THE NEXT 100 MW POWER PLANT FOR OAHU

Transcription

1 THE NEXT 1 MW POWER PLANT FOR OAHU University of Hawaii at Manoa Graduate Division Civil & Environmental Engineering CEE 699 Directed Research Report Prepared by Gabriel A. El-Swaify In partial fulfillment of MSCE requirements Submitted to Professor Panos Prevedouros May 6, 213

2 ABSTRACT The objective of this study is to address Hawaii s energy dependence on fossil fuels by investigating the cost effectiveness of options for the next 1MW alternative energy power plant for Oahu. Nine different energy sources (coal, oil, natural gas, geothermal, hydroelectric, photovoltaic solar, on-shore wind, waste-to-energy (WtE), and nuclear) were compared and analyzed. Most individual power plant specifications (capacity factor, construction cost, needed acreage, etc.) were retrieved from online corporate power plant profiles and from online periodicals and government energy-related sources. Plant construction costs were equalized 212 dollars using historical Construction Cost Indices (CCI) provided by Engineering News Record (ENR). The U.S. Energy Information Administration (EIA) provided data for national electricity generation pie charts; national historical power plant development charts; and the values necessary to conduct the 3 year power plant comparison analysis (i.e. capacity factors, costs of fuel, MWh generated per unit of fuel used, etc.). The Hawaii Department of Business, Economic Development and Tourism (DBEDT) provided data for local electricity generation pie charts, and for Hawaii energy trends. The EIA, the United States Department of Energy, and the National Renewable Energy Laboratory (NREL) provided information for energy source profiles and national energy trends. The results of this study indicate that WtE is superior (in terms of cost) to any other technology in the long term. Because fuel for WtE is municipal solid waste, it is the only option that profits from the source of energy while providing electricity. Ranking 2 nd and 3 rd are geothermal and hydro technologies, but these resources do not exist on the island of Oahu. Ranking 4 th is natural gas, and although is not a renewable energy source, it is a more affordable and cleaner fossil fuel option than oil. Ranking 5 th is coal, but coal use is counter-intuitive to the Hawaii Clean Energy Initiative (HCEI) goals of reducing fossil fuel dependence because coal produces the most pollution of all fossil fuels. Ranking 6 th is nuclear, but nuclear plants do not come with nameplate capacities of less than 5 MW and the average capacity of nuclear power plants in this study was 2, MW. Additionally, approval for nuclear power generation in Hawaii is a long and intensive process that will likely take years to approve if ever pursued. Ranking 7 th and 8 th is wind and solar, respectively. High costs for construction and standby energy are associated with their low capacity factors. Ranking 9 th is petroleum, which is unfortunate because oil-fired power plants currently generate the supermajority of Oahu s electricity. Given these results and the fact that Oahu already has a 3-boiler installation of WtE that take advantage of the solid waste production on the island, the next best choice for the next 1MW power plant is LNG. i

3 TABLE OF CONTENTS ABSTRACT... i LIST OF FIGURES... iii LIST OF GRAPHS... iv INTRODUCTION... 1 POWER GENERATION BY ENERGY SOURCE... 4 CHARACTERISTICS OF POWER GENERATION TECHNOLOGY COST ESTIMATES FOR ALTERNATIVE 1 MW POWER PLANTS CONCLUSIONS & FUTURE WORK REFERENCES APPENDIX A ADDITIONAL TABLES... 3 APPENDIX B PRELIMINARY ROOFTOP PV ESTIMATES ii

4 LIST OF FIGURES Figure 1. Pie Chart of Hawaii s Petroleum Use, By Sector (DBEDT, 213) 1 Figure 2. Electricity Production in Hawaii and the U.S. (Hawaii DBET, 213) 2 Figure 3. Nuclear Fission. 6 Figure 4. Combined cycle power generation (Gushwehnta Developmnets, 27) 9 Figure 5. US Total Energy Development, Figure 6. US Renewable Energy Development, Figure 7. Coal Total Capacity and Generator Units in the U.S. 12 Figure 8. Petroleum Total Capacity and Generator Units in the U.S. 13 Figure 9. Natural Gas Total Capacity and Generator Units in the U.S. 14 Figure 1. Nuclear Total Capacity and Generator Units in the U.S. 15 Figure Electricity Generation by Renewables in the U.S. 16 Figure Electricity Generation by Renewables in Hawaii 16 Figure 13. Solar PV & Thermal Total Capacity and Generator Units in the U.S. 17 Figure 14. Solar Energy as a % of Total Renewable Generation in Hawaii. 17 Figure 15. Wind Total Capacity and Generator Units in the U.S. 18 Figure 16. Biomass Total Capacity and Generator Units in the U.S. 19 Figure 17. Geothermal Total Capacity and Generator Units in the U.S. 2 Figure 18. Conventional Hydroelectric Total Capacity and Generator Units in the U.S. 21 Figure 19. Pumped Hydroelectric Total Capacity and Generator Units in the U.S. 21 Figure 2. Levelized Cost for Power Production: This study vs EIA averages 27 Figure B.1. Usable roof space in downtown Honolulu area. 31 Figure B.2. Iwilei Costco utilizing roof space for solar PV. 31 iii

5 LIST OF TABLES Table 1. Fossil Fuel Emission Levels 5 Table 2. Power Generation Plant Data to Produce 876, Mwh per Year 24 Table 3. Power Plant Costs with Standby Power to Provide 9% Capacity 24 Table A.1. Constants used to Calculate Values for Table 2 and Table 3. 3 iv

6 INTRODUCTION The state of Hawaii is a unique and beautiful land, rich in history, culture, and natural resources. Literally the most isolated population center on the planet (over 2, miles from the nearest land mass), there truly is no other place on Earth like Hawaii. Before Captain James Cook made contact with Hawaii in 1778, the islands had a self-sustained population of an estimated 1 million people (La Croix, 21). Today, however, the economy of Hawaii is almost entirely dependent on outside trade and commerce. Although Hawai i has plentiful agricultural land and year-round growing conditions, the state still imports more than 85% of its food and supermarkets have less than a 7-day supply of food in stores at any given time (Agroforestry Net, Inc.). On the island of Oahu, many of the prime agricultural lands which are currently used to grow crops such as pineapple, watermelon, and seed corn (8), are being re-zoned for the construction of the Honolulu Rail Transit and for the Ho opili housing development projects (Choon, 212). Even more alarming than Hawaii s food security issue is Hawaii s energy dependence on imported oil. Deriving 9% of its primary energy resources from oil (Arent et al, 29), Hawaii is the most heavily dependent state in the nation on petroleum for its needs such as electricity generation, ground transportation, and commercial aviation as seen below in Fig. 1. All of this oil is imported from the mainland or from other foreign countries, which adds to the rising costs of oil, priced at $96 per barrel in April 213 (EIA 1, 212). At a total statewide petroleum use of 43 million barrels per year (DBEDT, 213), that equates to 4.13 billion USD per year leaving Hawaii s economy to supply its energy needs. Figure 1. Pie Chart of Hawaii s Petroleum Use, By Sector (DBEDT, 213) As seen in Fig. 1, 75% of Hawaii s electricity production is based on fuel oil. The average residential electricity price in Hawaii in the first quarter of 213 was nearly $.35/kWh; over 3% higher than the national average (DBEDT, 213). Even though Hawaii has the 4 th lowest average residential monthly electricity consumption in the nation (585 kilowatt-hours), it still has the highest residential monthly electricity bill in the nation ($22.72), nearly two times that of the national average (EIA 2, 212). U.S. electricity production is primarily supplied by coal (45%) and natural gas (24%), which have fuel costs of $24 and $28 per megawatt-hour (MWh) respectively, as compared to oil, which has a much higher fuel 1

