我们负担得起大规模太阳能光伏发电吗?

Can We Afford Large-Scale Solar PV?
作者:Brian Potter    发布时间:2025-07-04 12:27:19    浏览次数:0
In the US solar energy has steadily risen in how much of our electricity it supplies. In 2024, it supplied just over 7% of total electricity generation, up from less than 1% in 2015. Because most planned US electricity generation projects are solar photovoltaics (PV), this fraction will almost certainly continue to rise.
在美国,太阳能在我们提供的电力中稳步上升。在2024年,它仅提供了总发电量的7%以上,高于2015年的不到1%。由于大多数计划中的美国发电项目是太阳能光伏(PV),因此几乎可以肯定会继续上升。

But how much can it continue to rise? Is it feasible for solar power to meet most of our electricity demand? In the essay Understanding Solar Energy, we used some simple simulations of solar power to understand how much electricity demand solar PV can supply under different conditions. We found that due to solar’s intermittency, supplying large fractions of electricity demand requires a fair degree of “overbuilding” (solar panel capacity well in excess of total electricity demand), as well as a fair amount of storage. For a single family home where power demand never exceeds 10 kilowatts (and most of the time is below 2 kilowatts), supplying 80% of annual electricity consumption requires at least 13.7 kilowatts of solar panels, and 40 kilowatt-hours of storage. And supplying even higher fractions of electricity demand — 90%, 95%, 99% — the infrastructure requirements gets even more burdensome. Going from 80 to 90% of electricity supplied requires nearly doubling solar panel capacity.
但是它能继续增加多少呢?太阳能满足我们大多数电力需求是可行的吗?在理解太阳能的论文中,我们使用了一些简单的太阳能模拟来了解太阳能光伏在不同条件下可以提供的电力需求量。我们发现,由于太阳能的间歇性,提供大量的电力需求需要相当程度的“过度建造”(太阳能电池板容量远高于总电力需求),以及相当多的存储空间。对于一个单一的家庭住宅,电力需求永远不会超过10千瓦时(大多数时间低于2千瓦),供应80%的年度电力消费量至少需要13.7千瓦的太阳能电池板和40千瓦时的存储空间。并且提供更高的电力需求分数(90%,95%,99%),基础设施需求变得更加繁重。从80%到90%提供的电力需要使太阳能电池板容量几乎翻了一番。

However, we also found that the falling costs of solar PV will make it feasible for solar to supply large fractions of electricity demand cost-effectively. Reaching 90 or 95% is indeed costly, but 70-80% appears to be well within the realm of possibility.
但是,我们还发现,太阳能光伏的成本下降将使太阳能可行地提供大量的电力需求成本有效。达到90%或95%的成本确实是昂贵的,但70-80%的可能性似乎很好。

One common objection to the large-scale use of solar PV is that, even with batteries, it effectively requires an entire parallel energy system to meet electricity demand when there’s little or no sun and no battery charge. Even if the solar plus battery system can meet demand 99.9% of the time, supplying that last 0.1% of demand might theoretically require a large amount of expensive infrastructure, making effective costs much higher.
对大规模使用太阳能PV的一个常见反对意见是,即使有电池,在很少或没有太阳且没有电池电量的情况下,有效地需要整个平行能源系统才能满足电力需求。即使太阳能加电池系统可以满足需求的99.9%,从理论上讲,持续0.1%的需求可能需要大量昂贵的基础设施,从而使有效成本更高。

For instance, if power demand in a state is a constant 20,000 megawatts, I might need a 20,000 megawatt solar and battery system, plus an entire other 20,000 megawatt energy system (say, 40 large gas turbines) to turn on in emergencies. Once you take these extra costs into account, so the theory goes, the economics of solar PV look much worse.
例如,如果一个州的电力需求是恒定的20,000兆瓦,我可能需要20,000兆瓦的太阳能和电池系统,再加上其他20,000兆瓦的能源系统(例如,40个大型燃气轮机)才能在紧急情况下打开。一旦考虑到这些额外的成本,理论就可以了,太阳能光伏的经济学看起来会更糟。

