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From the end of 2013 to the end of 2015, Brazil faced serious challenges to supply its demand for electricity due to a prolonged drought in the Southeast and Northeast regions with the consequent loss of hydroelectric generation. This paper presents an historical analysis of major world energy crises from 1988 to 2015 and in Brazil from 1924 to 2015. Analysing the natural river flow of key Brazilian dams from 1931 until 2017, this paper suggests that hydropower generation in Brazil has a 10–15 years cyclical pattern of hydropower generation. The periods of drought in this cyclical pattern usually coincides with energy crises due to the reduction in hydropower generation. It was found that the drought in 2015 had an impact of 110 TWh in hydropower generation, from which 25 TWh are due to head loss and 70 TWh are from lack of stored hydropower in July of 2014. In addition, 48 TWh were not generated due to delays in the construction of new power plants. Other causes of the Brazilian energy crisis of 2015 are presented and the overall electricity generation impact of these causes are compared. In addition, this paper presents the impacts on the energy, water and food supply sectors in Brazil, and the strategies employed to reduce the impact of the crises. With the intention of preventing future energy crises, the paper then shows the potential alternatives to improve electricity supply security in Brazil, particularly in terms of diversifying and widening the share of renewable sources and increasing the energy storage potential of the country. [ABSTRACT FROM AUTHOR]

In order to maintain greater control over the country's water resources and reduce the vulnerability of the Brazilian electricity sector, this paper presents a review of the Seasonal-Pumped-Storage (SPS) potential in Brazil, its benefits and the different ways in which SPS can be integrated with hydroelectric dams in cascade downstream. In addition to increasing the Brazilian energy storage potential, SPS has the potential to: regulate river flows allowing the control of hydropower generation; reduce the spillage and increase power generation in the hydroelectric dams in cascade; turn the construction of new dams more viable where there is no suitable geology for the construction of conventional storage reservoirs; control floods when the geology does not permit the construction of storage reservoirs; decrease the evaporation of accumulation reservoirs; store the electricity generated from intermittent renewable sources; store energy for peak generation; reduce transmission bottlenecks; decrease the cost of electricity transmission from hydroelectric plants in the Amazon; decentralize the energy storage capacity in Brazil to increase energy security and to reduce the risk of electricity rationing. [ABSTRACT FROM AUTHOR]

Before the COVID pandemic, oil and gas companies invested only a small fraction of their capital on sustainable energy technologies. With the substantial improvement in the performance of batteries and their rapid cost reduction, the oil and gas industry could potentially lose a large share of their market in the transport sector. A similar shift in energy sources is happening with the surge in renewable energy sources to supply electricity, heating and cooling. In an ever more sustainable future, the need for an oil and gas industry could reduce significantly. This paper reviews the possible paths that an oil and gas company could follow to become a sustainable development corporation and continue to be relevant in the future. This paper aims to describe alternative sustainable pathways such as the extraction of natural hydrogen, a hydrogen economy, offshore wind power, deep sea mining, biorefineries, seawater air-conditioning, geothermal and geoengineering. This paper also proposes the use of electrolysis ships for the flexible production of green hydrogen and showed that its investment cost can be three times smaller than in fixed electrolysis plants. The oil and gas industry has substantial intellectual, financial capital and geopolitical influence that would not be lost during a shift to a more sustainable world. Indeed, these assets should be used to facilitate the transition to a more sustainable future. • Hydrogen is a good alternative for sustainable development in O&G companies. • Natural hydrogen is a good alternative to the upstream O&G companies. • Benefits of electrolysis ships to produce green hydrogen. • Case study to produce green hydrogen in Brazil. [ABSTRACT FROM AUTHOR]

The energy sector is undergoing substantial transition with the integration of variable renewable energy sources, such as wind and solar energy. These sources come with hourly, daily, seasonal and yearly variations; raising the need for short and long-term energy storage technologies to guarantee the smooth and secure supply of electricity. This paper critically reviews the existing types of pumped-hydro storage plants, highlighting the advantages and disadvantages of each configuration. We propose some innovative arrangements for pumped-hydro storage, which increases the possibility to find suitable locations for building large-scale reservoirs for long-term energy and water storage. Some of the proposed arrangements are compared in a case study for the upper Zambezi water basin, which has considerable water storage limitations due to its flat topography and arid climate. Results demonstrate that the proposed combined short and long-term cycles pumped-storage arrangement could be a viable solution for energy storage and reduce the cost for water storage to near zero. • Review of existing pumped-storage types. • Pumped-hydro storage an effective alternative for water, energy and land nexus issues. • Proposed arrangement for combining short- and long-term energy and water needs. • Proposed arrangement for combining hydropower and pumped-hydro storage. • Comparison of proposed pumped-hydro storage projects in the Zambesi river basin. [ABSTRACT FROM AUTHOR]