Green Power Research

Ultra capacitors

Ultra-capacitors (or Super- capacitors) have been getting   attention recently for their use in alternative energy applications.  For my readers are unfamiliar with this technology capacitors  are used in electric devices to store energy. The energy is stored once a power source is connected to the capacitor by depositing a charge onto its two opposing plates with a dielectric material between them. Dielectric materials do not conduct electricity. When the power source is disconnected, the charge remains on the plates within the dielectric material. As soon as a load is attached to the capacitor, the charge flows through the load, providing power. A capacitor stores energy similar to a battery.  The power stored and made available for use when it is needed. Ultra-capacitors are the larger versions of these devices.

One of the properties which allow ultra-capacitors to be useful is the fact they can deliver a large amount of power in a short period of time.

These permit use as power boosters, for instance, when an electric car needs to accelerate rapidly, or wants to crest a steep hill these devices can provide the power while minimizing the use of the battery which will extend life of the battery. Ultra capacitors, used in this fashion in hybrid vehicles, are displacing a good deal of their current battery capacities with safer, lighter energy storage means.  Another key benefit of ultra capacitors is that charging them takes much less time (on the order of 1 percent of the time) than charging a battery.

Wind turbines are another example of an application where ultra-capacitors are used.  Obtaining the maximum energy from the wind requires keeping the blades in the optimal orientation. This is referred to as pitch control. The position of the blade is dynamically adjusted relative to wind speed in order to maximize efficiency for power generation. Ultra-capacitor technology supports the requirement for a quick burst of power to keep up with the rapidly changing speed and/or direction.

Another application related to wind power is Power Conditioning. The practice is intended to improve the quality of power which is delivered from the turbines.  As the contribution of wind power to the electricity generated increases, the grid becomes more susceptible to voltage fluctuations associated with rapid wind speed changes.

Another variation of ultra-capacitors is electric double-layer capacitor (EDLC). EDLC’s do not have a conventional dielectric. Rather than two separate plates separated by an intervening insulator, these capacitors use virtual plates that are in fact two layers of the same substrate. Their electrochemical properties, the so-called “electrical double layer”, result in the effective separation of charge despite the vanishingly thin (on the order of  nanometers) physical distance between of the layers.

The key feature of EDLC’s is their energy density is 10 percent of a typical battery while their power density is generally 10 to 100 times as great. This makes them most suited to an intermediary role between electrochemical batteries and electrostatic capacitors, where neither sustained energy release nor immediate power demands dominate one another.

In practical terms, ultra-capacitors can replace batteries in some applications. Ultra-capacitors won’t necessary supplant batteries in all likelihood; they will be used in conjunction with batteries. The future will require every possible means to extract energy and ultra-capacitors will certainly participate in our alternative energy future once other applications for these devices are discovered.

Image and reference information courtesy of Ioxus.com

Image of off shore wind farm

I just read an article in offshorewindpowerasia.com which discussed how    China  will increase its collective grid-connected installed wind-power capacity to 55GW this year and boost its cumulative installed wind-power capacity to 100 GW by 2015. By 2020, the country plans to have 200 GW of installed capacity.

Off shore wind will be a major portion of this push to increase the power provided from wind.  China will kick off the building of a 1GW offshore wind-power project in east China’s Jiangsu province. Additionally, China will accelerate offshore wind-power projects in the eastern coastal provinces of Hebei, Shandong, Zhejiang and Fujian as well as expediting progress on Shanghai’s East Sea Bridge offshore wind farm.

Furthermore, the publication stated China’s cabinet is considering a $758 billion emerging energy industrial development plan. If approved, some $227 billion of investment would flow into the wind-power sector.

China offshore wind does not need to be concerned with the issues onshore wind farms are often subject to which include restrictions based on their negative visual impact or noise limitations associated with obstructions (buildings, mountains, etc.). More importantly the genuine advantages of the offshore turbines consist of improved and more constant wind speeds and, as a consequence, higher efficiencies.

