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是什么让英国电网的“脱碳”进程急速加快?

是什么让英国电网的“脱碳”进程急速加快?

Katherine Dunn 2020年05月29日
在用电需求减少,太阳能发电量创下纪录的情况下,煤炭实在是显得太贵了,毫无存在的必要。这是长期趋势的一部分。

图片来源:GettyImages

随着英国在春季实施全国性封锁政策,“前所未有”一词屡屡被搬出来,来形容诸如关闭酒吧、全民致敬医护人员等事情。

但对于该国的电力运营商英国国家电网公司来说,“前所未有”这词却意味着打破一个又一个纪录(大多比原计划提前了数年实现),比如最大的太阳能容量、有史以来最低的碳强度(就在上个周日实现了),以及最长的无煤期。

到了周二,最长无煤期这一纪录仍在刷新中,英国的电力系统现在已经连续录得46个无煤日(超过1000个小时)。截至周二中午,无碳发电量占英国电网的53%,其余包括天然气发电、生物质发电,以及小部分进口电能。

英国国家电网突然转向低碳能源系统,这一举措并不令人意外,它的目标是到2025年使英国的电力系统完全脱碳。这次的封锁制造出了一个在疫情结束后仍会继续存在的试验场,从中可以一窥未来几年里新能源将如何影响到国家电网的运营。这会带来各种新挑战,比如怎么应对超低需求的时期,怎么处理负定价问题。此外,一个依赖于不稳定的风力和太阳能的能源系统的脆弱性,又该怎么去应对?

封锁政策影响能源消耗

英国于3月下旬实施封锁,当即就影响到了能源的消耗:国家电网称,整个电力系统的需求下跌了20%。

随着人们待在家中,一天到晚开着电视和洗衣机,家庭用电急剧增加,然而工业用电的下降更为剧烈,抵消了这一增长。虽然用电量下降得很大,但用电模式并不像我们以为的那样会发生很大变化:人们在早上为新一天做准备时会消耗更多电量(由于不必通勤,大家往往会稍晚一点起床),到了晚上因为煮饭和看电视,用电量又会增多。

国家电网的市场主管凯特•奥尼尔说,用电需求的急剧下降并不会让电力系统更容易管理,反而变得困难。电力需求下降要求非常精细的调节,以缓解系统电压同步下降的问题,使整个系统保持平衡,同时还要管控对邻国爱尔兰和欧洲大陆的电能输出和输入。电网系统的调节稍不到位,就有断电的风险。

英国国家电网一直想让整个电网“脱碳”,因此开始趁此机会采用了一部分脱碳方案:准备让英国一个核电站降低发电量,并开始讨论增加或减少可再生能源小供应商(比如小型太阳能农场或者安装在工业区的系统)的供应,不管增加或减少,它们都不足以对大型电网产生影响。

奥尼尔说:“在这个低能源需求的时期所做的事情加速了这些变化。”她称,原本要花数年实施的工作,突然在5到10天就完成了。

在这个低能源需求的世界,煤炭注定成为了牺牲品。奥尼尔说,虽然在“典型的高需求”日子里,需要动用所有的能源类型,但能源是按成本顺序进入到电网中的,而煤炭最昂贵。她还说,在用电需求减少,尤其是太阳能发电量创下纪录(阳光明媚的春季起到了重要作用)的情况下,煤炭实在是显得太贵了,毫无存在的必要。这是长期趋势的一部分:据国际能源署,2019年英国的煤炭发电量跌至2%,而可再生能源发电量却占40%。

2015年,英国国家电网控制室的数据显示,煤炭占该系统发电量的33%以上,而去年的煤炭发电量仅为2%。英国现在已经第二个月没有采用煤炭发电了。图片来源:Simon Dawson—Bloomberg/Getty Images

国际能源署称,煤炭需求受到冲击一直是全球实施封锁的一个特征。预计今年煤炭需求将下降8%。可再生能源更容易实现碳减排(比如,跟飞机相比),在电网系统中的地位因此更高,而随着需求下降,它们所占的比重更大了。这有利于减少碳排放,但也给运营带来了挑战,问题主要在于要确保一直都有可靠的备用能源(通常是水电或核电的形式),以维持稳定的供应,就像过去的煤炭一样。

