Transitioning away from fossil fuels and towards renewable energy is a hot topic right now. Well, natural processes harvest renewable energy all the time, and release it in excess to be recycled! When the focus is on stacking functions and transforming waste into resources, this becomes apparent–a concept we are intimate with as permaculturists.
Let’s cover some sources of renewable energy that haven’t been given as much media coverage as solar and wind have. Some of these methods can be implemented on the small scale of a single family homestead, others are more well suited for larger farms or entire urban areas and high-population density cities.
Ocean Energy: Mechanical and Thermal
Capturing energy from the oceans, which provide numerous ecosystem services as it is, is a way of further stacking functions while going with, rather than against, the grain of nature’s rhythms.
Thermal energy from the heat of the sun and mechanical energy from the tides and individual waves can be captured from the ocean. This is a way of gathering energy which is already being generated, and represents permaculture principles on a larger scale.
Mechanical Energy from Tides and Waves
The rhythmic pull of the moon, along with random yet potent gusts of wind, harness the power of the tides and waves as mechanical energy. The Bureau of Ocean Energy Management reports that “while ocean currents move slowly relative to typical wind speeds, they carry a great deal of energy because of the density of water. Water is more than 800 times denser than air. So for the same surface area, water moving 12 miles per hour exerts the same amount of force as a constant 110 mph wind.” While numerous concerns are still being addressed and the technology needs further development, it has potential for passively collecting energy in a way that does not poison the environment or harm marine life, if done mindfully.
Thermal Energy from Sun at the Surface
The raw power of the heat of the sun captures thermal energy from the shallow utmost layer on the surface. Because oceans span over 70% of Earth’s exterior, oceans are ”the world’s largest solar collectors….just a small portion of the heat trapped in the ocean could power the world,” Renewable Energy World writes. This form of energy is best captured in warmer areas (think Hawaii) because the temperature difference between the sun-heated surface water and the deeper, cooler waters must be at least 20 degrees celsius to drive the steam cycle (produce the steam needed to power turbines), according to World Ocean Review.
Capturing Excess Energy from Flushing Toilets
Energy is needed to flush a toilet and run water taps, but until now, nobody has thought to stack functions by capturing that energy. This method takes hydroelectric power and gives it a super local production factory; one that is already producing energy all day, every day, anyways. The energy can be used for the water filtration and transport process; making the infrastructure we take for granted so much more sustainable. So how does it work?
Homes in Portland, Oregon, USA
Old pipes can be retrofitted with turbines which spin each time a toilet is flushed; though it is far easier and more affordable to replace old pipes (which may be in need of a replacement anyways) with new ones which come pre-installed with turbines. The pipes being implemented in the homes of residents of Portland, Oregon, USA, “can produce power at any time of the day because the water is always flowing. The only hitch is that the turbines can only produce power where water is naturally flowing downward with gravity,” according to Inhabit.
High Rise Buildings–Taking Advantage of Gravity
Luckily, pipeline systems have traditionally been designed to take advantage of gravity, so the system is primed to handle turbines. In fact, the taller the building, the better it works, as was realized by an industrial designed student when “he emptied a bath in a hotel and found that it drained very quickly and with a large amount of force. He realized that it would be possible to harness this energy in some way to create green electricity.” He then designed a system specifically for high rise buildings.
We don’t need massive hydroelectric dams that disrupt animal migration patterns and destroy habitat. Consider busy malls which have a near constant cycle of people in and out of the restrooms. Just imagine how many homes, schools, parks, and commercial locations could, through utterly common activities, aid in the transition to a renewable energy society.
Using Compost to Produce Energy
We’ve been destroying soils and decimating animal populations from overharvesting, but here’s a way that we can rebuild soils whilst capturing the energy produced from the compost.
Electric, gas, propane, and wood water heaters are common–but permaculturists have found yet another way to stack functions by capturing the copious levels of excess heat from compost via the fast-hot compost method. An eco-lodge in Ethiopia placed the water heater inside the compost pile so that the source of heat is directly around the water; the article in the link gives a thorough report on how and why to do this.
500 Outdoor Showers in Two Months
Inspiration Farms in Bellingham, WA was able to capture enough water for 500 outdoor showers in two months from a small compost pile; rather than placing the water heater inside the heap, they ran a piece of piping through it. You can watch the video by Paul Wheaton here. Additionally, they inoculated the surrounding area with mushrooms; with the shower run-off keeping the mushrooms moist during the drought of summer months; and they were able to suffocate some plum suckers, once again stacking functions. The plan is to plant fruit and bamboo nearby to take advantage of the run-off water.
The Soil is the Limit
This isn’t the limit to what can be done. According to One Straw, French visionary Jean Pain “was able to produce methane and hot water for up to 18 months – enough for two winters – while also powering his truck, cooking, and producing electricity with the methane gas. My favorite part? No special machines, just a deep understanding of Permaculture before the word was even coined. Partner with Nature to meet your needs.”
If you’re interested in learning how to build a compost shower, this thread in Permies is also a great resource.
Energy from Manure and Urine
When composted correctly, manure creates the richest of soils, and urine contains the minerals needed for plants to grow, when watered down 10:1. There is another potential use–the methane produced from manure can be captured for use as energy.
Discovery News writes that in experiments with how to repurpose rather than simply discard dog waste, “dog walkers are provided biodegradable bags, which after they’re filled, are placed into a large container called a digester. Inside, microorganisms process the poo, giving off methane as a byproduct. The methane can be used to power lights.”
Discovery News continues on with the topic of agriculture; specifically, cattle–”In Pennsylvania, a dairy farm is looking to cow manure for energy. Six hundred cows that produce 18,000 gallons of manure daily are helping the farm save $60,000 a year. The waste is used to produce electricity, bedding, fertilizer and heating fuel.“
Compost toilets are a method for safely handling human manure, or humanure, and transforming it into usable loam over the course of multiple years. However, it’s arguable that, on such a small scale, it would take a large family to produce enough methane to make a difference. Most homes aren’t yet set up with compost toilets (though that’s the dream of would-be compost toilet entrepreneurs).
The majority of homes on a city grid run on a city sewage system, which, as it just so happens, produces an abundance of methane! Discovery News reports that the methane produced from just 70 homes could power a car for 10,000 miles. Imagine that on a larger scale. This is truly an untapped niche. The possibilities are endless, if we re-think what it means to waste or recycle materials.
In this moment, many of us can choose to catch a bus or drive into town without much more hassle than the price of gas or bus fare. The fragility and impending transformation of our regional and global dynamic with fossil fuels tells us that it’s smart to begin renewably producing food, energy, and other resources in a replenishing manner, closer to home; rather than relying on fossil fuel intensive resources shipped from halfway around the world.
The transition begins now, and it begins with us.
What about you–have you built a compost shower? Do you have any other alternatives to share with the community? Leave a comment below!