It is true that meeting 100% of electricity demand with large-scale solar PV requires some amount of parallel infrastructure, such as gas turbines, to fill in the gaps. But analysis suggests that at low enough solar PV and battery costs, this isn’t all that burdensome. Partly this is because in many cases (such as with gas turbines), a large fraction of electricity costs are due to fuel costs, which aren’t incurred when the system isn’t running. But it’s also because batteries can help reduce the need for this parallel infrastructure. Batteries aren’t just a complement to solar PV: they’re a complement to any energy generation system. We can use our gas turbines to charge the batteries too, helping us smooth out the peaks in demand and reducing how much “extra” infrastructure is required to meet demand.
的确,满足大型太阳能PV的100%的电力需求需要一定数量的平行基础设施,例如燃气轮机,以填补空白。但是分析表明,在足够低的太阳能光伏和电池成本下,这并不是那么繁重。部分原因是因为在许多情况下(例如燃气轮机),很大一部分电力成本是由于燃料成本所致,而在系统不运行时不会产生。但这也是因为电池可以帮助减少对这种平行基础架构的需求。电池不仅仅是太阳能光伏的补充:它们是任何能源发电系统的补充。我们也可以使用燃气轮机为电池充电,从而帮助我们平滑需求中的峰值,并减少满足需求需要多少“额外”基础设施。

Meeting electricity demand with solar PV
满足太阳能光伏的电力需求

To understand what sort of electricity generation infrastructure is required to meet large-scale demand, we’ll use electricity data from the state of California. The graph below shows hourly electricity supplied by CAISO (California’s independent system operator) for the first week of January 2024. Data is from Gridstatus.io.
为了了解满足大规模需求需要哪种发电基础设施,我们将使用来自加利福尼亚州的电力数据。下图显示了Caiso(加利福尼亚州独立系统运营商)在2024年1月的第一周提供的小时电力。数据来自GridStatus.io。

And this graph shows the daily maximum demand over the entire year of 2024.
该图显示了全年2024年的最大需求。

Day to day, we see a pattern of electricity demand that’s similar to our single family home simulation. We see electricity demand rise in the morning, decline around 9-10 AM, rise again in the evening around 5-6 PM, then decline again late at night. If we look at seasonal variation, we see electricity demand rise steeply in the summer, then decline in fall.
每天,我们看到的电力需求模式类似于我们的单一家庭家庭模拟。我们看到早晨的电力需求在上升,下午9点至10点左右,晚上下午5点至6点左右再次上升,然后深夜再次下降。如果我们看季节性差异,我们会看到夏天的电力需求急剧上升,然后在秋季下降。

Right away, we can see that the problem of needing “extra” infrastructure isn’t simply a solar PV and battery problem. During most of 2024, electricity demand didn’t exceed 30,000 megawatts, but during the summer months it regularly exceeded 40,000, and for one brief window it approached 50,000 megawatts. Meeting 100% of California’s electricity demand will require a lot of infrastructure that most of the time will sit idle, regardless of what system of electricity generation you use.
马上,我们可以看到需要“额外”基础架构的问题不仅仅是太阳能光伏和电池问题。在2024年的大部分时间里,电力需求不超过30,000兆瓦,但是在夏季,它定期超过40,000,并且在一个简短的窗口中,它接近了50,000兆瓦。满足100%加利福尼亚的电力需求将需要大部分基础设施,无论您使用哪种电力系统,大多数情况下都会闲置。

If we want to meet this demand with solar PV, we need to understand what sort of capacity factor (the ratio of actual solar PV power supplied to maximum theoretical capacity) we can expect to achieve. Gridstatus.io breaks down electricity supplied by the source of generation, letting us see how much electricity is being supplied by solar PV in California at any given time. By combining this with the total nameplate solar PV capacity in California, we can calculate an hour-by-hour capacity factor. Here’s CAISO’s solar PV capacity factor for the first week of January 2024.
如果我们想通过太阳能光伏满足这一需求,我们需要了解我们可以期望实现的容量因素(实际太阳能电力与最大理论能力的比率)。GridStatus.io打破了发电源提供的电力,让我们看到加利福尼亚州在任何给定时间在加利福尼亚州太阳能PV提供了多少电力。通过将其与加利福尼亚州的总铭牌太阳能光伏容量相结合,我们可以计算一个小时的容量因子。这是Caiso 2024年1月第一周的太阳能光伏容量因素。

