Energy in Cities – Peeing Out Of The Window.

25th May 2012

It’s a hot day, you’re drinking coffee and looking out across London from your apartment window. You’re thirsty and this is your third cup of coffee. You know coffee is a diuretic and it’s hardly surprising you need to visit the bathroom before setting off for work.

By the time you walk out through the front door of the building the liquid formerly know as coffee is already ahead of you. It is barrelling along through pipes under the street en route to a sewage processing plant. There it will be cleaned up and pumped into the Thames. At some point it will be extracted, purified and used as drinking water again: perhaps even turned back into coffee. This process is repeated up to seven times - actually that’s probably an urban myth.

We are lucky that, at some point, our forbearers took on the task of building a citywide sewage transport and processing system and mains water purification and distribution infrastructure. Actually that point was when central London stank of human waste thrown out of windows into the street and the population was poisoned by drinking water contaminated by excrement.

Now you have arrived at your glass palace of an office where the sun has already lifted the temperature to thirty degrees. If you’re lucky you can open a window; more likely you just crank up the air conditioning. Either way the heat from your office ends up out in the street. You probably noticed as you came out of Starbucks, with yet another cup of coffee, that the sun baked pavement and buildings had turned the street into an oven. Ironically, just a week ago, you were shivering and turned up the heating - no doubt you’ll being doing the same in the autumn.

So here we are today with energy where a hundred and fifty years ago the Victorian era city planners and engineers were with sewage. As was the case in their day the problem has become steadily worst until something needs to be done. We are now on the verges of the ‘Great Energy Stink.’ The heat we dump out of buildings makes summer in the city almost unbearable. That cocktail of warm air and particulates causes health problems. However, in the winter, the city uses vast amounts of electrical energy just to keep its inhabitants warm. Within months the city you live in will turn from being the country’s biggest solar panel and source of heat pollution into the country’s largest consumer of heat energy. Producing the energy needed to heat the city is also a pretty toxic process. It took some time to track down the source of cholera to a single water pump in a London street. With all of our scientific knowledge it has taken a lot longer to discover the link between electricity generation and global warming.

When I started work on the passive solar collection and thermal energy storage project I did so with the urban environment in mind. Having carried out research for a report called ’Watts in Store,’ I had spent some time looking the ‘urban heat island’problem. While renewable energy has becomes something of a feature, and money-spinner, in rural areas it is arguably more relevant in cities. Rural energy use is a megawatt-sized problem whereas London and other cities present the energy producer with a terawatt size challenge.

We take urban water and sewage systems for granted. They are an obvious and essential component of a modern city’s infrastructure. However for the Victorian engineer, building this basic amenity meant overcoming a number of daunting problems. It tested the limits of civil and mechanical engineering and required serious investment in infrastructure – miles of pipe work and massive pumping stations. For today’s architects, city planners and energy companies managing heat energy in urban areas will be no mean feat – far easier to keep peeing heat out of the window.

Stay cool and maintain a clear view all you glass and sunshine people on what looks like turning out to be a hot weekend.

Peter Kruger

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