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No! This is a popular question for which we have accordingly provided an in-depth answer. Confusion is rampant around renewable energy systems that are commercially available today and their field performance characteristics. Popular misconceptions often pertain to specific details about geographic suitability areas, renewability of the different systems, and the influence of climatological factors. This is due largely to the fact that the availability and performance of each system is intimately dependent on site related variables. It should be noted that our architects are trained to show no bias for or against any renewable system. They understand how the systems function and know the pros and cons of each. It is our goal simply to choose the system that best fits the needs of the client, budget, performance factor and overall building design. That said, the most energy efficient renewable design currently available is a hydroelectric system.

 

Hydroelectric System

These are very common in the world and chances are you are reading this website illuminated by electricity presently being produced by one of these systems. Hydroelectric systems work by using water pressure (flowing water) to turn Blades attached to a generator to produce alternating current.

 

Heat Transfer systems

The second is a hybrid design that utilizes “heat transfer” principles. Water is heated to boil, producing steam. That steam gathers pressure and is then used to turn a turbine that is connected to a generator producing alternating current. Chances are that if your computer is not being powered by hydroelectricity, it is being powered by this energy source. With the heat transfer system, lots of “heat” sources can be used to boil water such as natural gas, oil, diesel, coal, and radioactive elements (nuclear power plants). It can be argued that some of these, especially those using fossil fuels, are not renewable. This is an inaccurate statement over a lengthy enough timescale. Millions of years from now organic matter from today will have become natural gas, oil, diesel and coal. It is simply a natural process of the earth. We usually do not see it as “renewable” because of the vast amount time it takes to replenish the supply that we are presently consuming at an increased rate each year. As long as there is vegetation on this planet, there will be fossil fuels. It is interesting to conclude that, while fossil fuels are cheap and currently readily available, these systems use “combustion” to produce heat energy. Reconfiguring existing power production plants to use biofuels or biomass could add a higher degree of sustainability to their operation. Fossil fuels are nothing more than dead, decayed vegetation that is undergoing a natural process. When using biomass or biofuels, we are essentially using the same fuel source in a sped-up man made process to get it ready for combustion. Since we can plant vegetation- this is a sustainable solution, however it will still produce carbon dioxide, but at slightly lower levels that what is currently being produced.

 

Tidal & Wave

The most popular “renewable” energy sources are provided by the sun and moon. They power everything on the planet. There are two ways we can tap into this energy- directly and indirectly. The indirect way is by using renewable systems such as Tidal and wave power; which use the gravitational influence of the moon on the earth’s oceans to distort their distance from the moon and earth producing movement. This effect is witnessed with the coming (high tide) and going (low tide) of the world’s oceans. In addition, natural ocean convection currents are also in motion due to thermal radiation from the sun and are called ocean currents. These currents are fast and cross the world. Gravitational influence from the moon also increases this movement and together these natural effects can be used to produce electrical power since these movements can be predicted and occur with regularity per solar day.

 

Wind Turbine

Another, more popular system is a wind turbine; which uses wind velocities indirectly influenced by the thermal radiation from the sun to turn blades attached to a generator to produce alternating current. Wind turbines were first invented and used for milling in ancient Persia or what is present day Iran. They are very versatile and have been used by many civilizations to pump water from the earth and grind seed. Recently, they have been used to produce electricity. Our research into these devices has identified several areas of concern. While they are relatively efficient in producing electricity, they require routine maintenance and scheduled overhauls to maintain an operational status. This is further aggravated by the lack of trained personnel to repair them when they are down and offer very little comfort during their down time- leaving the consumer dependent on the power grid. These systems could only be used as an alternate power source and in no way frees you of the power grid. Even with a battery system grid-tie configuration they still offer very little dependence over the course of their lifetimes. Our study of these systems would indicate that after you have added up the maintenance and repair costs, down time and overhaul and subtract that from the purchase price and power generation capability- it would be cheaper to purchase the electricity from the grid. They are not a cost effective solution for electrical energy production for an individual building and can only be used as an alternative in electrical production for large power plants due to their unpredictability and high down time. If you decide to use these systems for you building design we have a list of brands that have scored the most reliability in performance/ cost effectiveness. Wind turbines should only be used in grid tie configurations and the consumers are encouraged to have them sized by a professional engineer.