7 cost of $177 per MWh (EIA 3, 212). This explains why Hawaii has the highest electricity cost in the nation. Figure 2. Electricity Production in Hawaii and the U.S. (Hawaii DBET, 213) With growth in population, tourism, and the economy, there has been a significant and growing demand for energy in the commercial, industrial, transportation, and residential sectors. Additionally, with lifestyle improvements and a high standard of living, a growing market for electric vehicles (EVs) and plug in hybrid vehicles (PIHV), and the retirement of old oil burning units (some of which date back to 1923) (EIA 4, 212), there is a growing demand for energy that needs to be met by alternative energy sources. A number of renewable energy sources are available in Hawaii: it has two active volcanoes, and is only one of eight states in the U.S. with installed geothermal power generation; has great solar resources (e.g., Hawaii ranks first in the nation for solar water heaters installed per capita); has one of the most robust and consistent wind regimens in the world; has an excess of municipal solid waste that can be used as fuel for Waste-to-Energy (WtE) plants; and is surrounded by the Pacific Ocean, making it rich in hydrokinetic and thermal resources. One would think that with all these resources, renewable energy in Hawaii would contribute more than the current 11%. There have been several actions taken to increase the contribution of renewable energy to Hawaii s electrical grid. The state launched the Hawaii Clean Energy Initiative (HCEI) which mandates 7% clean energy by 23, with 3% from efficiency measures, and 4% coming from locally generated renewable sources. By law, the Hawaiian Electric Company (HECO) on Oahu, and its sisters 1 on the neighbor islands Maui Electric Company (MECO) on Maui, Molokai, and Lanai, and Hawaii Electric Light Company (HELCO) on the Big Island, are required to establish a renewable portfolio standard of 1% of its net electricity sales by December 31, 21; 15% by December 31, 215; 25% by December 31, 22, and 4% of its net electricity sales by December 31, 23 (HCEI, 21). 1 Hawaii, as an island state, has a unique power generation and distribution system where its island has an isolate system and all but Kauai are owned by HEI, Hawaii Electric Industries, a publically held corporation that consists of HECO, MECO, HELCO and American Savings Bank. 2

8 With oil generating 75% of electricity, coal 14%, and renewables 11%, the first goal has been met, and Hawai i is on its way to meet the additional 4% of renewable electricity production by December 215 (Fig. 2). Currently, the primary renewable energy sources include H-Power on Oahu, which burns municipal waste to produce electricity, the Puna Geothermal Plant on the Big Island, which uses heat from volcanic sources to produce electricity, and wind turbines on Big Island, Maui and Oahu 2 to produce electricity. Currently, there are more than 1, megawatts (MW) of renewable projects in service (about 43% of the state s total electricity generation capacity) under construction, awaiting approval, or being negotiated. (HECO, 213) The HCEI seeks to address the following core challenges facing our state (HCEI, 21): 1. To be more independent and less reliant on other economies. 2. To achieve greater security. 3. To be more economically stable by keeping an estimated $6 billion in state that would otherwise go toward foreign oil investments. 4. Establish a new, green economies sector that will counter-balance a reliance on tourism and the military. 5. To position Hawai i as a worldwide leader in the clean energy category and that will attract more business and expertise to the region. In the long run, fabricating a society and economy that is less dependent on imported energy will benefit future generations. In the short run, it will provide greater security in the case of a natural disaster or war-time complications that could easily discontinue our imported supply of petroleum. Either way, this issue is of critical importance and must be addressed in a timely fashion. The objective of this study is to address Hawaii s energy dependence on fossil fuels by finding the next 1MW alternative energy power plant for Oahu. In order to simplify matters, the focus is on providing the next 1 megawatt (MW) power plant. Granted, 1 MW is only around 6% of Oahu s total electrical generation capacity (1,817 MW) (HECO 2, 213), but this capacity size of 1 MW is easily scalable and can act as a pilot for larger renewable energy projects in the future. By focusing on Oahu there is no need to consider the prospect of an undersea inter-island transmission cable to transport electricity from island to island. This study will also only consider technologies that are currently in operation; it will not consider those technologies that are still in the research and development stages. Nine different energy sources (coal, oil, natural gas, geothermal, hydroelectric, photovoltaic solar, onshore wind, WtE, and nuclear) were compared and analyzed to determine the best option for the next 1 MW power plant on Oahu. 2 The only wind farm on Oahu in Kahuku is inoperable since an August 1, 212 fire at its battery storage assembly. 3

9 POWER GENERATION BY ENERGY SOURCE Energy vs. Power Energy is a measure of how much fuel is contained within something, or used by something over a specific period of time. The watt-hour (Wh) is a unit of energy, but in this large scales, the kilowatt-hour (kwh = 1 3 Wh) and megawatt-hour (MWh = 1 6 Wh) will be used. Power is the rate at which energy is generated or used. The watt (W) is a unit of power, but in large scales, kilowatts (kw = 1 3 W) and megawatts (MW = 1 6 W) are used (Energy Lens, 213). Generally speaking, the Earth has a lot of energy but the humans on it have a limited ability to generate power from it. Power, not energy, enables the maintenance and improvement of people s standard of living. Thus the focus of this research is on power generation from various energy sources. The power rating of a generating plant is referred to as capacity. Renewable Energy Magazine explains with the helpful analogy: Capacity for a power plant (kw or MW) is probably best explained with a highway analogy. A 1-lane highway is able to allow more cars to get from one point to another in a given time period when compared to a three-lane highway. Likewise, a 1, MW power plant has the ability to put more energy, or MWh, to the grid in a given time period than a 5 MW power plant. The size of the highway is analogous to the capacity, or MW rating, of the power plant. The number of cars that pass from one point to another on the highway during a given time period is analogous to the energy, or MWh, that the power plant delivers during the same time period. So, the more lanes on the highway, the more cars that can pass from one point to another in one hour. Therefore, the larger the power plant s capacity, the more energy the plant can deliver to the grid in one hour. (Hynes, 29) For the analysis, this study considered the costs of operating a 1 MW power plant at theoretical capacity of 1%, which means it produces electricity 24 hours a day for 365 days a year. That translates to annual energy generation of 876, MWh. There is no generating plant that has 1% capacity; nuclear and geothermal have the highest capacity factor at 9% and wind and solar are the lowest with capacity factors ranging between 2 and 35%. Scaling all generating plants to a 876, MWh energy output is one way to levelize costs. Energy Sources Energy sources are classified in Non-Renewable and Renewable sources. Non-renewable sources are primarily fossil fuels such coal, petroleum, and natural gas. Millions of years ago, the remains of plants and animals (diatoms) decayed and built up in thick layers. This decayed matter from plants and animals is called organic material it was once alive. Over time, the sand and silt changed to rock, covered the organic material, and trapped it beneath the rock. Pressure and heat changed some of this organic material into coal, some into oil (petroleum), and some into natural gas tiny bubbles of odorless gas. Fossil fuels are considered non-renewable resources because they cannot be replenished on a human timeframe. Power plants burn these fossil fuels to make steam, and the steam turns turbines that generate electricity. 4

