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5/21/2015

small wind turbine diagram

HAWT and VAWT 

Small wind turbines occupy two main families: Horizontal-axis wind turbines (HAWTs), which comprise the vast majority of all small wind turbines, and vertical-axis wind turbines (VAWTs), which comprise a far smaller group. For the most part, people looking for a small wind turbine for their property will be reviewing their options in the HAWT family.

Upwind and Downwind

HAWT turbines have two primary subclasses: Upwind and downwind turbines. A downwind turbine has no tail and the wind blows into it from behind. Upwind turbines have tails, and they face into the wind.

Upwind turbines have the benefit of increased wind responsiveness. That is, they respond to wind direction and maximize the potential of the wind’s speed and power. Additionally, they tend to be quieter than downwind turbines; as the wind is hitting the blades first, the resonant sound is typically a white noise, rather than a strobing or chopping sound that can result from a downwind turbine, in which the wind hits the tower before hitting the blades.

Blades and rotor hub

Most small HAWT turbines use a three-blade design. The blades are affixed to a central assembly called the rotor hub. The rotor hub serves two functions: It holds the blades together, and it attaches to the spindle that drives the alternator.

Alternator

The alternator is the key mechanical element of the turbine, and it’s what generates electricity as the blades spin. It is housed inside the nacelle of the turbine.

Nacelle

The turbine’s nacelle is the body of the turbine that is connected at its front to the blades and rotor hub, at is base to the yaw assembly, and at its rear to the tail assembly (for an upwind turbine). The nacelle for large industrial wind turbines is the housing for the gear box and all other major power components of the machine. For a small wind turbine, the nacelle can house very few electronics in some cases, or much more circuitry in others.

Yaw assembly

If you’ve ever learned about aviation, you’ll recall that yaw is the pivoting action of the aircraft on a horizontal plane, left to right. Similarly, a wind turbine’s yaw is its horizontal planing motion. The yaw assembly attaches the nacelle to the tower while allowing the turbine to spin freely about the horizontal plane.

Tail assembly and vanes

Upwind turbines feature a tail assembly that includes tail vanes, which keep the turbine’s blades faced into headwinds.

Inverters and charge controllers

A home wind turbine won’t do much for you if you don’t connect it to anything. Like solar arrays, small wind turbines connect to inverters, and in the case of off-grid or battery-backup homes, battery charge controllers. These typically house the system electronics that let you retrieve, store, and output energy as needed, whether to your appliances, your battery bank or out to the grid.

In our next episode, we’ll get into the nitty-gritty on a major home wind turbine system component: The tower.


All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Best Practices, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on the byline link at the top of the page.



5/11/2015

In our first installment, we covered the basics of electricity generation and the process by which a wind turbine creates power. This time, we’ll look at the benefits of adding a wind turbine as a source of clean power for your home.

If there’s one core aspect of wind turbines that makes them a smart option for clean power, it’s that the wind is always doing its thing. It doesn’t “set” at night, and it doesn’t follow strict seasonality. And just like solar power, it doesn’t require any industrial activity to be brought to a level at which homes can use it. The wind is there, and a wind turbine can tap it in the same way a solar panel taps the sun for power. But wind’s real advantage is in those off-hours, when the panels go dark, but the turbine keeps spinning.

For this reason primarily, a wind turbine makes an outstanding complementary energy source when it’s working in concert with solar panels. Owners of these “hybrid” systems know the beauty of looking outside on a sunny, windy day.

This benefit is even more underscored for homes that aren’t connected to any utility. Off-grid homes use battery banks to store energy that they’ll need at night or during dark, rainy days when solar isn’t getting the job done. Off-gridders with wind turbines get the bonus feature of having a constant battery charging source. It’s a better night’s sleep when you know your batteries are staying full while the wind blows your turbine.

Beyond off-hour power and constant battery charging, small wind turbines provide a big benefit to homes that rely on backup generators as a source of energy. You don’t have to be living off-grid to have a very real need for a backup gas generator. Despite our advancements here in the technology age, there remain parts of the United States in which the grid is unreliable, prohibitively expensive, prone to extended outages, or all of the above. The home wind turbine provides energy security and reliability for people living in these regions. If a powerful storm blankets your solar panels in snow and knocks out your power lines, wouldn’t it be nice to use those wind gusts to a productive end? It’s certainly nicer than paying $1 per kilowatt-hour for a gas generator to run.

