National Renewable Energy Laboratory Technology Marketing Summaries

Methods for the production of fuels from biomass-derived sugars range from producing ethanol via fermentation to producing higher alcohols from genetically modified organisms. One current method to produce sugars from lignocellulosic biomass utilizes a thermochemical pretreatment step and enzyme cocktails to deconstruct cellulose and hemicellulose to soluble sugar. These enzyme cocktails are based on fungal or bacterial cellulose secretomes, where the fungal cocktails are an important... read more

Large scale energy storage systems, such as those used in electric vehicles or grid scale systems combine multiple electrochemical cells into a pack, or in the case of grid-scale systems, multiple packs into a large array of packs. However, battery packs often underperform due to cells or packs within the array having disparate states of health or performance capability. Consequently, the performance of the entire system is limited by the weakest unit. If these limits are unknown to a... read more

Wind power and capacity has risen dramatically with a 2015 increase in global capacity of 23.2%, according to Navigant’s 2016 World Wind Energy Market Update. This growth in wind capacity has occurred due to the increase in both on- and off-shore wind turbines and through the increasing presence of grid-connected wind power. As a result of this increased capacity, wind efficiency and blade design is increasingly important.

An important parameter for the design of wind turbine, or... read more

Wind resource assessment and turbine power performance testing are typically conducted through the use of instruments on meteorological towers. Recently, LIDAR (light detection and ranging) instruments have started to replace the use of meteorological towers for these applications due to their flexibility and ability to take accurate wind speed measurements from higher heights above ground. While LIDAR instruments can measure mean wind speeds accurately under most conditions, they frequently... read more

Smart windows, such as electrochromic or thermochromic windows, can intelligently regulate their transparency, allowing for control of transmitted light or heat into building interiors.  In turn, control of transmitted light and heat allows for improved energy efficiency and occupant comfort.  While electrochromic windows are user-controlled and change from a resting transparent state to a light-absorbing state when an external voltage is applied, thermochromic windows avoid the... read more

The process of photoelectrochemical (PEC) water splitting is a promising pathway for the generation of hydrogen due to its high conversion efficiency and potential for cost efficiency. Additionally, it is a renewable energy technology with relatively simple and inexpensive processes compared to other hydrogen production technologies. However, continued improvements in conversion efficiency, durability, and processing cost are needed to make the technology viable for use in the future... read more

Thin films and membranes are used in a number of commercial applications, including energy products (e.g. photovoltaics, batteries, and fuel cells) and separation processes (e.g. pervaporation, reverse osmosis, dialysis, etc.). According to the 2016 BCC report titled “Global Markets, Technologies and Materials for Thin and Ultrathin Films”, the market for thin films is expected to rise from the 2015 global demand of US $9.8 billion at an annual rate of 3%. In order to meet this... read more

An unexpected increase in the series resistance in a photovoltaic module can be a serious problem; not only does the increased resistance reduce current flow  - and hence power generation – from the cell, it can also be an indication of a component failure or other systemic flaw in the device. These failure mechanisms, including broken ribbons, failed solder bonds, or junction box contact issues, can be associated with excess heat and can pose a safety hazard in the device... read more

With the increased penetration of connected photovoltaic (PV) power systems in large-scale transmission grids and in consumer-scale distribution grids, the conventional rotating machines that have supplied rotational inertia and primary frequency regulation (PFR) on fast time scales are being displaced. The displacement of these conventional rotating machines threatens grid stability due to the time-intermittent outputs of PV plants.

The best way to mitigate the effects of PV energy... read more

Within the photovoltaic (PV) industry, the supply of the required metallurgical-grade (MG) Si feedstock at an acceptable cost is a pain point for manufacturers. One current method for the production and purification of this feedstock is the repetitive porous MG-Si etching, gettering, and surface removal of impurities. While this method is effective in the near-surface region, this process is impractical for the bulk purification of MG-Si feedstock due to the large number of process cycles... read more

Silicon solar cells have advantages over other solar cells materials in that they are generally less expensive and require fewer steps to manufacture than III-V solar cells, yet are more efficient than today’s thin film materials.  Nevertheless, the efficiency of Si solar cells has historically been limited by carrier recombination losses, particularly at the surface of the cell and at the metal contact interfaces. One approach to reduce recombination losses at the contact... read more

There has been vast research in developing cost effective processes to convert the polysaccharide components of plants, mainly cellulose and hemicellulose, into fuels and chemicals. However, the lignin component of biomass, which is an energy-dense polymer and the second most abundant biopolymer on Earth, is vastly underutilized in the production of biofuels, chemicals, and materials. In typical biofuel production, lignin is burned for process heat due to the difficulties faced when... read more

Biofuels are a major component of a balanced international renewable energy portfolio. Most methods for producing biofuels have been focused on utilizing the cellulose or hemicellulose components of biomass. Lignin, a major component of woody biomass that represents rich organic molecules, is underutilized in current biomass production due to the lack of economic and technically feasible routes for lignin depolymerization. One way to deconstruct lignin is through base-catalyzed... read more

The market for unsaturated polyesters, or UPEs, is projected to reach an excess of 10 Billion USD in 2020. UPE resins are versatile materials used in various industries due to their role in forming durable, light weight structures when cross-linked with monomers. Cross-linking monomers with unsaturated polyesters creates structures called fiber reinforced plastics, or FRPs. The current composite materials used in the production of FRPs possess limited recyclability and negatively impact the... read more

To improve solar cell conversion efficiency, researchers have been focused on making improvements to cell contacts in order to decrease the level of carrier recombination at the cell interface. One way to reduce carrier recombination is to passivate the surface of the cell. Surface passivation generally involves either applying another material onto the surface of the cell or doping the silicon wafer, which may be achieved through a variety of means including ion implantation. While ion... read more

