The Daniel Guggenheim School of Aerospace Engineering at Georgia Tech

Novel Energy Resource Extraction for Utilization on Shore

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Executive Summary

The U.S. Navy currently relies heavily on fossil fuels to meet its energy needs. The NEREUS project was implemented at the request of the Office of Naval Research (ONR) to study ways in which the Navy can reduce its dependence on fossil fuels and make progress towards the Navy’s aggressive energy reduction goals. These goals state that half the Navy’s energy usage must be obtained from an alternative source by the year 2020. As a part of this overall goal, the Navy desires 50% of its shore installations be “net-zero.” In light of these goals, the NEREUS team narrowed the scope of the open-ended problem statement in order to most effectively meet these goals. The NEREUS project studied ways in which renewable energies can be utilized on naval bases focusing on tradeoffs between different technologies and base requirements. A preference-driven tradeoff tool, ATHENA (Automated Tradeoff for Holistic Energy Needs Analysis), was created for use in strategic space planning and technological prioritization. ATHENA rapidly estimates cost and amount of energy harvested from alternative technologies on Navy bases. A wide variety of technological mixes are examined in order to determine which mix is the “best” for given user inputs of area and other preferences such as cost. The method behind ATHENA is generic so that it can be applied to any alternative energy technology and can compare many different technologies at one time. This tool was used to perform case studies that analyzed the energy needs of two naval bases—Guam and Coronado. Results from these case studies indicate that at bases with ample area available to use can likely achieve their energy needs; however, the cost required to install and maintain the large amounts of technologies needed can overshadow the benefits of installing these technologies. For bases with limited amounts of space available, only limited amounts of energy can be produced; however, projects in these locations can often “pay for themselves” by producing enough energy over their lifetimes to recoup the cost of acquisition and installation.

Team Members

Michael Patterson
Program Manager

Dr. Santiago Balestrini-Robinson
Technical Advisor

Andrew Flett
Chief Engineer

Jeff Naro
Technology Portfolio Researcher

Sang Min Yim
Framework Development Lead

Background

The U.S. Navy under Secretary of the Navy (SECNAV) Ray Mabus has set very aggressive energy reduction goals. These goals include: Energy Efficient Acquisition, Sail the “Great Green Fleet,” Reduce Non-Tactical Petroleum Use, Increase Alternative Energy Ashore, and Increase Alternative Energy Use DON-Wide (from Energy Program for Security and Independence, Jan 2011). These goals all focus on decreasing the Navy’s dependence on fossil fuels including foreign oil sources. The overall goal for the department as a whole is to generate 50% of its needed energy from alternative sources by 2020. SECNAV Mabus sees energy reform as “a strategic imperative” for the Navy and has stated that it is one of the three areas where he has “focused and will continue to focus [his] attention during [his] tenure as Secretary of the Navy.” In order to determine how the Navy can achieve these goals, the energy usage of the Navy must first be understood.

As of 2009, the U.S. Navy obtained approximately 57% of its energy from petroleum, 26% from electricity and natural gas, 16% from nuclear, and 1% from renewable sources. This means that only 17% of the Navy’s energy usage is from an “alternative” source (nuclear and renewables). In order to achieve the goal of 50% energy reduction as a whole, the Navy must reduce its petroleum usage. Current plans to achieve this goal are focused on using bio fuels. Furthermore to achieve its goals of having 50% of its shore installations be “net-zero” electricity must also be produced from alternative sources. While the breakdown of where the Navy produces its electricity was not found, the overall electricity production of the United States was studied. It was found that over 40% of the U.S.’s electricity was produced from coal and over 20% from natural gas. It was assumed that the Navy obtained its electricity from the same sources as the U.S. in general, which means that over 60% of electricity production comes from fossil fuels. In order to meet Navy goals, current means of electricity production and current petroleum use must both be modified to use alternative energy technologies.

