Vision, Goals, and Thematic Basis
Hawaii provides a unique environment to promote clean energy, energy efficiency, and island sustainability. Hawaii also has a closed energy system that can be studied and analyzed. The United States, Europe, and Asia have much more complex power systems that are much more difficult to study and analyze. The Hawaii power system will be changing in the next several years as we rely on more renewable energy sources, promote energy efficiency, develop a smart power grid, and eventually connect different islands together via undersea power cables. As an example wind farms are being proposed for development on Lanai. Power generated from the wind will be transported via undersea power cables to the population center of Hawaii, Oahu. Hawaii will serve as a laboratory where we can study renewable energy storage systems and transport, a smart Hawaii power grid, integration of renewable sources to the grid, energy efficiency, and applications of renewable energy to island sustainability.
On January 31, 2008 Governor Linda Lingle from Hawaii signed a Memorandum of Understanding (MOU) with the US Department of Energy for the Hawaii – DOE Clean Energy Initiative (HCEI) [1]. Hawaii predominantly relies on fossil fuels to supply its current energy needs. The principle source is from oil from tankers. However, Hawaii has a natural environment with abundant resources including wind, solar, wave, and geothermal that allows for the development of renewable energy sources. The HCEI sets a goal of 70% of total energy production in Hawaii will come from renewable energy by 2030.
In order to achieve these goals we must have an educated workforce to meet the complex challenges necessary to solve the difficult engineering, science, economic, and social problems that will be encountered. The University of Hawaii’s College of Engineering in conjunction with the Hawaii Natural Energy Institute, the Department of Economics, the Department of Urban Planning, and the School of Architecture propose a multidisciplinary integrated education and research program in renewable energy and island sustainability. Faculty on this proposal will work with their Ph.D. students and local Hawaiian utility and energy companies to develop projects in assisting Hawaii in achieving more energy independence, development and integration of more clean energy alternatives, and using clean energy to promote island sustainability. Special attention will be made to recruit underrepresented groups in science and engineering as Ph.D. students.
Major Research Efforts
The state of Hawaii in 2005 had a population of about 1.275 million with about 905,000 living in Oahu [2]. Energy consumption in Hawaii in 2005 was 10,539 million kWh which was 0.3% of the United States total with 5% coming from renewable sources and 95% coming from fossil fuels [3]. The average annual increase in Hawaii electricity consumption was 2% per year for the years between 1980 and 2005 [3]. Figures for 2007 are similar to 2005 percentages with just under 94% coming from fossil fuels and slight more than 5% coming from renewable energy sources [4]. Meeting the HCEI’s goal of 70% coming from energy efficiency and renewable energy sources by 2030 presents enormous technical and economic challenges. The big island of Hawaii already has a substantial generation of power from wind and geothermal sources, however the population center in Oahu has a much smaller percentage of power generated from renewable energy sources.
Hawaii has some unique advantages to be able to meet the challenges from HCEI. They include Hawaii being blessed with a unique environment with abundant resources that can be used to generate clean energy. Hawaii’s power grid is very small compared to the mainland United States and Europe. This allows researchers to study and analyze the grid as more renewable energy sources are integrated into Hawaii’s power grid and a smart grid is developed. The University of Hawaii at Manoa (UHM) is well positioned to assist the state of Hawaii in helping with the HCEI. The College of Engineering (COE) has listed one of its major thrusts in the sustainability area and recently held a retreat on issues associated with sustainability. We also have hired several new faculty that conduct research and education in renewable energy and sustainability. The Hawaii Natural Energy Institute (HNEI) has been a leading player in energy research and has substantial research efforts in many different renewable energy areas. UHM also has researchers in Economics, Urban and Regional Planning, and Information and Computer Science (ICS) interested in renewable energy and sustainability research and education.
At the UHM we have formed a multidisciplinary team from the COE, HNEI, Economics, Urban and Regional Planning, and ICS to develop an integrated graduate education and research program in renewable energy and island sustainability. From the expertise of our team and the needs of the state of Hawaii we have identified five major research thrusts with each effort being multidisciplinary and closely related to the other areas. Fig. 1 shows a diagram of the five major research thrusts.
Fig. 1 Research Themes
We view Hawaii as a laboratory where we can study the above research themes. Since the power system is closed and relatively small we can obtain a better understanding of renewable energy sources, their integration to the power grid, development of a smart power grid, development of energy efficient practices, and application of renewable energy sources to island sustainability. Details of research projects are presented below.
1) Renewable Energy Storage and Production
Wind Energy Prediction
Due to its geographic location, Hawaii’s natural environment is rich in wind energy resources.