Indium Phosphide (InP) is a semiconductor compound typically used in solar cells and high speed electronics. InP has a number of performance benefits compared to other III-V materials due to its higher mean and peak saturation velocities, which result in optoelectronic devices with higher frequency. InP solar cells, with a bandgap of 1.34 eV and high absorption levels, have a strong potential of reaching the Shockley-Queisser theoretical efficiency level of approximately 33%. Despite this... read more

The global market for solar technology is expected to grow by 21% in 2016 to reach a total of 66 GW. With demand for solar cells increasing, there is a renewed focus on improving energy conversion efficiency. One major problem for energy conversion in solar cells is the loss of solar energy due to the high refractive index of silicon. An effective way to reduce the reflective property of silicon is through surface texturing, or etching, which may improve the amount of photon absorption in... read more

Matching a semiconductor’s bandgap to incident photon energy is a well-known method to achieve the most efficient photovoltaic devices.  Since solar radiation consists of a wide range of wavelengths, having one semiconductor with a single bandgap to absorb all solar radiation is highly inefficient.  As such, the use of tandem or multi-bandgap converters having two or more discrete bandgaps to match different wavelengths of solar radiation has led to ultra-high efficiency... read more

The desire to improve grid resiliency and enable a sustainable capacity expansion has led to the growth of distributed energy resources (DERs) and the utilization of renewable energy sources. DER allows for smaller amounts of aggregate energy to meet the regular demand of the commercial, industrial, and domestic consumers. When combined with renewable energy sources, the distribution network supplying power is transformed into a smarter and more sustainable grid.

One major challenge in a... read more

Microgrids are a collection of energy sources interfaced to an ac electric distribution network that can be operated independently from the bulk ac system. Energy conversion is accomplished by power-electronics inverters, which are typically controlled to regulate the voltage amplitude and frequency of the inverters’ terminal voltage. Typically, the strategy employed to do this is droop control, which is only well defined in a sinusoidal steady-state and linearly trades off the... read more

Several research institutions are pursuing virtually connected, large-scale energy systems integration testbeds through the use of remote hardware-in-the-loop (HIL) techniques. This is driven by the ability to share laboratory resources that are physically separated (often over large geographical distances) and include devices or systems that are too difficult to relocate or model. Researchers are now investigating ways to virtually connect multiple HIL experiments – consisting of both... read more

Current oil and salt based heat transfer fluids have significant limitations such as usable temperature, high cost, and limited thermal conversion efficiency. To achieve the Department of Energy SunShot goal of high efficiency, low cost renewable power generation, a highly efficient and economical way to absorb solar heat and to store the thermal energy is important for broad deployment of concentrating solar power (CSP) plants as baseload power.

Photovoltaic (PV) solar cell fabrication often involves the process of “co-firing” where metallic electrical conductors are mechanically and electrically coupled to semiconductor materials to create an electrical p-n semiconductor PV device. For example, during fabrication, an aluminum “ink” would be applied to a back surface (e.g. a p-type region) of a wafer of semiconductor material (such as a silicon wafer). The opposing front surface (e.g. an n-type... read more

In the fields of vehicle telematics and navigation, there are algorithms for recommending potential travel routes from a given origin to a desired destination. Such potential routes may be presented as candidate routes from which a vehicle user may choose to travel. Further, in the field of vehicle energy use prediction, there are techniques for estimating vehicle energy consumption as a function of the vehicle’s driving cycle/speed profile. To predict vehicle energy consumption over a... read more

Transparent conducting (TC) materials are extensively used in electronics and electronic device applications. Presently, the most commercially used material involves indium-tin oxides (ITO) that have an unequalled combination of transparency and conductivity. In general, the conductivity and transparency are inversely related in the most common forms of transparent conductors (i.e. transparent conducting oxides) and ITO provides an optimum balance between the two. However, since indium is a... read more

Non-intrusive load monitoring (NILM) is an emerging class of load-disaggregation technology that promises to replace expensive submetering. NILM systems perform analysis on whole-building data taken at the main power panel to accurately estimate the energy consumption of individual appliances. Existing NILM technology requires extensive user inputs which result in inconvenience and low rate of adoption.

Radiative transfer (RT) models simulating broadband solar radiation have been widely used by atmospheric scientists to model solar resources for various energy applications such as operational forecasting. Due to the complexity of solving the RT equation, the computation under cloudy conditions can be extremely time consuming though many approximations (e.g. two-stream approach and delta-M truncation scheme) have been utilized. Thus, a more efficient RT model is crucial for model... read more

Different components within an electrochemical system (e.g., a battery) can generate heat due to inefficiencies in transport of the charges or exothermal reactions at different rates. For example, the joule heating of the connectors happens at a much shorter time period compared to the heat generated due to some of the reactions. By introducing current or voltage signals as input at the appropriate frequency and by carefully measuring the heat generated from the system (e.g.,... read more

Wafers find a variety of uses in the semiconductor, solar energy and other industries. Wafer quality often depends on variables such as thickness and surface characteristics. Depending on end use, poor quality wafers may have uneven thickness or uneven surface characteristics; whereas, higher quality wafers may have substantially uniform thickness and substantially uniform surface characteristics. In the semiconductor industry, where wafers are used as a substrate, wafer quality can... read more

Moisture or water vapor barriers are important in many types of packaging including moisture sensitive consumables and pharmaceuticals, as well as some photovoltaics applications, flexible displays and consumer electronics. Before barriers are used in packaging, they are tested for their Water Vapor Transmission Rate (WVTR) to determine how well they isolate the product from outside moisture. One current method for measuring WVTR through stand-alone barriers is an optical calcium test, which... read more