And here's the daily maximum capacity factor for the entire year of 2024.
这是2024年全年的每日最大容量因素。

As with our single family home simulation, we see that solar PV generation drops to zero at night, and rises to its maximum during the day. That maximum changes over the course of the year: during the summer months, California’s solar PV panels regularly generate 90% or more of their nameplate capacity, but in January that maximum is closer to 60%. And day to day, output might be reduced even more due to things like cloud cover. On some summer days in California, solar PV generation doesn’t exceed 70% of its theoretical maximum, and on some winter days it never cracks 20%.
与单一的家庭住宅模拟一样,我们看到太阳能光伏生成在夜间下降到零,并且白天上升到最大。在一年中的最大变化:在夏季,加利福尼亚州的太阳能光伏面板定期产生90%或更多的铭牌容量,但在一月,最大值接近60%。每天,由于云覆盖率之类的东西,可能会减少输出。在加利福尼亚州的某些夏季,太阳能光伏的生成不超过其理论最大的70%,在某些冬季,它永远不会破裂20%。

Using this electricity demand and solar PV capacity factor data, we can calculate what fraction of California’s electricity demand can be met by different combinations of solar and storage. The graph below shows the fraction of electricity supplied by solar PV systems ranging from 20,000 megawatts (slightly less than California’s current 22,000 megawatt capacity) and battery storage systems ranging from 50,000 megawatt-hours to 800,000 megawatt-hours. (If we simplify and assume that California’s maximum electricity demand is 50,000 megawatts, this is roughly equivalent to having 1, 2, 4, 8, and 16 hours of battery storage for the entire state.)
使用这种电力需求和太阳能光伏容量因子数据,我们可以通过太阳能和存储的不同组合来计算加利福尼亚的电力需求的哪一部分。下图显示了太阳能光伏系统所提供的电力比例,范围为20,000兆瓦(略低于加利福尼亚当前的22,000兆瓦容量),电池存储系统的范围从50,000兆瓦小时到800,000兆瓦小时。(如果我们简化并假设加利福尼亚州的最大电力需求为50,000兆瓦,这大致相当于整个州的电池存储1、2、4、8和16小时。)

We see here the exact same diminishing returns that we saw when simulating a single family home. Each additional watt of solar PV capacity and watt-hour of battery storage gets used less and less frequently, and contributes a smaller amount to meeting overall electricity demand. And as we approach 100% electricity demand, the infrastructure requirements become enormous to deal with the occasional long stretch of cloudy days and low panel output. Getting through that brief period in late January where maximum daily solar PV output never exceeds 20% requires a lot of extra panels and batteries.
我们在这里看到模拟一个家庭住宅时看到的完全相同的回报。每瓦的太阳能光伏容量和电池存储的瓦特小时的使用越来越少,并且可以少贡献满足总体电力需求的贡献。当我们达到100%的电力需求时,基础设施的需求变得巨大,以应对偶尔的漫长的阴​​天和低面板输出。在1月下旬度过这段短暂的时期,每日最大的太阳能光伏输出永远不会超过20%,需要大量额外的面板和电池。

These diminishing returns mean that it’s infeasible to meet 100% of electricity demand with just solar PV and batteries, and we need to make up the difference with some other energy generation technology. Let’s assume that we’ll meet any additional demand with combined cycle gas turbines, and that these turbines aren’t used to charge the batteries. The graph below shows how much gas turbine capacity is needed to meet 100% of electricity demand for different combinations of solar PV and battery storage.
这些减少的回报意味着,仅通过太阳能光伏和电池来满足100%的电力需求是不可行的,我们需要通过其他一些能源发电技术来弥补差异。假设我们将通过合并的循环燃气轮机满足任何其他需求,并且这些涡轮机不用于为电池充电。下图显示了需要多少燃气轮机容量来满足对太阳能光伏和电池存储不同组合的电力需求的100%。