With money and technology available shouldn’t the road be clear for significant adoption? Off shore wind in China without doubt possesses the potential to meet these forecasts but this may not become a reality for two reasons. Firstly, the lack of transmission capacity to bring the wind power which is generated where the demand is and the fact local electric utilities are not incentivized to connect renewable energy projects to the grid hinder large scale adoption. The end result is an underutilization of wind power capacity in China until upgraded transmission and incentive programs are in place.

Perhaps addressing these issues is a better use for all of the capital flowing into offshore wind sector instead of producing turbines. If you built a wind farm to create its electricity wouldn’t you want the ability to harness this resource as much as you could?

Photo courtesy of treehugger.com

Image of Industrial Smog

I read an article about a company who has proposed to use Titanium Oxide (TiO₂) panels to help reduce the amount of smog in the atmosphere while at the same time reducing the levels of Carbon Dioxide (CO₂). Typically, TiO₂ is used in car paint to allow the bonding of the paint to the metal in the body of the automobile.

Carbon Dioxide and the nitrogen oxides are the major contributors in the formulation of smog. Smog is a type of air pollution derived from vehicular emissions from combustion engines and industrial fumes which react in the atmosphere with sunlight to form pollutants which also combine with the other emissions to form smog.  Smog is also caused by large amounts of coal burning in areas caused by a mixture of smoke, sulfur dioxide (SO₂) and other components.

The chemical reaction of sunlight, nitrogen and carbon oxides in the atmosphere leaves airborne particles. Smog can also include additional compounds such as nitrates, ozone and volatile organic materials.  These particles are what contribute to the “haze” effect that is captured in images if cities affected by smog.

The panels are designed to reduce the availability of smog forming agents as follows.  TiO₂ caused electrons to be created within the panels when they are energized by sunlight. These electrons transfer energy to the panel from the oxygen and water present in the air. This results in the formation of compounds known as free radicals. These free radicals destroy the nitrogen oxide molecules which are components of the smog via oxidation by converting these to harmless compounds. Furthermore, hydroxyl groups (-OH) are formed which makes the surface of the building slippery which permits the particles to simply wash off whenever it rains.

This is just one example of where technology which has been designed for other uses can be utilized to make an impact on our environment. Clearly, this will not result in smog free cities or eliminate global warming on its own but at least it is a start.

Image of power cord used in standard electrical outlet

The concern with using petroleum to power vehicles has spawned the creation of words referring to alternate methods of propelling an automobile. One of the most popular keywords which incurred an increase in popularity is Plug-In Electric Vehicles.

The term Plug-In Electric vehicle (PHEV) may be obvious in regards to its definition. Its relation to other buzzwords such as hybrids and electric vehicles may not be so clear. A hybrid is a vehicle which can be propelled either by gasoline through an internal combustion engine or a motor powered by a battery. An electric vehicle is solely powered by a battery. A Plug In vehicle is a vehicle is driven by batteries but adds the capability of being charged by the standard electrical outlet found in your home.

Originally the car’s battery was designed to start the engine until its combustion engine came on line and provided for all of the power requirements.  Since the push to move away from gas and to utilize more fuel efficient transportation the car manufacturers began working with various possible technologies.  This resulted in the release of Hybrid vehicles such as the Prius which were the first that were marketed as a bridge to all electric cars as present  battery technology does not support a full electric vehicle which can be adapted to the mass automobile market.

In spite of the current status of battery technology the demand for Plug-In vehicles seems to be gaining momentum.  A 2007 report by the UNC Center for Sustainable Enterprise estimates there will be 1.1 million Plug In vehicles on the road by 2030.

The interest in Plug-Ins has been so strong some hybrid owners have purchased kits which permit their vehicles to charge its batteries with a standard electrical outlet. Conversion kits marketed by companies such as Hybrids Plus and Hymotion are designed, in large part, to convert Prius hybrids to Plug Ins by adding battery charger capability.

