Given the dire consequences of climate change and the war in Ukraine, decarbonization of electrical power systems around the world must be accomplished, while avoiding recurring blackouts. A good understanding of performance and reliability of different power sources underpins this endeavor. As an energy transition involves different societal sectors, we must adopt a simple and efficient way of communicating the transition’s key indicators. Capacity factor (CF) is a direct measure of the efficacy of a power generation system and of the costs of power produced. Since the year 2000, the explosive expansion of solar PV and wind power made their CFs more reliable. Knowing the long-time average CFs of different electricity sources allows one to calculate directly the nominal capacity required to replace the current fossil fuel mix for electricity generation or expansion to meet future demand. CFs are straightforwardly calculated, but they are rooted in real performance, not in modeling or wishful thinking. Based on the current average CFs, replacing 1 W of fossil electricity generation capacity requires installation of 4 W solar PV or 2 W of wind power. An expansion of the current energy mix requires installing 8.8 W of solar PV or 4.3 W of wind power.

As global temperatures warm and populations and incomes rise, the demand for cooling will soar, creating a positive feedback loop between global warming and electricity-related carbon dioxide (CO₂) emissions. This study explores the relationship between temperature, electricity, air conditioning (AC) and CO₂ emissions, and the sustainability of cooling in the Kingdom of Saudi Arabia. With the highest share of AC in household electricity consumption in the world and its already very hot summers warming by 3 °C in many areas over the last 40 years, Saudi Arabia provides an important case study of how the cooling challenge can be managed. Data from the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5) is used to illustrate local warming trends (1979–2018) and show the relationship between temperature and power generation within a typical year using hourly data (2011–2015). Using annual data (2010–2018), we then show that since 2016 the rapid growth in the Kingdom’s electricity demand for AC and its associated CO₂ emissions have plateaued. This suggests energy efficiency measures, higher electricity prices and a shift from the use of oil towards gas in the power sector are having a positive effect on energy sustainability. We identify key policies and technologies that will be important for the sustainable use of cooling in Saudi Arabia and beyond.

Ultra-sensitive solid-state magnetic sensors are in strong demand in many applications where currently available sensors are inadequate. We have used high performance magnetic tunneling junction (MTJ) sensors and pushed the magnetic sensing limit to a high level. We have incorporated double-staged magnetic flux concentrators, one on the MTJ chip level and the other on a more macroscopic level, to amplify the external field of interest. With this approach and undergoing a process of optimization on the flux concentrators, we have increased the sensitivity of the MTJ sensor by a large factor of 517 to 775.4%/Oe in terms of magnetoresistance response. The coercivity of the sensor is only 0.12 Oe. We have achieved a detectable field limit of $30\hspace{0.17em}\text{pT}/\sqrt{\text{Hz}}$ at 10 kHz. We have presented the noise spectrum and the sensitivity spectrum up to a maximum frequency of 100 kHz.

Saudi Arabia is one of the most arid countries in the world. Thus, freshwater availability and consumption are of crucial importance for the fast-growing population subjected to an escalating heat stress from climate change. We provide an overarching view of water resources in Saudi Arabia, in terms of supply, demand, vulnerabilities, and the associated implications on food supply and security. To estimate the effects of climate change on natural water supply, we use ERA5 for the reliable and complete statistics of the long term-precipitation (1950-2021) trends across the Kingdom’s territory. ERA5 is the latest generation of the reanalysis of global climate from the European Centre for Medium-Range Weather Forecasts. The average annual precipitation is about 50 mm/year and does not satisfy the freshwater needs of the country. Energy-intensive desalination, driven by fossil fuels, meets two thirds of municipal freshwater requirements, while non-renewable “fossil” groundwater addresses most of agricultural consumption needs. Total freshwater use has decreased in recent years due to a significant reduction of water use by agricultural sector. Nevertheless, this sector still accounts for 67% of the total freshwater consumption and provides a third of the country’s food supply. To understand efficiency of freshwater use in the agricultural sector, we have developed a novel methodology that allowed us to estimate the country-scale water consumption associated with crop production. Results indicate that water requirements for crop cultivation in Saudi Arabia are up to three times the global average. Date and cereal production consumes almost two thirds of the total freshwater supply, while mass production is dominated by forage crops.

We have analyzed the long-term temperature trends and extreme temperature events in Saudi Arabia between 1979 and 2019. Our study relies on the high resolution, consistent and complete ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF). We evaluated linear trends in several climate descriptors, including temperature, dewpoint temperature, thermal comfort and extreme event indices. Previous works on this topic used data from weather station observations over limited time intervals and did not include temperature data for recent years. The years 2010-2019 have been the warmest decade ever observed by instrumental temperature monitoring and comprise the eight warmest years on record. Therefore the earlier results may be incomplete and their results no longer relevant. Our findings indicate that over the past four decades, Saudi Arabia has warmed up at a rate that is 50% higher than the rest of land mass in the Northern Hemisphere. Moreover, moisture content of the air has significantly increased in the region. The increases of temperature and humidity have resulted in the soaring of dew point temperature and thermal discomfort across the country. These increases are more substantial during summers, which are already very hot compared to winters. Such changes may be dangerous to people over vast areas of the country. If the current trend persists into the future, human survival in the region will be impossible without continuous access to air conditioning.