We can see here the dynamic that we were worried about initially — while energy supplied by our gas turbines declines precipitously as our solar PV and battery system gets larger and larger, power demand (and thus infrastructure requirements) declines much more slowly. A small number of cloudy stretches, like that period in late January where PV capacity factors are under 20%, require a large amount of gas turbine capacity to deal with. Even with a huge 160+gigawatt solar PV + 16-hour battery system, capable of supplying more than 95% of our energy, we still require more than 27 gigawatts of gas turbines on top of that (more than 50% of maximum electricity demand) to meet 100% demand.
我们可以在这里看到我们最初担心的动态 - 尽管我们的太阳能光伏和电池系统变得越来越大,燃气轮机提供的能量却急剧下降,但功率需求(因此基础设施要求)下降了速度较慢。少数多云的延伸,例如1月下旬的PV容量因素不到20%的那个时期,需要大量的燃气轮机处理能力。即使有一个巨大的160 +吉瓦太阳能PV + 16小时电池系统,能够提供超过95%的能源,我们仍然需要超过27吉瓦的燃气轮机(超过最大电力需求的50%以上)才能满足100%的需求。

However, we can alter this calculus significantly by allowing our gas turbines to charge our batteries. By letting turbines charge batteries in periods of low demand (such as at night when demand drops), we can further smooth demand peaks in cloudy stretches when there’s little sun, and reduce the gas turbine capacity we require. The graph below shows how much gas turbine capacity is needed to meet 100% of electricity demand at different combinations of solar PV and storage, if we allow gas turbines to charge our batteries too.
但是,我们可以通过允许我们的燃气轮机充电电池来显着改变这种演算。通过让涡轮在需求低时期(例如在需求下降时)充电电池,我们可以在少太阳少时进一步平滑需求峰,并降低所需的燃气轮机容量。下图显示,如果我们允许燃气轮机也可以为电池充电,则需要多少燃气涡轮机能力来满足不同的太阳能光伏和存储组合的100%电力需求。

Without gas turbine charging, our 160+gigawatt solar PV and 16-hour battery system still required over 27 gigawatts of gas turbine capacity to meet demand. With gas turbine charging, that falls to 8 gigawatts. And those turbines run a lot more often: the 27-gigawatt system only generated around 1.4 million megawatt hours, or less than 1% of total demand. The 8-gigawatt, battery-coupled system generated almost 10 times that. (For reference, California currently has about 39 gigawatts of gas turbine capacity, though this will be both combined cycle plants and simple cycle plants used for peaking.)
如果没有燃气轮机充电,我们的160+吉瓦太阳能光伏和16小时电池系统仍需要27吉瓦的燃气轮机能力来满足需求。随着燃气轮机的充电,降至8吉瓦。这些涡轮机的运行频率更高:27吉加瓦的系统仅产生约140万兆瓦的小时,或不到总需求的1%。8立方间的电池耦合系统产生了近10倍。(作为参考,加利福尼亚州目前拥有约39吉瓦的燃气轮机容量,尽管这既是循环植物,又是用于峰值的简单循环植物。)

Cost of meeting demand
满足需求的成本

So by using gas turbines (or some other energy generation system) to charge batteries, we can dramatically reduce how much extra generation capacity we need to pick up the slack for solar PV. But what does this do to our overall costs for generating electricity?
因此,通过使用燃气轮机(或其他一些能源发电系统)为电池充电,我们可以大大降低太阳能PV的松弛度所需的额外发电能力。但是,这对我们发电的总体成本有什么影响?