Additional motivation for reducing fossil fuel use comes from their negative environmental impacts (both in mining and using) and limited supplies. It is a well known fact that the world has a limited supply of fossil fuels. While there are many projections about when the various supplies of fossil fuels will be completely depleted, it is accepted that eventually they will be depleted. Additionally, harvesting these resources from the earth can cause many negative environmental and health effects. Coal mining in particular can be particularly dangerous and contributes negatively to the health of people living near major coal mining operations.

In determining a direction for the project, several options that would aid the Navy in meeting its energy goals were considered. In selecting a direction, the team considered whether an option could meet the goals, if the option was near-term enough to be implemented on a large scale by 2020, the team’s skill set, and whether there was a clear “first step” option that should be considered before other options were considered. The team considered designing a new “green” ship, overhauling existing ships to run completely from alternative energy technologies, retrofitting existing ships with alternative energy technologies to power only the hotel loads (non-propulsive power needs), implementing alternative energy technologies on a network of buoys, and outfitting Naval bases with alternative energy technologies. After considering each of these options, it was determined that outfitting bases with alternative energy technologies was the clear “first step.” Implementing technologies on shore will allow the effects of a marine environment on the technologies to be studied, ships to use alternative energy technologies for power when in port, and potentially lead to 43% of the Navy’s energy usage coming from alternative energy technologies (the current 17% plus additional 26% of Naval energy usage that comes from shore). Additionally lessons learned in the project for the Navy could directly be applied to other civil applications as well, benefiting the entire United States.

Approach and Analysis

To conduct our analysis a tool with graphical front end was created in Excel. This tool was capable of running several types of analysis based on internal databases and user input. These analyses utilized a Design of Experiments (DoE) and utilized a Multi-Attribute Decision Making (MADM) technique. The results of these analyses were displayed in both graphical and tabular form. A database of environmental data for selected naval bases was created that including solar radiation, wind speed, wave height and wave period. The data was taken from nearest location in the National Solar Radiation Database and the National Data Buoy Center. The data was processed to create an hour by hour data set for each month of the year to represent an ‘average’ day for that month. Two additional hour by hour data sets were created for each month to represent ‘high’ and ‘low’ months. The ‘low’ data set was designed so to represent data that 90% of the historical data would equal or exceed. The ‘high’ data set was designed to represent data that 10% of the historical data would equal or exceed.

A second database was created that contained the technical characteristics for a variety of alternative energy technologies including fixed and tracking solar panels, wind turbines and wave power devices. This database was created from manufacturers’ information and publicly available data. Since hourly energy usage data for naval bases is not available two energy use profiles were created from data taken from the total energy usage in the United States on the assumption that naval bases were large enough and had large enough energy usage to mimic the overall energy usage of the country. The profile showed the monthly variation in average daily energy usage compared to the yearly daily average energy usage. The second profile showed the variation by hour of energy usage compared to the daily average hourly energy usage. The second profile can also be altered if the user wishes to enter a custom hourly energy usage profile

To conduct an analysis a base location was selected and the available amounts of area for the base entered. The areas to be entered were general land and sea area that could be used for any type of technology and areas to be dedicated to a specific type of technology such as fixed solar or wind. The energy need of the base would also be entered as either the yearly daily average energy usage or as a series of monthly daily average energy usage figures. If the yearly daily average figure was entered the profile showing the monthly variation in average daily energy usage created above would be used to create monthly figures. The second energy profile would then be used to create an hourly energy usage figure for each month based on the monthly daily average energy usage figure. Remaining inputs include the retail cost of electricity, the price paid for electricity sold to the grid and the number of storage units to be used. The user can also set preferences for area, lifespan, TRL, efficiency, cost, energy magnitude and energy reliability. Area, lifespan, TRL, efficiency and cost are then used to choose one of each type of technology to be used in the analysis.

For the main analysis a Design of Experiments is run in which the general areas are partitioned between the relevant technologies in 5% increments and all possible combinations are then taken. These areas were then added to the areas reserved for each specific type of technology. For each combination two analyses were run. In both the energy generated from the selected environmental data set (average, low or high) was calculated for each hour of each ‘average’ day for each month and compared to the amount of energy needed by the base. One analysis sold all excess energy back to the grid while the second analysis stored excess energy and used it later to meet any need not met by the energy generated by the alternative technologies.

