Modern Renewable Resources For Alternative Energy Generation

Summary

This article explores existing alternative energy capabilities that the U.S. Department of Defense (DoD) can leverage to ensure technological operability in austere environments, mitigate costs required for long-term installations, and provide clean energy considerations where feasible. It aligns with the government’s existing renewable energy generation and storage critical technology area and can provide researchers, engineers, and technical managers with the expertise and lessons learned from previously researched efforts. Various types of renewable resources, such as bioenergy, wind energy, geothermal energy, solar energy, hydropower, and tidal energy capabilities, are discussed.

Introduction

In a list of critical and emerging technologies published in February 2024 by the National Science and Technology Council’s Fast Track Action Subcommittee on Critical and Emerging Technologies, clean energy generation and storage was highlighted as being potentially significant to U.S. national security [1]. Several subcategories of interest are highlighted as key subfields to describe the scope of clean energy generation and storage. Progression in these subfields will support the target renewable energy generation of the 2022 National Security Strategy [2]. These subcategories include the following [1]:

• Renewable generation,
• Renewable and sustainable, chemistries, fuels, and feedstocks,
• Nuclear energy systems,
• Fusion energy,
• Energy storage,
• Electric and hybrid engines,
• Batteries,
• Grid integration technologies,
• Energy efficiency technologies, and
• Carbon management technologies.

Starting in fiscal year (FY) 2020, $7,343,126,002 have been included in budget justifications to research various renewable energies for research, development, test, and evaluation (RDT&E) budget justification (R2); procurement justifications (P40); unified research and engineering databases (UREDs); DoD grants; Small Business Innovative Research/Small Business Technology Transfer (SBIR/STTR) awards; and federal procurement data system (FPDS) spending (Figure 1) [3]. Most of this funding (total obligated funding since 2020 – $334,661,596) was sponsored by the DoD components ($232,041,495) and the U.S. Department of Energy (DoE) ($85,895,763) (Figure 2) and used to research bioenergy, wind energy, geothermal energy, solar energy, hydropower capabilities, and nuclear energy.

Energy Types

Several types of renewable energy efforts are highlighted. While not an exhaustive list, it should serve as a considerable start to find what information is publicly available on the types of renewable energy research efforts.

Bioenergy Research

“Bioenergy is a form of renewable energy derived from recently living organic materials, known as biomass, which can be used to produce transportation fuels, heat, electricity, and products” [4]. While the research into utilizing bioenergy is focused on generating energy, there are various pathways to generate or increase the efficiency of energy [5–7]. Organizations supporting this research under U.S. Army funding like Enexor BioEnergy use their knowledge in clean energy generation by using biofuels found in organic materials, plastics, and sargassum [5] to increase Army capabilities. Other agencies or organizations augment the research capabilities of their DoD partners. For example, Hedgefog Research Inc. provides a quantum-enabled, nondestructive optical microscopy approach to enable bioenergy-based research [6], allowing a deeper understanding of how to best use plant-based biomaterials as a fuel source.

Similar to Enexor’s organic material research, CF Technologies, Inc. has developed a process to utilize waste greases (previously unusable due to sulfur contaminations in the greases) to create a biofuel pure enough to use in transportation, heating, and marine industries [7]. These forms of bioenergy convert stored energy and transport it to austere environments for use as a fuel source, similar to current fossil fuels. These biofuels can also be stored under specific conditions in long-term facilities, such as military installations, to mitigate fossil fuel reliance and grid load.

Wind Energy

Wind energy “harnesses the power of wind to collect and convert the kinetic energy that wind produces into electricity” [8] and can generate a significant amount of energy from land-based farms and offshore platforms. In a 2022 assessment conducted by the National Renewable Energy Laboratory (NREL), it was estimated that offshore wind energy technology alone could generate three times the electricity consumption of the United States [9]. This identified a potential 1.5 terawatt (TW) of energy generation in modern fixed-bottom wind farm capabilities and another 2.8 TW from floating offshore farms (restricted to areas of the contiguous United States). Yet additional research is being conducted to mitigate the cost and increase the yield from modern designs.

When considering wind energy technology, the structure’s design and conversion capabilities are important in the cost and energy generation of these systems. Partnerships like those between the National Science Foundation (NSF) and RCAM Technologies and XFlow Energy Company [10, 11] and the DoE and Deep Ranch Technology, Inc. [12] are researching ways to promote cheaper or stronger materials and designs used in wind turbines. Although reliant on wind being present and in the proper environments, wind energy could be harnessed to ensure in-the-field priority technologies like medical operations or communications. This type of energy can have a primary or potentially redundant energy source or be used to charge energy storage devices like batteries for continued operations.

