When I was young I was fascinated by solar power. It seemed like we were only years away from having a significant amount of our power coming from alternative sources. Now more than thirty years later it seems things haven’t changed all that much. We have a tendency to explore alternatives when times are tough but quickly lose interest when the situation improves. According to the US Department of Energy for 2009 only 8% of power was from green and renewable energy sources (http://www.eia.doe.gov/energyexplained). In time I am sure that the percentage will increase but I’ve decided to try and make an impact, even if minor, on my own.
Where I live the power goes out with a fair amount of frequency during the active spring and summer storm seasons. Sometimes it goes out for hours, sometimes days. If I find alternative sources that help me get off the grid it means I can be less dependent on the unreliable power from the local energy company while decreasing my carbon footprint.
I started researching a combination of photovoltaic, wind and biodiesel generation for my power needs. The first challenge is figuring out how large of a supply is needed. I’ve seen people buy the largest generator they can afford, and I usually point out that they should consider how many hours it will run on a gallon of fuel. Having all that extra power becomes a disadvantage when you are burning through fuel at a higher rate.
Knowing how much power is needed is the first step in determining an alternative energy solution for your home. A similar challenge occurs when trying to come up with solutions for lowering your power usage. Just switching to compact florescent bulbs throughout your home will not have a drastic impact on your power bill if those lights do not get used regularly. You need to know what is consuming power, when and at what volume to develop an alternative energy solution.
To get a better understanding of how much power I am using I purchased the TED5000-G energy usage monitor from The Energy Detective (http://www.theenergydetective.com/ted5000-g). This unit has several interesting features including a web interface where you can monitor usage in real-time and it can also interface with the Google power meter project.
The unit itself uses two inductive AC amperage clamps that are attached to the main lines coming into the home breaker panel. It is capable of measuring power usage down to per second resolution. I find monitoring the usage and seeing the various patterns fascinating. It makes it easy to see how much power is used by different devices as you turn them on and off in the home. You can also identify “vampire power” devices, as many electronics still have power draw even when they are “off”.
From the TED5000-G data, I can tell that on average I am using .9 Kwh of power when I am home and awake. At night that is closer to .5 Kwh and as low as .3 Kwh when I am away from home. I am still doing further research, turning off and unplugging devices to find those that are drawing power that I am not aware of. Having this information is extremely useful. It means that when I start shopping for power generation equipment, solar, wind, and a generator, I know exactly how much power I use on average. I can turn on the devices I would like to have running and use that as a benchmark of how much power I need and how much I would like to have.
The TED5000-G is not too expensive at $200, but there are other devices that can give you the same information. For individual devices and outlets there is the “P3 Kill A Watt” which will let you track how much power you are using at that outlet. This is an especially interesting device because of the various hacks found online that expand its capabilities (http://www.ladyada.net/make/tweetawatt/).
The same inductive power measurement used by the TED5000-G is available in hand-held units usually referred to as inductive current clamp or clamp meters. It is possible to find handheld units units from several sources in a range of prices and features, for example the Fluke 321/322 (http://www.fluke.com/Fluke/usen/Electrical-Test-Tools/Clamp-Meters/Fluke-320.htm?PID=56068). In true DIY spirit you could build a similar unit using inductive AC current sensors. These sensors along with proper amplification can feed the current usage data into an Arduino, or other microcontroller, where it could be recorded or transmitted via WiFi or XBee radio.
Knowing how much power you use and how much you will need is the first step in coming up with an alternative energy system that can meet your power needs.
Do you know how much energy you are using in your own home? Have you done your own alternative energy project? Are you powering your house “off the grid?” If you have I would love to hear about it.