In review, the primary, basic benefits of home wind turbines are:

• Maximizing home energy production in areas that have windy climates
• Supplementing solar by generating more power at night, during storms, and winter months
• Enhanced battery charging efficiency for off-grid and battery-backup homes
• Cost control and protection from variable utility rates
• Energy security and reliability in areas with poor grid performance
• A clean, affordable alternative to running a backup gas generator

In our next episode, we’ll run through turbine terminology to make sure that when you’re talking about small wind, you’re talking like a pro.


All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Best Practices, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on the byline link at the top of the page.



4/24/2015

Wind Turbine 

While still hugely dependent upon fossil fuels, the home energy industry has evolved meaningfully in recent decades. Renewables are no longer cost-prohibitive or “special interest” options for homeowners; they’re commonsense solutions that provide a range of benefits to homes, businesses and the planet. 

The Solar Energy Industries Association (SEIA) reports the U.S. solar industry is on pace to complete its one millionth solar installation in 2015. As growth continues, homeowners now see solar as a realistic, investment-friendly option. State- and federal-level incentives have further contributed to what we now recognize as a solar boom.

Similarly, the small-scale (or, “distributed”) wind industry is evolving from a quiet companion of the solar movement to a front-and-center home renewable option—and the momentum for small wind is growing. As GreenTech Media reported in 2014, the distributed wind industry is looking to replicate the solar adoption boom. Federal incentives are now in the corner of distributed wind, in addition to solar. 

As more U.S. homes consider the benefits of small wind turbines (which I’ll cover in a later post), it is imperative that we fully understand the technology that could soon be as common a home fixture as solar arrays.

Wind Turbine Basics 

A wind turbine generates electricity by using the flow of air’s power to rotate an alternator inside the nacelle (body) of a turbine. This produces an electrical charge, which is then boosted and transmitted over wires, which deliver the electricity to wherever it needs to go.

In a big, coal-powered electricity plant, an electromagnet’s turbine is spun via steam power. This steam is produced by heating huge amounts of water. That’s where coal comes in; it’s burned to heat the water, to create enough steam to power the turbines in the plant. It’s a process that is as roundabout and inefficient as it is dirty. Worse, it’s by far the prevailing way electricity is generated in the U.S.: 90 percent of all the coal mined in the U.S. is used to generate electricity (Source: Hyman, Hyman and Hyman, America’s Electric Utilities. 2005.). 

Feeling greener by the minute?

Back to the wind turbine: When the wind spins the blades of the turbine, the alternator generates electricity. This is carried to an inverter, like the one your solar panels use. The inverter gives your home’s lights, appliances and outlets the power they need to run. It can also sell power back to the grid, inverting your meter, if you make more power than you need. 

As you can guess, a key feature of a small wind turbine is how simple, clean and direct that process is, versus buying power from utilities that burn coal (or use nuclear power) to generate your electricity.

Now that we’ve covered the electricity basics, we’ll use the next installment to dive into the true benefits of a small wind turbine for a home, and why homeowners who already have solar panels should be even more interested in adding wind power to complement their PV and round out their home electricity systems.


All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Best Practices, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on the byline link at the top of the page.



4/10/2015

The last in a series about Cuba and Vermont, Perspectives on Energy and Culture. based on my visit to Cuba with a delegation of energy industry professionals, and a Cuban colleague’s visit to Vermont where I developed a similar tour. Learn more in The Homeowner's Energy Handbook and read the entire story online with more photos and videos at The Creativist.

