Net Energy Use (black) is often negative (Click image for more photos.)
Solar Production Update: All of the recent sunshine has given us a series of net zero energy days. Will March be our first net zero energy month? We'll have to wait and see. For now, I can report that for the month of January, we used a total of 1,048 kW-h of energy and produced 208 kW-h for a net usage of 825 kW-h. Thus, we only produced about 20% of our total usage in January. Definitely not a great start to the year.
To determine if this is a reasonable amount of solar production, I visited the National Renewable Energy Laboratory's photovoltaic production calculator PV-Watts. This is a program that uses historical data to predict photovoltaic production at any location in the country. For our PV system at our location, PV-Watts predicted a January production of 386 kW-h, almost twice what we actually produced. This could be partly due to poor weather in January but I suspect most of it is a result of shadowing on the solar panels.
February has been much better. We used a total of 882 kW-h and produced 421 kW-h for a net usage of 456 kW-h. Thus, we produced nearly 50% of our energy usage in February. Not too bad. According to PV-Watts, the average solar production in February for our PV system should be 438 kW-h, which is very close to our actual production. This suggests that shadowing may definitely be causing some losses in the dead of winter. It also suggests that PV-Watts does provide a reliable estimate for our solar production during the rest of the year. If so, it looks like we will fall short of our quest for net zero energy on an annual basis.
Google Powermeter: Another fun tool I found recently is google powermeter. This is a tool that works with TED, our energy monitoring tool, to provide a real-time display of our energy use and production via the web. Thus, I can monitor our energy use from any web browser in the world, including the one on my phone. It's very cool. Unfortunately, I have not figured out how to incorporate powermeter into this blog. For some reason google has made the powermeter gadget so that it only works on your personal igoogle page. Hopefully that will change in the near future so I can place a real-time energy display on this blog.
Google Powermeter (Click image for more photos.)
Stained Glass: The last bit of news to share is a new stained-glass window we had installed. All along we planned on having a stained-glass window in our bedroom. Once the house was finished, Virginia's parents offered the stained-glass window as a house-warming gift. Well we finally found the time to design something and have it made and we absolutely love it. It makes the bedroom a true oasis.
Our new window (Click image for more photos.)
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