From the roof to the bathroom: the links between solar energy and water consumption
How the sustainable use of one finite resource could contribute to regulate the use of another? Could the sustainable generation of energy also regulate the use of water in areas characterised by water shortages? I am exploring these thoughts this week, as I talk to users of solar hot water systems in Mumbai and Thane. Leaving the theory aside for this blog post, I am searching for ways to draw links between ‘practices of production’ and ‘practices of consumption’ of energy and water. It would be great if you give me any comments on these thoughts, both positive and negative. Be harsh! That helps.
One thing that I like about solar hot water systems is the way in which the technology responds to the seasonality of the city. If it is cloudy today, then there will be no hot water tomorrow. Slowly, after many mornings of lukewarm water, users get to understand that. Next week, as the Monsoon arrives in the western coast of India, we will see how the solar hot water systems that now adorn Thane’s roofscape start producing less and less hot water. Solar hot water systems portray a technology that, instead of aiming to overpower, is aligned with nature and its cycles; they are an example of a modernity that acknowledges uncertainty and recognises the multiple links between nature and society. This stands in opposition to a modernity where technology is meant to severe nature and society by giving us full and antiseptic control over the environment (see Beck and van Loom 2010). The solar hot water systems depict a dance between nature and technology, where undoubtedly the city is recognised within the context of nature and urban infrastructure as a mediator between the two.
In a beautiful way, solar hot water systems link practices of production (of energy) and practices of consumption (of water). Commercial systems in India are usually designed to provide 125 lt of hot water for a family of five. Each person gets 25 lt of hot water every morning. This is sufficient in a country where, for the most part, each person uses between 20 and 30 lt of water during its daily bucket bath. Most of the Indian families that I have talked to have a clear awareness of the need to preserve water (an awareness that is strengthened by a water provision service limited to some hours per day!), so the practice of having a bucket bath is today very much rooted in a water conservation logic. If shower baths were predominant, since a typical mixer shower uses about 10 litres per minute and a typical shower lasts 5 minutes, the consumption per person would be 50 lt instead of 25 lt. Under this scenario, the typical commercial solar hot water system would be useless, as only the first two people who take a shower would get hot water! Up to a point, the amount of hot water available (an energy dynamic) plays a role in regulating the daily practice of taking a bath (a water dynamic).
Of course, the social mechanism for the regulation of water consumption is there regardless of the presence of a solar hot water system. People who use electric geysers to warm up the water for their baths also favour a bucket bath due to water conservation practices. Is the solar hot water system reinforcing a low water consumption practice? What are your thoughts?
Jonathan Silver
Andres Luque