It may not be clear what value Plug in vehicles would bring to the table. For starters, these vehicles reduce pollution by emitting no emissions, they reduce the carbon footprint since gasoline is not required for its power and it could be a cheap method to fill your “tank” especially if the charging occurs in the middle of the night taking advantage off-peak electrical rates.

Another benefit Plug In vehicles might provide is off hour demand for electricity which may go a long way to enable intermittent technologies such as wind and solar to become viable energy solutions by helping level the daily demand for electricity.

All PHEV’s are designed with plugs so their customers can plug them in at home using a standard electrical outlet. The main reason is battery technology is not at the point where batteries can meet driving requirements without a source to recharge the batteries.

The reader may be thinking, why would want a car which needs a plug? Well, there times where a minor inconveniences are a necessary evil.  Put another way, will anyone see any extension cords long enough to take drive to the market and pick up groceries?

Wind turbine farm as sunset

I was reading an article online the other day and was stunned to find out Denmark-based Vestas Wind Systems was making preparations in the event the Production Tax Credit expired at the end of the calendar year 2012.

A Production Tax Credit (PTC) provides a 2.2-cent per kilowatt-hour (kWh) benefit for the first ten years of a renewable energy facility’s operation. Originally enacted as part of the Energy Policy Act of 1992 the credit has been a major driver of wind power development over the past 7 years. The cash payment to the operators of the wind turbine is often the difference in making wind turbine projects viable.

For those of you familiar with the wind turbine industry whenever the PTC has expired the following year experienced a pronounced dip in the number of megawatts of power installed in comparison to the year before. This occurred in 2000, 2002, and 2004 when the credit elapsed.

The credit was renewed in 2009 for three years which, at the time, seemed to ensure the investments could be made in wind power which are necessary to result in a significant impact on our energy production in the years to come.

If wind power is supposed the cornerstone of our energy plans how can our politicians allow its expiration to become a possibility? Are the effects of letting the credit expire not clear enough? My idea is in light of the investigation of Solyndra’s loan guarantees perhaps our law makers may be beginning to question the viability of alternative energy.

I implore our elected representatives to do whatever it takes to ensure the credit not only gets reinstated but does not require speculation in regards to renewal every few years as our energy problem will extend far into the future and realistic options are at a premium.

Image of energy efficiency in a building

A good amount of discussion has occurred among which of the various alternative energy technologies are ready to be adopted in large degree. Wind, solar, bio-fuel, fuel cells and nuclear have been mentioned as viable solutions to our energy problems before the Japan calamity.

Surprisingly, there seems to be a concept currently emerging which not only can help with our energy woes but be an engine to drive employment in alternative energy sector on a large scale by being able to stand on its own as a business generating revenues without government subsidies.

What might that be? If you are thinking solar and bio-fuels think again. I am referring to Building Efficiency. Energy efficient buildings can be defined as buildings that are designed to provide a reduction of the power needed to operate a building with the results of lower fuel requirements and reduced carbon footprint. In general commercial buildings use large amounts of electricity, therefore, would see the greatest impact in lowering its energy use.

The energy demand required in a commercial building can be divided into the following categories: Lighting, Heating Ventilation, Air Conditioning (HVAC), Computer /Electronics, and Water Heating.

The reason this technology can be adapted is the one and the same rationale why wind solar are not ready to scale. First of all, is it is difficult to demonstrate a justifiable Return-On-Investment (ROI) and, secondly, other technologies require large capital investment requirement.

Typical parties who chose to install building efficiency solutions include Community Colleges in order to modernize their data center infrastructure. Not only did this prevent an expensive power upgrade but resulted in reduction in energy costs by 30% without having to make a capital outlay of funds.

In the case of building efficiency, in many circumstances ROI can be just by justified by looking at the electric bill and noting the reduced charges. There is not a much clearer indication of the effectiveness to reducing your energy use than seeing lower electric bills. Furthermore, many energy management solutions do not require a significant investment which can be installed into the current electrical infrastructure via plug and play.

