Part 2 of Julio’s Series on Clean Energy at Sol Homestead
Have you ever felt the metal fins on the back of your refrigerator? They can be very warm. That’s because your refrigerator transfers heat from the air to a refrigerant that absorbs the heat, making the air inside your fridge cold enough for milk, fruit, vegetables, etc. The refrigerant then evaporates, is compressed, and passes through a condenser where a fan releases the heat out of the back of the appliance. This is also how air conditioners work. Air is sucked into the unit, heat is transferred to a refrigerant, cool air blows through your home, and hot air blows outside. Heat pumps are just air conditioners that work in both directions (blowing hot or cold air into your home and cold or hot air outside).
It turns out that heat transfer via air circulation as I’ve described can be much more efficient than combustion-based temperature regulation at sustaining a home at room temperature. Internationally, this has been understood for decades. Air source heat pumps are all over Japan and Europe; ground source heat pumps (same idea, but pulling the air into the unit from a hole in the ground rather than the ambient air near the outdoor unit) have become popular in higher latitude areas (Canada, Norway, Greenland, etc). Consider that other heating methods still need a blower fan to circulate the heated air through your home; heat pumps are systems where the air circulation is most of the work done to maintain a set temperature.
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By Julio Santana
Happy Earth Week! One of our goals is to live gently on our acre, recognizing the impacts that our choices have on the environment around us. This past year, Julio has worked hard to take on the effect of the energy we use to power everything from our cars to the deicer for animal waterers. This is the first in a two-part series he has written about clean energy at Sol Homestead. -Kasey
Since Sol Homestead’s solar panels powered on in late October, we’ve observed a significant dip in our electric costs month to month relative to previous years. This is in spite of fueling one of our cars with electricity, which increases our electric consumption significantly. It was quite nice to see a reduction in after-tax dollars spent both on powering our homestead’s electric needs and in fueling one of our vehicles – especially since it’s been an extra cold winter in Colorado, natural gas prices have been high (dollars towards natural gas consumption have increased).
Recently, our power bill posted for February 24th through March 27th; the electric portion is $3.83. Those are just the fixed infrastructure costs to have electric service. We generated a surplus of 40 kWh relative to our usage over that span (~1.5 days’ worth of winter/spring time electricity inclusive of car battery charging).
Given that we’re hitting the long days of the year and that we are banking electricity credit from excess solar generation with our power company, I expect that we will only pay for the fixed infrastructure costs (ie, the service line drop, ~$5/month) for the rest of our time at this location. The cost of fueling one of our cars and of all of our home’s electric needs is accounted for in the solar panel installation (breakeven in about 8 years, depending on actual electric usage and unit cost of electricity).
The trajectory of renewable energy cost to households echoes the rapid commoditization of consumer-grade electronics and personal computers in the 1980s and 1990s. “By the time a statistic is written down, it’s already out of date. That’s how fast renewables and other clean technologies are becoming more affordable.” summarizes Leah Cardamore Stokes in her essay “From Destruction to Abundance” in Not Too Late: Changing the Climate Story From Despair to Possibility.
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