10 Extraction of fossil fuels from the Earth often requires deep drilling, which is an energy intensive process 3 that often produces runoff and spills. Refineries produce wastewater which can contain pollutants and can have high temperatures. Releasing this contaminated and higher temperature water into aquatic ecosystems, whether intentionally or unintentionally, can have drastic environmental consequences. Combustion of all fossil fuels releases pollution into the air, with coal emitting the most pollutants, then oil, and then natural gas. Table 1 gives some average values of emission levels for the three fossil fuels: Table 1. Fossil Fuel Emission Levels Fossil-fueled power plants use large quantities of water for steam production and cooling. When power plants remove water from an aquatic ecosystem, plant, animal, and human life can be interrupted and compromised (EPA, 211). The advantage to fossils fuels are their high fuel heat contents; their capacity to generate vast amounts of electricity in a single location; their cost-effectiveness (for gas and coal); their transportation through oil and gas pipelines; their consistency in continuous electricity production (base-load); their chemical stability; their existing infrastructure for harvesting, refining, and power generation. Strictly speaking nuclear energy is produced by a non-renewable source of energy because uranium ore is a finite source. However, the amount of ore needed for power generation versus the known deposits or uranium on Earth makes it incomparably more abundant than any of the aforementioned fossil fuels. In addition, nuclear power production is considered clean energy thus in some classifications nuclear energy is included together with clean, renewable energy sources. Nuclear energy is the energy in the nucleus of an atom. By breaking the bonds that hold the nucleus together, an enormous amount of energy is released. Nuclear power generation plants utilize nuclear fission to break these bonds to 3 The difficulty and cost of extraction has generated pass hyperbolas such as Peak Oil. Obviously a number of fossil fuel sources are not possible to extract and take to market when oil is priced at $3 per barrel. This limitation evaporates quickly if the price of oil doubles or triples. Thus peak oil is a moving target. Furthermore, very high oil prices for oil, e.g., $15 per barrel, dramatically reduce consumption and therefore push peak oil much further to the future. A 21 analysis of Oil Reserves by The Economist indicates decades and centuries of reserves for the various oil producing countries. (The Economist, 211) 5

11 produce electricity (Fig 3). During nuclear fission, a neutron hits the atom and splits it, releasing a large amount of energy as heat and radiation. In the process, more neutrons are released, bombarding other atoms, and the process repeats itself over and over again creating a chain reaction. (EIA 5, 212) Figure 3. Nuclear Fission. Unlike fossil fuel-fired power plants, nuclear reactors do not produce air pollution when generating electricity. The mining process of uranium and the construction materials of nuclear power plants, however, do require large amounts of energy. This energy is usually supplied by fossil fuels which release pollutants into the air. However, the primary environmental concern of nuclear power is radioactive wastes such as uranium mill tailings and spent reactor fuel. Although most of the waste related to the nuclear power industry has a relatively low-level of radioactivity, they can remain a human health hazard for thousands of years. There is currently no permanent disposal facility in the U.S for higher levels of nuclear waste, so the storage of spent reactor fuel and the decommissioning of nuclear power plants pose an environmental concern. (EIA 5, 212) Renewable sources include Solar: The potential for harnessing the sun as an energy source is enormous - more energy falls on the Earth in one hour than is used by everyone in the world in one year (NREL, 212). This energy can be used directly for heating and lighting homes and buildings, for hot water heating and for generating electricity. Some of the technologies that convert sunlight to usable energy include solar photovoltaic (PV) and concentrated solar power (CSP). Literally translated as light-electricity, solar PV cells convert sunlight directly into electricity. Solar panels are typically made from solar cells combined into modules. These panels are combined together to create a single system called a solar array. For large electric utility or industrial applications, hundreds of solar arrays are interconnected to form a large utility-scale PV system. Traditional solar cells are made from silicon, are usually flat-plate, and generally are the most efficient. (NREL, 212) CSP systems collect the sun's energy using long rectangular, curved (U-shaped) mirrors. The mirrors are tilted toward the sun, focusing sunlight on tubes (or receivers) that run the length of the mirrors. The 6

12 reflected sunlight heats a fluid flowing through the tubes. The hot fluid then is used to boil water in a conventional steam-turbine generator to produce electricity. There are two major types of linear concentrator systems: parabolic trough systems, where receiver tubes are positioned along the focal line of each parabolic mirror; and linear Fresnel reflector systems, where one receiver tube is positioned above several mirrors to allow the mirrors greater mobility in tracking the sun. (NREL, 212) The main benefit of solar energy is that it does not produce air pollutants or carbon-dioxide, and when located on building roofs, they have minimal impact on the environment. Its main disadvantage is that the amount of sunlight that arrives at the Earth s surface is not constant, which means intermittent electricity production. Sunlight constancy varies by location, time of day, time of year, and the weather. Additionally, in order to harness a useful amount of energy, a large surface area is required to collect the sun s rays. (EIA 6, 212) Wind: Historically, wind energy has been harnessed through windmills to pump water or to grind grain. Today the wind turbine, the windmill s modern equivalent, uses the wind s energy to generate electricity. Wind turbines use blades to collect the wind s kinetic energy. The wind flows over the blades creating lift, like the effect on airplane wings, which causes them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity (EIA 6, 212). Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. For utility-scale (MW-sized) sources of wind energy, a large number of wind turbines can be built close together to form a wind farm. (NREL, 212) The main benefit of wind energy is that it is a clean, free and renewable source of energy. Wind turbines do not release emissions and do not require water for cooling. Additionally, a wind turbine has a small physical footprint relative to the amount of electricity it can produce. Its main disadvantage is that wind does not blow constantly, and is therefore an intermittent power source, unable to produce electricity consistently. At those times, other types of power plants must be used to generate electricity. A few other disadvantages include wind turbines visual and sound impacts, their need for service roads which require energy for construction, their relatively short life of 1-12 years (The Courier, 212), and the impacts they have on some species of birds and bats (EIA 6, 212). Biomass energy has been used since people began burning wood to cook food and to keep warm. This bioenergy is harnessed from plants and plant-derived materials such as wood, food crops, grassy and woody plants, residues from agriculture or forestry, oil-rich algae, and the organic component of municipal and industrial wastes. Even the fume from landfills (mostly methane, the main component of natural gas) can be used as a biomass energy source. (NREL, 212) Biomass energy supports U.S. agricultural industries, forest-product industries, and cities. The main biomass feedstocks for power are paper mill residue, lumber mill scrap, and municipal waste. Instead of being landfilled, this waste, through incineration, can be converted into electricity by creating steam that powers turbines. This process has a double benefit of saving space and producing energy. Waste-toenergy (WtE) plants, however, do produce air pollution and can release harmful chemicals and substances found in the waste if not properly controlled. An additional challenge is the disposal of ash 7