Perhaps you believe alternative energy is occurring in far corners of the planet the fact is these emerging technologies are being implemented in your town. If nothing else the adoption of energy efficient technologies is something to think about the next time you visit a commercial office building.

Image of a dam, currently our largest source of utility storage capacity

The onset of alternative technologies such as wind and solar have mandated a method of storing the power produced by these resources for use when the power is needed. The reasoning is these sources are both intermittent as the power produced fluctuates over time. Wind power, for instance, blows the strongest at night and early in the morning. The largest energy usage is late in the afternoon. Furthermore, reduced wind speed limits the power output available. Solar, in particular, Photo-voltaic, has the same challenges since its maximum output is not coincident with demand and its output can rapidly drop.

According to the Institute of Environmental Energy, Safety and Energy Technology over 99% of the world’s storage capacity consists of hydroelectric. Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water.

In order to satisfy the requirements for grid storage any solution will need to have the following characteristics: safety, efficiency, fast response, long life and reliability.

The four most viable candidates for grid storage are as follows: Sodium Sulfur (NAS), Compressed air (CAES), Redox Flow, and flywheels. As of 2008 the installed capacities of the four possible storage technologies were as follows:  CAES 477 MW, 200 NAS, Redox 11MW with no flywheel capacity being on line. All of these method store electricity but the technology utilized varies.

A flywheel is a mechanical device with a significant moment of inertia used as a storage device. Flywheel Energy Storage (FES), also referred to as kinetic storage. The flywheels inertial mass is accelerated to a very high rotational speed and the energy in the system is maintained as rotational energy. The energy is converted back as needed to the desired application by slowing down the flywheel. In short, energy is stored in the rotor as rotational energy. The stored energy in a flywheel is proportional to the mass, and to the square of the tip velocity. Key features of flywheel-based regulation are its fast response (many times faster than conventional fossil fuel generators used for regulation); its high round trip efficiency (85 percent); and the fact that it produces zero direct CO2 or other emissions.

CAES electricity is used to compress air into a storage system. More specifically, Compressed Air Energy Storage involves directing surplus electricity to a compressor which pumps air deep into layers of porous sandstone underneath dense, almost impermeable shale.  The sandstone expands, trapping the air, which is later released when electricity is needed. The compressed air is released from the rocks and heated via combustion, and run through an expansion turbine to drive an electric generator thereby producing energy as needed when electricity is desired.

CAES is a promising candidate for large scale electricity storage because it allows for greater siting flexibility as compared to pumped hydro at acceptable costs. CAES is especially appealing when considering the storage of large amounts of fluctuating wind energy output in daily to weekly cycles.

A redox battery consists of an assembly of power cells in which the two vanadium electrolytes are separated by a proton exchange membrane. It is a type of flow battery in which  electrolyte containing one or more dissolved electro-active species flows through an electrochemical cell that converts chemical energy straight to electricity. Additional electrolyte is stored in tanks, and is more often than not pumped through the cells of the reactor. Flow batteries can be “recharged” by replacing the electrolyte liquid while recovering the spent material at the same time.

The vanadium redox battery takes advantage of vanadium ability to exist in solution in four different oxidation states, and uses this property to make a battery that has just one electro-active element instead of two which simplifies the design.

The main advantages of the redox battery are it offers almost unlimited capacity by using larger and larger storage tanks and it can be recharged by replacing the electrolyte if no power source is available. The main disadvantages with vanadium redox technology are a relatively poor energy-to-volume ratio, complexity of the system in comparison with standard storage batteries.

Other useful properties of vanadium flow batteries are their very fast response to changing loads and their large overload capacities. Their exceptionally rapid response times also make them well suited to UPS type applications, where they can be used to replace lead-acid batteries and even diesel generators.