Recently, there has been a rapidly growing demand for renewable energy, including wind energy. To meet this demand, wind turbine designers are working to provide blade designs that allow a turbine connected to the wind turbine blades or to the rotor to effectively convert wind into electricity. The blades must also be designed properly to withstand inertial forces, aerodynamic forces, and structural forces so as to provide a relatively long service life and safe operation. Like all rotating... read more

Wind energy is increasingly recognized as a viable option for complementing and even replacing other types of energy such as fossil fuels. In the early development of wind energy, the majority of wind turbines or wind turbine generators were constructed for operation at a constant speed, but more recently, the trend is toward using variable-speed wind turbines to better capture available wind power. In most cases, wind turbine pitch angles can be adjusted to control the operation of the... read more

Power converters are used to convert alternating current (AC) electric power from a fixed-frequency and fixed-voltage to different frequencies and different voltages for powering loads, such as electric motors. They are also used in reverse to convert variable-frequency, variable-voltage, AC electric power to fixed-frequency, fixed-voltage electric power. Electric generators driven by wind turbines rotate at different speeds, depending on wind conditions, so they produce... read more

Parabolic trough power plants use concentrated solar thermal energy to generate electricity by producing steam that drives a Rankine power cycle. Solar thermal energy is captured in a fluid medium which flows through receiver tubes. At high temperatures the vapor generates hydrogen gas which can leak into the annular volume of the heat collection element. The presence of low partial pressures of hydrogen gas in the annulus significantly decreases the thermal performance of the heat... read more

Batteries are electrochemical cells which store and supply electrical energy as a product of a chemical reaction. In their simplest conceptualization, batteries have two electrodes, one that supplies electrons by virtue of an oxidation process occurring at that electrode and a second one that consumes electrons by virtue of a reduction process occurring at that electrode. Thin film ion batteries, including those of the thin film solid state lithium ion type, can be prepared from... read more

Semiconductor wafers are used for a variety of purposes in microelectronics, solar cell, and other industries. Wafer quality often depends on variables such as thickness and surface characteristics. Poor quality wafers may have uneven thickness or uneven surface characteristics; whereas, higher quality wafers will have substantially more uniform thickness and substantially more uniform surface characteristics. Wafer quality can dramatically influence the mechanical and/or electronic yield of... read more

Concentrating Solar Power (CSP) systems utilize solar energy to drive a thermal power cycle for the generation of electricity. CSP technologies include parabolic trough, linear Fresnel, central receiver or “power tower”, and dish/engine systems. Considerable interest in CSP has been driven by renewable energy portfolio standards applicable to energy providers in the southwestern United States and renewable energy feed-in tariffs in Spain. CSP systems are typically deployed as... read more

Microalgae—photosynthetic microorganisms capable of converting atmospheric CO2 to biomass and oil—offer great promise to contribute a significant portion to our renewable fuels and meet the mandate to dramatically reduce our dependence on the world’s dwindling natural energy resources.

Despite its huge potential, the technology of using microalgae as biomass feedstocks for advanced biofuels faces major challenges from both technical and economic barriers.... read more

Air conditioning of building spaces consumes large amounts of energy in the United States, drives electricity usage during peak electricity demand, and is the single largest user of electricity in U.S. buildings. Thus, reducing our nation’s energy consumption requires innovative and cost-effective solutions for conditioning building spaces.

Approximately 25% of the installed air conditioning capacity in homes in the US is provided by window and/or portable air conditioners. These... read more

Permeation generally occurs by a three-step process. The analyte (e.g., water vapor, oxygen, carbon dioxide, hydrogen, hydrocarbon, or another gas) is absorbed into the surface of a permeable material. The analyte then diffuses through the permeable material and outgases from the other side. A permeation standard has a unique transmission rate for a particular analyte under specified testing conditions, such as temperature and relative humidity, so that the detection equipment may... read more

Electrochromic materials change optical properties upon the injection of charge or charge carriers into the material, with the subsequent movement of counterions or electrons to balance the charge in the material. Optical changes in electrochromic materials include a change from one color to another, a change from transmissive to reflective, and a change from transparent to opaque. “Smart” windows, utilizing electrochromic films, provide substantial savings and... read more

Most power-generation systems produce heat as a by-product. For example, internal combustion engines used to power most vehicles today combust a high-energy fuel (e.g., gasoline) to generate mechanical motion and heat. Fuel cells that convert hydrogen and oxygen into electricity and heat are also being developed for a variety of applications, including power production for vehicles and electrical appliances. Other power-generation systems, such as bio-fuel processing, petroleum... read more

Around the world, there is an increasing demand for satisfying energy requirements in ways that use less or no fossil fuels. These alternatives need to be reliable, cost effective, and environmentally sound to be adopted on a large scale. For example, as the need to stabilize energy resources increases, many nations and electric utilities are evaluating the increased use of wind as a portion of their power generation mix. Additionally, the use of hydrogen as a “clean” fuel to... read more

In order to provide a cost effective, environmentally benign and efficient means for storing electric energy from renewable sources, breakthroughs are needed in rechargeable battery technology that will substantially increase energy and power densities. Practical deployment of the batteries for transportation also requires them to be of low cost and safe. Organic radical batteries (ORBs) are a relatively new class of rechargeable batteries that are based on the utilization of stable organic... read more

Recent investigations by a number of groups have shown that a beta zeolite catalyst (and other solid Brønsted acids) will convert methanol and/or dimethyl ether (DME) to iso-alkanes such as triptane (2,2,3-trimethylbutane), with uniquely high selectivity to C₄ and C₇ (termed the DME to high octane gasoline process or DTHOG). In comparison, the Exxon-Mobil methanol to gasoline (MTG) process produces a broader mixture of hydrocarbons, which is heavy in benzene, toluene, and... read more

Certain materials, referred to as electrochromic materials, are known to change their optical properties in response to the application of an electrical potential. This property has been taken advantage of to produce electrochromic devices which can be controlled to transmit optical energy selectively.

