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Affordable synthetic ammonia (NH₃) enables the production of nearly half of the food we eat and is emerging as a renewable energy carrier. Sodium‐promoted chemical looping NH₃synthesis at atmospheric pressure using manganese (Mn) is here demonstrated. The looping process may be advantageous when inexpensive renewable hydrogen from electrolysis is available. Avoiding the high pressure of the Haber‐Bosch process by chemical looping using earth‐abundant materials may reduce capital cost, facilitate intermittent operation, and allow operation in geographic areas where infrastructure is less sophisticated. At this early stage, the data suggest that 0.28 m³of a 50 % porosity solid Mn bed may suffice to produce 100 kg NH₃per day by chemical looping, with abundant opportunities for improvement.

 

There has been increasing interest in low-carbon technologies to reduce climate change impacts. However, careful assessments of their implications for the vibrancy of local economies are rare. This paper employs techno-economic analysis to assess the technical and economic feasibility of investment in one such technology: local green ammonia production and its contribution to the economic viability of the local economy. The analysis considers price projection and debt financing options, and alternative energy-to-ammonia technologies. The approach is broadly applicable and is illustrated here using a case study in which 248,188 MT of traditional ammonia are replaced with local wind energy-produced ammonia for farmers in Southwest Kansas, United States. Economic feasibility is defined as the ability to accrue enough discounted cash flow at the end of the turbines’ 25-year lifespan to enable their replacement. The alternative technologies are the traditional Haber-Bosch and the emerging solid oxide electrolysis cell (SOEC). The total plant capital cost amounted to $781.72 million while the plant operating costs were set at $100/MT with the energy supplied by the project’s energy system. The results show how economic feasibility sensitivity to technology and financing options are evaluated and communicated to scientists, policymakers, and farmers. The 6.5 MWh/MT wind energy-to-ammonia SOEC technology presented the best economic results under all price projections. The community’s investment yielded the highest return when debt was used to finance 50% of the capital investment. Returns exceeded the average annual S&P return of about 7% from 1957 to 2021. The work shows how consideration of technology efficiencies and creative financing strategies can contribute to the economic welfare of farmers and their communities even as they contributed to reducing crop production’s carbon footprint. 

The purpose of this work is to quantitatively compare the energy cost of design alternatives for a process to produce ammonia (NH 3 ) from air, water, and renewable electricity. It is assumed that a Haber–Bosch (H–B) synthesis loop is available to produce 1000 metric tons (tonnes) of renewable NH 3 per day. The overall energy costs per tonne of NH 3 will then be estimated at U.S.$195, 197, 158, and 179 per tonne of NH 3 when H 2 is supplied by (i) natural gas reforming (reference), (ii) liquid phase electrolysis, (iii) solid oxide electrolysis (SOE) of water only, and (iv) simultaneous SOE of water and air. A renewable electricity price of U.S.$0.02 per kWh electric , and U.S.$6 per 10 6 BTU for natural gas is assumed. SOE provides some energy cost advantage but incurs the inherent risk of an emerging process. The last consideration is replacement of the H–B loop with atmospheric pressure chemical looping for ammonia synthesis (CLAS) combined with SOE for water electrolysis, and separately oxygen removal from air to provide N 2 , with energy costs of U.S.$153 per tonne of NH 3 . Overall, the most significant findings are (i) the energy costs are not substantially different for the alternatives investigated here and (ii) the direct SOE of a mixture of steam and air, followed by a H.–B. synthesis loop, or SOE to provide H 2 and N 2 separately, followed by CLAS may be attractive for small scale production, modular systems, remote locations, or stranded electricity resources with the primary motivation being process simplification rather than significantly lower energy cost. 

This paper proposes a home energy management system (HEMS) while considering the residential occupant’s clothing integrated thermal comfort and electrical vehicles (EV) state-of-charge (SOC) concern. An adaptive dynamic program- ming (ADP) based HEMS model is proposed to optimally determine the setpoints of heating, ventilation, air conditioning (HVAC), the donning/doffing decisions for the clothing conditions and charging/discharging of EV while taking into account the uncertainties in outside temperature and EV arrival SOC. We use model predictive control (MPC) to simulate a multi-day energy management of a residential house equipped with the proposed HEMS. The proposed HEMS is compared with a baseline case without the HEMS. The simulation results show that a 47.5% of energy cost saving can be achieved by the proposed HEMS while maintaining satisfactory occupant thermal comfort and negligible EV SOC concerns. 

Most large-scale ammonia production typically relies on natural gas or coal, which causes harmful carbon pollution to enter the atmosphere. The viability of a small-scale “green” ammonia plant is investigated where renewable electricity is used to provide hydrogen and nitrogen via electrolysis and air liquefaction, respectively, to a Haber-Bosch system to synthesize ammonia. A green ammonia plant can serve as a demandresponsive load to the electricity distribution system and provide long-term energy storage through chemical energy storage in ammonia. A coordinated operational model of an electricity distribution system and an electricity-run ammonia plant is proposed in this paper. Case studies are performed on a modified PG&E 69-node electricity distribution system coupled with a small-scale ammonia plant. Results indicate the ammonia plant can adequately serve as a demand response resource and positively impact the distribution locational marginal price (DLMP). 

Rooftop photovoltaics (PV) and electrical vehicles (EV) have become more economically viable to residential customers. Most existing home energy management systems (HEMS) only focus on the residential occupants’ thermal comfort in terms of indoor temperature and humidity while neglecting their other behaviors or concerns. This paper aims to integrate residential PV and EVs into the HEMS in an occupant-centric manner while taking into account the occupants’ thermal comfort, clothing behaviors, and concerns on the state-of-charge (SOC) of EVs. A stochastic adaptive dynamic programming (ADP) model was proposed to optimally determine the setpoints of heating, ventilation, air conditioning (HVAC), occupant’s clothing decisions, and the EV’s charge/discharge schedule while considering uncertainties in the outside temperature, PV generation, and EV’s arrival SOC. The nonlinear and nonconvex thermal comfort model, EV SOC concern model, and clothing behavior model were holistically embedded in the ADP-HEMS model. A model predictive control framework was further proposed to simulate a residential house under the time of use tariff, such that it continually updates with optimal appliance schedules decisions passed to the house model. Cosimulations were carried out to compare the proposed HEMS with a baseline model that represents the current operational practice. The result shows that the proposed HEMS can reduce the energy cost by 68.5% while retaining the most comfortable thermal level and negligible EV SOC concerns considering the occupant’s behaviors.