Globally, over 2.1 billion people still do not have access to safe drinking water. In fact, as a result of climate change, half of the world’s population is predicted to be living in areas of high water stress by 2025.

While travelling around Thailand in the 1990s, Dutch engineer William Janssen was impressed with the basic rooftop solar heating systems installed on many homes, where energy from the sun was absorbed by a plate and then used to heat water. Almost two decades later, Janssen used this basic idea to develop a portable device called desolenator, which uses energy from the sun to purify water. Janssen had spent a large part of his career living in water-scarce regions, including Abu Dhabi, which will soon be home to the world’s largest desalination plant and where almost all drinking water is produced through desalination. This motivated him to find a more sustainable way of producing safe drinking water. What started out as a hobby project in his living room became the desolenator prototype in 2012. It was originally developed in the Netherlands where it is registered as an intellectual property. Since then, the company has been working closely with Imperial College in the UK to build on the technology.

The desolenator is a mobile, off-grid desalination unit with a solar panel that distils water using the waste heat created during electricity production. The device can use water from the sea, rivers and boreholes as well as rainwater and clean it for human consumption. It does not require any kind of filter, membrane or chemical, and it can produce around 15 litres of distilled water per day. Typically, solar panels are only around 15 per cent efficient while the rest of the solar energy that they receive is wasted as heat. The desolenator uses a patented system that combines this “waste” thermal energy with the electrical energy produced by the panel and uses it to boil the water. The water vapour produced is then condensed in an internal heat exchanger, which results in clean drinking water. The leftover heat is fed back into the system in a continuous cycle to keep the production running. The device, which looks like a thick solar photovoltaic panel on wheels, can be used by a wide range of users. These include homeowners in the developing world who do not have a constant supply of water as well as people living off the grid in rural parts of the US.

The company initially targeted developed markets such as Cyprus and Australia, working with existing distributors on a commission basis to reach customers living in coastal areas with non-potable municipal water. In 2017, it entered the Indian market and in 2018, it was awarded the second prize under the $1 million Global Startup Challenge organised by the Andhra Pradesh government, winning $100,000 as an award sum. Desolenator has won many other awards in the past and received investment from several companies globally. Currently, three types of desolenator are expected to be manufactured – a portable model, a household model and a community model. According to the company, the device has a lifespan of 20 years and needs minimal maintenance. It also comprises a miniature computer, which enables pay-per-use mobile micropayment, remote monitoring and data analytics. As far as the price of the system is concerned, it varies depending on the place from where it is bought. In the developing world, the price depends on the deal negotiated with aid organisations while in developed countries it can be bought at around $1,000 per unit.

Janssen expects his solution to help people living in places where water is a scarce resource, in countries where there is not enough money to build desalination plants, and in remote places where tap water is unavailable.

Technology such as this could offer a truly sustainable way to address the growing global water crisis, with people no longer able to rely on local sources or a national water grid. It is part of a larger movement towards technologies that leverage renewable energy to improve water supply in a sustainable manner.


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