保持能源系统平衡是非常精细周密的流程,掌控好这个流程还需要其它的创造性措施,以确保有足够的身体健康的工程师在控制室里运行电网。这需要好好规划才行。封锁期间,一些员工需要把上班的地方当成家(他们住在一个个舱室中),连续几个星期不见家人。

在某些情况下,用电需求下降还造成了市场上的一些怪现象:在英国以及其它欧洲国家,电力市场严重供过于求,以至于在近几个月内,价格反复跌至负值——这实际上是要电企付钱给消费者去用电。在高效能源储存技术出现和应用之前,这种能源倾销的现象将一直是个问题。

如何重启电网

奥尼尔说,尽管英国首相约翰逊在本月初宣布稍微放松该国的封锁措施,不过能源需求仍然低迷。虽然现在民众能待在外面的时间更长了,但政府已经表示,非必要商店等场所直到6月中旬才可以开放。

不过,恢复至“正常”的能源需求并非是问题所在。

奥尼尔说:“随着需求上升,如果说有什么不同的话,那就是电力系统变得容易管理了。”她还补充说,国家电网仍然在观察,看新冠病毒带来的潜在长期转变(比如通勤减少了,居家工作的人多了)是否会显著改变英国的电力消费模式。

不管怎样,国家电网一直在为“低需求的夏天”而做准备,并将封锁期间的举措继续实施下去。在此期间,他们也做到了一些之前从来没有做到的事。

奥尼尔说,这次疫情表明,英国各个行业能更密切地携手合作,并且英国实现其脱碳里程碑的日期也可能远早于预期。 (188金宝搏 下载)

译者:李耀和

随着英国在春季实施全国性封锁政策,“前所未有”一词屡屡被搬出来,来形容诸如关闭酒吧、全民致敬医护人员等事情。

但对于该国的电力运营商英国国家电网公司来说,“前所未有”这词却意味着打破一个又一个纪录(大多比原计划提前了数年实现),比如最大的太阳能容量、有史以来最低的碳强度(就在上个周日实现了),以及最长的无煤期。

到了周二,最长无煤期这一纪录仍在刷新中,英国的电力系统现在已经连续录得46个无煤日(超过1000个小时)。截至周二中午,无碳发电量占英国电网的53%,其余包括天然气发电、生物质发电,以及小部分进口电能。

英国国家电网突然转向低碳能源系统,这一举措并不令人意外,它的目标是到2025年使英国的电力系统完全脱碳。这次的封锁制造出了一个在疫情结束后仍会继续存在的试验场,从中可以一窥未来几年里新能源将如何影响到国家电网的运营。这会带来各种新挑战,比如怎么应对超低需求的时期,怎么处理负定价问题。此外,一个依赖于不稳定的风力和太阳能的能源系统的脆弱性,又该怎么去应对?

封锁政策影响能源消耗

英国于3月下旬实施封锁,当即就影响到了能源的消耗:国家电网称,整个电力系统的需求下跌了20%。

随着人们待在家中,一天到晚开着电视和洗衣机,家庭用电急剧增加,然而工业用电的下降更为剧烈,抵消了这一增长。虽然用电量下降得很大,但用电模式并不像我们以为的那样会发生很大变化:人们在早上为新一天做准备时会消耗更多电量(由于不必通勤,大家往往会稍晚一点起床),到了晚上因为煮饭和看电视,用电量又会增多。

国家电网的市场主管凯特•奥尼尔说,用电需求的急剧下降并不会让电力系统更容易管理,反而变得困难。电力需求下降要求非常精细的调节,以缓解系统电压同步下降的问题,使整个系统保持平衡,同时还要管控对邻国爱尔兰和欧洲大陆的电能输出和输入。电网系统的调节稍不到位,就有断电的风险。