A sodium-sulfur (NaS) battery is a type of molten metal battery constructed from sodium (Na) and Sulfur (S). These batteries are noted for their high energy density, high efficiency of charge/discharge and long cycle life. As a result of its operating temperatures of 300 to 350 °C and the corrosive nature of the sodium polysulfides, such cells are suitable for large-scale non-mobile applications.

NaS batteries are a possible energy storage technology to support renewable energy generation, specifically wind farms and solar generation plants. In the case of a wind farm, the battery would store energy during times of high wind but low power demand. This stored energy could then be discharged from the batteries during peak load periods. In addition to this power shifting, it is likely that sodium sulfur batteries may possibly be used throughout the day to assist in stabilizing the power output of the wind farm during wind fluctuations. These types of batteries present an option for energy storage in locations where other storage options are not feasible due to location or terrain constraints.

From the evaluation of the possible technologies a viable scale-able solution is without doubt a long way off. Even though technology challenges need to be solved in order to enable these technologies to store the intermittent power sources in an efficient manner. This is the only way to take full advantage of these inexhaustible resources to meet our ever increasing appetite for energy.

Photo: Courtesy of dreamstime.com

Cogenra cogenation system in action

There are three methods of generating energy from the sun. The first one is photovoltaic (PV) cell which involves producing DC voltage from sunlight utilizing specially designed panels. The second one is Concentrated Solar power (CSP) which entails concentrating the rays of sun using mirror and the third one is Thermal which uses the sun to heat a heat transfer medium which is transferred to a turbine creating heat. Almost every solar company uses one of these three technologies for utilizing the sun order to provide power.

Previously no solar company had tried to use all three ways of converting the sun power to electricity in a commercial application. Now until now, Conegra a start-up based in Mountain View, California generates both electricity and heat to deliver low cost energy for commercial, industrial and institutional facilities with large hot water demands.

Its unique technology is intended for the mid-sized commercial market users such as food processors, hotels, restaurants, Laundromats and similar businesses.

The startup’s system uses mirrors to focus sunlight, much like the giant solar-thermal power plants operating in the Southern California desert. The focused light shines on rows of photovoltaic panels, similar to the ones being installed on residences and businesses worldwide. The light also warms a tube filled with a liquid chemical, which is then used to heat water – a variation on older solar water-heating equipment.

Traditional photovoltaic (PV) modules convert approximately 16% of the sun’s energy into usable electricity, discarding the remaining energy as waste, mostly in the form of heat. Solar cogeneration captures this waste heat and transforms the energy into real value—hot water. This co-generative solution has the added benefit of cooling the PV components, which boosts the overall electric generation by increasing its efficiency.

The huge benefit to those evaluating the Cogenra’s solutions is it qualifies for both PV and thermal subsidies set aside by California Solar initiative (CSI). Their use allows faster return on investment by any prospective investors.

The multiple uses of the sun’s rays can reduce heating bills, as well as electric bills. An innovative program called a Heat and Power Purchase Agreement has been created to allow customers to avoid upfront capital investments. Finally the product uses “off the shelf” standard products and a “low-tech” approach which reduces costs.

On the other hand, the permitting process remains as an impediment to faster implementations. Wildlife, water and environmental assessments and risk mitigation plans are required for many projects.

Also, at this early stage there are concerns as to whether the technology can be scale enough to benefit to enough people to support large –scale implementation.

The prospects for this concept are without a doubt very exciting not only because of the technology but the attention that has been produced in the press from the involvement of famed venture capitalist Vinod Khosla and former British Prime Minister Tony Blair.

However, publicity will not determine whether the technologies can be ramped up enough to make an impact and stand of its own two feet without government subsidies. Only time will answer that question.

Image of a Solar panel

A sweepstakes is in progress in the alternative energy sector. The participants are solar companies from startups to established companies here in the U.S., Europe and Asia all trying to take control of the solar market.  How will the winner be determined?

Success in the solar industry is all about cost. The reason is a matter of simple economics. If panels are cheaper than the projects to install solar become less expensive. This lower cost leads to less risk in regards to receive financing which in turn makes the project more likely to occur.

