Durham Energy Committee - Oyster River Middle School June Update

June Update

“A Tale of Two Panels”

Recently, the architects designing our new Middle School discussed how solar energy might be incorporated into the design vision for the facility.  Both photovoltaic panels and solar thermal panels were mentioned; our June Update focuses on both of these types of panels.

Photovoltaic (PV) panels are widely used to produce electricity and may be included in the Middle School design concept.  PV panels can convert 15% to 20% of incoming ultraviolet solar radiation to produce electricity.  The energy output of the panel compared to the solar energy input is known as the effectiveness of the panel.

Solar Thermal Panels are less widely used.    These panels absorb incoming infrared solar radiation to produce heat; the heat is typically used for heating domestic water, and sometimes for space heating.  Solar thermal panels can convert between 50% and 60% of the incoming infrared solar radiation into heat; this approach is three times as effective as PV panels.

So why aren’t solar thermal panels more widely used than PV?  Well, consider the type of energy that’s produced.  Solar thermal panels are great at producing heat.  However, photovoltaic panels produce electricity, which is much more useful energy than heat energy.  And as a bonus, we can actually sell excess electricity back to the electric utility grid! 

One of the biggest questions is; “Are solar panels worth the investment cost?”  Well, let’s look at this; when the average installed cost of each type of solar panels is considered, the return on investment of each approach looks like this:

Photovoltaic Panels- The price of PV panels has been dropping, and panel performance has been increasing, making these systems increasingly attractive.  If utility rebates are taken into account, the cost payback is in the 6 to 9-year range.
Solar Thermal Panels- Solar thermal systems involve piping, pumps, controls and other equipment, which add to the system installation cost somewhat.  However, these panels provide strong performance.  The cost payback is in the 4 to 10-year range, depending on whether utility rebates apply.

Typically, energy projects which have an installation cost/payback in the 7 to 10-year range are considered worthwhile investments.  The relatively low installation cost/payback of solar panels makes a very persuasive argument for including them in our proposed Middle School project!

Perhaps the greatest payback of all is that the energy of the sun can be used effectively to power our buildings without emitting carbon, and without damaging the environment.  On a recently-sighted bumper sticker: “When a massive spill of solar energy occurs, it’s just called a nice day.”

RESOURCES

There are many on-line resources available which pertain to solar energy.   Here are just a few places you can explore:

Renewable Energy World:   This is a rich resource to access current news and practice regarding solar energy, wind energy, electric vehicles, battery storage and more. You can find it HERE.

EERE (U.S. Office of Energy Efficiency and Renewable Energy) provides information on current U.S. Department of Energy programs and research on solar energy:

https://www.energy.gov/eere/solar/solar-energy-technologies-office

NREL (National Renewable Energy Laboratory) is the pre-eminent national laboratory researching renewable energy located near Denver, CO. NREL advances the science and engineering of energy efficiency, sustainable transportation, and renewable power technologies.  NREL posts analytical and design tools, data sets and modeling software for use by the general public. 

https://www.nrel.gov/research/data-tools.html