The cost, energy magnitude and energy reliability preferences were then used in a MADM (TOPSIS) to choose the two ‘ best’ combination of technologies, one with energy storage and one with excess energy sold to the grid. Detailed data on the chosen combinations including start up cost, annual cost and payback time are displayed.

The tool also includes a macro to run the DoE above with an initial cost limit. This used the same inputs as the regular analysis but would adjust the area available for all of the technologies until the chosen combinations had an initial cost lower than the chosen limit. The results of this analysis were then displayed along with the analysis performed without an initial cost limit.

To test the accuracy of the tools we duplicated an existing alternative energy installation and compared the results. For this a large solar panel array installed over a parking area at Naval Bases Coronado was modeled. The exact area and solar panel model used were input. The energy produced and costs estimated by the tool were within 5% of the actual figures for the solar panel array.

Two bases, Guam and Coronado, were chosen for our project. Guam was chosen because it had large amounts of land for installing alternative energy technologies and abundant available solar, wind and wave energy. Coronado was chosen because it has good energy availability and is representative of most large urban naval bases. The amount of land available for alternative energy use was estimate from published reports on the bases and analysis of publicly available satellite photo. The energy needs for each base were taken from published.

Conclusions

Upon completion of the project, it was found that alternate energy systems can successfully be employed in some areas. Guam was a good example of this. With its relatively small energy needs, as well as its large available area, the naval base could supplement a large portion of its power from alternative sources. However, power from a gas generator was required to meet all of the energy needs. On the other hand, alternate energy systems were less successful in highly congested areas, such as Coronado. Coronado has plenty of energy availability, but its extreme space constraints limit its ability to harvest the energy. In Coronado’s case, the alternative technologies can be used to supplement individual buildings but would be unable to be implemented successfully over the entire grid.

It was also found that currently, solar and wind technologies are the only viable alternate energy systems for harvesting energy given the time restrictions. Both have been well researched and the cost to acquire and maintain such technologies is reasonable. Solar heating technologies are also viable but were not the focus of this project. Other energy systems, such as wave and geothermal technologies, were found to be far too expensive to currently be employed. For the Navy to meet its energy goals by 2015, these technologies are too costly and immature to be useful. In the future, wave technologies could be promising but they require a lot more research to become efficient and cost effective. Geothermal energy is expensive and specific locations are required to harvest large amounts of energy. Unfortunately, many of these locations are not in the vicinity of naval bases. Other options for reducing the Navy’s dependence on fossil fuels were explored and found to be impractical given the timeline in which the Navy expects results. Implementing new technologies on current ships or creating new ships is far too costly and would require vast amounts of time. In order to satisfy the Navy’s goals by 2015, any options regarding the ships would take too long. Many of the changes to ships would require overhauls or engine replacements. This could be done for a single ship in the time allotted, but would not be successful for the entire fleet. Implementing alternative energy technologies onto ships was deemed impractical because it would limit the ship’s battle effectiveness and endanger the lives of sailors. All of these options are in the early conceptual stages and cannot be implemented in such a short period of time.

In conclusion, using alternative energy harvesting technologies on the Navy’s land holdings was found to be the most effective way to reduce the Navy’s use of fossil fuels by 2015. While the goal cannot quite be met, large steps in the right direction can be made. Implementing alternative technologies on a grid was found to be effective on bases with large amounts of open area and relatively small electrical loads. For bases with larger electrical loads and less available space, addressing energy needs on a per building basis was found to be most effective. While power from gas generators is still required, a sizable portion can be supplemented with alternative technologies if the Navy is willing to spend the money. Depending on the energy availability, many of the technologies can pay for themselves between 15 and 30 years. Implementing these technologies is costly; however it can be a viable way to decrease the Navy’s dependence on foreign oil. With careful planning and use of the methodology used for this study, the Navy can make large strides toward its energy goals.