Solar Powered Cities
Tech Level: 10

With energy costs soaring and dependence on fossil fuels in general is increasingly called into question, both municipalities and individual property owners will be looking for cheap, renewable sources for power. Far from being just a fashionable "green" trend anymore, more and more people are looking to solar power as a viable economic alternative to the often volatile costs of traditional power supplies.

Solar cells for buildings have been available for decades, but modern systems are proving cheaper, lighter, more versatile, and most significantly, far more efficient in converting sunlight into electricity than ever before. The most modern solar cells have an energy conversion efficiency rate (how much of the energy in the sunlight hitting the cell is converted into usable electricity) of between 42% to 56%. Also significantly different from earlier solar power set-ups, modern systems can feed power into rechargeable batteries during the day for use during the night. A few municipalities in Great Britain, for example, have adapted the wide-spread use of solar-powered streetlights.

Some cities in various parts of the world are beginning to mandate or heavily push for the use of solar power in individual homes, either in the form of solar water heaters or as the more traditional electricity-generating panels. Many companies are also showcasing "green" facilities and skyscrapers that are powered in whole or in part by solar energy cells. Individual home owners are discovering that power generated by their cells can not only lower their electricity bills, but excesses during low-use periods can be fed back into the grid, and actually earn them money back from local power companies. In many parts of the US, a number of tax incentives or rebates are available to home owners and contractors who install solar energy cells in new buildings, and more are being proposed at both the local and federal level.

This all points to a trend that can lead to solar-powered cities--urban areas with ubiquitous solar cells on every roof top or sunward-facing wall. Though it currently seems unlikely that this alone can meet all of a modern city’s energy needs, they can help to greatly offset energy costs to individuals as well as to the city as a whole.

Also of significance is the fact that solar cell systems are much simpler to repair and maintain than emergency generators, and as many modern designs incorporate themselves into the integral structure of a building roof, they are more likely to survive certain extreme conditions such as flooding. During the hurricane Katrina disaster, for example, many of the city’s emergency generators for hospitals and other facilities were knocked out by flooding and storm damage. The presence of a solar cell alternative could have offset at least some of the power loss to these critical installations.

There would be some downsides, of course. Those concerned with the visual aesthetics of historic cities (not a small concern in urban areas that depend on tourist dollars) may bemoan the sudden cropping up of thousands of large rectangular black panels that would suddenly dominate the skyline roofs and walls. Also, roof space on many building is already at a premium for a number of systems, including vents, air conditioners, water towers, and so on. Solar cells would only exacerbate roof crowding.

Even though solar powered cities are a technological innovation that could be created today, chances are it will be the end result of the gradual retooling of the industrial world’s energy production philosophy and infrastructure in the decades to come.


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