Hawaii has already developed many wind farms on both Maui and the big island of Hawaii. As wind energy becomes more prevalent in Hawaii there is a need for more accurate wind prediction algorithms for both the short and long term. Accurate wind prediction can ensure the efficient operation of wind turbines and wind farms. Short term prediction is crucial to damage protection and vibration control of wind turbines . Medium and long term prediction can help with the integration of wind energy to the power grid . The power wind turbines generates is difficult to forecast, because of fluctuations in wind speed and direction. The impact of wind direction becomes more prominent when wind is milder than in strong winds as placement of turbines becomes more critical. Previous research has found that using the augmented complex LMS algorithm can more accurately predict wind speed and energy. We extend this work by applying new machine learning methods using nonlinear complex kernel methods. We also study sensorless methods for wind prediction. Recently, wind prediction has used inverse modeling and machine learning tools such as echo state networks to perform accurate short term wind prediction. We extend these models by considering complex algorithms to predict both wind speed and direction. We will also look into more accurate long term forecasting using adaptive signal processing and machine learning techniques. Long term forecasting of wind currently is inaccurate (e.g. High winds were forecast on Oahu on Jan. 16, 2009 causing the University of Hawaii and many other schools to close down. These high winds for the most part never materialized).
Wave Energy
Due to its geographic location, Hawaii’s natural ocean environment is rich in wave energy resources. The state government has set the goal that by 2030, 70% of the energy produced in Hawaii will come from renewable energy and ocean wave energy will be part of the renewable energy to be integrated into the power grid in Hawaii. The first wave energy site has been selected in the coastal waters at Maui island.
Teng is currently a team member of the DoE National Marine Renewable Energy Center at the University of Hawii at Manoa. She will participate in the IGERT project and guide a Ph.D. student in the following research in collaboration with her colleagues at UH:
(1) analyze the wave energy resources in Hawaii and quantify its potential contribution to renewable energy in Hawaii;
(2) conduct wave tank experiments to develop wave focusing devices to increase the efficiency of wave energy extraction;
(3) conduct experiments to develop a combined wave focusing and energy extracting system.
Universal Buoy for Wave Energy Extraction Farm (WEEF)
Hawaii is located about two thousand five hundred miles away from any major city. Therefore, Hawaii is very dependant of imports from all over the world, especially oil. Right now, without oil, it is impossible to meet the energy and fuel demands. Increased development of alternative energy, such as wave power, must be substituted to decrease and eventually eliminate the use of nonrenewable resources before they are completely depleted.
Wave is an example of a renewable energy source that produces no greenhouse gases and does not hurt the environment. Approximately ninety percent of the state’s energy is produced from imported fossil fuels. Only 7.7% of the energy is produced from renewable energy. It is known that oil will be harder to obtain if companies continue to produce in excess to constantly meet consumer demands; therefore researcher and engineers are figuring out new ways to employ and utilize renewable, “green” energy sources before the oil wells dry up.
In this project a prototype of a universal buoy will be developed to convert wave’s kinetic and potential energy into electrical energy. Wave Energy Extraction Farm or WEEP has to be potentially distributed across the State of Hawai’i to generate electricity. Universal Buoy (UB) can extract the energy from the ocean wave in an adaptive and efficient way. Our research group in college of engineering deals with different aspects of developing the universal buoy such as dynamics modeling, detail design, prototype, test and verify the model as well as optimization. The environmental and social aspects of employing WEEP in Hawaii is going to be studied in the college of urban planning in UH.