A number of factors affect the operation of an electrochromic device. One limitation on how dark an electrochromic device can become is how much charge can be stored in the counter... read more

The future of wave energy will depend on developing a new generation of wave energy converters (WECs) that maximize energy extraction and mitigate critical loads while reducing costs. Today’s WECs are relatively inefficient compared to their theoretical upper limit and lack the ability to concurrently maximize power capture and minimize structural loads.  The majority of existing WECs consist of fixed geometrical bodies relying predominantly on control of the power... read more

Cab climate conditioning is one of the primary reasons for idling the main engine in a long-haul truck during driver rest periods. In the United States, long-haul trucks (trucks that travel more than 500 miles per day) use approximately 667 million gallons of fuel annually for rest period idling[1]. Including workday idling, over two billion gallons of fuel are used annually for truck idling[2]. Idling represents a zero freight efficiency operating condition for the truck. As... read more

Alternative fuel vehicles typically require large energy stores (e.g., for acceleration), resulting in the ongoing development of capacitor and supercapacitor technologies. These technologies have a broad range of applications including portable electronic devices such as cell phones, lap top computers and personal digital assistants and are not limited to use in automobiles.

Electrochromic coatings are also being developed in an effort to promote energy savings. Applications... read more

Energy sources such as electrical, mechanical, hydraulic, pneumatic, chemical, and thermal in machines and equipment can be hazardous to workers because there is a chance of unexpected energization. The Occupational Safety and Health Administration (OSHA) has standardized lockout/tagout procedures to prevent the unexpected startup or release of stored energy during the servicing and maintenance of machines and equipment. However, there is a need to make following these procedures... read more

The optical transmission and/or optical reflectivity of electrochromic coatings can be varied repeatedly and reversibly between low and high transmission states, and/or between low and high reflectivity, by applying an electrical potential between the top surface and bottom surface of the electrochromic coating. In the specialized application to architectural windows, or windows comprising the exterior envelopes of buildings, electrochromic coatings on the window glass can be used to control... read more

Existing battery management algorithms rely upon empirical correlations between the cell voltage and the load profile. This approach limits the predictive ability of the battery management system to forecast remaining useful life of a battery in a vehicle, or the range available at any given instant when the vehicle is in operation. 

The size, weight, and cost of power electronic components are factors which influence the cost of hybrid and electric vehicles. According to a report from Oak Ridge National Laboratory[1], power electronics can make up 40% of the total traction drive cost in hybrid vehicles. Increasing vehicle electrification, in an effort to reduce the nation's dependence on foreign oil, requires making electric drive vehicles cost competitive with conventional gasoline powered vehicles. A... read more

There is a growing interest in the design of wind plant control systems to coordinate the controls of individual turbines to achieve improvements in the overall wind plant performance, such as total power production. Currently, individual turbine controls are adjusted to improve the total output of the plant above what would be achieved if each turbine pursued its individual optimal output. In general, current methods look to improve performance by accounting for the way turbines interact in... read more

Energy storage cells (also referred to herein as "cells" or "batteries") sold for consumer use in portable electronic devices and other applications have occasional failure in the field. These cells have typically passed a wide variety of safety tests, such as those required by governmental shipping regulations and by other certification organizations, but fail after the cells have been in use over time (e.g., several months), even though there have been no other reported... read more

Magnesium ion batteries present a viable alternative to lithium ion batteries and are drawing the attention of major electric vehicle and battery manufacturers. This is due in part to each lithium ion carrying a single positive charge, while each magnesium ion has a plus-two (divalent) charge, allowing the magnesium ion battery to move twice as many electrons. Magnesium is also much cheaper and easier to acquire than lithium. Other benefits of using magnesium instead of lithium... read more

Future sustainable electricity systems will consist of billions of smart devices and millions of actors such as homes, buildings, microgrids, utilities, electric vehicles, etc. At the same time that the associated infrastructure is being instrumented with sensors and communications, appliances and distributed energy resources are being deployed with embedded computers, which are enabling distributed energy intelligence – thus enhancing the capability of these actors in energy... read more

Photovoltaic (PV) module performance can be characterized by imaging using baseline and periodic images to track defects and degradation. Both thermal images, which can be acquired during sunny operating conditions, and photoluminescence (PL) images, which could be acquired at night, can be collected without electrical connection. Electroluminescence (EL) images, which are useful to detect many types of defects such as cracks, interconnect and solder faults, and resistances, have... read more

In order to increase the speed and scale of energy efficiency (EE) project deployment in buildings, energy savings analysis and a strong business case is required. This software provides an analysis for energy conservation measures (ECMs) and calculates energy savings, demand reduction, cost savings, and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. This tool combines the capabilities of previously... read more

The ability to de-energize PV modules in the event of an emergency is of great interest for the firefighting community. A simple, low-cost method to do so involves integrating fault monitoring controls into the junction box of a PV module such that detection of a ground fault, either through local failure or intentional grounding for safety disconnect purposes will result in de-energization of the individual PV module.

