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Case Studies


Wasted Energy in the U.S. Could Power Entire Countries

The electrical power wasted by equipment known as miscellaneous energy loads (MEL) in the United States is enough to provide the power needs of nations like New Zealand, Mexico and even Australia, according to the American Council for an Energy-Efficient Economy (ACEEE). Those two billion devices, which do not fit into traditional energy-use categories such as refrigeration, HVAC or lighting, could be made to use 40 to 50 percent less energy by upgrading their technology.

The people at Nextek Power Systems hasten to add that powering most of these devices from a DC power system that is up to 8 percent more efficient than AC grid power, would make that goal much more easily achievable, and improve the power savings to well past the 50 percent mark. As much as 80 percent of electronic devices in the U.S. now run semiconductors (which only use DC power), making the strategy much more attractive, since DC systems also save 10 to 30 percent of the power lost to heat through conversion from AC.

The ACEEE’s full report can be downloaded for free at



Study Shows Energy Hogs Default on Mortgages One-Third More Often

Thought you could get away with leaving all the lights on or running appliances when you don’t need to? Think again. A recent study by the University of North Carolina at Chapel Hill’s Center for Community Capital and the Institute for Market Transformation (IMT), a nonprofit organization dedicated to promoting energy efficiency, has determined that homeowners who are not conscious of energy saving practices are one-third more likely to default on their mortgages. The study included 71,000 homes from 38 states and the District of Columbia. The sample was restricted to single-family, owner-occupied houses whose loans originated during 2002-2012 and were used for purchase only. About 35 percent of the houses in the sample were ENERGY STAR-rated for efficiency, with the rest forming a control group. The study determined that the odds of a mortgage default on an ENERGY STAR residence were one-third lower than those of a home in the control group.

According to Cliff Majersik, executive director of IMT, “It stands to reason that energy-efficient homes should have a lower default rate, because the owners of these homes save money on their utility bills, and they can put that money toward their mortgage payments.”

The authors believe that lenders should require an energy audit as part of the mortgage underwriting process, and that federal housing agencies could promote underwriting flexibility for mortgages on energy-efficient homes. They will recommend that Congress consider their findings as they create legislation to improve the accuracy of mortgage underwriting.



Want a Cheap Solar Panel? Just Print It.

A team of engineers in Melbourne, Australia, has developed an inexpensive method of producing solar cells from a standard industrial printer, raising the possibility that solar panels can be eventually mass produced for far less than current costs.

As reported by San Francisco public radio station KCET, engineers at the Victorian Organic Solar Cell Consortium (VICOSC) said on May 23 that they are able to use a $200,000 screen printer to make photovoltaic cells the size of an A3 sheet of paper (11.7 by 16.5 inches), using semiconducting inks. Such printers are typically used for applications such as screen-printing t-shirts and posters, can make a solar cell of that size every two seconds.

Currently, drawbacks to printed solar cells include the panels’ extremely low efficiency and short lifespan compared to traditional solar cells. The printed cells range from one to five percent efficiency, far lower than the 20 to 25 percent in most panels. They produce only 10 to 50 watts of energy per square meter, only enough to power a small light bulb. However, the advancement is a significant one if the technology can be improved. Solar cells like this could be added to building surfaces, billboards, and since they can be made translucent, tinted windows.

VICOSC is a collaboration between Australia's national science agency the Commonwealth Scientific and Industrial Research Organisation (CSIRO), The University of Melbourne, Monash University, and industry partners.



Nextek Involved in U.S. Military’s Research into Microgrids

When Hurricane Katrina hit the Gulf Coast in 2005, it wasn’t just cities and towns that experienced power outages—U.S. military facilities also went offline. For example, the regional relief operations center at the Naval Construction Battalion Center in Gulfport, MS, ran on backup power systems for two weeks, and then needed relief itself. Keesler Air Force Base near Biloxi lost its airfield lights and a hospital generator. The incidents prompted concerns at the Pentagon over the military’s ability to operate during and after a disaster. Perhaps even more important is the military’s ability to function after a terrorist attack. Such attacks don’t have to be military in nature. More and more, terrorist groups and even nations are looking for ways to infiltrate government agencies, utilities and businesses that use the Internet to communicate. Probes from hostile sources have been detected searching for weaknesses in the security of systems such as the electric grid. Should such an attack be successful in shutting down or damaging what may be the nation’s most important infrastructure, the military might be rendered inoperative for a critical period of time.

