Smart cities are coming.

Municipal governments around the globe are employing big data and Internet-of-Things applications to improve many aspects of daily life. Along with continued population growth, cities are facing increasing challenges such as congested transport and the need to supply sufficient energy to meet demands of their growing populations. A city’s ability to provide renewable energy, alongside its means to efficiently manage energy storage, will be increasingly important.

CNBC looks at three cities working on becoming “smart.”