Geothermal Energy

Geothermal energy is derived from the heat sources in the earth, such as reservoirs of hot water, or human-made resources found below the earth’s surface [13]. Current uses for geothermal energy include electricity generation since the stable presence of heat can be used to generate steam to power turbines. Geothermal energy can also be used to heat and cool buildings by using the ground as a heat sink to regulate thermal distribution. The largest geothermal power station, the Geysers geothermal plant located in California, can generate several terawatt hours (TWh) as an annual output [14]. Current research efforts seek to increase the potential capabilities of plants like these. Organizations like Nrgtek, Inc. and Tech4Imaging LLC, both funded through the DoE, have been researching potential system benefits for geothermal research [15, 16]. Harnessing geothermal energy could be very convenient for energy storage charging in the field or it could be used for permanent installations to provide a staging area for storage.

Solar Energy

Solar energy, also referred to as electromagnetic radiation energy, harnesses energy emitted by the sun to provide power through various technologies. Solar energy technologies can be broken down into two main types—photovoltaic (PV) and concentrating solar thermal power (CSP). According to the DoE’s Solar Energy Technologies Office, “the amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year” [17], indicating the potential usefulness of harnessing this type of energy. Under these two types of solar harnessing technologies, an estimated 238 TWh/year average was generated from U.S. PVs in 2023 [18], while a concurrent estimated 4.656 TWh/year average was generated across 27 national concentrating solar power project farms in the United States [19].

Additional capabilities are being researched to further the capabilities or mitigate the cost of both types of harnessing capabilities. For PVs, several research contracts are being coordinated between the DoE, the NSF, and the DoD, coordinating with industry partners to better utilize the peak PV energy generation times, budget PV cell real estate or viable staging locations, and mitigate costs of current systems [20–24].

In one research effort, the U.S. Air Force partnered with Digital Solid State Propulsion, Inc. to research how to mitigate costs and the potential load on the electric grid. By studying energy usage on Air Force housing installations, Digital Solid State Propulsion found that the energy generated during peak hours for PV activity was being wasted and instead could be used to heat water systems through a hot water controller. This would not only mitigate the cost of heating water during peak-cost hours, but the heated water could act as a thermal battery for later use or potential thermal energy conversion [20]. In addition to mitigating the costs, it would be challenging to intentionally deny an opposing force access to solar harvesting. This would provide DoD forces a potentially reliable alternative energy option to pair with energy storage capabilities in forward-operating, warfighting environments.

As an alternative to the DoD research, the NSF is funding efforts with industry partners to better utilize zones not fully optimized for PV platforms. Through Taka Solar Corp., a study is being performed to determine if PV cells or island platforms could be developed to harness solar energy that falls over oceanic environments [21]. Bodies of water within the United States could possibly generate over 300 GW with current technologies. Concurrently, NSF is partnered with Portable Solar Inc. to provide a solution for residential supporters of PV platforms, enabling more widespread access to renewable energy to the already established infrastructure [22]. As these systems become more widespread, demands on the electric grid will lessen.

The DoE is also supporting active PV research efforts. Similar to the NSF’s partnerships, one effort supported by the DoE is a symbiotic usage of agricultural settings [23]. In a partnership with VesprSolar, Inc., research is being completed to allow the agricultural sector to have “agricultural photovoltaics.” This effort colocates solar tracking cells with various agricultural products, allowing better usage of natural biological processes and economic relief to modern agricultural professionals as they contribute to local electrical grids while mitigating their own electrical demand.

In a second DoE-funded effort, Nanosonic Inc. is developing a production capability for low-cost, perovskite cells with resilience to environmental degradation [24]. With the current power conversation efficiency of perovskite solar cells and a goal to reduce production costs by roughly 90%, Nanosonic is looking to integrate these cells in many everyday commercial applications. This includes national electrical grid contributions, local power arrays, solar lamps, parking meters, emergency telephones, trash compactors, temporary traffic signs, charging stations, and remote guard posts and signals and replacing electric lines for remote locations.

A third effort funded by the DoE—focusing on the concentrated solar-thermal power generation—is testing new heat exchangers to mitigate costs and technology requirements for using supercritical carbon dioxide in CSP operations [25]. This funding will allow testing of various alloys for the heat exchangers in the CSP platforms and could enable technological developments for lower temperatures and pressure applications for next-generation designs.

