Solarist presents innovative solar powered solutions that solve environmental problems like water scarcity. Solarist’s first product is a small-scale seawater reverse-osmosis unit with excellent energy efficiency. Recently, the system delivers up to 400 L/Hr of potable water, from seawater (at 40,000 ppm), while consuming less than 1100 Watt of electrical power. We are also working on developing it to deliver up to 1500 litre/hour. This represents a specific energy consumption of less than 3 kWh/m3. Moreover, the flow is controlled in order to reduce the power consumption. The most important feature is the energy recovery, and the use of a variable water recovery ratio by a controlled algorithm. The significance of the system is that it may be operated from variable intermittent renewable-energy sources, such as solar-photovoltaic. The PV is characterized by its high capital cost (per kW) and the variability of the energy that they are able to provide. Thus, in order to make PV-RO economically applicable, the pumps and RO membranes must offer excellent energy efficiency, and this is achieved by carrying out maintenance over a wide operating range.