Solar energy, in simple terms, is converting sunlight into electricity. (Solar energy can also be in the form of heat—often termed "solar thermal"—but we are referring here to photovoltaics.) For a more complex definition, Live Science describes how solar panels work: they allow "photons, or particles of light, to knock electrons free from atoms, generating a flow of electricity."

While a commonplace for residential panels are on roofs, Mary and Gary constructed their project on the ground, approximately 200 feet from the house. The Carlson's 80-by-14 foot, 56-panel solar array rests on a sturdy metal frame with a concrete foundation. The productivity of each separate panel can be tracked over its lifetime using a software system. Gary is confident in his system and now only checks his array every other month or after a big storm.

The Carlson's prairie-style house has several features that boost this pair's success. For example, with this architectural design, there is an optimal ratio of walls to windows, which allows for natural light yet keeps the home well insulated. The roof overhang allows the winter sun to come in and shades the house in the summer. This house also has an above-average amount of insulation, with 6 inches in the walls and 10 inches in the roof. Their energy-efficient windows are not only double pane but also Low-E or low emissivity, meaning the surface reflects thermal energy. These features are known as "Passive House Principles" and help lighten the load for the geothermal and solar systems to cover the rest of the electricity that is needed. In fact, due to these design elements and additions, the Carlsons were able to install a much smaller solar panel system, saving them money and yard space.

Very Few Downsides

As with any home project, there are always some downsides to consider. Gary's first response to the question about the disadvantages was that solar panels "are an eyesore." It is a common concern. To hide the array, the Carlsons planted a row of trees between the solar panels and their house to make the system barely visible.

Another downside to installing solar panels is that on the rare occasion that traditional power lines are out, the house is without power. They are grid-tied and do not have backup battery storage. While the Carlsons have experienced a few power outages due to severe storms, most of these incidents were short-lived and did not have a significant impact on their lifestyle.

While building the base for the arrays saved a lot of money, it is not practical for most people. Gary advised that one must be a "handyman" to complete this project by saying, "On a scale 0 to 10, 10 being expert, this project requires a 7."

In terms of the geothermal system, the only inconvenience the Carlson family mentioned was that it takes longer to heat the house. This extended time is because the geothermal system is not able to blast out as hot of air compared to a traditional natural gas heater. However, both Gary and Mary said that this delay wasn't a huge problem. It is barely noticeable if you keep your house generally warm relative to the outside temperature.

Lessons Learned 

There is no one-size-fits-all approach to reducing your household carbon footprint. Depending on your location, energy needs, and financial goals, there are dozens of options for alternative energy and decreasing energy needs—and there will be even more to come in the future. It is essential to consider a holistic, well-rounded approach of both efficiency and renewable electricity generation. Some may start small by adding more insulation. Others may want to jump in with more significant investments like solar panels or wind turbines. Like the Carlson's home in Minnesota, it takes a combination of solutions to get to zero carbon emissions.

More Than Just Financially Rewarding

A big take away from the Carlson's project is the importance of tax breaks. Rebates can cut many project costs by almost half. Rise's website is an excellent resource for finding more information about rebates that may apply to you. The economics of both the geothermal and the solar panel systems justifies the Carlson's project alone. However, even without the financial incentives, both Gary and Mary said, "It has been one of the most rewarding things we have ever done." They strive to live a low carbon, sustainable life, and this combination allows them to do so with minimal sacrifice. The Carlson's hope that others can be inspired and that their home in Minnesota can become a model for creating a zero carbon footprint.

Madeline Carlson is a healthy home advocate and consultant living in Minneapolis, Minnesota.