When one thinks of “alternative energy,” most are immediately drawn to images of wind farms, solar power, rushing water or geothermal devices. But the truth is that alternative energy can come from the least expected places. All it takes to develop an alternative energy is a need and an idea. Most of those ideas came about from savvy people who needed a unique solution, businesses looking to save money and/or reduce their environmental footprint, or scientists.

Here are five examples of unique and obscure alternative energies.

Kites
According to the BBC, 4 percent of CO2 going into the air comes from ships due to their use in global trade. That is more than airplanes. In 2008, the timber cargo ship MS Beluga SkySails took to the seas with a goal to reduce emissions and it accomplished that with a kite and wind energy.

Once the MS Beluga would reach the ocean it would unfurl a massive 1,722 square-foot kite, which it used to carry the ship along the water and allow engines to work on reduced power. Aside from the environmental impact of reduced fuel use, the company behind the ship also estimated it would save nearly $1,500 a day with the kite.

“We can demonstrate that you can combine economy and ecology,” Verena Frank of Beluga Shipping told the BBC.

Texting
While texting on a regular phone or typing on your computer will not necessarily charge its battery, specially-made devices could allow you to do just that. It is called piezoelectric charging and is activated when certain metals are squeezed or have pressure applied to them. Dr. Madhu Bhaskaran with RMIT University popularized the idea when he released a study on the possibilities. The study was picked up by numerous tech blogs and websites.

“The power of piezoelectrics could be integrated into running shoes to charge mobile phones, enable laptops to be powered through typing or even used to convert blood pressure into a power source for pacemakers — essentially creating an everlasting battery,” Bhaskaran said during a GizMag interview

While the idea sounds interesting, little research has been done to confirm the findings or create an accessible version of the technology. Some have raised concerns over the science of these devices, including the expense, how much pressure would be required and the computer efficiency.

Tofu
There are about 150 small business dedicated to making tofu in the small Indonesian town of Kalisari Village. The locals in the town were constantly running into two problems: first, the tofu-making process wasted gallons of water at a time, and second, they depended on fuel deliveries to heat their stoves and make their product. The solution? Use the water as fuel.

The idea was to “treat” tofu wastewater (nearly four gallons are used to make a pound of tofu) with bacteria. This in turn would create a biogas that cut the reliance on outside fuel and re-purposed otherwise wasted water into an alternative energy. The initiative made international news when the South China Post visited the town to report on the process in 2016.

“One month you had (fuel), another one you didn’t. Thanks to this biogas, things are a lot easier for people here,” one villager told the news outlet about their new fuel.

Dog Feces
Taking your dog out for a walk might be the energy of the future, according to one San Francisco company. Norcal Waste, a trash company, explored the fuel capabilities of dog feces – as well as degradable material like food scraps. In addition to their potential alternative energy capabilities, dog feces are a major source of pollution (including run-off) and bacteria when left out.

The company once claimed that one ton of dog feces, food scraps and degradable material could produce 50 gallons of liquid fuel. Robert Reed, who worked with the company, told ABC News in 2006 that the animal’s feces contain a lot of protein, which is created by the “rich diet” of American dogs. Reed also talked about using cantaloupe skins and broccoli. The company hoped for a citywide collection program for dog feces that next year, but it never materialized.

A Crematorium
When a cash-strapped English town needed a heat source for its community pool, it found a strange – and morbid – solution. The project, known by many as “dead heat,” took the “waste heat” from a local crematorium and diverted it to create a heated pool. While some locals were disturbed and appalled by the idea, the town’s council estimated it would shave 40 percent off the center’s gas bill.

After many delays, the project was completed in 2013. It was also awarded a Green Apple Award, which denotes “environmental best practice.”