Smart bypass diodes in a PV module are already designed to... read more

Quantum dot (QD) solids are a solution-processed, composite thin film semiconductor system that is being developed for optoelectronics (display technology, solid state lighting, next generation photovoltaics, photodetector application, etc.). For photovoltaics, in addition to being solution processable, QD solar cells (QDSCs) have a higher limiting single junction power conversion efficiency than is possible using conventional bulk or thin film semiconductors due to enhanced... read more

A fundamental technology issue occurring in many organizations today involves balancing limited log management resources with the increasing supply of log data. The high number of log sources, inconsistent content, and variable format all contribute to this issue. Log management and analysis are key processes in dealing with security issues, fraud, and operational issues. Logs can also assist with record keeping, establishing baselines, identifying trends and performing audits.... read more

Thermoelectric materials are materials which are able to create electricity when exposed to a heat source. This phenomenon is caused by the flow of electrons from heated regions of the material to cooler regions, known as the Seebeck effect. While the voltage induced by the Seebeck effect is fairly small  - on the order of microvolts per degree Kelvin – due to the prevalence of heat as a waste byproduct of other processes, thermoelectric materials have found a foothold... read more

As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. The Distant Observer (DO) tool, developed by engineers at the National Renewable Energy Laboratory (NREL), is a fast and highly accurate tool that provides complete characterization of the performance of the optical components which include the mirror panels and thermal receiver. This tool is very useful for testing both prototype and... read more

Transparent conducting films (TCF) are typically used in various photovoltaic and display devices. Inorganic films typically consist of transition metal materials with a variety of compositions and doping to achieve a transparent conducting film, such as a transparent conductive oxide (TCO). In solar cell applications, the TCO may act as a transparent coating for light to pass through unimpeded to the active absorber material underneath the conducting oxide and/or as an ohmic contact for... read more

Encapsulant materials are used in a variety of applications to isolate components, areas, or other materials from potentially stressful conditions that can adversely affect the performance of a device. For example, the performance of photovoltaic (PV) modules may decrease over time as water penetrates the module and corrodes the metallic components essential for module function. In the absence of water, corrosion occurs relatively slowly because by-products are less able to diffuse away from... read more

The U.S. Department of Energy SunShot Initiative aims to reduce the total installed cost of solar energy systems to $.06 per kilowatt-hour (kWh) by the year 2020. Reducing the cost of solar electricity requires that solar cell modules become more efficient and much less expensive. Multijunction (MJ) solar cells present the best option for significantly increasing the absolute module efficiency beyond the single junction Schockley Queisser limit of 33%. To date, MJ solar cell designs have... read more

Lithium-ion batteries are a preferred battery technology due to its high energy density and lightweight features. The electrode in this technology can consist of lithium metal or lithiated material which can suffer degradation when exposed to oxygen. NREL scientists have invented a way to better-protect the lithium electrode from oxidation without compromising the other features of this technology. This invention applies to a broad category of thin-film electronic devices, including... read more

Wind turbine blades must undergo strength and fatigue testing in order to be rated and marketed appropriately. Presently, wind turbine blades are fatigue-tested in the flapwise direction and in the edgewise direction independently. This testing involves placing the blades through 1 to 10 million or more load or fatigue cycles, which may take 3 to 12 months or more to complete for each tested direction. There is a need for blade testing techniques that are less expensive to use and require... read more

Transparent conducting oxides (TCOs) are utilized in a wide range of opto-electronic applications such as the manufacture of LCDs, touch panel devices, window coatings, and photovoltaic solar cells. Manufacturing involves depositing a metal oxide as the thin film on top of a substrate. Achieving the desired opto-electronic properties of the thin film is typically dependent on the amount of oxygen introduced during the deposition process as it produces a tradeoff between electrical... read more

NREL is closing the LED "green gap" with a patent-pending technology that allows for easy manufacturing of low-cost amber LEDs that—when combined with red, green, and blue LEDs—produce brilliant broad-spectrum white light more efficiently than current LEDs. This RGBA color-mixing technique enables low-cost, easy-to-manufacture white LEDs with improved luminosity.

This novel device architecture achieves nearly double the efficiency of current amber LEDs by... read more

The primary fuel powering new fuel cell technologies is hydrogen. The market for fuel cells is expected to grow tremendously in the near-term as vehicle manufacturers start mass-production of fuel cell vehicles. As the market for fuel cells grows, so too does demand for hydrogen to supply the fuel cells. The two biggest obstacles in the way of hydrogen production are high cost and storage of product. 

While there are multiple methods of hydrogen production,... read more

Producing hydrogen from clean sources of energy has been one of the major challenges of hydrogen production. While production from fossil fuel processes has been the norm, one of the most promising clean technologies has been hydrogen production through photo-electrochemical (PEC) cells. The three main hurdles of PEC hydrogen production have been efficiency, durability, and cost of production. The U.S. Department of Energy (DOE) reports that for photo-electrochemical water splitting to be... read more

There are multiple methods for measuring fluid flow. Current methods rely on different physical principles such as: pressure measurement, particle tracking using images, heat removal from a wire and Doppler shift measurements. However, infrared images are not used to quantitatively measure flow properties, fluid mixing, or mass concentration of fluids.

These existing techniques for measuring two dimensional velocity fields, such as particle image velocimetry (PIV), require expensive and... read more

Water heating in residential homes can account for as much as 15% of total energy use. It is the second largest end use after space heating and cooling. With a renewed interest in energy efficiency for both financial and environmental reasons, water heater companies have seen increased demand from consumers for more efficient water heaters. While various technologies have been developed, control systems can add significant savings to the best technologies.

Lignocellulosic biomass is an abundant source of fermentable sugars, and biofuels derived from these renewable sources represent one of the best alternatives to petroleum-based fuels. Efficient conversion of lignocellulosic biomass, however, remains a challenge due to its inherent recalcitrance. Given the current state of technology of simultaneous saccharification and fermentation (SFF) and the commercial enzyme cocktails available, various chemical and thermal pretreatment steps are... read more

Thin film solar cells have been the focus of many research facilities in recent years that are working to decrease manufacturing costs and increase cell efficiency. Cadmium telluride (CdTe) has been well recognized as a promising photovoltaic material for thin film solar cells because of its near-optimum bandgap of ~1.5 eV and its high absorption coefficient. Researchers at NREL have found a unique way to dramatically increase efficiencies of substrate-configured CdTe solar cells.

Substra... read more

Data centers use large amounts of energy. Consistent large loads of energy are required for data center efficiency and reliability. Four different cooling technologies, including direct expansion (DX), the air-side economizer, the direct evaporative cooler, and the multistage indirect evaporative cooler, are examined for climate appropriateness and cooling energy reduction in data centers.