 

Geothermal Systems

Geothermal power systems are electrical configurations that extract heat energy stored in the earth to produce electricity. Since the original formation of the planet, radioactive decay of materials deep inside the earth has been giving off heat energy. This heat energy, in areas where the earth’s crust is thinnest, comes to the surface and can be tapped and used for electrical power production using the same “heat transfer” principles discussed above. Most of these facilities are located near natural fault lines and close to established volcanic activity. This system is very cost effective, reliable, sustainable, and offers very little environmental impact. However, you must be near a geothermal source to use its energy producing advantages and most cities are not. Currently, the technology to “tap” this resource is not cost effectively deployed for single or multi building application, but there have been some recent advancements in drilling that may one day allow for a more wide spread use. It is important to point out that geothermal describes “heat” energy being produced by radioactive decay of our planets core and does not apply to shallow applications used by ground source heat pumps (GSHP) where the heat is supplied by the suns radiation being absorbed into the surface of the earth. It is important to mention that “shallow” heat exchange systems are not “Geothermal systems”. They can be called: ground source heat pumps (GSHP), geoexchange systems, earth coupled systems, earth energy systems which is covered in greater detail underground source heat exchangers below.  

 

Photovoltaics

Solar panels have been popular since their invention in 1839 by French physicist Alexandre-Edmond Becquerel. However, it was not until 1954, with the work of Bell Laboratories that their full potential as renewable systems was fully realized. With funding from NASA space missions, photovoltaic technology evolved into what we know today. It is important to understand that solar arrays used in electrical production where originally designed for use in environments that have no atmosphere and that are void of air density and gases. In other words: space. Present day photovoltaic technology has come a long way in cost of production, availability and use in applications, but it has not come very far when in regards to operational performance and efficiency factors. The fact of the matter is photovoltaic panels are very inefficient in producing electrical energy. The best commercially available photovoltaic panel on the market today can only convert 15% to 18% of the suns photonic energy striking the panel into electrical energy. Let’s put it this way- 85% of the sunlight that strikes the photovoltaic panels will never become electrical energy and is wasted. Part of this is because of the physical properties of the materials used in the panels themselves, but the biggest problem is that the sunlight has to travel through a very thick and dense atmosphere to reach the panels. This greatly degrades their performance efficiency; of course, this is not the case in space based photovoltaic systems where they operate at a very superior operating range (No atmosphere) to those that are earth based. UDC has experimented with several brands and configurations of photovoltaic systems. Our field results confirm only one thing- They are not the answer! - At least not presently. A lot of work in Germany is currently underway to increase the efficiency of the panels. This is in the early stages, but we are following the work very closely. It has been rumored that the German scientist that are working on the problem have been able to convert 30% of the photons striking the panel into electrical current (this is not been confirmed). This is great news for photovoltaic industry if true, however; it does not come close to solving the problems or allowing sustainable professionals to accept photovoltaics as a cost effective renewable system without addressing the entire building design. Another words, it will do nothing for the existing buildings that require retro-fitting. For you to be able to cost effectively, considering present day cost of the systems, to retro-fit an existing building; the photovoltaic system would have to convert at least 80% of the photons that strike the panel. This type of performance is simply not available present day. If you are thinking about retro-fitting solar panels to augment or zero your existing building and you feel that you can accomplish this- the answer to your question is “yes” and I would reply that you can zero any building, but you could never do it cost effectively. If you put enough solar panels on the roof of you building you can zero the building. The big question; is how much would it cost. We figured this for a client of ours in Lubbock, Texas. They wanted to zero their existing house (2,000 SF Ranch home). Of course, they had a very large HVAC system cooling and heating the home, the home had large windows facing south that had now shading, it had (at best) an R-14 insulation envelope, very little energy conservation and the behavior of the occupants was very excessive and wasteful. The cost of installing a solar array (made up of the best performing photovoltaic panels currently available) would cost over $150,000 just to get close to zeroing the house. The cost of the house was $200,000.  This was NOT a very cost effective solution. If you designed one of our sustainable zero energy houses and our architects decided that photovoltaic system (despite their poor performance) was the best option for you- then it can be done. Remember, the entire building design including the renewable energy system is integrated together. If the building has a superior insulation envelope and is designed using passive solar strategies, is of proper orientation for the geographic location it inhabits; then it will be possible to cost effective to zero the home by using photovoltaic technology because the size of the solar array will be smaller. It will cost less and you will be able to get a return for your investment in a few years rather than 10 or 20 years. The systems are still only converting 15% to 18% of the photons striking them to electricity, but our architects have already accounted for this in the overall building design allowing photovoltaic panels to be a cost effective solution.

