Climate change and fossil fuel depletion are the main reasons leading to hydrogen technology. There are many processes for hydrogen production from both conventional and alternative energy resources such as natural gas, coal, nuclear, biomass, solar and wind. In this work, a comparative overview of the major hydrogen production methods is carried out. The process descriptions along with the technical and economic aspects of 14 different production methods are discussed. An overall comparison is carried out, and the results regarding both the conventional and renewable methods are presented. The thermochemical pyrolysis and gasification are economically viable approaches providing the highest potential to become competitive on a large scale in the near future while conventional methods retain their dominant role in H2 production with costs in the range of 1.34–2.27 $/kg. Biological methods appear to be a promising pathway but further research studies are needed to improve their production rates, while the low conversion efficiencies in combination with the high investment costs are the key restrictions for water-splitting technologies to compete with conventional methods. However, further development of these technologies along with significant innovations concerning H2 storage, transportation and utilization, implies the decrease of the national dependence on fossil fuel imports and green hydrogen will dominate over the traditional energy resources.

A comparative overview of hydrogen production processes

A review of computer tools for analysing the integration of renewable energy into various energy systems

Smart Energy Systems for coherent 100% renewable energy and transport solutions

Smart energy and smart energy systems

Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation TES systems are used particularly in buildings and in industrial processes This paper is focused on TES technologies that provide a way of valorizing solar heat and reducing the energy demand of buildings The principles of several energy storage methods and calculation of storage capacities are described Sensible heat storage technologies, including water tank, underground, and packed-bed storage methods, are briefly reviewed Additionally, latent-heat storage systems associated with phase-change materials for use in solar heating/cooling of buildings, solar water heating, heat-pump systems, and concentrating solar power plants as well as thermo-chemical storage are discussed Finally, cool thermal energy storage is also briefly reviewed and outstanding information on the performance and costs of TES systems are included

A Comprehensive Review of Thermal Energy Storage

A 100% renewable energy system in the year 2050: The case of Macedonia

Energy demand of a transport sector has constantly been increasing in the recent years, consuming one third of the total final energy demand in the European Union (EU) over the last decade. A transition of this sector towards sustainable one is facing many challenges in terms of suitable technology and energy resources. Especially challenging transition is envisaged for heavy-weight, long-range vehicles and airplanes. A detailed literature review was carried out in order to detect the current state of the research on clean transport sector, as well as to point out the gaps in the research. In order to calculate the resources needed for the transition towards completely renewable transport sector, four main alternatives to the current fossil fuel systems were assessed and their potential was quantified, i.e. biofuels, hydrogen, synthetic fuels (electrofuels) and electricity. Results showed that electric modes of transport have the largest benefits and should be the main aim of the transport transition. It was calculated that 72.3% of the transport energy demand on the EU level could be directly electrified by the technology existing today. For the remaining part of the transport sector a significant demand for energy resources exists, i.e. 3069 TWh of additional biomass was needed in the case of biofuels utilization scenario while 2775 TWh of electricity and 925 TWh of heat were needed in the case of renewable electrofuels produced using solid oxide electrolysis scenario.

The future of transportation in sustainable energy systems: Opportunities and barriers in a clean energy transition

Planning for a 100% independent energy system based on smart energy storage for integration of renewables and CO2 emissions reduction

Portugal is a country with an energy system highly dependent on oil and gas imports. Imports of oil and gas accounted for 85% of the country's requirements in 2005 and 86% in 2006. Meanwhile, the share of renewable energy sources (RES) in the total primary energy consumption was only 14% in 2006. When focusing only on electricity production, the situation is somewhat better. The share of RES in gross electricity production varies between 20% and 35% and is dependent on the hydropower production in wet and dry years. This paper presents, on a national scale, Portugal's energy system planning and technical solutions for achieving 100% RES electricity production. Planning was based on hourly energy balance and use of H 2 RES software. The H 2 RES model provides the ability to integrate various types of storages into energy systems in order to increase penetration of the intermittent renewable energy sources or to achieve a 100% renewable island, region or country. The paper also represents a stepping-stone for studies offering wider possibilities in matching and satisfying electricity supply in Portugal with potential renewable energy sources. Special attention has been given to intermittent sources such as wind, solar and ocean waves that can be coupled to appropriate energy storage systems charged with surplus amounts of produced electricity. The storage systems also decrease installed power requirements for generating units. Consequently, these storages will assist in avoiding unnecessary rejection of renewable potential and reaching a sufficient security of energy supply.

How to achieve a 100% RES electricity supply for Portugal?

http://powerlab.fsb.hr/neven/pdf/How%20to%20achieve%20a%20100%20RES%20electricity%20supply%20for%20Portugal.pdf

Goran Krajačić

Papers

A 100% renewable energy system in the year 2050: The case of Macedonia

The future of transportation in sustainable energy systems: Opportunities and barriers in a clean energy transition

Planning for a 100% independent energy system based on smart energy storage for integration of renewables and CO2 emissions reduction

How to achieve a 100% RES electricity supply for Portugal?

How to achieve a 100% RES electricity supply for Portugal?