These technologies are examined individually and in combination with others to categorize seven... read more

The efficient action of cellulases to release fermentable sugars from biomass cellulose is an important step in making biomass-derived products economically viable. Despite efforts to engineer cellulases with significantly improved activities, few successes have been demonstrated.  Prior cellulase engineering has focused upon screening small sets of rationally guided mutations for higher thermal stability and subsequent modest gains in activity at higher conversion temperatures.... read more

Geothermal resources, the steam and water that lie below the earth’s surface, have the potential to supply vast amounts of clean energy. But continuing to produce geothermal power efficiently and economically requires innovative adjustments to the technology used to process it.

In the late 1990s, the pressure of geothermal steam at The Geysers (A geothermal plant in northern California) was falling, reducing the output of its power plants. NREL partnered with Pacific Gas and... read more

Moisture barriers serve as a robust packaging solution to enclose moisture sensitive encapsulated materials. They enable a device, product, substrate, or apparatus which in use will be exposed to moisture, water vapor, freeze thaw cycles or other environmental elements that could compromise the longevity or integrity of the device or product. For example, a photovoltaic cell must able to withstand long durations of rain, snow, fog, dew, environmental contaminants or other substances. The... read more

The power electronics market has started to grow dramatically with the onset of new technologies in automotive applications, power generation, energy storage, and other growing markets. 

Critical elements in the operation of electric drive systems are power electronics and power semiconductor packages. Improving thermal management of power electronics can help reduce the cost, weight, and volume of electric drive systems and thus increase market acceptance. The power semiconductor... read more

There are many potential applications for high-performance devices fabricated using III-V materials, including high efficiency solar cells, solid-state lighting, and high-speed transistors. In each case, the specific device designs rely on combinations of various materials where the lattice mismatch between the different materials can introduce problems for device performance and the deposition processes can be cost-prohibitive. With each of these markets approaching multi-billion dollars... read more

NREL scientists have discovered a unique way to quickly grow epitaxial Si using hot-wire chemical vapor deposition (HWCVD), which holds the potential to greatly decrease costs within the manufacturing of Si substrates.  With NREL’s HWCVD technology, Si material use and costs are dramatically reduced with scalable manufacturing and lower deposition temperatures.  NREL’s unique HWCVD technique can easily be integrated into existing manufacturing processes, allowing... read more

The photovoltaic market remains dominated by silicon wafer-based solar cells. Therefore, there is a need for improvements in the manufacturing processes of first generation solar cells that can achieve higher conversion efficiency without exorbitant increases in production cost. Improvements to the minority charge carrier’s lifetime through new manufacturing methods offer the desired increase in overall efficiency without extreme capital costs. There is a need in the art of preparing... read more

To be commercially viable, superconducting materials used in various applications must have high critical current densities because high electrical current is required to power any significant load. It has been shown that superconducting materials formed with bi-axially textured layers have superior critical current densities. The National Renewable Energy Laboratory has developed electro-deposited, bi-axially textured buffer layers for depositing a superconducting material onto a substrate... read more

There are numerous options for renewable energy systems development. Location, size, type of system, and a number of other criteria need to be considered. The objective of this program is to determine the optimal size (capacity, Kilowatt (kW)) of a renewable energy generator, based on minimizing life cycle cost (LCC).

The reason for developing such a program is driven by three major issues. First, the need to evaluate a very large number (tens of thousands) of project opportunity sites.... read more

Biomass-based fuel and chemical production has shown significant promise.  However, costs and utilization rates of biomass have still been a challenge for large scale commercialization.  Through appropriate decomposition and treatment, biomass can be transformed into many of the same chemicals and fuels as petroleum-based products. Most research has focused on biomass with heavy sugar and starch content such as corn. Recent work has focused on lignocellulosic biomass such as... read more

In order to increase the speed and scale of Renewable Energy (RE) solar project deployment on buildings, energy savings analysis and a strong business case is required. This software provides an hourly simulation to optimize rooftop area for combined solar photovoltaic (PV) and solar hot water (SHW) systems or solely PV. The program calculates energy savings, demand reduction, cost savings, C02 reduction, and building life cycle costs including: simple payback, discounted payback,... read more

The most common way of describing the quality of an existing or potential wind or solar power generation site is the total amount of energy expected to be generated based on typical weather patterns. This total amount of energy is characterized by the capacity factor (the ratio between the expected generated amounts to the maximum possible amount for hypothetical conditions of constantly blowing wind or sunshine for a 24 hour period). The capacity factor gives a correct estimate for the... read more

This algorithm calculates the solar and lunar zenith and azimuth angles in the period from the year -2000 to 6000, with uncertainties of +/- 0.0003 degrees for the Sun and +/- 0.003 degrees for the Moon, based on the date, time, and location on Earth.

The solar industry has shown significant growth over the past decade. From 2002 to 2007 the market for Copper Indium Gallium Selenide (CIGS) grew at a 60% annual rate and it is estimated that the global CIGS market will grow to $7.6 billion by 2016.

CIGS solar cells are one of the most promising material systems for thin-film PV because of their proven efficiency advantages over other thin film materials such as cadmium telluride and amorphous silicon. Because of extreme competition and... read more

The hydrogen fuel cell market is still in the early stages of development.  However, with advances in technology the market and associated fuel cell applications is starting to gain traction. Recently, major vehicle manufacturers have announced production-level hydrogen vehicles as soon as 2015 and the fuel cell market is expected to grow from an estimated $775 million in 2012 to over $14.1 billion by 2022. 

