Storing corn stover in wet, anaerobic conditions is an active management approach to reduce the risk of significant aerobic degradation and catastrophic loss due to fire. An estimated 50% of the corn stover available in the U.S. is too wet at the time of harvest to be stored safely in baled formats and is compatible with wet, anaerobic storage through ensiling. A logistics system based on field-chopping and particle size reduction early in the supply chain removes the dependency on field-drying of corn stover prior to baling, allows for an expanded harvest window, results in diminished size reduction requirements at the biorefinery, and is compatible with ensiling as a storage approach. The unit operations were defined for this chopped logistics system, which included field chopping, bulk transportation to a biorefinery site, on-site preprocessing to meet biorefinery size and ash specifications, industrial-scale storage through ensiling, and delivery of corn stover at a rate of 2,000 tonnes per day for ∼50% of the year. The chopped system was compared to the conventional bale system for 30% moisture (wet basis) corn stover, a likely delivered moisture content for baled corn stover harvested wet. Techno-economic analysis showed that the chopped logistics system is cost competitive, costing only 10% more than the baled logistics system, meanwhile reducing the energy consumption by 48% and greenhouse gas release by 60%. In summary, a chopped logistics system utilizing on-site preprocessing and storage at a biorefinery gate is an economically viable approach to provide a stable source of corn stover for use when dry bales are not available, meanwhile reducing the risk of loss in long-term storage.

Increased electricity production from renewable energy resources coupled with low natural gas prices has caused existing light-water reactors (LWRs) to experience ever-diminishing returns from the electricity market. Via a partnership among Idaho National Laboratory (INL), The National Renewable Energy Laboratory (NREL), Argonne National Laboratory (ANL), Exelon, and Fuel Cell Energy, a technoeconomic analysis of the viability of retrofitting existing pressurized water reactors (PWRs) to produce hydrogen (H2) via high-temperature steam electrolysis (HTSE) has been conducted. Such integration would allow nuclear facilities to expand into additional markets that may be more profitable in the long term.To accommodate such an integration, a detailed analysis of HTSE process operation, requirements, and flexibility was conducted. The technical analysis includes proposed nuclear system control scheme modifications to allow dynamic operation of the HTSE via both thermal and electrical connection to the nuclear plant. High-fidelity Modelica simulations showcase the viability of such control schemes. However, due to limited knowledge of solid oxide fuel cell (SOFC) stack degradation due to thermal gradients, thermal cycling of the HTSE was not included. Therefore, the control schemes proposed are only utilized to re-distribute steam at startup, and only the portion of electricity utilized in the electrolyzers is cycled.From the detailed analysis of the nuclear integration and the HTSE process design, a comprehensive cost estimation was conducted in the APEA and H2A models to elucidate capital and operational costs associated with the production, compression, and distribution of hydrogen from a nuclear facility. Alongside this costing analysis, market analyses were conducted by NREL and ANL on the electric and hydrogen markets, respectively, in the PJM interconnect.Utilizing the electricity data market projections in the PJM interconnect from NREL and hydrogen demand/pricing projections from ANL, a five-variable sweep over component capacities, discount rates, and hydrogen pricing was completed using the stochastic framework RAVEN (Risk Analysis Virtual ENvironment) through its resource dispatch plugin HERON (Heuristic Energy Resource Optimization Network). Each combination of variables was evaluated over a seventeen-year timespan, from 2026-2042 (inclusive), to determine the most economically advantageous solution. Following the five-variable sweep, an optimization was conducted to establish the best sweep point to determine optimal component sizing and setpoints.Results suggest positive gain is achievable at all projected hydrogen market pricing levels and at all discount rates. However, exact component sizing and net returns vary based on these values, and if incorrect sizing is selected, major net losses can occur. The optimal result occurred with set points as follows: high hydrogen prices, the largest possible HTSE unit in the sweep set at 7.47 kg/sec (645.4 tpd), a contractual hydrogen market agreement 7.29 kg/sec (...