13 created by the combustion process of WtE plants. Ash can contain high concentrations of various metals that were present in the original waste. Not all ash is useless, however, as one-third of it is used in landfills as a daily or final cover layer, to build roads, to make cement blocks and artificial reefs for marine animals (EIA 6, 212). Landfill gas, or biogas is composed mainly of methane and carbon dioxide that forms as a result of biological processes in sewage treatment plants, waste landfills, and livestock manure management systems. Many of these facilities capture and burn the gas for heat or electricity production. Burning methane (CH 4 ) is actually beneficial because CH 4 is a more potent greenhouse gas than CO 2. (EIA 6, 212) Liquid biofuels, ethanol and biodiesel, were the fuels used in the first automobile and diesel engines, but lower cost gasoline and diesel fuel made from crude oil became the dominant engine fuels. The federal government has promoted ethanol use in vehicles to help reduce oil imports since the mid-197s. Although biofuels are considered carbon-neutral because the plants that are used to make biofuels absorb CO 2 as they grow, growing plants for biofuels is controversial as the land, fertilizers, and energy used to grow biofuel crops could be used to grow food crops instead. Ethanol and ethanol gasoline mixtures burn cleaner and have higher octane than pure gasoline, but have higher evaporative emissions from fuel tanks and dispensing equipment, contributing to the formation of harmful, ground level ozone and smog (EIA 6, 212). Geothermal: technologies harness heat resources from within the Earth including heat retained in shallow ground, hot water and rock found a few miles beneath the Earth s surface accessed by drilling, and extremely high-temperature molten rock (magma) located deep in the Earth accessed by geothermal reservoirs (volcanoes). Most geothermal activity is located in the western U.S., Alaska, and Hawaii. Geothermal resources can be used on large and small scales for producing heat directly from hot water within the Earth (direct use), for generating electricity (power plants), and for heating and cooling using the Earth s shallow ground temperature (heat pumps) (NREL, 212). Geothermal direct use has been used since people began using hot springs for bathing and cooking food. In modern systems, a well is drilled into a geothermal reservoir to provide a steady stream of hot water called brine. The brine is brought up through the well, and a mechanical system piping, a heat exchanger, and controls delivers the heat directly for its intended use. A disposal system re-circulates most of the cooled brine to minimize demand for water resources. (NREL, 212) Geothermal power plants use steam produced from reservoirs of hot water (3 F to 7 F) found a few miles or more below the Earth's surface to produce electricity. These resources are accessed by drilling wells (1-2 miles deep) into the Earth and piping the steam or hot water to the surface. There are three basic types of geothermal power plants: dry steam, flash steam, and binary cycle power plants. (EIA 6, 212) 8

14 Geothermal heat pumps take advantage of the nearly constant temperature of the Earth to heat and cool buildings. The shallow ground, or the upper 1 feet of the Earth, maintains a temperature between 5 and 6 F (1 16 C). This temperature is warmer than the air above it in the winter and cooler in the summer. (NREL, 212) Geothermal power is a baseload power source, so plants produce electricity consistently and continuously regardless of weather. Generally, plants are compact, using less land per MWh than coal, wind or solar. (NREL, 211) Geothermal power plants do not burn fuel to produce electricity, so their emission levels are very low. Scrubber systems are utilized to clean the air of hydrogen sulfide that is found naturally in the steam and hot water. Once the steam and water from a geothermal reservoir has been used, they are injected back into the Earth. Geothermal power plants release less than 1% of the CO2 emissions and less than 3% of the acid rain-causing sulfur compounds emitted by fossil fuel plants. (EIA 6, 212) Of all renewable power plants geothermal plants and some CSP plants use the combined cycle (CC) power production methods used by fossil-fueled plants. CC is a series of heat engines that work in tandem using the same source of heat. Typically residual hot steam or other heat source that was used in the primary turbine for power generation is reused as shown in the numbered parts of Fig. 4: 1) Electric generators, 2) Steam turbine, 3) Condenser, 4) Pump, 5) Boiler/heat exchanger, 6) Gas turbine. Figure 4. Combined cycle power generation (Gushwehnta Developments, 27) Hydropower technologies harness power from flowing water by directing it through a pipe, or penstock, so that it pushes against and turns blades in a turbine to spin a generator to produce electricity. Conventional hydro consists of run-of-the-river systems, where the force of the current applies the needed pressure, and storage systems, where water is accumulated in reservoirs created by dams, then released as needed to generate electricity. Pumped hydro facilities pump water from a lower reservoir to an upper reservoir when demand for electricity is low. When demand is high, the water is released back to the lower reservoir to generate electricity. (EIA 6, 212) Hydropower is a clean renewable energy source fueled by water, that doesn t release emissions of air pollutants. Since water is flowing consistently, hydropower is considered a baseload power source and can produce electricity on demand. In some cases the combination of drought, evaporations and seepage may cause insufficient storage of water and result in reduced or curtailed power production. Although hydropower generators do no directly produce emissions, hydropower dams, reservoirs and the operation of generators can negatively impact native plants and animals by obstructing fish migration and altering the natural water temperatures, chemistry, flow characteristics, and silts loads. Reservoirs may cover important natural areas and agricultural lands, causing the relocation of entire communities. The construction of new hydropower dams require the manufacturing of steel and concrete which requires energy. This energy is usually supplied by fossil fuels which release pollutants into the air (EIA 6, 212). 9

15 Ocean: The ocean has vast amounts of energy potential, from tidal, to wave, to ocean thermal conversion, but most technologies are still in the research and development stage and currently do not produce any significant amounts of electricity. There have been two successful applications of tidal energy harnessing: the 24 MW Rance Tidal Power Station in France which opened in 1966 (Wyre Tidal Energy, 213), and the 245 MW Sihwa Lake Tidal Power Station in South Korea which opened in 211 (Renewable Energy World, 25). Tidal energy: Tides are caused by the gravitation pull of the moon and sun, and the Earth s rotation. Near shore, tides can cause water levels to rise and recede up to 4 feet. Tidal barrages, tidal fences and tidal turbines are three technologies that capture tidal energy. Tidal barrages have sluice gates (gates commonly used to control water levels and flow rates) to allow the tidal basin to fill on the incoming high tides and to empty through the turbine system on the outgoing tide, also known as the ebb tide. There are two-way systems that generate electricity on both the incoming and outgoing tides. A tidal fence has vertical axis turbines mounted in a fence. All the water that passes is forced through the turbines. Tidal fences can be used in areas such as channels between two landmasses. Tidal turbines are basically wind turbines in the water that can be located anywhere there is strong tidal flow. (EIA 6, 212) Wave Power: Waves are caused by currents in the ocean and winds blowing over the ocean. Ocean waves produce tremendous amounts of energy; an estimated total potential off the coasts of the US is 252 billion kwhs a year, which is about 6% of the US electricity generation in 211. One way to harness this energy is to focus the waves into a narrow channel, increasing their power and size. The waves can then be channeled into a catch basin or used directly to spin turbines. Ocean Power Technologies has been testing a single 4 kw buoy in 9 ft. depth water in Kaneohe Marine Corps Base Hawai i (HNMREC, 213). Ocean Thermal Energy Conversion (OTEC): Solar energy heats the surface water of the ocean, making it much warmer than the deep water. OTEC systems harness the temperature difference, which must be greater than 77F, to produce electricity. Hawaii has worked with OTEC since the 197s, but there are many challenges with this technology including energy efficiency and water pumping. A 26 announcement to build an OTEC plant on the Big Island mentioned on a HEI website (HECO 3, 213) did not occur. 1

16 Total Wattage (Mw) CHARACTERISTICS OF POWER GENERATION TECHNOLOGY This part of the study provides a general overview of the past and current energy outlook for the U.S. and Hawaii. A data set was collected from EIA to compile a list of every power plant on record, dating as far back to the late 18s and spanning the years until 211. The total wattage and the total number of generating units were plotted over time for each type of power plant. These plots act as a visual representation of the development of different energy in the U.S. In order to look at the current energy situation in the U.S. and Hawaii, 211 data was collected for total electricity generation by energy source. The data were extracted from EIA and DBEDT sources. Fig. 5 reveals that coal, natural gas, and nuclear are the top three sources for total installed capacity. Conventional hydro has the longest history and the highest installed capacity of all renewable sources. Wind and pumped hydro are second and third in installed capacity, but have only taken off within the past 3 years. The trends of each major energy source on a national level and in Hawaii are compared and discussed below. 5, 45, US Energy Development - Total Capacity Coal Petroleum 4, 35, 3, 25, Natural Gas Nuclear Conventional Hydro Wind 2, 15, 1, 5, Time Solar Thermal & PV Wood Geothermal Other biomass Pumped Storage Figure 5. US Total Energy Development,

