Ok, ok I know I said that I’d go into our specific energy uses in this post, but I feel there’s more to say about other ways to electrify a tiny house. So bear with me (roar) as I shuffle through some more potentially helpful alternatives besides solar.
When all the factors of embodied energy, supply, waste, ease, and cost are considered, being tied into the grid can be the steadiest, cleanest, and cheapest. This is especially true for places like New York City, New Jersey or Oregon where you can choose what source the energy is coming from via: www.greenmountainenergy.com/for-customers/contact-my-utility.
Using grid-tied energy, the approximate cost per kilowatt hour (kWh) = $0.10-$0.15
Biodiesel + battery bank hybrid
This involves using any regular diesel generator with waste vegetable oil biodiesel and a battery bank. The major downside to using a biodiesel generator is that “generator sizing in a traditional site is based on peak load so that it can handle the peak load requirement when/if it is required. However, a site seldom reaches its peak load for more than a few minutes at a time. When the generator starts on a hybrid site, it runs at a high load during the boost recharge period to charge the battery bank and power the existing site load. The generator is therefore running at a much greater efficiency (80-90%)…” (excerpted from: www.clean-power-systems.com/resources/hybrid-power-resources).
In common English this means that when the generator is on, it produces at five kW (or more), no matter what. If you only need three kW, two kW are wasted. With a battery bank and a controller, however, you can collect this excess energy and run all your electric-heavy things at once. When the batteries are charged, the generator turns off, and the units run on battery power. It’s not 100% efficient but the price is comparable to a grid-tied system, and it’s reliable, upgradeable, and initially cheaper than solar.
Here is the math on biodiesel:
~34.5×106 J/liter = 9.58 kWh/Liter (www.roperld.com/science/biofuelsfromalgae.htm)
1 gallon=3.785 liters. 9.58kWh x 3.785L. = 36.2603 kWh/Gallon.
If one gallon of biodiesel costs $3.00 (current cost in Oregon) then that works out to $0.08/ KWH (1/36th of $3.00), assuming all power generated is stored or used. If half of its max is used, it’s about $0.16/kWh. With the battery bank and hybrid charge controller it would run on 80-90% efficiency, or about $0.10/kWh.
Here are some sources that discuss what biodiesel is, and the pros and cons therein:
A government-operated site that includes information on all available renewable energy sources including biodiesel fuel: www.eere.energy.gov/afdc/fuels/biodiesel.html
Wind turbines are just too big and need to be placed up too high to be of practical use to our tiny house. While it’s a great technology that offers little to no hassle and an unlimited capacity to turn in the wind, it is limited by the wind (or lack thereof) that is present and the location/zoning where we park our tiny house.
This is super cool. An explanation from All Power Labs: “Gasification is the use of heat to transform solid biomass or other carbonaceous solids into a synthetic “natural gas-like” flammable fuel. Through gasification, we can convert nearly any dry organic matter into a clean burning fuel that can replace fossil fuel in most use situations. Whether starting with wood chips or walnut shells, construction debris or agricultural waste, gasification will transform common “waste” into a flexible gaseous fuel you can use to run your internal combustion engine, cooking stove, furnace or flamethrower.”
While this is an incredible technology, the fuel for it is difficult to find and the maintenance would be a lot to keep up with. It’s also not as efficient, dependent upon an unreliable source of fuel and the technology is still emerging.
Here is a link to the “Power Pallet” bio-gas generator and the fuels that it can use:
This is just another nod to a great technology that would be extremely difficult to implement.
So that’s the skinny on various electricity sources. I’m almost done running wire through the tiny house and will have a blog about that in the coming weeks.