Why don’t we cover the desert with solar panels? - Dan Kwartler

譯者: 柏陞 郭

Every day, the sands of the Sahara Desert reach temperatures up to 80° Celsius.

攝氏 80 度的高溫 是撒哈拉沙漠的每日常態。

Stretching over roughly nine million square kilometers,

連綿約 900 萬平方公里，

this massive desert receives about 22 million terawatt hours of energy

這片廣闊的沙漠每年吸收 約 2200 萬兆瓦

from the Sun every year.

來自太陽的的能量。

That’s well over 100 times more energy than humanity consumes annually.

這可比人類每年消耗的能源 多出 100 倍之多。

So, could covering the desert with solar panels solve our energy problems for good?

那麼，我們能透過將這片沙漠覆蓋 太陽能板，永遠解決能源問題嗎？

Solar panels work when light particles hit their surface with enough energy

太陽能板若要起作用，則必須要有 帶足夠能量的光子撞擊表面，

to knock electrons out of their stable bonds.

使電子成為不穩定的狀態。

On their journey back to stability, these electrons produce electricity.

在電子回歸穩定的過程， 它們就會釋出電能。

However, there’s a limit to how much power panels can generate.

然而，太陽能板能產出的 能源是有上限的。

Solar panels can only interact with certain wavelengths of light,

由於太陽能板只會對 特定波長的光起反應，

making it impossible to convert over half the sunlight they receive.

導致過半接收的陽光 無法轉換能量。

And even light particles they can convert often bounce off them

就連能夠轉換的光子 也時常在撞擊電子之前

without ever hitting an electron.

就從太陽能板上彈開。

But thanks to clever scientists and engineers

拜聰明的科學家和工程師的努力，

and substantial government investment,

加上政府大量的資金挹注，

solar panels are generating more electricity than ever.

現在的太陽能板比以往 產出更多的電能。

Anti-reflective coatings and patterns on the panels’ surface

面板上的抗反射塗層和圖樣

create more opportunities for incoming light particles to hit electrons.

使得前來的光子更有機會撞擊電子。

These techniques have increased commercial solar panel efficiency

這些技術讓商業太陽能板的發電效率

from the low-teens to 25%,

從原本的低於 10% 提升到 25% ，

with experimental models reaching up to 47%.

實驗性的模型甚至高達 47% 。

What’s more, solar has gotten 89% cheaper over the last decade,

此外，太陽能的價格 比起過去十年低了 89% ，

thanks in part to global supply chains for other technologies

這都要歸功於全球供應鏈中

that use the same materials.

許多的科技都使用了相同的材料。

Together, these factors have made solar power

綜合以上原因，太陽能成為地球上

the cheapest source of electricity on Earth.

最便宜的能源。

Countries including India, China, Egypt, and the US,

像是印度、中國、埃及和美國等國家，

have already taken these new panels into the desert.

早已將新型太陽能板置於沙漠當中。

Their massive solar farms range from 15 to 56 square kilometers,

這些太陽能發電廠面積 約 15 到 56 平方公里不等。

and when the sun is high in the sky,

當太陽高掛空中時，

these plants can provide energy

這些電廠將供給當地 數十萬餘的居民用電。

for hundreds of thousands of local residents.

But these farms also get extremely hot.

但同時這些區域也異常炎熱。

Light that solar cells don’t convert or reflect is absorbed as heat,

那些無法為太陽能板轉換 或是反射的光被作為熱能吸收，

which reduces a panel’s efficiency.

導致太陽能板的效率降低。

And the cooling systems employed by many farms can use huge amounts of energy

而許多電廠使用的冷卻系統 如電風扇或是流水，

powering fans or moving water to maintain optimal temperatures.

都需耗費大量能源 維持適當的溫度。

Even with these systems, solar panels in the desert absorb far more heat

即便有了這些系統， 在沙漠中的太陽能板吸收的熱能

than the natural sandy environment.

