In the sci-fi film Sunshine, a spaceship’s crew goes insane after staring at the sun for too long. Those hoping for profits from solar power investments might also go mad. While healthy solar panel demand does catch the eye, prices have fallen more than a fifth during the past two years due to a glut of manufacturing capacity.

在科幻电影《太阳浩劫》(Sunshine)里，飞船上的宇航员因为盯着太阳看了太久而精神失常。那些渴望从投资太阳能发电而获利的人可能也会发疯。尽管对太阳能电池板的旺盛需求的确引人注目，但制造产能严重过剩导致过去两年里价格下降逾五分之一。

Solar installations should keep growing, another 40 per cent to 81.4 gigawatts before the end of the decade. Much of this expansion will come in the US, the second-largest solar market. One driver for panel demand there has been a federal investment tax credit for 30 per cent of the spend. Originally meant to end this year, a last-minute reprieve by Congress extended it for another three years — good news for panel makers.

太阳能发电装机容量应该会持续增长，在本十年结束之前新增40%，至81.4吉瓦。这一扩张有很大一部分将发生在全球第二大太阳能市场——美国。刺激美国市场太阳能电池板需求的一大动力是30%的联邦投资税收抵免。该计划原定今年截止，但美国国会在最后一刻将其延长了三年，这对太阳能电池板制造商来说是个好消息。

Yet volumes will still need to grow faster than solar panel prices are falling. Forward valuations for companies in the New York Stock Exchange’s Solar index have compressed; the index’s price/earnings ratio has dropped nearly a third this year to 18 times, suggesting the market does not yet believe that prices will stop falling.

尽管如此，太阳能电池板的销售量增长仍需要跑赢价格下跌。纽交所(NYSE)太阳能指数成分股公司的预期估值已经缩水，今年以来该股指的市盈率已下跌近三分之一，至18倍，似乎表明市场尚不认为价格将停止下跌。

Excess capacity in China is usually blamed. Worldwide, demand this year for solar panels at 66GW should still trail well behind capacity of 75-80GW, says renewables specialist BNEF. Most makers of the polysilicon for these panels lose money on every kilogramme they sell; spot prices now run at $13 per kilogramme. News this year that polysilicon producers such as REC Silicon had closed US factories understandably improved spirits, lifting shares of US-listed Chinese silicon maker Daqo and Korea’s OCI.

这通常被归咎于中国的产能过剩。据可再生能源专家BNEF介绍，今年全球66吉瓦的太阳能电池板需求，仍将远远落后于75-80吉瓦的产能。用于太阳能电池板的多晶硅的多数生产商，每销售一公斤都在赔钱；目前的现货价格是每公斤13美元。难怪今年有关多晶硅生产商（如REC Silicon）关闭美国工厂的消息令人振奋，此类消息推高了在美国上市的中国多晶硅厂商大全能源(Daqo)和韩国OCI的股价。

Matters could still get worse, though. Norway’s Elkem, now owned by Bluestar Group, a subsidiary of ChemChina, can make polysilicon profitably even at current prices. Demand from China, the largest market for installations, is slowing and represents little of future growth, according to IHS. More heat and less light required.

然而，情况可能还会变得更糟。目前由中国化工(ChemChina)的子公司蓝星集团(Bluestar Group)所有的挪威埃肯公司(Elkem)，即便以当前的价格生产多晶硅尚能盈利。据研究机构IHS表示，全球最大太阳能装机容量市场——中国的需求正在放缓，且未来增长预计将微不足道。显然这个市场需要多一点热度，少一点刺眼的光。