能源storage innovations provide a boost for renewables

This article originally was published by耶鲁环境360and is reprinted here with permission.

Intermittency long has been considered the Achilles heel of renewable power generation. The U.S. electricity grid, after all, is largely built around big, centralized coal and nuclearpower plantsthat can run all the time, whether demand is high or low. In contrast, grid engineers have no control over when the sun shines or when the wind blows, making it difficult for solar or wind to fully supplant the dirty-but-reliable fuels that keep the power grid humming along smoothly.

终于可以被改变。大型，技术先进energy storageprojects — from massive lithium-ion battery installations in the California mountains to giant, compressed air caverns under the Utah desert — recently have been commissioned or announced. And while numerous hurdles remain — including needed improvements in reliability and safety, regulatory and market changes and, of course, cost — policy moves in many states are steadily nudging the industry forward.

In a report published last month, the consulting firm Navigant Researchestimated that 362.8 megawatts of new energy storage projects- 足够功率数万家园 - 已经在全球独自宣布在过去的一年。通过研究公司的另一份报告预计IHS全球能源储存装置将上升由6个千兆瓦annually by 2017, reaching 40 gigawatts by the end of 2022. In the United States, the Department of Energy’s全球能源存储数据库列出了在规划和建设阶段104个项目。在世界各地，还有另外158个这样的项目。

“这是怎么回事，”卫林，女主席说全球能源存储联盟，储能贸易集团的一个新成立的国际联盟。“我们超越了临界点。”

Storage technologies take on a variety of forms, including the most familiar: pumped-storage hydro. Here, water is simply pushed uphill, where it is held in a large reservoir and allowed to flow back down as needed to generate electricity. This technology is the oldest form of bulk energy storage and currently represents the vast majority of such installations around the world. But with support waning for the sort of big dams needed to make pumped-hydro work, alternatives are being developed or refined.

技术供电的iPhone和其他设备基本上巨头版本 - - 各种设计，包括锂离子电池，例如电池电量迅速与一些工具抬头。一些公司在压缩空气储存，使用的可用电力来推动空气进入一个密闭的空间，无论是在地下或坦克试验，并让它扩大和转涡轮在需要时。飞轮，一个古老的技术，利用现有的电力来启动低摩擦轮旋转，动力储存动能;车轮然后逐渐慢下来，释放电力回馈到电网。一些大型的太阳能发电厂可以关注太阳的能量巨热交换器充满专业液体盐，它可以保留以备后用热发电。

In its December 2013 overview of grid energy storage technologies, the U.S. Department of Energy identified four challenges(PDF)阻碍广泛部署或收养：可靠性和安全性证明;合理和公平的规定;行业验收;和成本。

抽水蓄能水电站Glems的涡轮机和泵的大厅附近的麦琴根，巴登 - 符腾堡州。抽水蓄能水电是体积能量储存的最古老和最广泛使用的形式。（来源：通过维基共享资源费利克斯·柯尼希）

但是，州政府在政策方面努力，以启动该行业，并得到它在许多隆起。一些国家和他们的大事业 - 特别是纽约(PDF)，夏威夷和华盛顿- 已开始推动大存储计划。而在加利福尼亚州，2013年法案要求该州的三个最大的公用事业2020年纳入存储的1.3万千瓦到电网。

Southern California Edison, one of the state’s biggest utilities, recently unveiled one of the largest battery storage systems in the country — a32兆瓦 - 小时的锂离子设施in an area projected to generate 4,500 megawatts of wind energy within a few years. Other developers in the state already have applied to connect close to twice the amount of California’s new storage mandate, although Anissa Dehamna, a senior research analyst with Navigant Research, cautioned that the queue represented more of a “wish list” than an actual projection of what will get built.

Still, fledgling efforts are underway across the country. Last year, the Solana concentrating solar plant in Arizona began operations using molten salt storage, allowing the plant to keep feeding power to the grid for六小时太阳下山后。一种索拉纳的发言人老板，阿文戈亚太阳能，在一封电子邮件中表示，该公司有八个涉及在建或在世界各地的先进的开发类似的存储更多的大工厂。

More recently, a huge project was announced that will involve a massive new wind farm in Wyoming, hundreds of miles of new transmission lines and a $1.5-billion compressed-air storage system involving four massive underground caverns near Delta, Utah.

“I think we’re in the in-between stage between proving the technologies — which has happened — and getting the technologies ready to scale in the market,”Dehamna说过。她补充说，公用事业规模的锂离子电池均领先于其他技术的市场准备方面。

但大卫·马库斯，存储公司的创始人General Compression说，风电场与存储相结合，如他的公司的压缩空气技术已经具有成本效益的解决方案。“风加上适当的存储应该能够提供相同的服务作为一种新的联合循环燃气电厂，并且是有竞争力的，其中天然气价格都很高，”他在一封电子邮件中说。

A project involving a new wind farm in Wyoming, hundreds of miles of new transmission lines and a compressed-air storage system near Utah recently was announced.

压缩空气存储在大洞穴等proposed site in Utah are likely to remain a niche market, experts say, given that it requires a very specific underground geology. But companies such as General Compression, SustainX and LightSail Energy are working on smaller, more modular systems that use a variety of storage media and tackle efficiency losses and other challenges. Such modular applications could range in size from one to dozens of megawatts.

Flywheels, meanwhile, are ideally suited for short-duration needs, such as smoothing out brief hiccups in electricity flowing through the grid or filling in while big power plants ramp up to full capacity. Dehamna said that flywheel technology costs have come down significantly in recent years, that they are extremely efficient and that they don’t face the same degradation problems that batteries do. “For second-to-second balancing of the frequency of the grid, flywheels do exceptionally well,” she said.

可以肯定，存储技术的发展不仅限于美国。在362.8兆瓦的新项目是Navigant的强调几乎均匀北美，欧洲和亚太地区之间进行分配。

Lin pointed out that while storage is great for incorporating可再生能源into modern grids, it also could play a big role in developing countries, where people lack electricity access and grids are weak. India, for example, with a notoriously shaky electrical grid, is开始推硬for storage for both renewables integration and rural electrification projects.

In the United States, the regulatory environment still lags behind the industry, and stakeholders, led by the储能协会，正在推动提高联邦政策既激励存储技术和消除障碍的持续发展，将其纳入电网。

“Rules haven’t been written so that the benefits can be monetized appropriately,” said Ravi Manghani, a senior grid analyst focusing on energy storage for GTM Research.

其他专家提醒说，所有这些新兴的存储技术，娶一个陈旧的电网结构将证明艰巨。虽然成本是电池，飞轮及压缩空气储存迅速下降，Navigant公司的Dehamna建议，辅助费用可能没有跟上。需要连接存储到电网的硬件，例如，以及使其正常运行所需的软件，她说，仍然需要删除。

Richard Brody, vice president of business development and sales at flow-battery producerPrimus Power, said the recent increase in interest in his technology has brought in peripheral developers as well. “We’re seeing strong interest from equipment and integration partners ... as well as from developers and end-users in building new storage projects,” he said.

In 2012, the National Renewable Energy Laboratory’s landmark可再生电力期货研究奠定了它认为在美国的一个清晰的路径，以80％的可再生能源发电到2050年该机构，能源部的一部分，估计需要80和131之间吉瓦(PDF)的存储，以支持所有的阳光和风力发电。

这是否会发生是不可能的y for certain, but storage developers such as Marcus are optimistic.

“像风前的太阳能，成本也在不断降低，装置正在上涨和监管机构与适当的补偿拼杀，”他说，“这些东西走到一起 - 比许多慢想，但他们来了。”