仍遠比原生沙地環境還多。

This hasn’t been a problem on the scale of existing solar farms.

對現存規模的太陽能發電廠而言， 這還不構成問題。

But if we tried to cover the Sahara,

但我們若是要覆蓋整個撒哈拉沙漠，

this effect could create massive changes in the region's climate.

則會讓當地的氣候產生巨變。

Constructing solar farms already disrupts local ecosystems,

光是架設太陽能發電廠就已破壞 當地的生態系，

but a plant of this scale could dramatically transform

何況是此等規模的發電廠， 這必然巨幅改變沙漠的景觀。

the desert landscape.

Thankfully, solar panels aren’t our only option.

幸好，太陽能板並非唯一的選項。

And some of the largest solar plants in the world are trying a new approach:

世界上一些大型的大陽能電廠 正試著一個全新的方案：

giant mirrors.

巨大的鏡子。

Morocco’s Noor Power Plant,

位於摩洛哥的諾爾(Noor)發電廠，

which will eventually cover roughly 30 square kilometers of the Sahara,

是一座密集型的太陽能發電廠， 最終它將覆蓋撒哈拉沙漠

is a concentrated solar power plant.

約 30 平方公里的土地。

This design reflects light onto a receiver,

這個設計會反射陽光給接收器，

which converts that energy to heat, and then electricity.

將其能量轉換成熱能， 最後由熱能產生電力。

These mirrors still create a dangerous temperature shift for local wildlife,

這些鏡子產生的熱能移轉 對當地的野生動物而言仍然危險，

but they have less potential to transform the landscape.

但是這個方法較不會改變沙漠的景色。

And since it takes time for the materials being heated to cool off,

由於加熱的太陽能板需要時間冷卻，

these plants often continue producing electricity past sunset.

這些發電廠即使在日落後 通常還能繼續發電。

Whether they use panels or mirrors,

不論是用板子或是鏡子，

industrial solar farms are often easy to fit into existing energy infrastructure.

工業用的太陽能發電廠都能輕易地 與現存的能源建設結合。

However, getting their electricity beyond local power grids is much more difficult.

然而，在當地能源運輸網之外取得電力 是十分困難的事。

Some countries are working on ways to connect electric grids across the globe.

部分國家正嘗試不同的方法， 例如將全球的電力運輸網連結。

And many farm store energy in massive batteries,

有的將能源儲存在一個巨大的電池裡，

or convert their electricity into clean gas that can be used later.

或是將電力轉換成乾淨的燃氣 供未來隨時使用。

But right now, these techniques are still too expensive and inefficient to rely on.

但目前這些技術仍因所費不貲 且效率低落，所以不太可靠。

Worse still, industrial renewables can share some of the same problems

更糟的是，工業再生能源 與化石燃料有共通的缺點。

as fossil fuels,

relying on destructive mining operations and carbon-emitting global supply chains.

兩者的開發過程都具破壞性， 以及全球供應鏈的碳排放。

Fortunately, solar can exist on many scales,

值得慶幸的是， 太陽能發電的規模可大可小。

from industrial solar farms to smaller installations

從大型的發電廠，小至安裝在個人住宅

that power individual buildings and rural communities.

以及偏遠社區的家戶用電。

These projects can supplement energy use or provide a passive source of energy

這些計畫除了能增加可用的能源，

在供電網之外的地區 也能有被動能源供給。

for regions off the grid.

And since solar panels rely on a few simple components,

因為太陽能板由一些簡易的零件組成，

they’re quick to install and relatively easy to update.

它們可以迅速安裝， 也能夠容易更新。

In fact, it’s this flexibility that enabled solar

事實上，這也是自上個十年以來 太陽能板變得如此便宜且普及的原因。

to become so cheap and ubiquitous over the last decade.

So if we want to keep up with humanity's rising energy use,

因此，如果我們要跟上 人類與日俱增的能源消耗，

we'll need answers both big and small.

太陽能板的配置勢必要雙管齊下。