Energy Innovation Center

EIC3

At Green Mountain Power’s Energy Innovation Center in Rutland ,Vermont, we meet with a large portion of GMP staff, all eager to share their experiences and to hear Mario’s. The EIC is more than just a workspace; it’s a place to put words into action. We learned about GMPs all-encompassing energy savings efforts that range from total home and lifestyle energy makeovers, to their unique “Cow-Power” energy service. Cow-Power involves investing in on-farm methane digesters for electricity generation, and providing that power at a premium cost to customers who want to support clean energy. The premium payments go directly to help offset the cost of building the processing facility. After our meeting, we toured the renovated historic building that was, in itself, a huge investment in a downtown that desperately needed the encouragement provided by this project. The education center showcases energy efficiency and renewable energy projects promoted by the utility, including a talking cow that tells the Cow-Power story. The building sports solar electric panels, a small wind generator, super-efficient windows and insulation, cold-climate air-source heat pumps, and an Ice Bear energy storage air conditioning system. The Ice Bear use off-peak electricity to make ice that can be used to provide cooling during peak power times, thus reducing energy demand (and cost) for midday air conditioning needs.

EIC2

Mario’s Message

Mario finally delivered his own message to an engaged and curious crowd in White River Junction. The event was sponsored by two non-profit institutions: New Community Project, and The Center for Transformational Practice. He spoke about Cuba’s energy system and efficiency efforts that were quickly instituted during the difficult Special Period. These reforms and austerity measures lead to Cuba’s Energy Revolution in 2006, which has now become a model to the rest of the world for delivering energy efficiency and renewable energy, along with other sustainable practices such as organic farming. Mario told personal stories of having no power for 18 hours or more every day. Nobody knew when the power would be on. Mosquitoes and sweltering heat drove families out of their homes at night where they would also find and commiserate with neighbors in the same predicament. In stark contrast to the abundance of the North American lifestyle, there were food shortages and water was scarce. Breakfast was often whatever fruit was in season, then off to work. A different planet. All because of a ridiculous embargo.

Today, Cuba is slowly developing infrastructure with modest investments from the European Union and Latin America. Ninety five percent of the eleven million inhabitants have electricity. Tourism is a big part of the economy, but cannot currently support the influx of visitors that would occur with relaxed U.S. policy. There is a small photovoltaic panel manufacturing facility, a growing medical industry with quality health care and a Doctors-for-oil trade arrangement with Venezuela (human labor is considered a national commodity, a resource to be sold or traded), farmers are revered, there is active oil exploration off the coast. A thriving educational system considers future needs and delivers knowledge that will be required at the time students graduate because the government is required to provide a job to citizens. The stakes are high. Universities are focused on energy, technology, and biotech. Kids have never seen an incandescent light bulb, bring recyclables to school, and most schools have community gardens. Cubans are educated, engaged, motivated to join the world economy, nimble, and readily able to re-invent themselves.

When we arrived home that evening, the temperature had warmed into the 20s and even Mario said that it didn’t feel so cold now. Not quite open-window temps, but we stood in the driveway and threw snowballs in our cosmonaut suits until our hands were numb.

artwall 

Be sure to read the entire story online with more photos and videos at The Creativist.


All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Best Practices, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on the byline link at the top of the page.



4/3/2015

This post is a follow-up to five others I have done on Cuba and Vermont, Perspectives on Energy and Culture: Part 1Part 2Part 3, Part 4, and Part 5 - about my visit to Cuba with a delegation of energy industry professionals, and a Cuban colleague’s visit to Vermont where I developed a similar tour. Learn more in The Homeowner's Energy Handbook!

Jasper Hill

Jasper Hill Farm is a clandestine world treasure that you could drive right by even if you had a map and GPS (forget about cell service here). This is a success story of two brothers who started with 40 dairy cows and went on to win the title of “World's Best Unpasteurized Cheese" for their Bayley Hazen Blue at the 2014 World Cheese Awards in London. Here you can see the entire process of making cheese from grass to cow to milk to cheese. The crew constructed underground cheese aging caves where each cave is specifically controlled for environment and inoculated with the right culture.

They didn’t stop at great cheese though; Andy and Mateo are working to close the loop from food to energy by converting the farm’s waste products to energy in their Green Machine. Cow manure is separated into liquids and solids. The solids are composted, the heat generated from decomposition is used to heat the green house, and composted manure fertilizes the soil. The liquids are combined with waste whey from the cheese making process and put into an anaerobic digester to produce methane gas that is burned to heat water. On this record breaking day of cold, we also enjoyed fresh greens from the greenhouse which gains heat from both the sun and from the manure composting on the other side of a mass wall that stores and re-distributes the absorbed heat.