Concentration dependent SPS FO water treatment processes energy model. • SPS FO process modeled with and without geothermal energy contributions. • SPS FO found to be economically viable over a wide range of concentrations.A model was developed to estimate the process energy requirements of a switchable polarity solvent forward osmosis (SPS FO) system for water purification from aqueous NaCl feed solution concentrations ranging from 0.5 to 4.0 molal at an operational scale of 480 m 3 /day (feed stream). The model indicates recovering approximately 90% of the water from a feed solution with NaCl concentration similar to seawater using SPS FO would have total equivalent energy requirements between 2.4 and 4.3 kWh per m 3 of purified water product. The process is predicted to be competitive with current costs for disposal/treatment of produced water from oil and gas drilling operations. Once scaled up the SPS FO process may be a thermally driven desalination process that can compete with the cost of seawater reverse osmosis.

Nuclear energy is increasingly being recognized as a valuable low-carbon, low-emissions energy source that can help meet clean energy targets being set by states, commissions, and utilities in the United States. Currently, nuclear power provides about one-fifth of the country's electricity. Nuclear power plants (NPPs) further provide the grid with all-weather season-long baseload capacity that is important to grid reliability and resiliency.An innovative revenue model that has been proposed for U.S. LWRs is to alternatively use the heat and electricity from nuclear reactors to produce indemand industrial products-hydrogen for use in fuel cell electric vehicles (FCEV), cofiring with natural gas (NG), petroleum and biofuel refining, ammonia production, direct-reduced iron (DRI) for steel production, and synthetic fuels (synfuels) and chemicals (synchems) such as methanol, polymers, formic acid, and others-via thermal and electrochemical processes during seasonal and daily periods of low grid-electricity market pricing (overgeneration) in lieu of being curtailed or producing electricity to the grid at a less-than-optimal electricity price. Repurposing NPPs to flexibly produce nonelectric products and clean-energy carriers could help alleviate the economic pressure on NPPs and enable decarbonization of the power sector, as well as the transportation and industrial sectors. Key AssumptionsParameters taken into account in this analysis are grouped as floating variables, which can be optimized (e.g., the size of the HTSE), fixed parameters (e.g., HTSE O&M costs), estimated parameters for which a range is provided (e.g., H2 demand distance), and key results that are derived as part of the analysis (e.g., H2 daily production rate, HTSE overcapacity, and HTSE CAPEX). The price of hydrogen,

This report addresses new market opportunities for nuclear energy at a time when existing light-water reactors (LWRs) are experiencing diminishing revenues in the electricity market. This initial technical/economic assessment indicates LWR hybrid operations can increase the revenue of LWR power-generation stations.A hybrid system provides an offtake for energy produced by an LWR power-generation station when the price offered for committing electricity to the grid is lower than the cost of producing this electricity. A secondary user benefits by purchasing electrical power, steam, or thermal energy directly from the LWR site at a cost that is lower than it can be purchased from the grid at either the electricity transmission-customer level or the electricity distribution-customer level. At a minimum, this requires a tightly coupled connection to the power-generation operations of the nuclear plant. The LWR hybrid plant may then apportion energy between the industrial user and the electricity grid to optimize the revenue of the nuclear plant, depending on specific day-ahead electricity-grid capacity commitments and reserve capacity agreement requirements. For this market arrangement to work, the non-grid user is sold electricity without paying grid service fees (i.e., being considered a house load). This mode of energy sharing may require approval of governing utility commissions, depending on whether the hybrid operations can affect grid supply and pricing, and in consideration of provisions for grid-capacity payments that may apply to a hybrid system.

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This report concludes that there is a cost-effective strategy for seasonal storage of heat that will provide firm, but dispatchable, electrical generating capacity in times when other renewable energy is not available to meet demand. Deployment of the technology appears to require no new technology, but instead combines solar, geothermal, and conventional oil and gas drilling technologies in a novel way. The study basis is the use of sedimentary geologic formations as a medium for thermal energy storage (TES), specifically for heat collected in concentrating solar collectors.

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