 

Parabolic Trough

A parabolic trough is a solar thermal collection device that is used to focus the suns photonic energy onto a specific point located within the trough assembly. That point has a pipe filled with either water or oil to act as a heat transfer medium. As the sun’s rays reflect off of the trough assemble and are concentrated onto the pipe it super heats the liquid inside. UDC has experimented with this technology and currently have two prototype designs in the field. We believe it is the most cost effective way to produce renewable electrical energy per dollar spent. We have integrated the system into the building design and have drastically reduced cost and increased operational efficiency. The parabolic technology has been around for some time. Most people have not heard of it because it does not get a lot of attention as a “primary” electrical production system. Power companies have been using this system since the early 80’s but only as an alternate power production system for times when the electrical consumption of their customers increase (usually mid day). Presently, the largest of these plants is located at Kramer Junction, California and has the capability of producing over 33 MW of electricity. There are two other research plants being studied in Nevada and Spain that have the capability to produce twice as much electricity as the California plant. Of course, these systems are being developed for “large scale” operation. We have never felt that electrical power should be produced at a regional site and then transferred to buildings via power lines. The cost for infrastructure and routine maintenance is extreme. The infrastructure is an eye sore and a hazard to the environment. We subscribe to the design philosophy that each building should be designed and constructed to produce its own electrical energy on site without any power grid or regional support from a power station. While some say this is impossible, we have gone ahead and done it in a cost effective manner. Having completed a tremendous amount of research with parabolic assemblies, we are positioned to provide this as a key solution for renewable energy systems. Field studies have proven that we can super heat the oil contained in the heat transfer pipe in excess of 700 degrees Fahrenheit. This technology has shown the greatest potential for integration in our building designs.  

 

Hydrogen Fuel Cell

Many combinations of fuels and oxidants are possible. A hydrogen fuel cell uses hydrogen as its fuel and oxygen (usually from air) as its oxidant. The process works as such; A fuel cell works by catalysis, separating the component electrons and protons of the reactant fuel, and forcing the electrons to travel through a circuit, hence converting them to electrical power. The catalyst typically comprises a platinum group metal or alloy. Another catalytic process puts the electrons back in, combining them with the protons and oxidant to form waste products (typically simple compounds like water and carbon dioxide).

A typical fuel cell produces a voltage from 0.6 V to 0.7 V at full rated load. Voltage decreases as current increases, due to several factors:

· Activation loss

· Ohmic loss (voltage drop due to resistance of the cell components and interconnects)

· Mass transport loss (depletion of reactants at catalyst sites under high loads, causing rapid loss of voltage)

To deliver the desired amount of energy, the fuel cells can be combined in series and parallel circuits, where series yields higher voltage, and parallel allows a higher current to be supplied. Such a design is called a fuel cell stack. Further, the cell surface area can be increased, to allow stronger current from each cell. UDC is presently experimenting with a fuel cell/ Parabolic hybrid design. To follow our work in this area, go to our research & Development page.