That night at dinner Mario said “I’m worried that I’m not sweating. It’s bad for the skin.” Another hidden-in-plain-sight difference in what’s engrained in us as ‘normal’. When I was in Cuba, I didn’t stop sweating and I found it annoying and uncomfortable.

“You are sweating” we told him. “You just don’t feel it because the air is so dry in the winter that sweat evaporates before it has a chance to bead up.” I was reminded of my southern California cousins who came to live in New York City for a summer. They never sweat in their home climate and were uncomfortable and embarrassed at how they were constantly sweating in the unfamiliar east coast humidity. 

Unnatural Timekeeper

Friday, our last day together, would be a long one. After an extended breakfast conversation came the ‘ridiculous’ process of dressing for winter. We were late before we left and this day was already over-planned. I wanted to do it all! I don’t know how I ended up as a tour guide and event planner, I’m usually the one who’s late for everything and now I find myself in the unnatural role of timekeeper and whip cracker. I was very aware of taking up people’s time during their workday, and was continuously surprised at their understanding welcome despite our consistent lateness. I wondered why we do it. Our lives are so busy, bills keep coming in, clients are waiting, and nobody stood to earn anything from our visits. As an introvert, I know I have shortcomings around social graces, but I was getting an education in building a social economy of my own, learning from the grace of both my guest and our hosts.

Better World Workshop

On the way to The Better World Workshop in Bradford VT I took a wrong turn on a dirt road. Ahead was a hitchhiker and Mario asked if lots of people hitch rides here. “Maybe not as much as they once did.” I replied. “In Cuba, everybody hitches a ride and everybody picks up riders, all the time, every day.” I recalled that our tour busses and taxis in Cuba were always stopping to pick people up. We picked up the rider who set us down the right road to Bradford.

Engineer Carl Bielenberg has been developing biomass based renewable energy systems for nearly thirty years. At the Better World Workshop, he is currently developing a small biomass gasification system for rural villages in developing countries called the Village Industrial Power (VIP) generator. Gasification is the process of heating biomass to combustible temperatures and controlling the air to the combustion chamber so that the material doesn’t burst into flames. Controlling combustion in this way allows for an extremely clean, efficient, smoke-free source of heat. The VIP burns a variety of biomass types ranging from wood to corn, or even nut hulls, making it a versatile power producer in almost any region of the world. The heat produced is used to operate a simple steam engine that powers a 10,000 watt electrical generator, while waste heat is used to heat water.

South of Bradford, and on the way to our next stop, is the King Arthur Flour baking center in Norwich Vermont where we enjoyed a delicious lunch from their café. As we pulled into the parking space he asked "What is that noise? It sounds like it's coming from the car." I sighed inside, because I hadn't told him that the car had suddenly lost power and the engine light was on. Not hearing anything unusual, I asked him what it sounded like. "A squeaking sound." All I had to offer was an unknowing shrug and sighed to myself. Walking across the parking lot after lunch we stopped to wait as a car backed out of its spot. "That's the sound I heard!" he exclaimed, pointing at the front tire. It was the sound a tire makes as it slowly rolls over fresh snow. We both laughed, but I still didn't know why the engine light was on. While he was busy talking to Carl about the VIP I slipped out to get the error code off my OBDC scanner. Vague as usual. Was it the $25 fix or the $900 fix? In the end, it was right in the middle. With 230k miles on my VW Jetta TDI, repairs are inevitable, but the maintenance cost is still less than new car payments.

Next week, final installment: The Energy Innovation Center and Mario’s message.


All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Best Practices, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on the byline link at the top of the page.



3/27/2015

This post is a follow-up to four others I have done on Cuba and Vermont, Perspectives on Energy and Culture: Part 1, Part 2Part 3, and Part 4 - about my visit to Cuba with a delegation of energy industry professionals, and a Cuban colleague’s visit to Vermont where I developed a similar tour. Learn more in The Homeowner's Energy Handbook!