17 Megawatts (Mw) Total Wattage (Mw) 8, US Energy Development - Renewable Capacity Wind 7, 6, 5, 4, 3, Solar Thermal & PV Wood Geothermal Other biomass Conventional Hydro Pumped Storage 2, 1, Time Figure 6. US Renewable Energy Development, Around 87% of total electricity generation in the US is provided by non-renewable sources (Fig 2). In Hawaii, 89% of total electricity generation is provided by non-renewable sources. 4, 35, 3, 25, 2, 15, 1, 5, Total Wattage No. Generator Units Coal Time 1,6 1,4 1,2 1, Generator Units Figure 7. Coal Total Capacity and Generator Units in the U.S. 12

18 Megawatts (Mw) In 1961, coal became the major fuel used by electric utilities to generate electricity. In , the oil embargo by the Organization of Petroleum Exporting Companies (OPEC) focused attention on the energy crisis, resulting in an increase of demand for U.S. coal. With the popularity of natural gas skyrocketing in the mid 198s, the construction of new coal power plants declined. Through the Energy Policy Act of 25, clean coal technologies are promoted (American Coal Foundation, 25). Today coal accounts for 43% of the nation s total electricity generation (Fig. 7). Coal in Hawaii accounts for 14% of the state s total electricity production (Fig. 2). This electricity is provided by one 23 MW coal plant (AES Hawaii) that was built in There are currently no proposals, either active or cancelled, to build coal-fired plants in Hawaii. (Sourcewatch, 211) Petroleum 7, 4, 6, 3,5 Total Wattage 5, 3, No. Generator Units 2,5 4, 2, 3, 1,5 2, 1, 1, Time Generator Units Figure 8. Petroleum Total Capacity and Generator Units in the U.S. Petroleum in the US only accounts for 1% of the nation s total electricity production. It is mostly used for transportation or home heating purposes. Petroleum in Hawaii accounts for 75% of the state s total electricity production (Fig. 2). With the Hawaiian Clean Energy Initiative mandate of 15% renewable by 215, HECO and its sisters on Maui and the Big Island are incorporating more renewable energy sources into the fuel mix. The Hawaii Public Utilities Commission has developed programs such as net energy metering and feed-in tariffs to encourage individuals, small, businesses, or government entities to sell renewable energy to their utility. (HECO 1, 213) 13

19 Megawatts (Mw) Natural Gas 6, 6, 5, 5, Total Wattage 4, 4, No. Generator Units 3, 3, 2, 2, 1, 1, Time Generator Units Figure 9. Natural Gas Total Capacity and Generator Units in the U.S. In the 195s and 196s, thousands of miles of pipeline were constructed throughout the U.S., which led to rapid growth of natural gas markets. It was during this time that the first gas-fired electrical plants came on-line. Technological advancements over the years such as hydraulic fracturing or fracking have increased gas well productivity, while new drilling techniques have allowed extraction of gas from shale, and have made offshore sites more valuable. The record-setting hurricane season of 25 caused massive damage to the U.S. natural gas and petroleum infrastructure, curbing development. However, the popularity of natural gas worldwide is on the rise because of its low CO 2 emissions (for a fossil fuel) and the discovery of new reserves in Texas, Louisiana, and Wyoming as well as in Poland, Russia, China and elsewhere (EIA 5, 212). Currently natural gas accounts for 24% of the total electricity generation in the US (Fig. 2). Currently natural gas is not used for electricity generation in Hawaii. However, according to Hawaii Gas Company s proposed 3-step liquefied natural gas (LNG) plan, electrical generation is a goal for the near future (Levine, 212). 14

20 Megawatts (Mw) Nuclear 12, 12 Total Wattage 1, 1 No. Generator Units 8, 8 6, 6 4, 4 2, Time Generator Units Figure 1. Nuclear Total Capacity and Generator Units in the U.S. The first large-scale US commercial nuclear power plant was commissioned in Shippingport, PA in Since then, the use of nuclear-generated electricity has grown, increasing quickly from 5% in 1973 to 9% in 1975 and then to the current level of 2% by The last nuclear plant to begin commercial operation was the Tennessee Watts Bar plant in Since then, the capacity of existing plants has been expanded through uprating. Four new nuclear reactors, Vogtle Units 3 and 4 and Summer Units 2 and 3, are expected to come on-line between 216 and 217 (EIA 5, 212). Currently, nuclear power accounts for 19% of the nation s total energy production (Fig. 2). Currently nuclear power is not used for electricity generation in Hawaii, and there are no proposals for implementing nuclear power for that purpose. Although at any time there are at least a handful of large nuclear powered vessels in Pearl Harbor (less than 1 mile distance from Honolulu), an article of Hawaii s Constitution (Article XI, Section 8 ) prohibits the installation of nuclear power plants anywhere in the state. A two thirds majority of the State Senate is required to modify this constitutional prohibition. (HECO 4, 213) Solar (PV and CSP), wind, biomass, geothermal and hydro power are the main renewable energy sources that have been harnessed to generate electricity in Hawaii and the U.S. In the U.S. around 13% of total electricity generation is provided by renewable sources. In Hawaii, 11% of total electricity generation is provided by renewable sources. Although the totals are very similar, the mix is vastly different with US mainland renewable power production clearly dominated by hydro (Fig. 11), whereas Hawaii has a more diversified portfolio with WtE claiming about one third of the pie (Fig. 12). 15

21 211 Electricity Generation by Renewables in US (Approx 13% of total generation) Biomass 11% Geothermal 3% Solar % Wind 24% Hydro 62% Source: 213 EIA Electric Power Monthly Figure Electricity Generation by Renewables in the U.S. 211 Electricity Generation by Renewables in HI (Approx 11% of total generation ) Wind 25% PV 4% Biomass 13% Geothermal 16% H-Power 31% Source: 211 State of Hawaii Data Book Hydro 11% Figure Electricity Generation by Renewables in Hawaii 16

22 Megawatts Solar PV & Thermal 2, 35 Total Wattage 3 1,5 No. Generator Units 25 1, Time Generator Units Figure 13. Solar PV & Thermal Total Capacity and Generator Units in the U.S. Solar accounts for.4% of the nation s total renewable energy production, making it the smallest contributor (Fig. 11). There has been a sharp rise in total solar developments since 26. This is primarily due to government subsidies that encourage solar PV and CSP projects, and the declining production cost of these technologies. Solar energy in Hawaii accounts for 4% of the state s total renewable energy production, making it the smallest contributor (Fig. 12). However, due to Hawaii s high energy prices, great solar resource potential, and progressive energy policies, the state has experienced rapid growth in solar generation (Fig. 14). Solar PV capacity increased 15% in Hawaii in 211, making it the 11th biggest state for PV capacity (EIA 7, 212). Two important energy policies include Net Energy Metering (NEM), which allows residential customers to receive full retail value for excess solar energy occasionally fed to the grid, and Feed in Tariffs (FIT), which allow the owners of small renewable energy projects to receive fixed rates of renewable electricity provided to the grid (DBEDT, 213). Because of the intermittent nature of solar as well as Hawaii s small, individual, non-interconnected island grids, the integration of large amounts of solar generation can be challenging. Therefore, solar power is generated mostly through distributed panels on residences and businesses. Commercial solar farms contribute minimally to power generation. Figure 14. Solar Energy as a % of Total Renewable Generation in Hawaii. 17