Hydropower/Tidal Energy Platforms

A hydropower platform, also referred to as hydroelectric power, is one of the most traditional forms of renewable energy that “uses the natural flow of moving water to generate electricity” [26]. In an article published in 2023 by the U.S. Energy Information Administration, hydroelectric power accounted for 28.7% of the total produced renewable energy domestically in calendar year 2022 [27]. While being one of the most established forms of renewable energy to date, hydroelectric power still relies on climate and weather, which can prove challenging to regulate in less-robust environments. In a study from Intersphere Inc. and funded by the NSF, research is being conducted to mitigate the weather and climate risks associated with hydropower applications [28] by training machine-learning (ML) models and integrating those models into current geoscience practices. These models can generate powerful assistance platforms for not just hydropower considerations but for closely related research efforts like wind energy, geothermal energy, and tidal energy. By leveraging this research, the DoD could use hydropower capabilities and the developing models to preemptively parse the most reliable waterways for energy generation, while leaving minor footprints in austere environments, and provide allied forces key details to these potential capabilities if these waterways fall within their domains.

Tidal Energy

Tidal energy, like hydroelectric energy, can be a harvestable form of renewable energy by converting the kinetic energy from water whose “natural rise and fall of tides caused by the gravitational interaction between Earth, the sun, and the moon” can be fed through turbines, converting the kinetic energy into electric energy [29]. In support of utilizing this type of renewable energy, the DoE has partnered with two organizations to further tidal energy capabilities. In two studies, the Ocean Renewable Power Company, Inc. is developing a scalable application of marine renewable energy to generate a microgrid in False Pass, Alaska [30] and the Cook Inlet of Alaska [31]. Both efforts serve to study the reliability and capabilities of tidal energy in a similar geography while highlighting challenges that should be considered for follow-on studies.

Another effort funded through the DoE engages with industry partner Industrial Consulting Inc. to provide a pathway for marine spatial planning specialists to have informed and collaborative planning capabilities that do not detrimentally impact the sociocultural, ecological, environmental, and economic barriers which could limit deployment [32]. With many permanent DoD installations dotting the coastlines, tidal technologies could find a wide breadth of testing environments, with domestic, long-term energy considerations as the primary focus. In addition to civilian application, DoD-specific testing could focus on ways to leverage tidal technologies for military operations in nonlandlocked locations that allow an alternative form of energy storage when converted properly.

Conclusions

While renewable energy efforts are wide in scope and effect and some funding is available, there are still many gaps in research and barriers for entry across the different renewable energy capabilities [33]. Solar energy platforms can be further refined for more efficient energy generation or more ubiquitous zones [19–25]. Hydropower platforms are learning from ML applications via modern research capabilities [28], identifying some additional challenges where innovative research efforts can be applied. Similarly, tidal energy and hydroelectric capabilities are negatively affected by climate and geological limitations, and uncertainties in ecological impacts could result in detrimental conditions going forward if not properly developed [32].

However, as research efforts continue, researchers can create more efficient methods to harness alternative sources of energy. These efficiencies create untapped potential in contributing positively to current large- and small-scale electrical grids. When seen from a combined standpoint, these forms of renewable energies are ubiquitous, allowing energy capture to occur almost anywhere globally. As the DoD leverages these technological advancements, renewable energies could provide a solution to generate and store energy and distribute power to small, expeditionary teams and larger, stationary, permanent installations while reducing the environmental impact and long logistics tails associated with fossil fuel use.

References

1. Fast Track Action Subcommittee on Critical and Emerging Technologies of the National Science and Technology Council. “Critical and Emerging Technologies List Update,” February 2024.
2. The White House. “National Security Strategy,” October 2022.
3. DTIC. “Renewable Energy.” Advanced Search Terms: FY2020 – FY2027, Types, RDT&E Budget Justification, Procurement Budget Justification, Research in Progress, and Completed Research/Technical Report, [Data Set], https://www.dtic.mil/horizons/, accessed on 29 June 2024.
4. Office of Energy Efficiency & Renewable Energy. “Bioenergy Basics.” https://www.energy.gov/eere/bioenergy/bioenergy-basics, accessed on 29 June 2024.
5. Enexor. “Enexor BioEnergy.” https://www.enexor.com/, accessed on 29 June 2024.
6. Choi, J. “Quantum Enabled Non-destructive Optical Microscopy (QENOM).” https://www.sbir.gov/sbirsearch/detail/2232881, accessed on 29 June 2024.
7. Moses, J. “Targeted Removal of Sulfur from Brown Grease Feedstocks.” https://www.sbir.gov/sbirsearch/detail/1835285, accessed on 29 June 2024.
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Biography

Daniel Fleming is a research inquiry analyst for the Homeland Defense and Security Information Analysis Center. He has six years of military experience and four years of experience in a clinical pharmaceutical setting. As a Marine Corps combat engineer, he used his skillsets both domestically and internationally. During his time in the pharmaceutical industry, he served as a lead analytical technician, executing established methods; assisting in developing site-specific methods and programs; performing registration, storage, and testing; and ensuring accurate reporting of tests on thousands of drug and vehicle suspensions. He also executed on-site training plans at several stages to ensure modern compliance with federal regulations.