Modeling Sustainable Energy
There are many ways to generate renewable energy, but some methods make more sense for us than others. In the long run, we see our primary energy source as the solar energy that falls on Windward at about one kilowatt per square meter.
Windward's approach to renewable energy is focused on finding ways to (1) utilize the solar energy that is available to us, in its variety of forms, (2) miniaturize commercially proven systems so that they can function at the scale of a small rural village, and (3) build energy and food systems that reuse materials which would otherwise go to landfills or scrap-yards.
With that in mind, there are several ways we are working to meet our energy needs. Each one of them is technically complex and highly integrated into to the rest of what we are doing. Below are links to more information about these core energy technologies we currently are utilizing and developing.
- Woody Biomass to Liquid Fuel
- Solar Steam Engine
- Biologically Transforming Energy
- Harnessing Diffuse Energy & Negawatts
- A Note on Photovoltaics
- Economies of Scale
Woody Biomass to Liquid Fuel
This Windward project has it's own website! Check it out:
Official Biomass2Methanol Site
Simply put, gasification is the process of taking a carbon-based material (like wood or coal) and burning it to produce carbon monoxide, hydrogen gas, and carbon dioxide (a.k.a. woodgas). This gas can then be stored or piped to a seperate location.
Gasification is the process and technology which seperates the two stages of what is commonly refered to as "burning":
pyrolysis- the thermochemical decomposition of organic material at high temperatures and
combustion- the chemical reaction between the gases created during pyrolysis and oxygen, which produces heat and flames.
"The process of producing energy using the gasification method has been in use for more than 180 years. During both world wars especially the Second World War the need of gasification produced fuel reemerged due to the shortage of petroleum. Wood gas generators, called Gasogene...were used to power motor vehicles in Europe. By 1945 there were trucks, buses and agricultural machines that were powered by gasification. It is estimated that there were close to 9,000,000 vehicles running on producer gas all over the world."
With a gasifier, we can run internal combustion engines off of wood from our forest. We can also use gasifiers to cook with a much greater level of efficiency than an open fire, or even run a kiln to make pottery.
Another feature of gasification is that the gas mixture produced is able to be stored in containers, transported and used in remote sites, much like we use propane today. Gasification technology is an important part of our work to convert woody biomass into liquid fuels such as methanol.
To learn more about gasification at Windward, check out our Windward Gasification Articles
Solar Steam Engine
Sunshine is everywhere, and it can be used in many different ways to meet our energy needs. One of the primary avenues we are developing to generate electricity is to concentrate solar energy using horizontal parabolic trough reflectors to generate steam to power a modernized steam engine driving an axial flux alternator. There are well-proven examples of the mega version of Solar Energy Generating Systems that have been reliably generating megawatts for the past two decades.
An efficient steam engine system generates electricity with an efficiency of around 20%, a figure which we hope to double by using secondary systems such as an atmospheric steam engine/condenser and eventually tertiary systems using refrigerant driven engines to tap even more energy out of the gathered solar heat. But even without the enhancements, since we're using sunlight which we have in abundance some 200 days a year, efficency isn't the critical issue it would be if we were running a fossil-fuel based system.
To learn more about Solar Steam work at Windward, check out our Solar Steam Articles
Biologically Transforming Energy
All of life is a flow of energy.Forest and pastures are, from an energy perspective, solar collectors. They work tirelessly to absorb the sun's energy and use it to fix chemicals into more concetrated froms, storing them in their tissues, seeds, and fruits.
We use these plants directly for energy, such as for food, firewood or to run a gasifier. Several species of animals also live at Windward. Each species prefers to eat something slightly different, helping us to harvest the energy from the full spectrum of plant materials available, and concentrate the energy even further.
Additionally, each type of animal has different ways of embodying the energy they collect. Pigs produce pig-skin, pork and lard. Ducks produce eggs, meat and duck down. Goats produce milk, meat, tallow, bones, etc.
The role of living creatures, big and small, in concentrating and transforming energy is something which cannot be ignored. They perform the natural alchemy of turning grass and acorns into such nutrient dense materials as fat and bone. They are miracle workers, everyone!
Diffuse Energy and Negawatts
One of the primary uses for energy in any homestead is for heat. Either to warm a house, cook food or heat water.
With regard to these energy uses, there are numerous ways we can let natural flows of diffuse energy do much of the baseline heating for us. One example is earth-sheltered construction. Earth sheltered buildings allow the thermal mass of the earth to moderate the cold of winter and the heat of summer. Another example is designing buildings in ways that maximize heat retention and natural lighting.
These methods of construction produce what can be called a Negawatt: a theoretical unit of power representing an amount of energy saved. For example, earth-sheltered buildings are very well insulated and require minimal heating to achieve a comfortable indoor temperature even in the middle of December. We utilize about one cord of wood to heat our kitchen- an earth sheltered building- compared to the 2-3 cords we use to heat non-earth sheltered buildings of comparable size.
Windward is full of examples of how we can harness and concentrate the diffuse energy all around us, and generate Negawatts in the process. If you come here, you will get a chance to see and experience how developing systems from the ground up allows us to utilize the abundant diffuse energy all around us.
A Note on Photovoltaics
Lots of people use photovoltaic panels, and we do too to so some degree, but they're expensive. Moreover, they actually function more as a battery than as an energy source in that they require huge amounts of energy and environmental resources to create, energy which you can then recover over the years by exposing them to sunlight. That makes sense for locations where you only need a modest amount of power, but when looking for energy to fuel a small community- photovoltaics makes less sense.
Economies of Scale
While there certainly are economies of scale involved in the mega-systems, the micro route, particularly when integrated into a community context, offers real advantages too. For example, the methane recovery system at our county's landfill burns 10,000 btu's worth of methane in huge 12-cylinder engines to generate a kilowatt/hour (3,400 btu's) of electricity. The math shows that the majority of the energy contained in the methane fuel is lost as heat from the engine's exhaust--an inefficiency that can be mined at the community level by using that otherwise lost energy to heat water and homes, run air conditioning in summer, operate a greenhouse in winter, and so on.