One of the most attractive aspects of hydrogen is that it has a very... read more

Parabolic trough collectors are one of the main concentrating solar power (CSP) technologies used in commercial utility-scale power generation plants. A key param­eter for trough performance evaluation is the collector optical efficiency, which is the ratio of the absorbed solar power by the receiver to that intercepted by the collector aperture. This has a direct influence on annual electricity generation, annual plant revenue, and, eventually, the levelized cost of energy (LCOE).

Th... read more

Distributed energy (DE) systems have begun to make a significant impact on energy supply and will certainly affect energy needs in the future. These systems include, but are not limited to, photovoltaics (PV), wind turbines, micro-turbines, fuel cells, and internal combustion (IC) engines.  Beyond these generation systems, energy storage and electric vehicles are expected to have an increasing impact. The PV-inverter market alone totaled $7.2 billion in 2011 and is expected... read more

Manufacturers of semiconductor devices in the microelectronic and photovoltaic industries have long been plagued by the costs of wafer fabrication. Currently, process steps such as phosphorous diffusion, aluminum alloying, coating deposition, hydrogen passivation and contact formation must be completed at extremely high temperatures. In addition to the substantial cost of heating the system, high process temperatures can introduce impurities and reduce the overall quality of a device. ... read more

Solar power generating capacity has grown from 83 MW in 2003 to over 7,200 MW in 2012, in the U.S. alone. As the solar industry grows, there is a significant need for quality control and testing methodologies. Both testing and quality control of photovoltaics (PV) and power electronics are essential to innovation and efficient production. Accurately testing new materials and manufacturing techniques in a quick and simple way can lead to unique insights and reduced manufacturing costs and... read more

Producing hydrogen from clean sources of energy has been one of the major challenges of hydrogen production. While production from fossil fuel processes has been the norm, one of the most promising clean technologies has been hydrogen production through photo-electrochemical (PEC) cells. The three main hurdles of PEC hydrogen production have been efficiency, durability, and cost of production. The U.S. Department of Energy (DOE) reports that for photo-electrochemical water splitting to be... read more

Energy savings achieved via occupant behavioral changes could be as high as 25%, and could rival savings achieved by technological measures. For example, energy audits often show that more than 50% of the energy used in a building is consumed at night. Occupants leaving equipment and lighting on after they leave work is a large contributing factor. Similar savings opportunities have been identified when occupants were away from their desks 50% of the time, while most of their computers,... read more

The development of high-power, high-energy, long-life, and low-cost rechargeable batteries is critical for the next-generation electric and hybrid electric vehicles. Among various battery technologies, lithium-ion batteries (LIBs) are promising energy storage devices as a result of the high energy densities, low self-discharges, and long cycle lives of known LIBs. Market analysis projects that the LIB market will increase to over $77 billion within the energy storage, electric vehicles, and... read more

With the annual potential of over 1.3 billion dry tons of biomass, the prospective growth of biomass related industries is tremendous. The National Renewable Energy Laboratory (NREL) leads the DOE’s National Bioenergy Center, with research spanning the full spectrum from fundamental science to demonstration in fully integrated pilot plant scale operations. Plant cell walls represent a vast renewable carbon source. Biofuels derived from plant cell wall material is a promising renewable... read more

Antireflective (AR) coatings on solar cells increase the efficiency of the cells by suppressing reflection, which allows more photons to enter a silicon (Si) wafer and increases the flow of electricity. Traditional AR coatings however, add significant cost to the solar cell manufacturing process. NREL scientists have devised a method and created a nanostructured Si wafer, or black Si, which eliminates the need for a traditional AR coating while achieving comparable or higher solar cell... read more

Duty cycles capture the influence of one variable in relations to the whole system. This allows for analysis in determining the impact of new variables, which are important in accurately gauging the systems in vehicles. In the collection of large data from fleet vehicles, there still exists a need to easily and accurately quantifying overall fleet operational characteristics (driving speed, distance, amount of stops…). The potential benefits of new vehicle technologies being introduced... read more

With the annual potential of over 1.3 billion dry tons of biomass, the prospective growth of biofuels is great. The National Renewable Energy Laboratory (NREL) leads the DOE’s National Bioenergy Center, with research spanning the full spectrum from fundamental science to demonstration in fully integrated pilot plants.

The distinguishing aspects are that currently, lipid extraction from algae is a difficult process and is performed with solvents or high pressure. These processes use... read more

Lighting controls offer significant potential for reducing that energy use, and new technologies that have emerged in recent years have enabled a wide range of innovative strategies, from room-level awareness of occupancy and daylight sensing to building-wide coordination of a fully networked system. About 40% of the average facility’s electrical load is dedicated to lighting, creating a sizeable market for energy efficient lighting hardware and software tools. The global market for... read more

Cellulose is the most abundant renewable fuel resource on Earth, accounting for about half of the organic material in the biosphere, and is the major polysaccharide found in plant biomass. Cellulosic biomass is a favorable feedstock for fuel ethanol production because it is both readily available and less expensive than either corn or sugarcane. A typical biomass feedstock is comprised of approximately 30-45% cellulose, 30-40% hemicelluloses, 15% lignin and 10% of other components.... read more

Lithium-ion batteries (LIBs) are a promising candidate for energy storage of electric drive vehicles due to their high power and energy density. The total electric vehicle LIB market shipped 2,400 units in 2008 generating over $28 million in revenue and is predicted to be greater than $10 billion by 2015. However, violent incidents reported for LIBs and consequent safety concerns pose a major obstacle to LIB market acceptance. Safety mitigation technologies used in small capacity consumer... read more

A parabolic trough power plant generates electricity using concentrated sunlight as the heat source for its power cycle. A parabolic trough plant is comprised of multiple rows of single- linear focusing collectors concentrating direct beam radiation onto tubular receivers (also known as heat-collection elements [HCEs], absorbers, or receivers) located along the focal line. Receivers are designed to minimize heat loss to the environment while absorbing as much sunlight as possible. NREL has... read more

At production costs less than $.80/Watt, Cadmium Telluride (CdTe) thin film technology exists as the lowest cost per watt choice for solar technology.  This characteristic is due partly to the single-phase nature of the absorber layer and the ease with which the CdTe source material can be formed into thin films required for module production.