23 Megawatts (Mw) 5, Wind 1 4, 3, 2, 1, Total Wattage No. Generator Units Generator Units Time Figure 15. Wind Total Capacity and Generator Units in the U.S. In the wake of the oil shortages of the 197, an interest was created in alternative energy sources, providing an opportunity for the re-entry of the windmill to generate electricity. With the growing concern for the emissions of fossil fuel generation and the rising costs of these fuels, state policies (production tax credit and state renewable electricity portfolio standards) have continued the push for wind energy development, which has skyrocketed in the last dozen years. (EIA 6, 212). Currently wind accounts for 24% of the nation s total renewable energy generation (Fig. 11). Wind energy is Hawaii s second most utilized renewable resource, accounting for 25% of the state s total renewable energy generation (Fig. 12). Existing projects are located on the islands of Oahu, Maui, and Hawaii. Hawaii has one of the most robust and consistent wind regimes in the nation that could potentially provide over 1 MW of wind energy, which would constitute 94% of the State s HCEI goals. Unfortunately, since over 7% of Hawaii s energy load is on Oahu, but over 9% of the existing wind potential is on the outer islands, reaching that level of production would require interconnection of the electricity grids of the islands (DBEDT, 213). There has been talk about an Inter-Island Transmission Cable, but there is no action toward its construction. In August of 212, a major fire destroyed the battery storage facility of the 3 MW Kahuku Wind Farm. The wind farm also experienced two previous fires that destroyed inverters after coming online in 211. Repairs to the farm are not expected to be completed until the third quarter of 213. Unfortunately, besides the Kawailoa wind project this is only the only other wind farm installed on Oahu, and does not help promote wind power in Hawaii. (Cocke, 212) 18

24 Megawatts (Mw) Wood and wood derived fuels (Biomass) 1, 4 8, Total Wattage 35 No. Generator Units 3 6, , 15 2, Time Generator Units Figure 16. Biomass Total Capacity and Generator Units in the U.S. Combustion of wood and wood derived fuels at a large scale has been around since the 194s. Capacity and generator units have steadily increased over the years, with a jump between 198 and the late 199s that was most likely caused by a rise in construction of WtE plants. Currently biomass accounts for 11% of the nation s total renewable energy generation (Fig. 11). Biomass energy is Hawaii s most utilized renewable resource, accounting for 44% of the state s total renewable energy generation (Fig. 12). By-products from food, feed, or fiber production account for 13% of the total. Hawaiian Commercial and Sugar (HC&S) generates energy from the fiber by-product of sugar production (DBEDT, 213). Burning of waste materials such as used cooking oil and municipal solid waste accounts for 31% of the total. H-Power recently installed a third boiler and now has a total operating capacity of 9 MW, incinerating up to 1,1, tons of waste annually and reducing the need to landfill Oahu s municipal waste (Covanta Energy, 213). Hawaii has the world's largest commercial electricity generator fueled exclusively with biofuels. The State s energy plan aims for an agricultural biofuels industry that, by 225, can provide 35 million gallons of biofuels (EIA 7, 212). Currently, however, there is no local production of biodiesel fuel, and imported biodiesel fuel costs are significantly higher (by nearly 2%) than the fossil-based fuels used for electricity generation in Hawaii (DBEDT, 213). 19

25 Megawatts (Mw) Geothermal 4, 25 3,5 Total Wattage 2 3, No. Generator Units 2,5 15 2, 1,5 1 1, Time Generator Units Figure 17. Geothermal Total Capacity and Generator Units in the U.S. In 196, the country s first large-scale geothermal electricity-generating plant began operation at The Geysers, CA. Several legislative actions were taken between 197 and 198 to encourage the development of geothermal resources for power generation and direct-heat uses. In the early 198s two developments, binary technology and crystallizer-clarifyer technology, allowed feasibility of larger-scale commercial power plants, causing a steep increase in total capacity and generator units until the mid 199s. Currently, geothermal accounts for 3% of the nation s total renewable energy generation (Fig. 11). Recently, geothermal development is slowly on the rise. (DOE, 211) Geothermal energy is Hawaii s third most utilized renewable resource, accounting for 16% of the state s total renewable energy generation (Fig. 12. This energy is produced exclusively by the 4 MW Puna Geothermal Venture (PGV) on the Big Island. Draft requests for proposals have been issued by HELCO on the Big Island for a 5 MW addition to PGV, and by MECO on Maui for 3 MW of renewable firm dispatchable capacity resource, which could include geothermal. (DBEDT, 213) Continued geothermal exploration is taking place on Maui, focusing on the southwest rift zone of Haleakala, with partial funding from the U.S. Department of Energy. Although geothermal resources are difficult to characterize without exploration and drilling, estimates from exploration efforts in the 197s and 198s have shown that there may be possible geothermal reserves of over 1, MW, sufficient to provide 2% of the State s HCEI goals. Reaching that level of production, however, would require interconnection of the islands electricity grids. 2

26 Megawatts (Mw) Megawatts (Mw) 1, Conventional Hydro 5, 8, 6, 4, 2, Total Wattage No. Generator Units 4, 3, 2, 1, Generator Units Time Figure 18. Conventional Hydroelectric Total Capacity and Generator Units in the U.S. 25, 2, 15, 1, 5, Total Wattage No. Generator Units Pumped Hyrdro Generator Units Time Figure 19. Pumped Hydroelectric Total Capacity and Generator Units in the U.S. Hydropower is one of the oldest sources of energy, first used thousands of years ago to turn a paddle wheel for such purposes as grinding grain. Hydropower was first used to produce electricity in 188 when Michigan s Grand Rapids Electric Light and Power Company used a dynamo belted water turbine to light up 16 brush-arc lamps. Since then, conventional hydroelectric generation has steadily grown, with the efficiency of generators increasing especially from 19 to 197. Construction of new conventional hydro power plants leveled off in the 199s. Pumped hydro took off in 196, with construction leveling off in the early 2s. Today, there is about 8, MW of conventional capacity and 18, MW of pumped capacity (DOE, 211), accounting for about 62% of the nation s total renewable energy generation (Fig. 11). 21

27 Hydroelectric power accounts for 11% of the state s total renewable energy generation (Fig. 12). While Oahu has no streams suitable to harness hydroelectric power, small-scale, run-of-the-river plants provide hydroelectricity on Maui and the Big Island when rainfall provides sufficient flowing water. These small scale plants range in capacity from.5 MW to 4.5 MW. Generally for the state of Hawaii, there are no rivers that could drive large hydroelectric plants. (HECO 5, 212) COST ESTIMATES FOR ALTERNATIVE 1 MW POWER PLANTS This part of the study estimates the cost for nine different 1 MW rated power plants. These power plants were ranked on three levels: 1) cost to install, 2) cost to install and run for 3 years, and 3) cost to install and run for 3 years plus the cost of standby power to cover intermittency and capacity limitations. A literature and internet review was conducted to compile a database of over 75 power generation plants for the following energy sources: Coal Petroleum Natural gas Nuclear Solar Wind WtE (biomass) Geothermal Hydro Plant capacity (MW), construction costs (212 $), and footprint (acre) were recorded. This information was used to calculate plant construction cost per MW (M$US/MW) and land productivity (acre/mw). Using the cost of farmland on Oahu (M$US/acre), the plant Installation Cost was calculated for each energy source. This is the first level for ranking the power generation alternatives, as shown in top half of Table 2. The capacity factor, cost of fuel, MWh generated per unit of fuel, and maintenance costs were obtained from the EIA online database (See Appendix A for references). Using this information, the annual Operational Cost was determined for each technology. By adding the Installation Cost and the annual Operational Cost, and multiplying it over a period of 3 years, the total 3 year cost was determined for each technology. This is the second level for ranking the power generation alternatives, as shown in bottom half of Table 2. For those technologies with a capacity factor less than.9, natural gas was assumed as standby power so that the technology could produce electricity 1% of the time. The total 3 year cost plus the cost of 22

