Soaking Up Solar

This week we fired up the new solar panels for the first time. Under the clear February sun, electrons jumped right into action, creating almost 40 kW of electricity for the new Margaret A. Cargill Lodge. This is a big step toward our goal to make the MAC Lodge net-positive for energy, and towards meeting the Living Building Challenge requirement that all electricity in the dorm be made from renewable energy.

Flipping a switch to turn on the solar was a simple move; behind that action is a trail of decisions and lots of planning. Each new solar installation presents unique challenges to consider. How much power is needed? Where will the panels be located so they can gather the most energy? What path will the created electricity follow as it travels from the panels to, for example, the light in the dining room? What system design and components are most efficient? Which will have the smallest impact on ecosystems?

Here in northern Minnesota, studies show that reliable renewable power systems incorporate a variety of strategies. The best plans begin by examining ways to reduce the demand for electricity. A smaller system will cost less right off the bat. In the case of MAC Lodge, architects incorporated daylighting through window locations with the strategic placement of solar light tubes to bring sunlight into the interior hallways and larger group spaces. When purchasing appliances like washers, driers, and refrigerators, we chose those with the best energy ratings.

Next, we made the decision to enlist the help of every student living in the dorm. Each person will be challenged to help reduce the dorm’s need for electricity through their actions and choices — and they will have evidence of the difference those actions make. Energy use data is displayed near the light switch in each dorm room. When a light is turned on or off, there will be an immediate change on the display. Out in the dorm’s main gathering space, people will be able to compare use from room to room and day to day, and adjust their choices to reduce their personal use of electricity, establishing conservation habits they can bring back to their home communities.

After taking conservation measures to reduce the size of the system needed, proper siting of the solar panels will make a big difference in its efficiency. Brand new buildings have the luxury of designing the structure to support roof installations or to keep clear areas where ground panels can access consistent sunlight all year round. In the case of MAC Lodge, which was an interior remodel with small additions, we chose to locate the solar panels about 200 yards away, near the Science Center parking lots.

Next, consider how power will travel through the system and be either shared or stored for future use. Storing created power in an on-site bank of batteries gives total local control over the power, but does not allow for high electricity demand during long cloudy periods or spikes in use. Special electric fixtures and appliances that run on direct current (DC) must be purchased, or alternately, inverters that can change the solar DC power to AC. Batteries themselves are environmentally intensive to produce.

The other possibility, grid-tied power, made the most sense for Wolf Ridge’s system. This choice allows us to use existing copper wires laid by our local power company, Co-op Light and Power of Lake County, to move electricity from the new panels to the MAC Lodge. Any extra power can be distributed to other buildings on site, and theoretically to our neighbors down the road through existing power lines. In rural situations, solar power grid tie-ins can also help stabilize local surges and dips, so-called brown power, which in turn helps pumps and electronic appliances last longer.

Co-op Light and Power was a key player in making this all work. They helped us tie into the local power grid and facilitated ways to help us measure the power we produce and the electricity we use. Interestingly, Wolf Ridge is now the largest renewable energy producer for their system, and our tiny Crystal Bay Township has one of the highest per-capita solar PV installed in the continental USA!

Solar electric power is now considered more cost effective to produce than coal or nuclear in most markets, and it is usually on par with natural gas. Solar technology advances every day. A kilowatt hour of solar power created today costs less than half as much to produce as it did just 10 years ago. Large-scale power producers are turning more and more to renewables because they are cheaper than other methods. Here in northern Minnesota, low sun angles will almost certainly mean that we will need to include a mix of wind and power from combustibles like biomass to augment our solar electricity.

Meanwhile, fresh snow sparkles as a class skis across Raven Lake, the towering cliffs etched in brilliant white. A student stops to rest and soak in the view. Then it happens. They look up to the sky and close their eyes, making small adjustments until they find the sweet spot where the warmth of the late February sun is felt most intensely on their face. They breathe in, then their shoulders relax down as they pause, mesmerized by the warmth and the view. Maybe you’ve done this too – caught yourself in a moment outdoors, face to the sun, breathing it all in while time stands still.

Solar is powerful.

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