Whether we are talking about wind, solar thermal, or photovoltaic projects, a proper installation is key to the success of the project and the health of the industry. Quite often we as contractors will see either minor errors in understanding of the technology or resource, system design, or placement that will negatively impact the long term productivity of a project. Most often these errors are seen with the application of wind turbines and, separately or together, with grant funded projects. Today we’ll focus on wind.

North Carolina has a terrible wind resource. There, I said it. If you are not within a mile or so of the ocean coast or up in the mountains, there is no justifiable resource. We have plenty of potential clients that come clamoring in the winter, when winds in places from Greensboro to Kinston are stronger and more consistent, but even those winds are only going to last part of the day and disappear into still doldrums come the spring and summer. Wind is variable, and we need an average annual of a certain threshold, not just a strong winter afternoon.

There is so much beautiful and undeveloped land in this state that you have to think if it made economic sense we’d see a lot more of them. The investors that put up these big GE and Vestas turbines flock to quality wind resources. Believe me, if we could put up a 1.5MW somewhere outside of Greenville and it would be productive, I’d be all for it. Unfortunately, the only place it really does make sense is in Eastern NC, but they are having real issues in this challenging economy. Some of these challenges include financing, migratory birds, zoning, and military restrictions. The mountains have similar issues and Ridge Top restrictions.

Baker Renewable Energy (BRE) has, in addition to using the historic records databases, performed extensive long term anemometer testing throughout the state. The anemometer is a tool used for measuring wind speed. Our philosophy is that if you truly do not believe the data of record, then let’s put up equipment to give you a site specific sample. Does it cost money? Yes, but far, far less than having an ornament up in your front yard for the next 25 years that will never pay for itself.

Back in 2009 BRE was contracted by the NCDOT to do a wind resource study on what the construction teams were calling “Windy Hill”. Windy Hill sits atop a minor bump along the southbound stretch of I-73/74, State Highway 220, between Black Ankle and Seagrove, NC. The DOT was in the throes of building a beautiful LEED certified rest area, up upon the hill, just below the peak. The hill above had pathways leading to it from which travelers have an overlook that allows you to see for more than 20 miles in every direction. If ever there was a location in central NC with an opportunity for good wind, this would be it, right?

We set up the anemometer in January, a cold and clear day like today, and immediately it started spinning. Knowing construction workers and tradesmen told our team and the NCDOT rep we were working with that we were wasting our time, and needed to just install a turbine.

We went back months later to retrieve our anemometer, and the data. The anemometer was truly one of the best positions we had ever dropped, with no obstacle at the hub height not just for 200 meters, but for nearly ½ mile or greater. When we processed the data we saw what we expected, but not what we wanted. We were within a rounding error of the historical wind speeds. Keep in mind if are talking about a 6mph wind, even if we were off by 20% (+/-) that still only means a 5-7mph wind give or take a little. There is no chance that our equipment is off by a 20% discrepancy. The 10-11mph average winds needed to generate power, and the consistency needed just did not exist to produce electricity consistently from the wind. Wind resource needs to be thought of like current in the ocean. You need a strong and consistent current, not just an occasional tidal flux. Long term averaging, whether speaking about wind resource or solar exposure, is the real key to successful renewable energy projects.

So what about all of those windy days? Well, when graphed out, we could see good strong winds in the mornings and the afternoons nearly all of January, but that still really only meant in the mid-teens for mph. Shouldn’t that be good enough? Well, unfortunately every night the wind died down and brought a bunch of 0’s into our averaging, and that is a key word. Average wind speed.

It does not matter if you have 2 hours every day at 24mph if you had zeroes the rest of the time. Using a popular model like the Southwest Windpower Skystream 3.7 (Yes, we are dealers, this is not meant as a plug) in conditions like that, with 24mph winds 2 hours per day and zeroes the rest of the time, we would make about 5kWhrs per day. A similar investment in a photovoltaic system nowadays would get you about 3-3.5kW and should produce conservatively 10.2kWhrs in a day. The reality at the overlook was that when it was windy the power was more like 16mph as an average, and as the power curve of these generators is exponential (ramping up) a 16mph wind has it only putting out 1kW, not the rated 2.4kW at 24mph.