英国国家电网一直想让整个电网“脱碳”,因此开始趁此机会采用了一部分脱碳方案:准备让英国一个核电站降低发电量,并开始讨论增加或减少可再生能源小供应商(比如小型太阳能农场或者安装在工业区的系统)的供应,不管增加或减少,它们都不足以对大型电网产生影响。

奥尼尔说:“在这个低能源需求的时期所做的事情加速了这些变化。”她称,原本要花数年实施的工作,突然在5到10天就完成了。

在这个低能源需求的世界,煤炭注定成为了牺牲品。奥尼尔说,虽然在“典型的高需求”日子里,需要动用所有的能源类型,但能源是按成本顺序进入到电网中的,而煤炭最昂贵。她还说,在用电需求减少,尤其是太阳能发电量创下纪录(阳光明媚的春季起到了重要作用)的情况下,煤炭实在是显得太贵了,毫无存在的必要。这是长期趋势的一部分:据国际能源署,2019年英国的煤炭发电量跌至2%,而可再生能源发电量却占40%。

国际能源署称,煤炭需求受到冲击一直是全球实施封锁的一个特征。预计今年煤炭需求将下降8%。可再生能源更容易实现碳减排(比如,跟飞机相比),在电网系统中的地位因此更高,而随着需求下降,它们所占的比重更大了。这有利于减少碳排放,但也给运营带来了挑战,问题主要在于要确保一直都有可靠的备用能源(通常是水电或核电的形式),以维持稳定的供应,就像过去的煤炭一样。

保持能源系统平衡是非常精细周密的流程,掌控好这个流程还需要其它的创造性措施,以确保有足够的身体健康的工程师在控制室里运行电网。这需要好好规划才行。封锁期间,一些员工需要把上班的地方当成家(他们住在一个个舱室中),连续几个星期不见家人。

在某些情况下,用电需求下降还造成了市场上的一些怪现象:在英国以及其它欧洲国家,电力市场严重供过于求,以至于在近几个月内,价格反复跌至负值——这实际上是要电企付钱给消费者去用电。在高效能源储存技术出现和应用之前,这种能源倾销的现象将一直是个问题。

如何重启电网

奥尼尔说,尽管英国首相约翰逊在本月初宣布稍微放松该国的封锁措施,不过能源需求仍然低迷。虽然现在民众能待在外面的时间更长了,但政府已经表示,非必要商店等场所直到6月中旬才可以开放。

不过,恢复至“正常”的能源需求并非是问题所在。

奥尼尔说:“随着需求上升,如果说有什么不同的话,那就是电力系统变得容易管理了。”她还补充说,国家电网仍然在观察,看新冠病毒带来的潜在长期转变(比如通勤减少了,居家工作的人多了)是否会显著改变英国的电力消费模式。

不管怎样,国家电网一直在为“低需求的夏天”而做准备,并将封锁期间的举措继续实施下去。在此期间,他们也做到了一些之前从来没有做到的事。

奥尼尔说,这次疫情表明,英国各个行业能更密切地携手合作,并且英国实现其脱碳里程碑的日期也可能远早于预期。 (188金宝搏 下载)

译者:李耀和

As the U.K. went into nationwide lockdown this spring, the words “unprecedented” were trotted out to explain everything from pubs being closed to national clap-alongs for health care workers.

But for the National Grid, the country’s electricity operator, “unprecedented” meant blowing through one record after another, often years ahead of schedule: max solar capacity in the energy system, lowest-ever carbon intensity—just this Sunday—and longest stretch without coal.

That record was still in place on Tuesday, with the country’s system now on its 46th consecutive coal-free day—over 1,000 hours—and counting. As of midday Tuesday, the country’s grid was 53% carbon-free, with the remainder comprising supplies of gas, biomass, and a small proportion of energy imports.

This sudden shift to a dramatically lower-carbon energy system isn’t an unexpected development inside National Grid—the goal is to completely decarbonize the country’s electricity system by 2025. But the lockdown has produced a kind of testing ground that will outlive the pandemic, giving a taste of how a mix of new energy sources will impact National Grid’s operations in the coming years. This will give rise to new challenges: periods of ultralow demand, negative pricing, and how to manage the delicate balance of an energy system dependent on the fluctuations of wind and sun.

