ClearSense Building December Update

December saw lots of changes at the ClearSense building on Rigsbee Ave in downtown Durham. We started the month with the new steel frame, roof, and floor slabs in addition to what remained of the exterior shell of the original single story building. We are very pleased with our choice of roofing panel. The R-42 insulated metal panel is both super insulated and aesthetically pleasing on both surfaces. The underside will be the finished ceiling to the second floor interior space. (see photo below)

By the holiday break (at our required pace for this project, none of our team took much time off), one interior stair was roughed in, plumbing, mechanical and electrical systems were at 50%, storefront window frames were installed, and some of the second story siding work was completed. Most prominently, the wind turbines and photovoltaic array are up! (see photo of the ClearSense rooftop below) These systems combine for a rating of approximately 35.5 kW to power the building of just under 12,000 square feet. The turbines are quite prominent, practically a beacon of clean energy generation. We're very proud of them - are they the first building mounted wind turbines in Durham, in the triangle, in the piedmont? Please let us know. Unless someone tells us otherwise, we'll take credit for that as another of many "firsts" in our local building industry (see our website “Recognitions” page for more).

Our goal is that the building itself will be constructed to be approximately 50% more energy efficient than a typical existing commercial building of the same size and use and that the clean energy generation will provide approximately 37% of the remaining power needs of the building. Though our team only designs and builds energy efficient and certified "green" buildings, we were able to exceed our regular standard and install the clean energy generation systems with the help of a grant proposal accepted by the North Carolina Green Business Fund. We are very pleased to have established this relationship and thankful to the NCGBF for their assistance. Stay tuned for more on the innovative work at 502 Rigsbee Avenue.

Solar Panels: That Simple?

When installing solar panels, you stagger the rows so that one row of panels does not shade the next. And, of course, it makes sense to tilt them towards the sun. That simple? Nope. Throw in a few more factors like limited area for the array installation, the limitations of the rack systems, the relative cost of more and less efficient panels, and the surprisingly small reduction in efficiency if the panels are not at the optimal angle to the sun and another, better route emerges.

For the array that we are installing on our commercial building in Durham, we made choices that yield a cost-effective solution but that seem counter-intuitive. While slightly more complicated than this, our options boiled down to two alternatives that both exceeded our energy generating goals. Option one: expensive and highly efficient panels installed in consistent and optimally tilted rows. Option two: a larger quantity of considerably less expensive and somewhat less efficient panels installed mostly in consistent and optimally tilted rows but with two leading rows that are not tilted towards the sun. In fact, they are tilted slightly to the north. The lack of tilt allowed us to install the first rows more compactly without shading the next row. We picked option two. Option two delivers slightly more power. Option two saves over $40,000 in up-front costs. Not bad. Our only concern is hearing the comment: “Hey, Mr. Solar Intelligence, the sun is to the south.” To those folks, I’m happy to tell this story, enjoy the clean energy, and put the money in the bank.

For any energy geeks (this term used endearingly) reading this, the first rows of panels are on a separate inverter so the reduced output from these rows does not degrade the output from the optimally tilted rows. Option two schematic roof panel layout shown below.

10,000 kWh

In same way that you notice when your car rolls past 100,000 miles, we noticed that our clean energy generation system hit the 10,000 kWh milestone this week. The system has been in operation for less than two years and has consistently performed beyond our expectations. We have a "buy all, sell all" system which means that we buy every watt that we use and we sell (back to the utility) all of the power that we generate. We get paid for that power two ways. One, our utility pays us wholesale rates for the power and two, a clean energy company pays a premium rate for the clean power.  In 22 months of operation, we have earned $3,250.00 from the clean energy company and another $450.00 from wholesale power sales. Without taking the value of the tax credits into account, we are making a 7.4% return on our investment. If I immediately offset our investment by the significant state and federal tax credits (which we realize, but not right away), the return on our investment goes up to a whopping 21.3%. If you are doing better than that in the market right now, will you please send me the name of your broker?

There are caveats, of course.  The clean energy company is very slow to pay (but they do). Our energy generation system is the first in our county and I had to work with our planning board to write a new ordinance that supports these systems. The federal tax credit is realized in the first year but the state tax credit is spread out over 5 years. A good spot with generous solar access is required (we designed and oriented a shop building specifically for this purpose). Lastly, our initial investment was a bit lower than most as my father and I installed the system and just hired a professional to set up the inverter and grid tie-in. Still, we find that our system is well worth the effort.

Another way to look at the financial value of a clean energy generation system is to check the time line on seeing your initial capital back. At that point, you still own the system and its capability to continue to produce energy and revenue for decades to come. Without tax credits, our system would pay us back in 13.4 years.  With tax credits, 4.7 years.