One of the solutions the Pentagon is looking at to thwart such attacks is the conversion of military power systems from reliance on the AC grid to the use of microgrids. These systems create and store energy from renewable sources like solar power, and use AC grid power only when needed. Because the microgrids are self-sustaining, they can be disconnected from the main grid (called islanding), and will continue to operate even if other systems are down.

Recently, Nextek Power Systems, Inc. completed a Direct Current microgrid demonstration project at Fort Huachuca in Arizona. One of the base’s buildings is 100% powered from solar panels on the roof, which provided electricity without reliance on the AC grid, even during off hours. In fact, the panels produced power to spare that is stored in batteries until it is needed. Since the installation nearly a year ago, the facility has not drawn any power from the AC grid!

The project also showed that expanding the program and implementing microgrid systems on a wider basis could achieve significant savings.

Microgrid technology is a viable solution to the military’s concerns over operational status and security. And they also offer the added benefit of achieving the administration’s goals for cutting energy consumption and switching to renewable energy sources. Nextek is committed to developing this technology for both government and commercial clients.

Further Reading: Fort Huachuca Case Study (pdf) 



Fanworks Blows the Skin Off the Rice Pudding: A Case Study in Greenhouse Ventilation

We are fortunate to have Fanworks customers all over the globe. Not every installation is “text book” and recently we had to use some creative problem solving after receiving an e-mail from a less than satisfied customer. A greenhouse owner in Southern Australia had installed one of our Vari-Cyclone fans to provide cooling and ventilation for his employees during the hot days. The initial installation was not performing as intended and they sent us an e-mail saying that the fan would not move enough air to “blow the skin off the rice pudding”! Although that’s not a phrase we use here in the United States very often, we understood the sentiment immediately.

After a number of phone calls, e-mails and photographs a solution was determined: move the fan closer to the ground. The initial installation was 9.5 feet from the ground, which in this outdoor environment was too far away. Additionally, the ceiling of the greenhouse was curved, not allowing for enough air flow above the fan. After a few modifications the Australian greenhouse owner was happy to report that not only did the fan blow the skin off the rice pudding, it blew him over, too!

Another Satisfied Customer of Nextek Power's Fanworks

Another Happy Fanworks Customer!



Enhancing Reliability and Efficiency Using Locally Generated DC Power: The Hybrid Building


Since Edison's day Alternating Current (AC) and Direct Current (DC) have co-existed by necessity: AC to make the trip from the generating plant and DC to power electronic loads. This has resulted in billions of electrical compromises in the form of the ubiquitous power supply, or a rectifier that must stand in front of DC loads to convert AC to DC.  As Arthur Rosenfeld, California Energy Commissioner calls them, our Energy Vampires.

But now, many buildings are generating power of their own, usually Direct Current energy. Is this wasteful back-and-forth conversion really necessary?  Just as the automobile industry has advanced to the hybrid car, buildings can use multiple sources of power to achieve dramatic increases in efficiency.


Edison and Westinghouse fought the AC/DC battles around the turn of the century. AC won because Tesla's transformer allowed AC voltage to be boosted for easy transmission from Niagara Falls into the city. Edison's DC network required unpopular 'backyard' DC generation stations every few miles. But where AC won in the transmission, it's DC that is now used inside almost all of our devices. You see, only DC can be precisely regulated to get the exact voltages we need for sensitive electronics. So our current building electrical systems are fed with AC that is converted to DC at every fluorescent ballast, computer system power supply, phone system, and other electronic device.

This model works fine until we bring back Edison's original idea and buildings begin generating power of their own usually DC power such as solar, fuel cell, and wind. The inefficiencies involved with inverting to AC, matching grid frequencies, and protecting linemen from hazards are all avoidable by creating a Hybrid Electrical System.

