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Confronting Energy Demand Using Renewables

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This is a cross-post from the original post that I made on my element14 Blog on 3/20/2011

In my last blog post I talked about how we can define sustainability, and the broader implications of “going green” that often go unexplored. As I stressed in that post, devising new, more efficient means of energy generation is important, but far from the only way to achieve a level of true global sustainability. The recent tragedy in Japan and ongoing nuclear crisis has shed a new light on the importance of safe and dependable energy sources. Nuclear power is widely held to be an important means of power production – just ask France: Nearly 80% of their power is generated in nuclear power plants (Enerpub 2007) (Figure 1b).

I’ll be the first to concede that I am not enough of an expert on nuclear power to say whether or not we should be using it; however, there is no doubt that the meltdown in Japan will stir up lots of feelings on the subject (See Hank Green’s video for a superb explanation of nuclear power and the situation in Japan). The Japanese nuclear tragedy will certainly cause the world to turn its eyes to new forms of renewable energy – means that will allow us to simultaneously cut our dependence on fossil fuels while providing a safer and more environmentally friendly form of power than most of the ones we currently rely on. Making this paradigm shift will be no easy or expeditious task; a glance at the graphs below showing America’s and France’s sources of energy reveals the embarrassingly small amount that we currently derive from renewables (Figure 1).

 

Energy Consumption

Figure 1: Power Sources in the USA and France

The world consumes an enormous amount of power, and non-renewable resources won’t last forever (obviously), so let’s take a look at some promising, weird, and awesome means of renewable energy generation…

Piezoelectric Wind Energy

Figure 2: Energy Capture Using Piezoelectric Leaves (Credit: Cornell Computational Synthesis Lab)

Figure 2: Energy Capture Using Piezoelectric Leaves (Credit: Cornell Computational Synthesis Lab)

This isn’t your ordinary wind turbine. Power-generating wind turbines are spectacular, but they are gigantic, disliked by nearby residents, dangerous to flying wildlife, and they require a ton of space. So what if we could scale down wind harvesting into something much smaller? Piezoelectric wind harvesting uses small “leaves” fitted with vibration-sensitive piezoelectrics (Figure 2). When they flap in the wind, the motion is converted to electricity. The power that can be obtained from these is still quite small (Li, 2011), but they offer the unique ability to placed almost anywhere. For example, they could make up the façade of a structure, similar to the ivy that creeps up many buildings.

Meat Power

Figure 3: A Microbial Fuel Cell

Figure 3: A Microbial Fuel Cell

No, that’s not a typo – researchers at Bristol Robotics Laboratory have recently devised a microbial fuel-cell that is capable of generating electricity by digesting bugs (Figure 3). Bacteria inside the fuel cell digest biomass, and devices powered by this fuel-cell are able to steal and utilize the electricity that results. In their research video, they demonstrate a clock that can power itself by attracting bugs to its revolving flypaper and a driving robot that can run for 12 days on just 8 flies. The project derives its idea from carnivorous plants that ingest insects to supplement their diet with extra nitrogen.

Underwater Turbines

Figure 4: Scaled Down Model of the Underwater Turbines (Credit: Daily News)

Figure 4: Scaled Down Model of the Underwater Turbines (Credit: Daily News)

Imagine a wind turbine. Now, stick it underwater. That’s essentially the idea behind Verdant’s generation-five water turbines (Figure 4) which will soon be gracing the bottom of the New York City’s East River. About 30 of these turbines will be placed at the bottom of the river to generate energy from the water’s strong current. This energy will be pumped into the electrical grid where it can power portions of the city. There are already plans to begin installing these turbines in other places, assuming the successful performance of the devices in the East River. The 4th generation of the system has already successfully delivered 70 megawatt hours of grid energy to NYC customers (Verdant).

Biogas Anaerobic Digestion

Figure 5: Biogas Plant

Figure 5: Biogas Plant

A lack of clean renewable energy sources is far from the only problem that we face; humans also produce an inordinate amount of waste, both biological and inorganic. Biogas plants aim to resolve part of this problem while simultaneously providing a source of renewable energy (Figure 5). Similarly to the microbial fuel cells explained earlier, anaerobic generation employs microbes to break down organic matter and release a methane/CO2 mixture call biogas. The biogas can be harvested to provide cheap, clean, on-site energy. This form of power generation is ideal for energy reclamation at waste sites that already have biomaterials available for breakdown (Energy News, 2010). However, it’s not highly feasible as a means of distributed power due to the refinement required to turn it into usable natural gas.

Those are just a few interesting new means of creating energy – it’s far from a comprehensive list. Have you stumbled across any really cool new forms of electrical energy generation? Let me know if the comments, I’d love to hear about them!


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