Just this morning, as I was writing this piece, a potential client called from Trenton, NC. Mapping showed that what he was interested in, a Skystream 3.7 would generate less than 2,000kWhrs per year. He told us straight away he was not so sure since yesterday someone was there telling him wind would outperform solar and solar could never pay for itself. Trenton’s average wind speed is close to 6mph. This eagerness to sell, versus selling what’s correct is a strain on the industry.

We, as integrators, have to help you install what is most efficient when you use your other non-renewable resource, money. In this case, not only would solar have dramatically outperformed the wind, but the wind would not have been able to achieve the required ROI (return on investment) for the client to invest in the first place.

The real point here is the importance of citing a wind project where there is a resource for generation. Next time I will talk about the physics of wind, different wind technologies, and what to look for when considering a turbine.

Often owners of photovoltaic systems ask about their power production. “If I bought a 100kW system, and it is sunny, why does it only say 65kW at the inverter? What is wrong?”

PV systems have what is called a DC rating. That is the capacity in DC, direct current, for output based on a standardized testing procedure, STC. These numbers reference the amount of energy that the system is capable of producing. If we install (100) 240watt panels, that is a 24kW (DC) system. So is that what it puts out? Well, no. many factors in real world environments impact the production of solar.

Let’s move away from solar for a second and look at your automobile. It may have a top speed rating of 120mph however have you ever been able to get it to that speed? The answer is probably “no,” that is a speed which is given by the auto manufacture to give an example of what the auto is capable of and does not fully represent real world conditions such us traffic, road construction, law enforcement, etc.

The same is true of solar arrays, they have their own “speed bumps” that prevent them from fully reaching their potential. In an ideal install, factors such as temperature and angle of the sun, even on a wide open roof can impact performance. In less than ideal conditions, other variables that can add to a difference in production are soiling (dirt), shading, and inefficiencies with the wiring.

“PV systems deal in power versus energy production so it is important to understand the differences”

Power is a term that is used to evaluate energy production instantaneously, which is why it is a popular term to evaluate PV systems. It makes more sense for PV systems to be rated based on the energy that they are capable of producing so that they may be compared more easily to similar systems. One solar panel is rated at 240w, so that is what it puts out in standardized test conditions in the lab. In the field, again, with higher or lower temperatures, dirt and different sun angles this panel puts out much different readings.

Energy is that instantaneous power which is accumulated over time. Citing the aforementioned panel, (10) of them together would be a 2.4kW system. If it is partly cloudy and they are running at a lower output, they may make only one kilowatt hour over the course of an hour. Is that low? Not necessarily. If they only had so much light, it should be right in line if the system was installed properly. This is where commissioning comes in.

This is OK! PV installers take these losses into account and size your system accordingly. For example if you were to purchase a system that had a DC rating of 10.000kW your installer would acknowledge that this system would be producing between 7-8.000 kW/hour and that a 8.000kW inverter would be more than adequate to fully maximize your system’s potential. The energy that your system produces is the figure which should be paid the most attention, ultimately any kind of long term benefit from the system will be seen in the form of performance based incentives.

Written by Sean Price, a Contract Manager at Baker Renewable Energy

This represents the largest solar hot water system in VA.

[/slider_custom]

RALEIGH, N.C. (November, 2011) – Baker Renewable Energy, a division of Baker Roofing Company, announced today that it has completed the first phase of a solar energy initiative in Belize in conjunction with the Holy Cross Education Foundation (HCEF) and donors from GlobalGiving. HCEF selected Baker for the project because of its unparalleled experience in the construction industry, track record of success and unique view on construction project management. Funding for the initiative was attained through GlobalGiving.