28 natural gas as standby power is the third level for ranking the power generation alternatives, as shown in Table 3. Table 2. Power Generation Plant Data to Produce 876, MWh per Year To Produce 876 Mwh (1Mw*24hr*365day) Coal Oil i Natural Gas Nuclear Solar Wind ii WTE - trash Geothermal Hydro Equivalent Capacity (MW) Construction cost for Equivalent Capacity (M$US) $29.62 $11.48 $94.56 $ $2, $1, $1,29.88 $ $225.2 Req'd acreage for Equivalent Capacity (acres) Cost of land for Equivalent Capacity (M$US) $1.14 $.75 $.22 $2.43 $43.61 $7.87 $1.87 $2.9 $2.6 Install Cost: Cost of LAND + cost of CONSTRN (M$US) $ $ $94.78 $ $2,331.3 $1, $1,31.76 $25.26 $ st level ranking Annual energy produced (Mwh) 876, 876, 876, 876, 876, 876, 876, 876, 876, Annual fuel consumption****** 468,449 1,616,236 7,8, 35,4 1,1, Annual cost of fuel (M$US) $21.8 $ $24.53 $1.96 $. $. -$89.1 $. $. Annual cost of Maintenance (M$US) $3.69 $1.8 $1.8 $1.43 $8.9 $11.78 $12.86 $1.79 $3.69 Op Cost (Annual): Cost of fuel + maintenance (M$US) $24.77 $ $26.33 $12.39 $8.9 $ $76.24 $1.79 $ year cost (M$US) $1,34.74 $4, $ $1,46.67 $2,598.3 $2,5.86 -$1, $573.9 $ nd level ranking Table 3. Power Plant Costs with Standby Power to Provide 9% Capacity With Standby Power to Provide 9% Capacity Coal Oil i Natural Gas Nuclear Solar Wind ii WTE - trash Geothermal Hydro 3 year cost $1,34.74 $4, $ $1,46.67 $2,598.3 $2,5.86 -$1, $573.9 $356.2 Capacity Difference from Nuclear (.9) Cost of gas as standby power (M$US) $44.23 $26.54 $ $ $ $ $17.69 $ year cost (M$US) $1,79 $4,846 $911 $1,47 $3,173 $2,51 -$1,194 $556 $692 3rd level ranking At the first level of ranking, natural gas comes in first as the most affordable at 95 M$US, and oil is second at 11 M$US. In last place is solar, wind, and then WtE at 2.3 B$US, 1.7 B$US, and 1. B$US, respectively. When considering only installation cost, fossil-fueled power plants are most affordable, while renewable energy fueled power plants are least affordable. However, when considering the installed cost plus the annual operational cost over 3 years, WtE comes in first as the most affordable at -1.3 B$US (1.3 B$US profit), and hydro and geothermal in second and third at 356 M$US and M$US. In last place is oil at 4.8 B$US, solar at 2.6 B$US, and wind at 2. B$US. The biggest difference between renewable and non-renewable energies over the 3 year cost is the cost of fuel. WtE pays, renewable energy is free, and fossil fuel costs. At a tipping fee of $81 per ton of municipal solid waste, WtE technology generates electricity and profits! Although wind and solar energy are free, PVs and turbines have low capacity factors and require more solar panels and wind turbines to produce the same amount of electricity. This significantly increases construction costs. Additionally, the life expectancy of a wind turbine is between 1 to 12 years, which means it must be replaced 2 to3 times over a span of 3 years, more than doubling the original construction cost. Oil-fueled plants do not make sense in light of high oil prices ($18/MWh). Natural gas fueled plants, however, do make sense because of the relative affordability of natural gas ($28/MWh) (EIA 3, 212). 23

29 When considering the total 3 year cost plus the cost of natural gas as standby power, WtE still comes in first as the most affordable at -1.2 B$US, with geothermal and hydro in second and third at 556 M$US and 629 M$US. In last place is oil at 4.8 B$US, solar at 3.2 B$US, and wind at 2.5 B$US. The addition of a gas fueled generating unit to provide standby power is important to incorporate into final costs, but this factor did not significantly affect the ranking order of the technologies. Some other important considerations are as follows: To take advantage of solar energy, it is recommended that commercial and residential rooftop space be utilized, especially in Hawaii where land is limited and expensive. A brief rooftop PV feasibility study was conducted as part of this research and found that an estimated 33 acres of rooftops on Oahu are available (between Kahala and the airport) for solar PV installation, which could provide a total of 6 MW of power (Appendix B). Although this would help a bit with land costs, the main issue with solar is its high cost due to its low capacity factor. Expanding WtE not only generates electricity with an alternate source, but it also reduces landfilling, which is a growing problem on Oahu. With three boilers and approximately 9 MW generation, WtE on Oahu is taking advantage of almost all of its municipal waste production. An option is to import trash from outer islands like Kauai and Maui and to burn it on Oahu for power production. Barges often return to Honolulu from outer islands empty. With the expansion of a WtE plant, it is recommended that a sophisticated materials recovery facility (MRF) be ordered to increase the efficiency of the sorting process. It is important to note that if the desired expansion of WtE capacity far exceeds 1 MW, then Oahu and the outer islands may not generate enough trash to fuel the plant. One consideration is to import trash from California, which has banned incineration and has limited landfill space (GTC, 213). This would continue the financial benefits associated with receiving trash, and would continue to supply Oahu s electricity needs. Further research should be conducted to assess the impacts of incineration by WtE plants because, although they burn cleaner than fossil fuel plants, they are not zero emission technologies like solar and wind. 24

30 CONCLUSIONS Deriving 9% of its primary energy resources from oil (9), Hawaii is the most heavily dependent state in the nation on petroleum for its needs such as electricity generation, ground transportation, and commercial aviation. With 75% of Hawaii s electricity production based on fuel oil, the average residential electricity price in Hawaii in the first quarter of 213 was nearly $.35/kWh; over 3% higher than the national average (DBEDT, 213). With growth in population, tourism, and the economy, there has been a significant and growing demand for energy in the commercial, industrial, transportation, and residential sectors. Additionally, with lifestyle improvements and a high standard of living, a growing market for electric vehicles (EVs) and plug in hybrid vehicles (PIHV), the potential rail installation, and the retirement of old oil burning units, there is a growing demand for energy that needs to be met by alternative energy sources. The objective of this research was to address Hawaii s energy dependence on fossil fuels by investigating the cost effectiveness of options for the next 1MW alternative energy power plant for Oahu. Nine different energy sources (coal, oil, natural gas, geothermal, hydroelectric, photovoltaic solar, on-shore wind, waste-to-energy (WtE), and nuclear) were compared and analyzed. Most individual power plant specifications (capacity factor, construction cost, needed acreage, etc.) were retrieved from online corporate power plant profiles and from online periodicals and government energy-related sources. Plant construction costs were equalized 212 dollars using historical Construction Cost Indices (CCI) provided by Engineering News Record (ENR). The U.S. Energy Information Administration (EIA) provided data for national electricity generation pie charts; national historical power plant development charts; and the values necessary to conduct the 3 year power plant comparison analysis (i.e. capacity factors, costs of fuel, MWh generated per unit of fuel used, etc.). The Hawaii Department of Business, Economic Development and Tourism (DBEDT) provided data for local electricity generation pie charts, and for Hawaii energy trends. The EIA, the United States Department of Energy, and the National Renewable Energy Laboratory (NREL) provided information for energy source profiles and national energy trends. The results of this study indicate that WtE is superior (in terms of cost) to any other technology. Because fuel for WtE is municipal solid waste, it is the only option that profits while providing electricity. Ranking 2 nd and 3 rd are geothermal and hydro technologies, respectively, but these resources do not exist on the island of Oahu. Ranking 4 th is natural gas, and although is not a renewable energy source, it is a much more affordable and cleaner fossil fuel option than oil and a reliable baseload provider that can assist intermittent power generation from wind and solar energy sources. Ranking 5 th in affordability is coal, but its use is counter-intuitive to the Hawaii Clean Energy Initiative (HCEI) goals of reducing fossil fuel dependence, especially since coal produces the most pollution of all fossil fuels. Ranking 6 th is nuclear, but the average capacity of nuclear power plants in this study was 2, MW and current installations scale down to 5 MW but not to 1 MW. Additionally, approval for nuclear power generation in Hawaii given its constitutional prohibition is a long and intensive process that will likely take over a decade to accomplish if it is ever pursued. Ranking 7 th and 8 th is wind and solar, respectively. High costs 25

