While solar energy has been an emerging source of renewable energy for many years now with various studies delving into building more robust and compact solar cells, their use as a power source for mobile and small machinery such as wireless sensor networks (WSN) is less discussed. However, with increasing global efforts in subsidizing more sustainable technology and energy, many studies have emerged in the past decade on building solar power based wireless sensor networks. The combination of novel harvesting circuits, mechanisms to obtain maximum possible power, smart power management algorithms and improving energy technology has provided the necessary framework for self-powered WSN nodes that have much longer lifetime. This paper reviews the newer proposed technology that aids the development of Solar Energy Harvesting Wireless Sensor Networks.