Novel Nanostructured Proton Exchange Membrance Fuel Cells
There are three primary components in fuel cells: 1) Gas Diffusion Layers (GDLs) that function as cathodes and anodes, 2) Catalyst Layers (CLs) that are the catalysts that facilitate the proton transfer through the electrolyte, and a 3) Proton Exchange Membrane (PEM) that functions as the electrolyte and possesses electronegativity and allows the proton transfer through the electrolyte. The overall goal of this project is to develop and test novel fuel cells, employing nanotechnology, to enhance the performance of the current state-of-the-art fuel cells. The specific objectives of this proposal are to develop novel high-performance, low-weight, low-cost, nanostructured hybrid polymer fuel cells that: 1) have novel GDLs primarily made of Carbon Nanotubes (CNTs) that have high performance and are hydrophobic, and hence will cause the fuel cell to operate more efficient and at much lower humidity, substantially reducing the needs for high humidity, and hence reducing the costs, 2) have novel CLs, primarily made of CNTs with in-situ/on-line Platinum Nanoparticles creation and dispersion techniques that have high-performance and are hydrophobic, and hence will cause the fuel cell to operate at low humidity (i.e., reducing the needs for the humidity), with much lower percentage of Platinum nanoparticles, and hence to substantially enhance the performance and durability of fuel cells while greatly reducing the costs, and 3) have a novel nanocomposite nanostructured hybrid membrane with three different substructures containing a top dense skin layer with optimum pores to provide mechanical stability, an in-situ/on-line generated middle nano/micro porous layer to accept foreign moities (i.e., alien fillers), and finally a bottom “transporter” gutter layer with well-defined colonies of hygroscopic materials to provide tunneling pathway for the percolation of the protons. Self destructive “nano-robots” will be created in this proposed nanostructured membrane to function as a vehicle media for the transport of the desired materials to the vacant sites. The proposed nanostructured hybrid membrane will have a tendency to retain water (and hence will work even at low humidity) and other foreign species with even an elevated temperature usage. A strong electronegativity will be generated within the membrane that will facilitate the percolation of the protons. These membranes will have higher efficiency, higher mechanical performance and durability, higher temperature performance, lower fuel cross-over, lower cross-over contaminations, can be integrated with the CLs, and can function at lower humidity, at elevated temperatures, and using either hydrogen or methanol (a biofuel), and are tougher, can last longer, and hence can replace Nafion polymer. In addition, an attempt will be made to develop bipolar plates, used to clamp the cell, out of light weight composite materials.
Renewable Energy Devices
Microscale energy scavenging devices include thermoelectric and piezoelectric devices.
However, in the microscale regime, thermoelectric energy scavengers can generate power more
readily than piezoelectric devices. In order to create efficient thermoelectric generators, the
aspect ratio of the thermoelectric elements should be maximized, along with the density of
thermocouple elements in the device. Both of these goals can be accomplished by improving
microfabrication processes. Compact microfabricated thermoelectric devices can be employed
wherever temperature gradients exist, to supplant or supplement existing power sources. On an
island, it is important to generate energy from whatever sources are available, with devices that
are as compact as possible. Thus, micro-thermoelectric generators are an attractive renewable
energy source.
2) Integrating Renewable Energy Sources to Power Grid
MEMS sensors can be used to monitor voltage, current, and power levels of renewable energy
sources or as a distributed sensor network to monitor conditions in a grid. Small size and low
power requirements make MEMS sensors attractive for widespread sensor networks.
3) Smart Grid
4) Energy Efficiency
Energy Efficiency for Fossil Fuels
Although extensive efforts have been devoted to the development and use of renewable energies in recent years, the majority of energy we currently enjoy comes from the burning of fossil fuels, e.g. coal, natural gas and petroleum. The demand of fossil fuels will remain high in the near future. In the whole United States of America, Hawaii has the highest percentage of energy production through the use of fossil fuels. Even if Governor Lingle’s plan that requires 70% of the energy used in Hawaii is supplied by renewable resources is successful, Hawaii still needs a large amount of fuel imports. While these energy sources contain high energy density and are able to provide stable energy supply, burning of carbon based fuels produces significant amounts of pollutants such as carbon dioxide and soot that damages our environment and health. Based on the tremendous demand of fossil fuels, any improvement in burning efficiency will lead to huge reduction in the consumption of fossil fuels and production of pollutants. The use of biofuels also requires the fuels to be burned. Any initiative in sustainability, therefore, cannot ignore the improvements of combustion efficiency. A novel approach in enhancing burning efficiency is through inert re-distribution. By extracting part of the inert gas, primarily nitrogen, from air and be supplied with the fuel, the burning efficiency can be significantly improved. Recent studies already confirm that such a modification in flame structure is capable of reducing soot formation. The optimum percentage of inert diversion still needs to be determined and will be studied in the proposed research.
Novel nanostructured solar cells
The objectives of this project are to develop novel, hybrid polymer, light-weight, high-performance, “third generation photovoltaic” nanostructured solar cells, employing nanotechnology. To achieve the objectives, a hybrid approach is employed where first a carbon nanotube based photogeneration and charge carrier system will be developed and its performance will be evaluated. Next, a hybrid polymer technique, where novel insulating high-performance polymers in conjunction with nanomaterials and nanostructures will be developed and its performance will be evaluated. A novel new blended material will be developed that can absorb the light radiation in red and IR region of the spectrum. Blend nanomorphology in the material will be controlled by choosing a proper and common solvent for each component. In addition, the top electrodes will be coated with a transparent but harder material to extend the life time of the solar cell assembly, particularly in harsh environment. A better efficiency, lighter weight, higher temperature applications, flexibility, and extended life time of the solar cells can be warranted employing the proposed research.