Inefficiencies in an inverted solar system:

The inverter model of the traditional solar system has several flaws:

  1. Inverter Efficiency. Rated inverter efficiencies rated between 90% and 95%, Actual field efficiencies are even less. Many inverters consume power at night. Several models do not turn on in low light conditions.
  2. Anti-Islanding For the protection of utility line workers, inverters are required to shut down in the event of grid failure. This means that, for most solar systems, there is no energy production during a power failure (when we need it the most).
  3. Net Metering. Power sent back into the grid is not always repurchased at full cost. Sending excess power back into a sometimes overburdened grid may not be the best way to manage the resource. Net-Metering, as a business practice for utilities, is not sustainable and is likely further erode the value of power sent back to the grid. Net-Metering agreements and the meters that they require can be expensive.
  4. Reconversion losses. Now that we've suffered the losses of inverting, additional losses are incurred converting back to DC in the electronic devices like fluorescent ballasts, computers, and more.

The Hybrid Solution The theory is simple: In a building that produces DC power of its own, use the DC power for the DC devices and use the AC power of the grid for everything else. If more DC power is needed then is available, take some grid power, convert it to DC, and use it to supplement the local source.

  • Efficiency gains come from the fact the locally generated DC power is never converted and AC power from the grid is only converted when necessary.
  • The system is more reliable because there are redundant sources of power. It is not necessary to shut down a DC system during a grid failure like it is with an AC system.
  • The system is simpler because no net-metering or utility interconnection agreements are necessary. The utility cannot even 'see' the system and, in most cases, does not even need to be notified.

Drawbacks of the Hybrid Solution The only drawback of the hybrid system is that there is no efficient provision to store excess electricity. It cannot be sent back into the grid and re-purchased later and storing excess power in batteries can be too expensive to justify.

The solution is to identify base DC loads that will always be on when the system is generating. If solar panels are the local DC source, then the local DC loads need to be on all day every day. An ideal example of this is commercial fluorescent lighting.

Example of a Hybrid Lighting System In this example (which can be seenlive at solar panels are connected to DC ballasts in the lighting.

Daytime: The solar power from the panels is sent directly to the lighting, with no conversion, at nearly 100% efficiency. Wiring losses are the only significant losses. The system is designed so that, at full sun, about 90% of the power needed for the lighting is supplied by the panels. The additional 10% is taken from the grid, converted to DC at the NPS1000 power gateway.

Clouds: When clouds reduce the PV production, more power is taken is taken from the grid and converted to DC. The system is using all available power from the panels (the least expensive source) and using the grid as the backup.

Night: When there is no solar power available, all the power is taken from the grid and converted to DC. As we discussed previously, a typical AC lighting system takes AC power from the grid and it is converted to DC at every ballast. In this DC system the conversion is handled centrally. The number of conversions is not increased.

Power Failure: In the event of a grid outage, the lighting system continues to be powered by the solar panels and, if needed by optional batteries. In a traditional inverter based solar system the inverter is required to shut down, shutting off the lights.

Other suitable DC loads in commercial buildings include telephone systems, motor controllers, computer server systems, and more. Current installations include grocery stores, offices, big-box retailers, and, most recently, a Frito Lay Distribution center in Rochester, New York.

Whole Foods, Berkeley

This 30k system powers the lighting and was installed with Powerlight Photovoltaics. One of the primary benefits of this system, besides increased efficiency, is the reliability aspect. Power failures are extremely expensive for grocery stores, not because of the freezers, but because 200 people with shopping carts full of frozen food abandon the carts and leave the store. This creates an expensive emergency for the store as the staff need to scramble around, reshelving the food by opening coolers which should really stay closed. This, as well as the lost sales cost the average small grocery store over $8,000 per five minute failure. Shortly after the installation, Whole foods experienced a brief power failure. The lights were powered by the solar panels and did not shut off. Customers remained in the store.

Frito Lay, Rochester

One of the other benefits of low voltage DC ballasts is the ease at which they can be controlled. Each ballast has a phone wire-type connector which can be used to provide DC power to, and a light switch for an occupancy sensor. This reduces the installation cost of an occupancy sensor for $200.00 each to $75.00 each.

Target Stores, El Cajon, CA

This system uses the Nextek system for part of the store, and an inverter for the rest. This allows us to monitor each of the systems and compare the efficiency of both. Initial readings illustrate that the Nextek System is providing over 20% more power than the inverter based system.


The most efficient way to utilize locally generated power is to consume it all, where, when, and how it is generated. We can accomplish this by identifying DC devices in a building and powering them with the locally generated energy and use the grid as a backup.

Mr. Mark Robinson, LEED VP Sales and Marketing Nextek Power Systems