A world of increasing energy demands and diminishing resources must necessarily seek novel sources of power.

Renewable energy has been a perennially popular topic of conversation in recent years, but the idea far predates all talk of “peak oil”: For example, both wind and solar power are centuries-old ideas. US Patent number US389124, “Solar Cell” dates from 1888, while wind energy is older still: In Europe, windmills have been used to grind grain for much of the last millennium. (However, a windmill was first used to produce electricity relatively recently, in the year 1887 in Glasgow.)

Alternatives to fossil fuels and other nonrenewable resources continue to be developed today. Here are 8 of them. Though many involve considerable startup costs and are not really implementable on a large scale, they nonetheless represent exciting new directions of thought. Let’s optimistically hope that they’ll help steer energy production towards a more sustainable future (through cool engineering).

1. Ocean waves

This is a story about a buoy and a girl. That’s a horrible pun, but really, it is: Electrical engineer Annette von Jouanne is attempting to harness the power of the sea via a carefully built buoy. The idea is remarkably simple: Anchor a copper wire. Put a magnet around it. Move the magnet up and down (in this case, that’s the job left to the waves). This induces an electric current in the wire, as many will remember from high school physics lab. Inspired by the heaving of the water while surfing off the coast of Hawaii, von Jouanne made the idea bigger and put it in the sea in an attempt to utilize the constantly present kinetic energy of ocean waves.

It turns out that the idea works: A buoy she tested in her lab with a simulated average wave produced three kilowatts of power, or enough to power two houses, which provided impetus for further tests. Her first prototypes worked poorly, but, as she says, breakthroughs are almost always born of failures, and the trajectory of her work is optimistic: Over the years, her designs have improved, and she has subsequently seen an increase in both governmental science funding and the interest of clean-energy companies.

Von Jouanne remains a leading figure in the rapidly developing field of wave energy research and works in the hope that her buoys will one day help bring clean renewable power to the public.

2. Trash

The idea is utopian: a machine that turns trash into energy. In this case, a little bit of utopia has withstood real-world field tests, albeit in a less than utopian locale: The US Army used two refuse-powered generators to power its operations near Baghdad, Iraq. This helped alleviate several problems for the army in hostile conditions, because it meant a reduced need for fuel convoys and garbage runs, both of which were easy targets of attack. This is how the army came to run partly on its own shredded paperwork and food scraps.

The system works roughly like this: Dry trash like cardboard and Styrofoam is compressed into pellets and heated until it becomes a synthetic gas somewhat like propane. Meanwhile, food scraps and liquids are fermented into ethanol. The syn-gas and the ethanol are combined to power the generator. The generator does need some external energy as well, but it uses about 5% of the diesel that such a generator would normally require, while the base produces just 1/30th of the trash it ordinarily would.

The exploits of the US Army have demonstrated the viability of garbage power, so perhaps it’s time to put our trash to use in a less martial context.

3. Soccer

Imagine using the energy generated by a game of soccer to power your reading lamp. That’s exactly the idea behind the Soccket, a soccer ball that stores the kinetic energy generated by its use in play as electrical power.

Jessica Matthews, a Harvard undergraduate with roots in Nigeria, wanted to find a way to use soccer, the world’s most popular game, to improve the lives of people in developing countries. The Soccket, which can produce 3 hours of LED light with 30 minutes of play, is the result. Matthews says she hopes her invention can supplant the use of kerosene, recalling visits to Nigeria during which the toxic lamp fuel made it hard for her to breathe.

Though limitations of the project are evident — the Soccket’s relatively high cost, the small scale on which it produces power — the idea of creating power out of play is an elegant one.

4. Bicycles

Turn your crank, turn on a light? Bike-powered generators can generate a fair bit of power: For example, a professional cyclist can pedal at well over 400 watts for an hour (a mere mortal may produce half that). Of course, this barely puts a dent in most people’s energy consumption: The average American home used 940 kilowatt-hours a month in 2011. Nevertheless, your bike is more than enough to charge small devices, while perhaps giving you a healthy sense of how much effort a kilowatt-hour really entails.

Some organizations have put bike generators in the spotlight: This Danish hotel offers its clients meal vouchers in exchange for riding its generator bikes for 15 minutes, while the San Francisco (where else?) based music festival Rock the Bike uses bikes to power its sound system.

Do-It-Yourself enthusiasts can find multiple free plans to build one online.

5. Urine

Sometimes, scarce resources make for innovative solutions. Four Nigerian girls have created a method of generating electricity that’s powered by pee. Their design extracts hydrogen from urine and can produce six hours of power for every liter.

Naturally, their prototype has considerable limitations — its electrolytic cell requires energy to start, and its fuel source, pure hydrogen, is volatile. However, their invention remains an impressive feat of engineering, especially given their ages: None of them was older than 15 at the completion of their project.

6. Speed bumps

Commuters in southwestern England may be creating power with their cars these days: The city has begun installing electro-kinetic road ramps. Each ramp contains metal plates that are compressed when a car passes, powering an internal generator. The resulting energy produced ranges from 5 to 50 kW, depending on the weight of the passing vehicle.

Dorset-based inventor Peter Hughes spent 12 years designing his concept, which can help power traffic lights, road signs, and other city infrastructure.

7. Marine microbes

To a layman observer, electricity-producing microbes seem to teeter on the edge of science and science fiction. However, they’re very much real: Researchers at the university of East Anglia have been studying a strain of bacteria called Shewanella oneidensis, which produces proteins that can transfer electricity into metals.

The marine microbe has successfully been synthesized artificially, and laboratory tests have demonstrated that the energy produced by proteins on its surface can be harnessed for electrical power. Dr. Tom Clarke, a biologist at East Anglia, explains:

Scientists have known for some time bacteria have an effect on minerals and metals, but this is the first time it has been shown they discharge an electrical current directly. There may be other species that do it even better than ours. These bacteria show great potential as microbial fuel cells, where electricity can be generated from the breakdown of domestic or agricultural waste products.

8. Windbelts

The idea of wind turbines is an established one in alternative energy circles, but the idea of a windbelt is relatively new: Shawn Frayne conceived of it during a 2004 trip to an off-grid fishing community in Haiti. Unlike a traditional geared turbine, which uses wind to power its rotors, a windbelt uses an aerodynamic phenomenon known as aeroelastic flutter to pull energy from wind.

The technology is capable of extracting energy from the wind at scales and costs inaccessible to traditional turbines. Headed by Frayne, the Humdinger Wind Energy Group is currently working on developing and deploying several sizes and models of its prototype around the world — windbelts now exist in Hong Kong, Spain, Ecuador, and Canada.