The project, which involved the installation of one of the largest photovoltaic systems in the Central American country, will provide eco-friendly electricity to a computer lab and medical clinic at Holy Cross Anglican School, which serves more than 500 K-8 students in San Mateo, Belize.

“Baker is uniquely positioned to facilitate the efficient delivery of logistics expertise to challenging environments around the globe,”

“The solution we have designed and installed for Holy Cross will not only significantly reduce the amount it spends on energy consumption, but can also be scaled to meet the future needs of this growing community,” added Jason Epstein, executive vice president of Baker Renewable Energy.

In December of 2010, Baker Renewable Energy traveled to Belize to perform a full site assessment and determine the technological needs of the community. Since then, it has facilitated the logistics of the project in conjunction with the local utility company, Belize Electricity Limited. After completing preparation work and repairs, Baker installed the 24 photovoltaic panels, micro-inverters and wiring that will offset approximately 900 kWh of usage per month. The reduction of diesel power consumption will have a positive long-term effect on the environment as well as on the community’s educational and medical experience, which will benefit from the reliable power source and lower energy costs.

“Many of the residents in this area of Belize earn less than a dollar a day and would have nowhere to receive an education if not for Holy Cross,” said John McHenry, a board member for the Holy Cross Education Foundation and the chief scientist of Baron Advanced Meteorological Systems and visiting scholar at North Carolina State University. “In working to become energy-independent, we are reducing our operating expenses so that more donor money can go directly to feeding and educating the area’s children. Our experience with Baker has been unequivocally positive and I would truly recommend the company to anyone interested in pursuing a renewable energy initiative.”

About Holy Cross Education Foundation The mission of Holy Cross Education Foundation is to provide funding and administrative assistance to primary schools that strive to provide the highest quality primary education to children in disadvantaged areas in developing countries. HCEF will assist in preparing students for the challenges of life in the 21st century—spiritually, mentally, morally, emotionally and physically—by providing a state-of-the-art educational environment. The foundation is a 501(c)(3) organization that was organized by volunteers across North America with the goal of ensuring schools like Holy Cross Anglican School in Ambergris Caye, Belize continue to make positive change in the world. For more information, please visit www.hcefoundation.org.

About GlobalGiving GlobalGiving is a charity fundraising website that gives social entrepreneurs and nonprofits from anywhere in the world a chance to raise the money that they need to improve their communities. The organization allows donors to find and fund grassroots projects that appeal to their specific interests in more than 100 countries and of a variety of themes ranging from education and healthcare to economic development and the environment. Since 2002, GlobalGiving has raised more than $51 million from 217,285 donors who have supported 4,525 projects. For more information, please visit www.globalgiving.org.

Read more at: Engineering News Record Southeast

Source: Boeing

Jason Epstein, Executive Vice President (BRE): “This single project will be the equivalent to twice the solar that has currently been installed in the State of South Carolina. We are proud to be part of this growing industry, and the new jobs it is creating through projects like this.” Epstein predicts this project will create between 12-15 permanent jobs in the North Charleston area.

John Matthews, President (BRE): “This is a very positive step for the development of distributed renewable energy in the United States – an example of a utility and a multi-national business partnering in an effort to further the integration of this critical resource.”

Richard Wright, Senior Contract Manager (BRE): “This is not a typical integration. A project of this scale and scope will require industrial logistics and professional management. This is very substantive new energy construction.”

Baker Renewable Energy installed the first Wind for Schools Program wind turbine in Virginia. The Turbine was installed at Northumberland High/Middle School in Heathville, VA (1 hour east of Richmond). Wind for Schools is a US Dept. of Energy Program that has a goal to raise awareness in rural America about the benefits of wind energy while simultaneously developing a wind energy knowledge base among future leaders of our communities,states, and nation.

Representatives from the district school board, government, Dept. of Energy Employees, James Madison University Students & Staff, as well as hundreds of local students where there to dedicate the turbine.

The Turbine installed was a Skystream 3.7 manufactured by Southwest Wind Power, at a height of 55′. The turbine will generate 2.4kW of electricity at peak wind speeds.