Washington Electric Cooperative

To ease the pain of 29 below 0 (Celsius), I turned the car’s internal and seat heaters all the way up to their respective Caribbean climate setting and headed north with Mario still reeling from the extreme cold. Almost immediately he called a friend in Florida to claim bragging rights to the experience.

 

First stop was Washington Electric Coop, a member-owned electric company and the country’s most rural electric utility in the sense that it has very few customers for every mile of electrical transmission line. WEC has a large renewable energy portfolio and our goal was to visit their landfill gas recovery power plant in Coventry.

landfill

This system consists of an active landfill with buried pipes to collect the methane gas produced by decaying organic material. The gas is piped to the power house where it is first scrubbed of impurities and then delivered to five diesel engines, each of which is connected to a 1.6 megawatt generator. Each year, this power plant delivers about two-thirds of the coop’s electrical needs from garbage, while preventing the powerful greenhouse gas methane, from entering the environment.

engine

Along the way, we stopped to take photos of landscape and local scenes. Mario looked out the car window and asked if that wide open expanse of snow was a lake or a field. We pulled into the parking area where I pointed to the sign that called out the lake’s name, jumped out of the car and ran onto the frozen surface with Mario yelling “NO!” I cleared away the snow so he could see the frozen water below, jumped up and down a few times, and he finally came out to join me. “This is like a different world!” he exclaimed. “I’m in a cosmonaut suit on another planet!” After several photos and experiments with walking on water that was so thick you could drive a car on it, we were on our way again.

Lunch

NEKtasting

Lunch today was at the Northeast Kingdom Tasting Center in Newport, where local food and beer are available for sampling and purchase. Our meal was expertly prepared by the Brown Dog Bistro. At this point, I felt comfortable enough to ask Mario a personal question about the Cuban experience. I knew what I wanted to ask, but didn’t know quite how to phrase it. And I didn’t think it would make us late for our next stop. In retrospect, we probably needed a few more drinks before I launched into this.

“What is it like to be a Cuban” I began tentatively, searching for the right words “in a world where you are the international underdog?” After over 50 years of the U.S. led embargo that has kept their economy in near ruin, Cubans have gained a level of global empathy for their plight. Their shared struggles have only served to make them a stronger island community, and I wanted to know how that experience has shaped him as he travels into the world with almost no budget. I imagined his story to be something similar to those many American (OK, North American) college students who once traveled the world on a shoe string, and to my own experience of getting on my bicycle as a young man with only a sleeping bag, tent, bags of gorp, and a probable destination in mind. These times of throwing yourself into the world and reveling in its unpredictable unfolding are often described as magical. People of the world welcome the open-hearted traveler.

Language and cultural barriers quickly became apparent. “What do you mean? What are you trying to say?” he asked. “Just tell me what you are trying to say and I will tell you.” I struggled for more words.

“When I go out into the world as an American” I said “I go with a plan, a credit card, and an attitude. I want to go someplace to have an experience, and I pay as I go. It’s expensive to be an American!”

“Listen, do you want me to pay for my lunch? Is that what you’re asking? I have a little bit of money, but you know I only make $40 a month! You spend that on one meal here.”

“That’s not what I mean!”  I tried to downplay my embarrassment at this misunderstanding.

“Before I came here, you asked me if I had a stipend, and I said no. I knew then that you did not understand about Cuba. I would like to travel and choose the experiences to have on my own terms, but I can’t. I’m here as a guest of Community Solutions, who have provided me with transportation and I hope to earn a little cash for my professional speaking engagements. I am only here in Vermont because of you, I am relying solely upon you while I’m here because we made a professional connection several years ago.” Now I was really feeling bad, I had embarrassed him.

I tried again, taking a deep breath. “I think you’ve hit on it, Mario. You rely on your connections, I rely on my credit card. There is a cultural difference there, a different way of being in the world. How does it feel to go out into the world relying only on the trust of friends and colleagues? How can you be sure things will keep opening up for you?” This time he got my meaning and I suddenly, sharply, realized that I was a long way from that kid on the bicycle of my past.

“Look around you. The windows are closed. Outside, people have their heads down with their chins in their collars to stay warm. In Cuba, our windows are open. We are in the community all day and all night. We are all neighbors. We hitchhike everywhere, and everybody stops for us. I don’t call my friends before I visit, and when I don’t drop in on them for a while, I am in trouble with them! We trust each other, that is all we have. That is how I live my life. I have to trust people.”

