On estimating solar output and voltage drops
12.9 volts?! I want 18.9! When I started tinkering with off-grid solar one of the first questions I asked myself was “how long is it going to take to charge this battery?” Or, similarly, “how much...
View ArticlePower surge
My back yard solar farm has doubled in size to a massive 200 watts! If you remember from the last post, the wooden frame was half empty (who built it like that?), and was feeling really lopsided...
View ArticleHome solar: adding MPPT and marvelous data
As part of my plan for the eventual expansion of my off-grid solar energy system, I recently added a new charge controller with Maximum Power Point Tracking (MPPT). Besides being much more efficient,...
View ArticleCounting every watt hour
This little device is an ethernet to wi-fi adapter. It connects my solar charge controller to my home wi-fi network so I can make fancy graphs. It uses 1.2 watts per hour. I know this because I...
View ArticleMapping Minnesota’s solar resource
Boston, New York City, Denver, Cambridge and other cities have created solar potential maps to help their residents understand that solar photovoltaic systems are viable in dense urban areas, and to...
View Article100 days of solar
Watt hours to the battery, first 100 days Today I noticed that my solar charge controller has been running for 100 days (it logs this among many other data points). Here are some highlights from the...
View ArticleKSTP on the Minneapolis Commercial Building Benchmarking Ordinance
With a short appearance by yours truly. Watch the video here. Unforunately, it won’t embed.
View ArticleHow much energy could Minneapolis get from solar?
Solar PV seems to be the current darling of the renewable energy world. But how much “resource” is really out there? How much should cities rely on the development of local solar resources to meet...
View ArticleNovember solar doldrums
I made this gif of visible satellite imagery from the NOAA’s Geostationary Satellite Image Archives. It basically shows cloud cover over the last 12 days at about 1 pm (19:15 zulu) each afternoon....
View ArticleThoughts on Xcel’s 2030 Resource Plan
Xcel Energy, the state’s largest electric utility, has filed their 2016-2030 Resource Plan with the Public Utilities Commission. This begins a long process of commenting and modification until their...
View ArticleHome solar update – to the roof!
My small experiment with solar started with one 100 watt, battery-connected panel resting on the ground in the backyard. I soon added a second and eventually a third panel. I learned a lot about every...
View ArticleElectricity from wind is cheap in Minnesota
Wind in Minnesota, even un-subsidized, is cheaper than the national average lifetime cost for coal and natural gas sources. This comes from the April 2015 Bloomberg New Energy Finance state factsheet...
View ArticleWind and solar now provide 10% of growth in China’s energy consumption
I got into a twitter discussion about a blog post that was challenging the idea that China is seeming a “renewables revolution”. I do not claim to be a China expert, and I hope I do not qualify as an...
View ArticleLow-carbon energy, land use and community planning
At Energy Collective, Jesse Jenkins looks at the land use impacts of three low-carbon energy sources: solar, wind and nuclear. On solar: According to the MIT authors, powering 100 percent of estimated...
View ArticleOnly Wikipedia is accurately tracking solar PV capacity in Minnesota
GreenTech Media recently showed that the main energy statistics agency for the United States, the Energy Information Agency (EIA) was missing information on a whopping 45 percent of installed solar PV....
View ArticleThe grid is good
We’ve had an Egauge monitor that tracks our home’s solar production on for about a month now. It’s fabulous. For the last week, it’s also been tracking our whole-home electricity usage. Here’s a graph...
View ArticleShould more solar panels should face west? (with local data)
Here are two charts I made using data from the output of our grid-tied solar array and data from the Midcontinent Independent System Operator (MISO), the people who keep the regional grid (including...
View ArticleMinnesota residential solar installation prices in line with national trends
Depending on how you count, this is my sixth post in a row here about solar. I’ll do my best to discuss something non-solar next time. CY 2014 was the first year the Minnesota Department of Commerce...
View ArticleWhat are the upstream impacts of internal combustion and electric vehicles?
My previous post comparing the nitrogen oxide emissions of electric and fossil-powered vehicles generated a number of comments (via social media and the blog) to the effect of: “Power plants may be...
View ArticleOne year with solar
In late June or early July of 2015, the grid-connected solar at our house was switched on by Xcel Energy (I’ve lost the precise date). By July 19th of 2016, I had twelve months worth of electrical...
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