The chart below shows the levelized cost of electricity (LCOE) for meeting 100% of electricity demand at different combinations of solar PV and battery storage, with combined cycle gas turbines picking up the slack. Costs are based on approximate current US costs (see Appendix below for details).
下图显示了在太阳能光伏和电池存储不同组合时满足100%电力需求的电力成本(LCOE),并且循环燃气轮机组合起来可获得松弛。成本基于当前美国的近似成本(有关详细信息,请参见下面的附录)。

And here’s how much electricity is provided by the solar panels (either directly or via batteries) for each combination of solar PV and battery storage capacity.
这是太阳能电池板(直接或通过电池)提供了多少电力,可用于太阳能光伏和电池存储容量的每种组合。

Putting these together, this graph shows the generation costs required to meet 100% of electricity demand at different fractions of solar PV capacity.
将这些组合在一起,该图显示了在太阳能光伏容量不同的分数下满足100%电力需求所需的发电成本。

We can see that at current US costs, it does indeed get very expensive to meet large fractions of electricity demand with solar PV. Up to around 40% of demand, costs remain fairly low, but beyond that they rise quickly. The current costs for meeting 80% of electricity demand with solar PV are more than three times the costs of meeting 40% of electricity demand.
我们可以看到,在美国目前的成本上,满足太阳能PV的大量电力需求的确确实非常昂贵。最多约40%的需求,成本仍然相当低,但除此之外,它们迅速上升。满足太阳能PV的80%的电力需求的当前成本是满足40%的电力需求的三倍以上。

But what happens if costs for solar PV and batteries continue to fall? The graph below shows current US costs against current worldwide averages, and some speculative future costs. (Current average US nuclear costs and combined cycle gas turbine costs are per Lazard.)
但是,如果太阳能光伏和电池的成本继续下降,会发生什么?下图显示了当前针对当前全球平均值的美国成本,以及一些投机性的未来成本。(目前,美国的平均核成本和循环燃气轮机总成本为Lazard。)

Current worldwide average costs for solar and battery storage let us get to around 50% of total electricity demand with solar PV for around the current LCOE of gas turbines in the US. If we can hit $400 kw solar and $100 kw-h storage, we can push that percentage to around 80%. And while these costs are substantially lower than current US costs, they’re not outside the realm of possibility (they’re probably roughly the lowest costs currently achievable in China).
当前的太阳能和电池存储的全球平均成本使我们可以达到美国当前燃气轮机LCOE的总电力需求的50%。如果我们可以达到$ 400 kW的太阳能和$ 100 kW-H的存储空间,我们可以将该百分比提高到80%左右。尽管这些成本大大低于当前的美国成本,但它们并不超出可能性的范围(它们可能是中国目前可实现的最低成本)。

Conclusion
结论

These are still somewhat simplified simulations. For one, they only look at generation costs, and totally ignore transmission or distribution. They also only look at costs, and not prices: what generators would actually charge, which could easily be much higher. (More generally, they ignore electricity market dynamics, which are very complex.) And they totally ignore the fact that in the real world states can share electricity, further damping demand peaks. But they can nevertheless help us understand the mechanics of large-scale solar PV deployment. My main takeaways:
这些仍然是简化的模拟。首先,他们只查看发电成本,而完全忽略了传输或分配。他们还只看成本,而不是价格:哪些发电机实际上会收取的费用,这很容易更高。(更普遍地,他们忽略了非常复杂的电力市场动态。)他们完全忽略了这样一个事实,即在现实世界中可以共享电力,进一步抑制需求的峰值。但是,它们仍然可以帮助我们了解大型太阳能光伏部署的机制。我的主要收获:

Solar has a lot of room to grow at current prices. The simulations above suggest solar PV can meet 30-40% of electricity demand without requiring burdensome additional generation infrastructure.
太阳能以当前价格有很大的增长空间。上面的模拟表明,太阳能光伏可以满足30-40%的电力需求,而无需繁重的额外发电基础设施。