During the 20+ years of research, NREL’s CdTe Group has directed its efforts at producing CdTe structures that allow more light to... read more

Ethylene is the most produced gaseous organic compound in the chemical industry and future demand is forecasted to grow at an average of 4.1 % per year.  It is the raw material used to manufacture polymers such as polyethylene, polyester, polyvinyl chloride, and polystyrene as well as fibers and other chemicals used in the industrial and consumer markets of packaging, transportation and construction. It can be used directly as a fuel, or serve as a precursor for longer carbon chain... read more

Alpha-ketoglutarate (AKG) is widely used as an organic synthesis intermediate, a medical and biochemical reagent, and as a nutritional additive in food and sports drinks.  Typically, it is produced from a derivative of petroleum and concentrated hydrochloric acid.  However, the rising cost of petroleum has led to the exploration and development of alternative, biological production systems for fuels and chemicals.  Recently, a number of organizations have successfully... read more

According to the U.S. Energy Information Administration’s 2010 International Energy Outlook, solar energy is expected to grow globally by 12.7% per year until 2035; more than any other renewable energy source. To meet this demand, the renewable energy industry must develop and manufacture photovoltaic (PV) cells that are less expensive, more reliable, and more efficient in converting solar energy into electricity.

Quantum efficiency (QE) is the standard test which indicates how... read more

According to the U.S. Energy Information Administration’s 2010 International Energy Outlook, solar energy is expected to grow globally by 12.7% per year until 2035; more than any other renewable energy source. The growth of on-site DC (Direct Current) power in new and existing buildings has significant energy savings potential through the elimination of inverters necessary to convert DC source power into AC (Alternating Current) as well as the elimination of equipment normally used to... read more

Neutron detectors are vital in the national security effort to detect special nuclear material at the hundreds of U.S. ports of entry. Special nuclear material emits neutrons which rarely occur spontaneously, therefore detection can be correlated to the existence of special nuclear matter found in plutonium and plutonium based weapons. Currently, the most common type of neutron detector uses pressurized tubes containing rare Helium-3 gas. This 60 year old instrumentation is bulky, costly,... read more

In the United States, residential and commercial buildings together use more energy and emit more carbon dioxide than either the industrial or transportation section.  According to the Department of Energy, buildings use 39% of our total energy, two-thirds of our electricity, and one-eighth of our water. As a result of these fundamental environmental issues, the increasing cost of energy and our current economic challenges, there has been a growing urgency to operate building systems... read more

Many current cooling systems for hybrid electric vehicles (HEVs) with a high power electric drive system utilize a low temperature liquid cooling loop for cooling the power electronics system and electric machines associated with the electric drive system.  These vehicles may contain additional cooling or thermal management systems for other vehicle components, such as an internal combustion engine, batteries, or the vehicle passenger cabin.  The cost of the separate low temperature... read more

The U.S. Department of Energy (DOE) estimates that a $1 per watt installed photovoltaic (PV) solar energy system - equivalent to 5-6¢/kilowatt hour (kWh) — would make non subsidized solar competitive with the wholesale rate of electricity, nearly everywhere in the United States.  In order to reach this goal, manufacturers in the highly competitive solar manufacturing industry have placed a greater focus on two important aspects of their processes - throughput and efficiency.... read more

Portable electronic applications including cell phones, laptop computers, as well as electric vehicles or hybrid electric vehicles require dependable rechargeable batteries.  The lithium ion (Li-ion) battery is the preferred source for portable energy storage due to its desirable energy to weight ratio. The materials used in the development of anodes, cathodes and electrolytes are directly responsible for the performance characteristics of Li-ion batteries.  In order to meet... read more

Batteries are one of the leading cost drivers of any electric vehicle project. Current practices require that batteries be oversized by design in order to meet the battery warrantee’s end-of-life (EOL) power and energy requirements. This quickly increases the cost of electric vehicles and can price them out of the realm of consideration for most users. NREL scientists have developed a software model that analyzes the performance of batteries over a lifetime of use in real world... read more

Electrochromic cells change their light transmission characteristics based on the direction of an applied electric field. In short, they are comprised of an electrolyte sandwiched between two electrodes (a cathode and an anode), where each electrode will darken or bleach based on the flow of ions (and electrons) in or out of the electrode. For lithium-based electrochromic cells, the electrolyte contains mobile lithium which enables lithium ion transfer between the electrodes. The present... read more

Design. Build. Test. Break. Repeat. Developing batteries is an expensive and time-intensive process. Testing costs the automotive industry an estimated $1 million for every 50 battery cycling channels, with additional costs for designing and building prototypes totaling millions of dollars. To reduce this process and associated costs, scientists at NREL have designed computer models to predict thermal, electrical, and electrochemical battery performance. These models are so advanced they can... read more

Historically, building performance professionals have not had reliable tools for estimating energy usage. This information deficiency has led to building upgrade and retrofit recommendations which may not be reliable or cost-effective. Scientists at the National Renewable Energy Laboratory (NREL) have designed SUNREL, an hourly energy simulation engine which precisely estimates the energy consumed by a residential building. This technology enables auditors to accurately predict energy usage... read more

This algorithm calculates the solar zenith and azimuth angles in the period from the year -2000 to 6000, with uncertainties of +/- 0.0003 degrees based on the date, time, and location on Earth. (Reference: Reda, I.; Andreas, A., Solar Position Algorithm for Solar Radiation Applications, Solar Energy. Vol. 76(5), 2004; pp. 577-589).