????太陽能的一大缺陷，也是比較明顯的一個缺陷就是，沒太陽的時候不能發電。現在，特斯拉（Tesla）、比亞迪（BYD）和博世（Bosch）等多家公司都推出了新一代鋰離子蓄電系統。它類似于電動汽車蓄電池，只不過儲備的是住宅太陽能系統發的電。它就相當于在你家里放一塊大電池，然后把你家屋頂太陽能系統發的電存儲在里面，以備雨天之用。

????這種系統的優點是停電時它能為你家的照明和家電提供1-2天的電力。你還可以在用電的時候進行控制。實行浮動電價的地區，也就是說峰值時段電價較高的地區，普通家庭可以在谷值時段儲備太陽能電力，然后在峰值時段使用——比如某個炎熱的下午，家家戶戶的空調都嗡嗡作響的時候。

????它對電力公司也有好處。大量太陽能電池可以幫助電力公司將可再生能源整合到電網中。太陽能時斷時續，也就是說它會突然涌進電網，也會突然消失，從而造成供電不穩。把太陽能電力存儲下來就能消除這樣的波動。今年10月份，加利福尼亞州監管部門要求電力公司在2020年之前將其可再生能源電力儲備能力提高到1.3吉瓦，大大促進了太陽能電力存儲的發展。

????不過，太陽能電力存儲的一大障礙是成本。這類系統造價很高，而且還不清楚回報率如何，甚至都不知道能否產生回報。中國電池制造企業比亞迪的太陽能電池系統售價介于3000-10000美元（18435-61450元人民幣），具體價格視電池規格而定。沃倫?巴菲特的伯克希爾哈撒韋公司（Berkshire Hathaway）持有大量比亞迪股份。截至目前，比亞迪的這些產品在歐洲一直銷路良好。比亞迪高級副總裁李柯說：“歐洲對我們來說不僅僅是個市場，同時還因為歐洲政府推出了很好的獎勵機制。”

????美國的情況則有些不同。在美國，太陽能電力存儲沒有補貼。李柯認為，租賃模式——就像屋頂太陽能系統供應商SolarCity和SunRun所做的那樣——也許會激活美國市場（家庭不必承擔前期成本，只需每個月支付較少的使用費）。

????雖然存在定價問題，但越來越多的專家相信，隨著電池產量上升，技術進步以及成本的最終下降，太陽能電力存儲有著光明的長期前景。布隆伯格能源（Bloomberg Energy）預計，到2020年，太陽能電力的電池存儲成本每度可下降57%。投資研究機構Lux Research估算，得益于來自日本和德國的旺盛需求，全球太陽能系統及電力存儲市場的規模將從今年的不足2億美元（12.29億元人民幣）猛增到2018年的28億美元（172.06億元人民幣）——這個消息對希望擺脫供電網絡限制的家庭來說一個好的開始。（財富中文網）

????譯者：Charlie

????One of the great -- and somewhat obvious -- shortfalls of solar power is that these systems cannot generate electricity when the sun's not shining. Now a number of companies including Tesla (TSLA), BYD, and Bosch are offering a new generation of lithium ion battery storage systems -- similar to those used to power electric cars -- to capture electricity generated by residential solar systems. Put a big battery in your home, and store the electricity generated by your rooftop system for a rainy day.

????The advantage of such systems is that in power outages, you can still have as much as a day or two of power to run your lights and appliances. You can also control when you use your electricity. In markets where utilities have variable pricing -- which means higher prices during peak hours when demand is high -- a homeowner can store his solar power when rates are cheap and use it when rates soar -- like on a hot afternoon when everyone has the air conditioning humming.

????There are advantages for utilities too. Having lots of batteries in the system helps power companies integrate renewables into the grid -- solar produces power intermittently, which means it surges in and out of the grid, causing instability. Storage helps level off these bumps and dips. Solar storage got a big boost in October when California regulators required utilities to procure 1.3 gigawatts of renewable storage capacity by 2020.

????The big drawback for storage, however, is price. These systems are expensive, and it's not at all clear what the payback is or even whether there is one. BYD, the Chinese battery maker in which Warren Buffett's Berkshire Hathaway (BRKA) owns a significant stake, sells a solar battery system that ranges from $3,000 to $10,000, depending on size. So far BYD's system is selling well in Europe. Says BYD's senior vice president Stella Li: "We have more of a market in Europe because the government incentives there are good."

????It's a different story in the U.S. where no subsidies exist for solar storage. Li thinks that a leasing model -- like the ones available for rooftop solar systems from providers like SolarCity (SCTY) and SunRun -- might help kick-start the market here. (Instead of paying the full cost of a system upfront, the homeowner pays a low monthly fee for solar power.)

????Despite the pricing problem, a growing number of experts believe the long-term future looks bright for storage as battery production goes up, technology improves and costs eventually come down. Bloomberg Energy predicts that battery storage costs will fall 57% a kilowatt-hour by 2020. Thanks to strong demand in Japan and Germany, Lux Research sees the global market for solar systems combined with energy storage growing to $2.8 billion in 2018 from less than $200 million this year -- a good start for homeowners who want to free themselves from the grid.