风力发电作为新能源的第一大发电主力,具有间歇性和随机性的特点。风力发电出力难以精确预测,从而面临着一大发展瓶颈就是弃风限电问题。由于近年来风机大规模建立,但是电网设备没有能够及时跟上,导致如果全部风机都运行会有拖垮整个电网的危害。因此部分风场会被强制限制发电量,让风机停止发电。

弃风限电问题已严重困扰着我国风电行业,已经成为制约产业健康持续发展的最大绊脚石,也是我国兑现应对气候变化国际承诺的巨大障碍,到了非解决不可的地步。风电与大蓄电相结合就是伴随新能源快速发展的契机下诞生的应对措施,由于其能改善电能质量与吸纳弃风弃光电量的优势得到新能源业内的各方重视。

风电直接应用与大规模蓄电相结合可以均衡供电,提高风电对用电企业的供电质量和能力,从而减轻电网“谷”期的压力,增加“峰”期的供电能力,同时提高风电的使用价值并充分发挥风电分布式供电优势,扩展风电的作用。所以,与大规模蓄电相结合,是单纯风电直接应用的发展和拓宽;既适用于大型风电场,也适合中、小型风电场;并可提高分布式供电的质量和经济性。

目前,可以应用于智能电网领域的化学电源主要有钠硫电池、全钒液流电池和锂离子电池。 钠硫电池是美国福特(Ford)公司于1967年首先发明公布的,它以金属钠为负极,硫为正极,陶瓷管为电解质隔膜。但是钠硫电池系统成本高,运行需要附加供热设备来维持温度,同时过度充电时很危险,因此在安全性和免维护性方面存在不足。

全钒液流电池的研究始于1984年澳大利亚新南威尔士大学的Skyllas-kazacos研究小组,它是一种基于金属钒元素的氧化还原可再生燃料电池储能系统。全钒液流电池可以达到风电的全寿命周期不更换电池,可通常使用的电解液储槽大、较难管理,而且正极液中的五价钒在静置或温度高于45℃的情况下易析出五氧化二钒沉淀,影响电池的使用寿命。

锂离子电池储能则是目前储能产品开发中最可行的技术路线。锂离子电池具有能量密度大、自放电小、没有记忆效应、工作温度范围宽、可快速充放电、使用寿命长、没有环境污染等优点,被称为绿色电池。

锂电池储能系统在电网正常运行时能够快速、有效地平滑风电系统输出的有功功率波动,在电网故障时能够为电网提供一定的无功支持,并在脱离电网运行时能够稳定系统的电压和频率,有效地提高了风电系统的运行性能。

目前储能形式经济性不明显,不能给风电场带来更多收益,但随着技术进步成本下降,未来可能会有效缓解现阶段限电带来的影响。新能源风力发电需要稳定的储电装置,在这方面,高能量密度的锂离子电池正好胜任这项工作。

As the primary source of new energy generation, wind power has the characteristics of intermittency and randomness. The difficulty in accurately predicting the output of wind power generation poses a major development bottleneck, which is the issue of wind power curtailment and power rationing. Due to the large-scale establishment of wind turbines in recent years, but the failure of power grid equipment to keep up in a timely manner, running all wind turbines would pose a risk of dragging down the entire power grid. Therefore, some wind farms will be forced to limit their power generation, causing wind turbines to stop generating electricity.

The problem of wind power curtailment and restriction has seriously plagued China's wind power industry, becoming the biggest obstacle to the healthy and sustainable development of the industry, and also a huge obstacle for China to fulfill its international commitments to address climate change, to the point where it must be resolved. The combination of wind power and large-scale energy storage is a response measure that emerged with the rapid development of new energy. Due to its advantages in improving power quality and absorbing abandoned wind and solar power, it has received attention from all parties in the new energy industry.

The direct application of wind power combined with large-scale energy storage can balance power supply, improve the quality and capacity of wind power supply to electricity consuming enterprises, thereby reducing the pressure on the power grid during the "valley" period, increasing the power supply capacity during the "peak" period, and at the same time improving the value of wind power use and fully leveraging the advantages of wind power distributed power supply, expanding the role of wind power. So, combining with large-scale power storage is the development and expansion of direct application of wind power alone; Suitable for both large and medium to small wind farms; And it can improve the quality and economy of distributed power supply.

At present, chemical power sources that can be applied in the field of smart grids mainly include sodium sulfur batteries, vanadium flow batteries, and lithium-ion batteries. The sodium sulfur battery was first invented and announced by Ford in 1967. It uses metal sodium as the negative electrode, sulfur as the positive electrode, and ceramic tube as the electrolyte separator. However, sodium sulfur battery systems have high costs and require additional heating equipment to maintain temperature during operation. At the same time, overcharging can be dangerous, resulting in deficiencies in safety and maintenance free performance.

The research on all vanadium flow batteries began in 1984 with the Skyllas kazacos research group at the University of New South Wales in Australia. It is a redox renewable fuel cell energy storage system based on vanadium metal elements. The all vanadium flow battery can achieve the full life cycle of wind power without replacing the battery. However, the commonly used electrolyte storage tank is large and difficult to manage. Moreover, the pentavalent vanadium in the positive electrode liquid is prone to precipitate vanadium pentoxide under static conditions or at temperatures above 45 ℃, which affects the service life of the battery.

Lithium ion battery energy storage is currently the most feasible technological route in the development of energy storage products. Lithium ion batteries are known as green batteries due to their high energy density, low self discharge, no memory effect, wide operating temperature range, fast charging and discharging, long service life, and no environmental pollution.

The lithium battery energy storage system can quickly and effectively smooth the active power fluctuations output by the wind power system during normal operation of the power grid, provide certain reactive power support for the power grid in case of grid faults, and stabilize the system's voltage and frequency when operating off the grid, effectively improving the operational performance of the wind power system.

At present, the economic feasibility of energy storage is not obvious, and it cannot bring more benefits to wind farms. However, with technological progress and cost reduction, it may effectively alleviate the impact of current power restrictions in the future. New energy wind power generation requires stable energy storage devices, and in this regard, high-energy density lithium-ion batteries are perfectly suited for this job.