The lockdown drop

When the U.K. went into lockdown in late March, the impact on energy consumption was immediate: Demand dropped about 20% across the system, according to the National Grid.

While domestic demand increased sharply as people stayed home and ran TVs and washing machines all day, that increase was offset by the much sharper decline in industrial consumption. But other than that drop, the patterns of demand didn’t look as different as you might expect: People used more energy in the mornings as they got ready for the day (they just tended to get up a bit later, as commuting was taken out of the equation), and again in the evenings as they cooked and watched TV.

But rather than making the electricity system easier to manage, a drop in demand at that scale makes it harder, says Kayte O’Neill, head of markets at National Grid. A demand drop requires fine brushwork, to ease the system’s voltage down in tandem and keep the entire system in balance, while managing the imports and exports of energy to neighboring Ireland and mainland Europe. Not keeping the system perfectly aligned means risking blackouts.

National Grid turned to programs it had been considering as part of the long-term strategy to decarbonize the whole grid: arranging for one of the U.K.’s nuclear stations to turn down its output, and entering discussions to turn up or down supply by the kinds of smaller renewable producers—mini solar farms or systems installed in industrial parks, for example—that otherwise wouldn’t be significant enough to have an impact on the larger grid.

“What this lower-demand period has done has accelerated those changes,” O’Neill says. Work that was expected to be rolled out over years was suddenly done in as little as five to 10 days, she says.

In this low-demand world, coal is a natural casualty. While a “typical, high-demand” day would draw on the full range of energy sources, O’Neill says, sources of demand are drawn into the grid in order of cost—and coal is the most expensive. With less demand and record supplies of solar power, in particular—a sunny spring has helped—coal is simply too expensive and not necessary, says O’Neill. That’s part of a longer-term trend: in 2019, coal fell to just 2% of electricity generation overall in the U.K., according to the International Energy Agency (IEA), while renewables provided 40%.

That hit to coal demand has been a feature of lockdowns around the world, according to the IEA. Coal demand is expected to drop 8% this year. With demand falling, renewables—which are more highly represented in energy grids, because they are easier to decarbonize than, say, airplanes—have come to make up a larger part of the total energy pie. That’s good for emissions, but it comes with its own operational challenges, largely in making sure that there are always reliable backups (frequently in the form of hydropower or nuclear) to underpin stable supply, the way coal has in the past.

Managing the careful process of keeping the energy system in balance has also required other, creative measures—how to make sure that enough control room engineers would remain healthy in order to run the grid itself. That required planning, with some workers during the lockdown living at work—in pods—and not seeing their families for weeks at a time.

That drop in demand has also produced bizarre market distortions, in some cases: In the U.K. as well as other European countries, power markets have become so oversupplied that prices have repeatedly dipped into negative territory in recent months—effectively requiring utilities to pay consumers to use energy. This kind of energy-dumping phenomenon will continue to be a problem until efficient energy storage technologies can be developed and deployed.

How to reopen the grid

Even after Boris Johnson announced slight easing measures to the country’s lockdown earlier this month, energy demand remained low, says O’Neill. While people can now spend longer outside, nonessential shops—for example—won’t be opened until mid-June, the government has said.

But a return to “normal” energy demand isn’t the concern.

“As demand goes up, if anything the system becomes easier to manage,” O’Neill says, adding that National Grid was still waiting to see whether potential long-term shifts caused by COVID-19—less commuting, more working from home, for example—would markedly shift the country’s electricity consumption patterns.

Either way, the National Grid has been preparing for a “low-demand summer”; keeping in place the measures it has used throughout the lockdowns. New precedents have also been set.

The pandemic showed that every sector of the U.K. is capable of working together in closer cooperation, O’Neill says—and that it may be possible for major decarbonization milestones to be hit far sooner than expected.

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