SolarCity and Tesla shine spotlight on solar-battery systems

When SolarCity and Tesla上个月宣布that they are teaming up to offer battery backup for residential solar PV systems, they generated much excitement and a disproportionate amount of press. FromGreentech Mediato the纽约时报, stories abound about how the union of these two companies heralds the next stage in the evolution of distributed energy resources.

Yet solar-plus-storage actually has been around for decades. In fact, it kickstarted the solar industry in the early 1980s. A bunch of marijuana "farmers" in Northern California who weren't connected to the grid needed a way to get electric lights for their grow operations. Ayoung hippiestumbled upon an ARCO solar panel at a consumer electronics show, founded AEE Solar soon after, and started powering off-grid homes with solar panels and car batteries. His customers always paid with cash.

With the 1990s' deregulation and incentives for solar PV, grid-connected systems became popular. The only people still worried about storage were those trying to electrify remote homes in less developed countries. But solar and storage systems became a hot topic once again in 1999, when people worried about Y2K and the potential end of society as we know it. "We were glad when homeowners wanted to learn about grid-tied PV systems with battery storage," Johnny Weiss, founder of Solar Energy International, told RMI. "After Jan. 1, 2000 came and went without disaster, interest in batteries clearly seemed to become less important."

这种兴趣又回来了。无论是由于诸如超级风暴桑迪（Superstorm Sandy）之类的灾难，当数以百万计的房屋失去动力，或者由于商业客户通过刮胡子而减少大量需求费用的能力，将太阳能和电池组合在一起的想法都引起了很多重新注意。

Making storage sexy

新的太阳能和特斯拉合作伙伴关系使用特斯拉的电池技术为Solarcity的住宅太阳能客户提供备用功率。但是，实际产品并不是那么新。其他人多年来提供了类似的产品。

Green Charge Networks' GreenStations and Stem's battery systems, for example, decrease electrical costs for commercial and industrial customers by storing power during non-peak hours for use during peak periods.绿色站already have been installed in multiple locations throughout New York City.干claims utility bills for companies using its storage system will be cut by 10 to 40 percent. Then there's Solar Grid Storage.Maryland's first microgrid, installed in October at Konterra headquarters, uses a 402 kW array with a Solar Grid Storage system that will keep 50 kW online for more than four hours if the grid goes down. On the residential side, NRG offerssolar canopies- 由光伏面板构建的阴影结构，并带有电池，以存放电力，供晚上或停电期间使用。公用事业公司也正在参加比赛，圣地亚哥Borrego Springs和萨克拉曼多市政区目前都在测试房屋存储。

What is exciting is all the attention that storage is now attracting, thanks to the big names ofTesla and Solar Cityand the man who links them: Elon Musk. Musk seems to bring high visibility to anything he does, and the solar-plus-battery offering is no exception.

RMI高级助理Leia Guccione说：“众所周知，太阳能城和特斯拉都是叛乱分子和破坏者，这就是为什么对这一特定产品的关注。”虽然没有多少人注意太阳能电池系统，但“特斯拉添加了这种性感元素，人们现在肯定在关注。”

Yet the significance is not that Tesla and Solar City are bringing us into a new paradigm, but that the solar-plus-storage idea is gaining a whole lot of traction.

Guccione说：“很长一段时间以来，电池能量存储被称为能量的圣杯；人们说，当我们弄清楚冷融合时，它将变得可行。”“现在人们知道这是一项从婴儿期出现的技术，越来越多的公司推出商业产品。这进一步证明了电池能量存储在这里，并且可以留在这里。”

RMI助理Bodhi Rader补充说：“越来越多的人进入该空间。我们可以称其为改变游戏的时刻。”

Beyond backup

What's really exciting in the solar-plus-battery arena is what batteries offer beyond backup — to both solar PV and the grid and utilities. Voltage and frequency regulation. Black-start capability after macro- or microgrid outages. Using batteries as a less expensive alternative to peaking plants during high demand periods. Demand charge reductions via peak shaving. Shifting load profiles with batteries to take better advantage of time-of-use electricity pricing. The list goes on.

如果当前的趋势是任何迹象，那么很快电池可能会成为包括住宅在内的太阳能光伏系统的常见部分。Guccione表示：“这将是一个全家能源解决方案。”“这就是下一个边界的地方，我们希望看到太阳能和特斯拉去那里。”

And pretty soon it won't just be for those in the higher-income bracket. Bloomberg New Energy Finance predicts[PDF]that电池存储成本will fall 57 percent by 2020. Lux Research sees the global market for PV systems combined with battery storage growing from the current $200 million a year to $2.8 billion in 2018.

"We look at economics as the thing that will bring the critical mass to the tipping point," says Guccione. "There has to be a whole wave of first movers, but the increasingly favorable economics will evolve solar-plus-battery systems from early adopters to a mainstream solution."

这就是为什么如此令人兴奋的原因，以至于越来越多的公司开始提供电池存储。将询问太阳能安装人员是否会更频繁地提供电池存储选项，并且随着需求更多，参与者进入该领域，价格将下跌，公用事业公司将提出创新的商业模型，而没有电池存储的太阳能系统似乎会如此最后- 十年。

New business models will make it easy for customers to add storage to existing systems or build storage into new systems, through leasing and third-party financing models similar to what has made rooftop PV so accessible. And solar-plus-battery systems will be available to the masses, not just to off-grid pot farmers who can pay in cash. This is all good news for people wanting clean, reliable electricity.

LucAdp通过的太阳能电池图像Shutterstock.