be more challenging. More extensive progress will be slowed by institutional, economic, and political constraints. These obstacles rise in importance as remediation shifts from narrow technical solutions to long-term strategies for transforming the energy sector and restructuring the economy, strategies that could have major effects on governance, business, and policy. In fact, the overwhelming focus of recent air quality plans on China's three leading urban regions yielded progress in those areas partly by relocating heavy industry to other parts of China. Unsurprisingly, air quality outside of the target regions has not made similar progress and the success of the plans is less complete when viewed nationally.

On top of these air quality challenges, the government is also committed to greenhouse gas reduction, introducing a national CO2 emission trading system (ETS) in the power sector, now scheduled to begin in 2020. Decarbonizing electricity generation means a shift from coal to renewables, nuclear, or natural gas. These shifts also reduce emissions of sulfur dioxide, nitrogen oxides, and particles that contribute to poor air quality.

In addressing formidable policy tasks such as the ETS, there is a further undertaking that could help progress, or hinder it, if done poorly: reform of the electric power sector. In an industry long regulated tightly by planning authorities, reforms initiated by the so-called “Decree No. 9” of 2015 could, in principle, make market-oriented pollution reduction more effective. Reforming the huge power system, which currently accounts for 45% of total coal use in China, is one of the most complex tasks for the government. While the controls on pollutant emissions in the electric sector are much tighter compared to other coal-burning industries, the sector is still a major contributor to air pollution given its sheer size.

The Ministry of Electric Power ran the power system until it was transformed into the State Power Company in 1996. Privately-owned generators were permitted to help ease electricity shortages that were then common. In 2002, the generation assets were separated into five large state-owned companies, and the State Grid and Southern Grid formed to manage transmission of energy. Over this period, the shortages gave way to excess capacity, and a system of planned allocation of generation hours was devised to ensure a “fair” allocation of total demand to the generators. Thus a dispatch system was created that did not prioritize efficiency or cost; in a more rational, market-oriented system, the most inefficient (often also the dirtiest) plant would be dispatched last. Various efforts since 2007 at introducing a more environmentally friendly system, such as “Energy Conservation Dispatch,” have had limited success and the “fair allocation” system remains largely in place.

China has expended great efforts on renewable power and now leads the world in wind, solar, and hydro power capacities. Renewables, however, must operate largely within the “fair dispatch” system where incumbent coal plants retain their centrally planned share of generation hours despite higher marginal costs. Also, state-owned coal generators are important sources of employment and revenue for local governments, pushing provincial authorities to protect their market share and resist renewable power from other provinces. These factors, along with others, result in very high wastage of clean and cheap electricity; wind power, for example, was curtailed by 21 percent in the first half of 2016. Even hydropower is curtailed due to its geographic concentration in the southwest, far from load centers.

These obvious inefficiencies are one of the targets of the Decree No. 9 reforms. The reform proposals include the establishment of spot markets and power trading centers, and allowing retail competition. A spot market for electricity is a market for narrow time intervals (e.g., an hour) where generators offer bids specifying price and quantity and the trading center manager finds the lowest price that would cover enough bids to satisfy demand for that time interval. The demand comes from enterprises and households who face prices that are mostly regulated. Such a spot market requires an advanced trading system and sophisticated market participants, and has thus taken a long time to develop in an industry with central planning origins like China's.

In a typical spot market, demand would be close to capacity during peak hours and the highest marginal-cost generator would be able to sell its power. In the U.S., the highest marginal cost generators would normally be gas turbines, which can shut down and start up quickly. In China, there are currently very few gas-fired generators and the highest marginal cost plant would likely be the most inefficient coal plant. During off-peak hours, a market system would reduce output of such plants. Wind and solar have essentially zero marginal costs and would be used when feasible, peak or off-peak. Such a system is very different from the current setup where the majority of generation hours are allocated according to a centralized plan. If such a market system succeeds, with coal plants generating less and renewables selling more, the contribution to reduction of air pollution and carbon could be substantial.

On top of this, if the CO2 permit system (ETS) is effectively implemented, it would require that the cost of burning coal includes the CO2 price, raising the spot price bids from coal generators. This would further advantage low-carbon sources.

These two “ifs” are big uncertainties given the complexity of the systems, resistance of politically powerful incumbent coal generators and other economic challenges facing the government in 2018.

Finally, relaxation of investment controls in the mid-2010s sparked a huge over-building of coal-fired power plants. This overcapacity has led to a sharp fall in utilization rates of coal generators, leaving them idle more than half the time in 2017. Estimates of “stranded” coal power assets exceeded $500 billion in 2015. Yet recent satellite evidence indicates even more coal plants are being added, despite suspension of their construction permits, exacerbating the problems posed by overcapacity.

There is a strong possibility that dealing with stranded assets and grappling with power sector reforms that challenge entrenched interests will preoccupy those in charge of energy policy, and distract from efforts to implement the CO2 ETS and reduce emissions from the electricity sector. But for a major transition to clean power in China to gain real traction — and for the carbon pricing of the ETS to function as intended — the first priority must be getting power sector reform right.