This study presents a novel hybrid solar chimney power plant (HSCPP) design. The HSCPP preserves the typical solar chimney power plant (SCPP), with an additional seawater pool at the base and water sprinklers at the top. This new and novel design configuration offers an opportunity to run the system during the daytime as a traditional SCPP and as a downdraft cooling tower at night. The performance of the HSCPP was analyzed in 16 cities in the Kingdom of Saudi Arabia (KSA) that span the entire geographical area of the country to select the optimal location for installation. The results showed that the highest annual electrical energy production of 676.20 MWh was achieved in the southern city of Shahrurah. However, the lowest annual electrical energy production of 347.59 MWh was found at Wajh, in the west. The highest annual freshwater production was 143,898 tons at Riyadh, in the center. However, the lowest annual freshwater production was 77,868 tons at Muwayh, in the west. Furthermore, the results showed that the proposed HSCPP increased electrical power production by 55% and freshwater production by 20% when compared to traditional SCPP. In addition, an outstanding reduction in CO2 emissions by approximately 56% was associated with such an application of HSCPP. The performance of the HSCPP is very promising, however, the geographical location to install the HSCPP is performance‐critical. Hence, the optimal locations were found to be from the center to the southern part of the KSA.

The classical solar chimney offers passive electricity and water production at a low operating cost. However, the solar chimney suffers from high capital cost and low energy output density per construction area. The high capital investment increases the levelized cost of energy (LCOE), making the design less economically competitive versus other solar technologies. This work presents a new noteworthy solar chimney design for high energy density and maximizing water production. This was achieved by integrating a cooling tower with the solar chimney and optimizing the operating mood. The new design operated day and night as a hybrid solar double-chimney power plant (HSDCPP) for continuous electricity and water production. During the daytime, the HSDCPP operated as a cooling tower and solar chimney, while during the night, it operated as a cooling tower. The annual energy output from the cooling towers and solar chimney (i.e., the HSDCPP) totaled 1,457,423 kWh. The annual energy production from the cooling towers alone was 1,077,134 kWh, while the solar chimney produced 380,289 kWh. The annual energy production of the HSDCPP was ~3.83-fold greater than that of a traditional solar chimney (380,289 kWh). Furthermore, the HSDCPP produced 172,344 tons of fresh water per year, compared with zero tons in a traditional solar chimney. This led to lower overall capital expenditures maximizing energy production and lower LCOE.

The increase in energy demand as the world population grows, as well as the competition in the liquefied natural gas (LNG) market, force producers to work hard on developing cost‐effective production technologies. Upfront nitrogen removal (UNR) before the LNG plant's cold section is considered a promising option to save energy that would otherwise be wasted to cool down a large volume of unused nitrogen in the gas stream. In this study, the use of the lithium cycle (Li‐Cy) as a cost‐effective method for UNR is investigated. The Li‐Cy is compromised of three stages: lithium chemisorption of nitrogen (Chem normalN 2 ${\mathrm{Chem}}_{{{\rm{N}}}_{2}}$), hydrolysis of lithium nitride (HydLi 3 normalN ${\mathrm{Hyd}}_{{\mathrm{Li}}_{3}{\rm{N}}}$), and electrowinning (Elec.‐w) of the final product to precipitate lithium metal for further reuse. The relevant chemistry, applicability, economic, and future challenges of Li‐Cy as a UNR technology from natural gas (NG) were explored and discussed. The main challenges that required further investigation to apply Li‐Cy to large‐scale applications were highlighted for future works. The literature review revealed that Li‐Cy can spontaneously remove nitrogen from NG even at low temperatures and produces ammonia as a valuable hydrogen storage material. The used lithium can be regenerated via HydLi 3 normalN ${\mathrm{Hyd}}_{{\mathrm{Li}}_{3}{\rm{N}}}$ and Elec.‐w and reused again many times. The cost of the Li‐Cy can be compensated by energy savings, the increase in production rate, and by selling the generated ammonia. Calculations showed that selling the produced ammonia from LNG plants with capacity in the range of 1–5 MTPA would not only offset the costs of Li‐Cy but would generate a net profit of $21MM to $103MM, respectively.

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