One of the direct tools to lower cost the costs of panel is vertical integration. It is defined on answers.com as a form of business organization in which all stages of production of a good, from the acquisition of raw materials to the retailing of the final product, are controlled by one company.

The stages in the above definition can be adapted for the value chain in solar.  This begins with the silicon which is used to construct the panels. The silicon is formed into ingots. The ingots are sliced into wafers. The wafers are assembled individual solar cells. These cells are bundled into modules. The modules are installed into commercial and residential applications as systems.

The value chain for silicon is an oligopoly meaning a few large established players dominate the market while the supplier base for ingots is concentrated with few players who are the silicon suppliers to semiconductor industry.

In contrast the supply chain for cell, modules, and systems has been fragmented with many players.  Therefore opportunities exist for any parties that can consolidate the cell modules and systems portion of the value chain.

A prime example of the with MEMC acquisition of Santa Clara based Soliacx last July. MEMC produces poly-silicon for the solar and solar industries. Soliacx produces wafers, in this example the MEMC will be able to supply wafers to its customers with the advantage of not having to purchase the poly-silicon required to manufacture them.

Another example is China based Yingli Solar. The company produces poly-silicon, ingots, cells and modules. This allows them to provide panels at reduced cost due to its ability to address a large portion of the value chain required to assemble panels internally.

What has made it advantageous to be a player at multiple points of the supply chain? They are able to offer same value at lower cost than their competitors.

If the chain can be manipulated like the example above the companies who accomplish this will have a distinct advantage. Look for parties seeking to grab solar market share to attempt to become more involved on other portions of the solar value chain through acquisition of mergers in the module and system portions of the supply chain.

As we move towards grid parity keep your eyes out for the companies making moves to vertically integrate. In the long term these will be you winners. Something good to know if you are hedging bets….

Photo: Courtesy of dreamstime.com

I was reading an article in Chemical Engineering Process (CEP) about making smarter Clean Tech investments. It mentioned the Hype Cycle observed during the dot com boom was extremely similar to today’s Clean Tech investment environment.

For those of you who are not familiar with hype cycle it refers to the marketing of emerging disruptive technologies resulting in the respecting technology being over hyped in the early stages of growth.

According to the latest Cleantech.com Clean Trends report 2.2 billion dollars flowed into U.S. based clean energy investments in the last year alone. Even though this amount was lower than the 3.2 billion invested in 2008 the percentage of clean investment increased to over 12% which is the largest in history. The top green investments were wind, solar and biofuel.

Upon initial inspection one would think the differentiating factor would be the technology. The more ground breaking and revolutionary your advance in technology was the better your chances. Isn’t this what changing the world is all about?

Yes and no. The authors made the point the key is what can be commercialized in the large scale. Repeat. The technology alone will not change humanity. For example, examine the adoption of wind turbines. This sector as be ready to take off, however, issues with connectivity to Grid are limiting adoption. In addition, wind turbine projects are very capital intensive and need financing to order to implement. The current financial climate speaks for itself.

Another example mentioned by the authors in the article highlighted microalgae.  Research has proven the material grows fast and contains a high level of oil which could be readily extracted for use as a biofuel. But the challenge due to factor associated with scaling up is producing enough material in large enough quantities at a comparable price to make a difference.

So how is one to figure out which new technologies have any chance of experiencing wide scale adoption? The authors touched on this question as well. A model was proposed including the technical, operational and financial assumptions many of the projects which have a low probability of being successful in the large scale can be identified.

An example pointed out the article involved a case study that had been done which evaluated the maximum monetization possibility and examined the lower limit to capital costs by using comparable examples and making some assumptions. In short appropriate diligence can guide through the hype and identify the most worthwhile ventures.

In order to ensure the adoption of all alternative technologies these factors will need to taken into account and addressed.  It would be amazing if only evaluating the actual emerging technology resulted on correctly predicting its success.