Cheap batteries are as big a deal as cheap solar PV. Low cost batteries are transformative, not simply because of how they complement solar but because of how well they complement other energy generation technologies. Batteries act as a buffer to overcome a mismatch between solar PV supply and electricity demand, and that buffer works just as well to smooth out variation in demand more generally.
便宜的电池和便宜的太阳能光伏一样大。低成本的电池具有变革性,不仅是因为它们如何补充太阳能,还因为它们对其他能源产生技术的补充程度。电池充当缓冲,以克服太阳能光伏电源和电力需求之间的不匹配,并且缓冲液也可以更普遍地平息需求的变化。

If solar PV and battery costs continue to fall, supplying very large fractions of electricity demand with solar PV becomes feasible. At $400 a kw solar and $100 a kwh batteries (costs China is probably achieving right now), we could meet 80% of electricity demand with solar PV for roughly current US average combined cycle gas turbine costs. If, like some folks, you think solar PV and batteries will get even cheaper than this, the path to almost total solar and battery dominance is very clear.
如果太阳能光伏和电池成本继续下降,那么可为太阳能光伏提供了很大的电力需求。每千瓦太阳能和每千瓦时100美元的电池(中国现在可能正在实现),我们可以满足80%的电力需求,而太阳能PV的80%,大约是美国平均循环燃气轮机成本。如果像某些人一样,您认为太阳能光伏和电池会比这便宜,那么几乎总太阳能和电池优势的道路就非常清楚。

Concerns that large-scale solar PV requires a lot of parallel infrastructure aren’t unreasonable, but large-scale storage deployment dulls them significantly.
担心大型太阳能光伏需要大量平行基础架构并不是不合理的,但是大规模的存储部署会大大降低它们。

Appendix: LCOE calculation assumptions
附录:LCOE计算假设

Current solar PV capital costs: $1100/kw (source).
当前的太阳能光伏资本成本:$ 1100/kW(来源)。

Current battery capital costs: $475/kw (source).
当前电池资本成本:$ 475/kW(来源)。

Current combined cycle gas turbine capital costs: $1000/kw
当前循环燃气轮机资本成本:$ 1000/kW

Gas turbine fuel costs: $23/mwh (source)
燃气轮机燃料成本:23美元/兆瓦(来源)

Solar PV maintenance costs: 1.5%/year (source)
太阳能光伏维护成本:1.5%/年(来源)

Battery maintenance costs: 2.5%/year (source)
电池维护成本:2.5%/年(来源)

Gas turbine maintenance costs: 4%/year (source)
燃气轮机维护成本:4%/年(来源)

Solar PV output degradation rate: 0.5%/year (source)
太阳能光伏输出降解率:0.5%/年(来源)

Discount rate: 7%
折现率:7%

Solar PV lifetime: 30 years (source)
太阳能光伏寿命:30年(来源)

Battery lifetime: 15 years (source)
电池寿命:15年(来源)

Gas turbine lifetime: 25 years (source)
燃气轮机寿命:25年(来源)

For gas turbines, there’s a lot of variation in costs. $1000/kw would put this somewhat on the lower end of Lazard’s cost estimate. It’s on the high-end of what Gas Turbine World estimates for current large, combined-cycle plants, but well below smaller, simple cycle peaker plants. But it’s much lower than what power companies are currently paying for combined cycle plants, which seems to be closer to $2400/kw (possibly due to high demand driving up prices). Similarly, maintenance costs varied from source to source (these are somewhat higher than what Gas Turbine World estimates.)
对于燃气轮机,成本有很大差异。$ 1000/kW会将这一点放在Lazard成本估算的下端。这是关于当前大型,合并的循环植物的燃气轮机世界估计的高端,但远低于较小,简单的循环峰值植物。但这远低于目前为合并循环工厂支付的电力公司,该工厂似乎接近2400美元/kW(可能是由于需求量升高而提高了价格)。同样,维护成本因来源而异(这些价格远高于燃气轮机世界的估计。)

Thanks to Austin Vernon and Nathan Iyer for reading a draft of this. All errors are my own.
感谢Austin Vernon和Nathan Iyer阅读了此书的草稿。所有错误都是我自己的。

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