31 Natual Gas set to 1 and scaling the rest Coal Oil Natural Gas Geothermal Hydro Solar Wind, on shore WtE - trash Nuclear for construction and standby energy are associated with their low capacity factors. Ranking 9 th is petroleum largely due to the high price of the fuel. This is unfortunate because oil-fired power plants currently generate the supermajority of Oahu s electricity. In turn this explains the high cost per MWh in Hawaii which is 3% of more above US mainland average. In the long run, fabricating a society and economy that is less dependent on imported energy will benefit future generations. In the short run, it will provide greater security in the case of a natural disaster or war-time complications that could easily discontinue our imported supply of petroleum. Either way, this issue is of critical importance and must be addressed in a timely fashion. FUTURE WORK As can be seen in Fig. 19, this study did not produce the same levelized costs as the EIA for each technology. The main contribution to this discrepancy is data variation as well as Hawaii-specific costs that favor some technologies and penalize others. For example, the big discrepancy in WtE results is that our estimate is Oahu-specific using the actual (high) tipping fee on Oahu, whereas the EIA cost comes from biomass. Hawaii solar and wind estimates are high and part of the reason is the high cost of land per acre in rural Oahu Levelized Cost for Power Production UHM.CEE 3 yr Estimates US Average, EIA.gov Figure 2. Levelized Cost for Power Production: This study vs EIA averages 26

32 REFERENCES 1. American Coal Foundation (25). Timeline of Coal in the United States. Accessed on 4/1/13. ( 2. Arent, D., Barnett, J., Mosey, G., Wise, A. (29). The Potential of Renewable Energy to Reduce the Dependence on the State of Hawaii on Oil. National Renewable Energy Laboratory. 3. Choon, James (212). Hoopili Business Model Not Sustainable for Hawaii. Honolulu Civil Beat. Accessed on 4/1/13. ( 4. Cocke, S. (212). After Fire, Kahuku Wind Farm Fends of Safety Concerns. Honolulu Civil Beat. ( 5. Covanta Energy (213). Covanta Honolulu Resource Recovery Venture Kapolei, Hawaii Accessed on 4/1/13. ( 6. Department of Planning and Permitting City and County of Honolulu (211). Oahu Agriculture: Situation, Outlook and Issues. Accessed on 4/1/13. ( 7. Energy Lens (213). kw and kwh Explained. Accessed on 4/1/13. ( 8. Gasification Technologies Council (GTC) (213). 25 Million Tons/ Year of Municipal Solid Waste. Accessed on 4/1/13. ( 9. Gushwehnta Developments (27). Combined Cycle Power. Accessed on 4/1/13. ( 1. Hawaii Clean Energy Initiative (HCEI) (21). Accessed on 4/1/13. ( 11. Hawaii National Marine Renewable Energy Center (HNMREC) (213). Kaneohe Site. Hawaii Natural Energy Institute at the University of Hawaii. ( 12. Hawaiian Electric Company (HECO 1 ) (213). Clean Energy for Hawaii. Accessed on 4/1/13. ( 6caf2b154da91VgnVCM15311bacRCRD&vgnextfmt=default) 13. Hawaiian Electric Company (HECO 2 ) (21). Power Facts. ( 14. Hawaiian Electric Company (HECO 3 ) (213). Ocean Thermal Energy Conversion (OTEC)? Accessed on 4/1/13. ( 15. Hawaiian Electric Company (HECO 4 ) (213). FAQ: What about nuclear power in Hawaii? Accessed on 4/1/13. ( 16. Hawaiian Electric Company (HECO 5 ) (212). Renewable Energy Basics. Accessed on 4/1/13 ( eeaf2b154da91vgnvcm15311bacrcrd&vgnextfmt=default) 17. Hynes, J. (29). How to Compare Power Generation Choices. Renewable Energy World. Accessed on 4/1/13. ( 27

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34 APPENDIX A. Additional Tables Table A.1. Constants used to Calculate Values for Table 2 and Table 3. Variables (all costs in 212 USD) Coal Oil i Natural Gas Nuclear Solar Wind ii WTE - trash Geothermal Hydro Plant cost per MW (M$US/MW) Land productivity (acre/mw) Value of farm land* (M$US/acre).25 1MW at 1% capacity (Mwh) 876, 876, 876, 876, 876, 876, 876, 876, 876, Capacity Factor** Cost of Fuel ($US)*** $45. $96. $3.5 $56. $. $. -$81. $. $. MWh generated per unit of fuel used:**** Maintenance Cost ($/MWh)***** $4.21 $2.5 $2.5 $11.9 $1.16 $13.44 $14.68 $12.31 $4.21 i Low construction cost ii. Wind turbine lifespan = 12 yrs * 22 acres in Kahuku for sale for 6.5 million USD rounded down to 25K per acre ** EIA (212). "Levelized Cost of New Generatin Resources in the Annual Energy Outlook 213" ( *** lb for coal, 1 ft^3 for natural gas, bbl for oil, lb U3O8 for nuclear, and ton of trash for WTE **** EIA (212). Frequently Asked Questions: How much coal, natural gas, or petroleum is used to generate a kilowatthour of electricity? Accessed on 4/1/13. ( ***** EIA (212). "Levelized Cost of New Generatin Resources in the Annual Energy Outlook 213" ( Coal price: EIA (212). "Coal Explained". Accessed on 4/1/13. ( Petroleum price: EIA (212). "Oil: Crude and Petroleum Products Explained". Accessed on 4/1/13. ( Natural Gas Price: EIA (212). "Natural Gas Explained". Accessed on 4/1/13. ( Nuclear Price: EIA (212). "Nuclear Explained". Accessed on 4/1/13. ( Tipping Fee: Coney, S. (212) "The Economics of Recycling in Hawaii." Hawaii Business Magazine. Accessed on 4/1/12. ( Recycling-in-Hawaii/) 29

35 APPENDIX B. PRELIMINARY ROOFTOP PV ESTIMATES (ACRES) Table B.1. Honolulu Area Rooftop Study for PV Potential ROOFTOP STUDY Downtown Ward, Ala Moana Sand Island Waikiki & Chinatown & Kaka'ako & Nimitz Totals Total roof area (acre) Total solar panel area (m2) 49,731 94,82 34,884 24,768 42,186 Total Capacity (Mw) Land productivity (Mw/acre) n/a Figure B.1. Usable roof space in downtown Honolulu area. Figure B.2. Iwilei Costco utilizing roof space for solar PV. 3