“It’s like a different planet.” I said. “You go through the world with connections, trust, and graciousness.”

A different planet.”

saturn

“I’ll call your perspective the ‘open window theory.’”  I knew this intellectually, that Cuba has a social economy not a monetary economy, but this interaction drove it home for me in a way that I could feel, and that makes me think I finally ‘get’ Cuba. North Americans use money to insulate themselves against a social economy. Riches manifest in many forms and translate into how we live in the world.

“Open window theory!” We shared a laugh, finished up and sped off to our next stop, one I was particularly looking forward to.


All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Best Practices, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on the byline link at the top of the page. 



3/5/2015

When last we left you, I was talking about my friend from Sri Lanka, and the prospect of helping the poor in that country— and worldwide— through low-cost biogas. (And my apologies for the radio silence: I’ve been busy…)

Ideals are important, to be sure. And some say that we are either idealistic or realistic, as if becoming aware of injustice somehow necessarily prevents us from addressing it. But at least in my experience, that’s just not the way the world works. Just look around: there are a fair number of people who are both idealistic and realistic: but we could always use many more.

No doubt talk is cheap, and many things are difficult. That means that whether our goals are noble or selfish, failure to achieve those goals is not uncommon. But hey: Surely it’s better to fail when trying to help people escape poverty than it is to fail to add another zero to our personal wealth, no? (The zero is supposed to go on the right-hand end of the number, for any who were unsure…)

My father taught me a lot about how to find ways to have high ideals and achieve goals. (He invented the cochlear implant, if anyone can be said to have done so. Dr. William House: you could look it up.) And after all, I reasoned (underneath my gray hair), I’ve done my service to capitalism, established a strong marriage, raised a family and launched them into their amazing success stories (and they are amazing; just ask me)… So what was preventing me from trying for this brass ring— helping the poor worldwide— except a desire to sleep late on Sunday?

Well naturally then when my friend from Sri Lanka woke me up to the potentials of biogas for global benefit, I began to pursue this dream of helping many, many others, with limited resources and all by myself. How does one do that in a practical, step-by-step, realistic manner?

Well, you won’t be surprised if I tell you that thus far, it’s fair to say that what I’ve tried has met with limited apparent success. I won’t bore you with all the messy details, but let me give you a sketch.

I first tried a very conventional approach, developing a darn spiffy, multi-page, gee-whiz spreadsheet, a timeline and other accoutrements, and using these to pursue grants. But after shopping it around and doing the standard hey-there-fund-this-grant two-step, I was left with the feeling that I was standing on a field— along with 10,000 other folks— where all of us were waving our particular fistful of paper about our particular Good Idea, trying to gain some funding, then maybe some attention. Up close maybe you could hear one of us. From a few yards further away, where I imagined the closest grantors were standing, it would have been just sort of a lot of noise.

The experiences left me with the thought that, well, this would be a lot easier if I was able to get the attention first; the funding will follow. So I began to plan and build a solar-heated greenhouse with some fairly revolutionary features, intended to house a 10-cubic-meter digester fed entirely with food waste from a local restaurant. I got some modest funding from a few good friends, developed the design, spent months going up and down a ladder, and gradually the thing began to take shape. Here was to be something that people could point cameras at, to come and watch biogas in action.

Then, months into the build, a huge winter storm came through and brought it all down. Wham. Flat. Kindling. I had neither the heart nor the funds to start such a large project again…

Meanwhile, I had developed a small, very cheap digester suited to the tropics and intended to be manufactured in quantity. Materials cost? $10.

Now, I happen to know something about design and manufacturing because of my past work experience, and I knew that for something like a digester-for-the-poor— which is supposed to work well where every floor is a dirt floor— one crucial design process is to have people bang on the thing and try to break it. It should be reasonably sturdy, right?

So to provide funding for efforts to improve the design, to get the designs out and about and under stress, and to begin the process of gaining attention, I decided to start teaching workshops about biogas, capped with a half-day segment where we would all manufacture these low-cost digesters from kits and parts.

That went very well. I love to gab and I had something useful to say. My dear friends Tim and Suzanne of Friendly Aquaponics invited me to come to Hawaii and teach, I got invited to Australia, and the National Center for Appropriate Technology organized a workshop in Iowa, just to mention a few. From California to upstate New York, groups of charged-up folks had a good time and learned all about biogas. And they loved it, at least according to the evaluation forms I gathered from each class.

The favorite part of these workshops for most of the participants, it seemed, was building those low-cost tropical digesters. But at the same time, that was also the key problem, that little word there: “tropical”. The information was good, the folks were enthusiastic, the workshop was humming and the digesters were… tropical. In Iowa there was snow on the ground. In New York, it was early spring. Too cold. Even in Hawaii, perhaps surprisingly: it was too cold almost everywhere.

Then this last spring I was invited to do a workshop in Brooklyn, and as I was doing the work to prepare for it, I gradually came to realize two things. The first was that these workshops, as popular and fun as they were, were not going to get me close enough to the brass ring. It was a great job description to add to a number of others, like “scriptwriter” that I had accumulated— “Biogas workshop leader”— but all by themselves, these get-togethers probably weren’t going to get me to Sri Lanka, organizing the manufacture and distribution of many thousands of digesters.

It hit me: I had given a lot of thought to low-cost, practical, tropical digesters, but I hadn’t thought at all about digesters that would work in Burbank, upstate New York, or Iowa in the winter during a hard freeze: That is, almost anywhere on this continental land mass here that I’m sitting on just now.

The good news, as I came gradually to realize, was that all the design ideas and testing, all the invention of manufacturing equipment that I had undertaken in my quest for tropical, could help me— it could help you, come to think of it— to produce that utterly rare creature: A low-cost, well-designed, small biogas digester that will work profitably here, where tropical is a travel brochure, not a weather pattern.

The key ideas, as it turned out, were pretty simple. What I knew was that if I took two sheets of plastic and carefully pressed them— compressed them— together along a line, say with a couple of 2-by-4s and a bit of weather-stripping, nothing would leak through that line: not liquid, and not gas (at least not at low pressures). So in fact, with a bit of ingenuity and modest folding, I could create a water- and gas-tight container out of plastic sheets pressed into place by rigid pink polystyrene foam insulating boards, held in place by plywood. The polysty would provide good insulation. I knew from my experiments how to create a very cheap, very strong bung— a pipe-hole through the wall— and that’s all anyone really needs: A tight box with some pipes, minimum three: a slurry inlet, an effluent outlet, and a gas collection pipe.

And that’s it right there, really. That’s an entirely new design for a biogas digester which is cheap and well-insulated: the grail. And for the next many posts in this blog, that’s what I’m going to tell you, in some detail, how to make.

It will take more than a few posts and therefore some time, because there’s only so much you can say in a 1,000 words or so, even with pictures to multiply the syllable count. If you want to learn much more, a lot more quickly, then you are welcome to attend the next Beginner’s Biogas Workshop, which will be held in Washington DC in mid-April. (Read the details.) There and then, we will be revealing all. (Well, almost all. But in any case, enough.)

And if you can’t make it there, then no worries. There will be more workshops (sign up to be notified on the TCBH site), and whether or not it's practical for you to attend a workshop, keep reading the blog and I’ll tell you everything I can.

Here’s my hope, finally. This isn’t just about providing practical, cheap, small biogas to a small set of dedicated crazies in the US. I firmly believe that this effort can help catalyze greater use of wasted food in this lovely, forgetful-of-its-high-ideals nation, and that in turn, it is my fond hope, can have a measurable impact on the release of climate changing ‘wild’ methane from out of landfills. (Food wasted around the world produces as much greenhouse gas as all the annual emissions of the entire country of India, the third largest GHG emittter! And if we can reduce methane emissions, according to the New Scientist magazine, we can delay the impacts of climate change by 15 years... Hey: that's worth doing, right?)

Then finally, if I can create enough excitement and pay down my mortgage from these efforts, I’ll bet I can take it all the way to Sri Lanka. What do you think? What are my chances?

Keep reading, and we’ll both find out.


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