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

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 H₂RES software. The H₂RES 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.     

Study on electrical energy and prospective electricity generation from renewable sources in Australia

Nowadays renewable sources are being used as clean sources to generate electricity and to reduce the dependency on fossil fuels. The uses of renewable sources are being increased in electricity generation and contributed to reduce the greenhouse gas emission. The function of any electrical power system is to connect everyone sufficiently, clean electric power anywhere and anytime of the country. This can be achieved through a modern power system by integrating electrical energy from clean renewable sources into the nation's electric grid to enhance reliability, efficiency and security of the power system. The paper on the status of review the driving force of the generation of renewable energy and proposing electrical energy generation from renewable sources to be ensured at least 20% of total energy of Australia. This paper has been studied the existing electricity generation capacity of Australia from renewable and non-renewable sources. Optimal electricity generation from renewable sources has been examined. The environmental impact of electricity generation from renewable sources has been considered. Under this paper the yearly average wind data of past 20 years and above for some meteorological stations of Australia have been used. The prospective electricity generation from wind turbines and solar photovoltaic panels has been proposed in the paper that will increase electrical energy of the power grid of Australia. It was estimated the capital cost of prospective electricity generation farms from wind and solar PV sources.     

Assessing the impact of renewable energy sources on the electricity price level and variability – A quantile regression approach

The literature on renewable energy sources indicates that an increase of the intermittent wind and solar generation affects significantly the distribution of electricity prices. In this article, the influence of two types of renewable energy sources (wind and solar photo voltaic) on the level and variability of German electricity spot prices is analyzed. The quantile regression models are built to estimate the merit order effect for different quantiles of electricity prices. The results indicate that both types of renewable generations have a similar, negative impact on the price level, approximated by the price median. When the price volatility, measured by the inter-quantile range (IQR), is considered, the outcomes show that wind and solar influence prices differently. Conditional on the level of the total demand, the wind generation would either increase (when the demand is low) or decrease (when the demand is high) the IQR. Meanwhile, the increase of solar power stabilizes the price variance for moderate demand level. Thus, policy supporting the development and integration of RES should search for a balance between the wind and solar power.     

A hydrogen standard for future energy accounting?

Present methods of energy accounting include both primary energy and final energy consumption. Both these methods have inconsistencies, although today their impact is minor. Some level of inconsistency and approximation in energy accounting is unavoidable when energy inputs come from such heterogeneous sources. We argue that in the decades to come, renewable energy will probably come to dominate the energy supply system, with most from intermittent energy sources, particularly wind and solar. In such an energy system, existing measures will become increasingly irrelevant for tracking energy use over time, for assessing a renewable energy source’s technical potential, and in determining future energy infrastructure needs. Further, conversion of most primary electricity to a storable energy form will be needed, with some then perhaps converted back to electricity as needed. We propose that in this case energy production and demand, and technical potential for renewable energy sources, will be more accurately measured by use of a new energy accounting framework, based on the energy content of hydrogen.     

Hydropower for sustainable water and energy development

Turkey has a total gross hydropower potential of 433 GWh/year, but only 125 GWh/year of the total hydroelectric potential of Turkey can be economically used. By the commissioning of new hydropower plants, which are under construction, 36% of the economically usable potential of the country would be tapped. Turkey presently has considerable renewable energy sources. The most important renewable sources are hydropower, biomass, geothermal, solar and wind. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. Over the last two decades, global electricity production has more than doubled and electricity demand is rising rapidly around the world as economic development spreads to emerging economies. Not only has electricity demand increased significantly, it is the fastest growing end-use of energy. Therefore, technical, economic and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix, particularly in the developing countries.     

Renewable energy potential on brownfield sites: A case study of Michigan

Federal priorities are increasingly favoring the replacement of conventional sources of energy with renewable energy. With the potential for a federal Renewable Electricity Standard (RES) legislation, many states are seeking to intensify their renewable energy generation. The demand for wind, solar, geothermal and bio-fuels-based energy is likely to be rapidly expressed on the landscape. However, local zoning and NIMBYism constraints slow down the placement of renewable energy projects. One area where land constraints may be lower is brownfields; whose development is currently constrained by diminished housing, commercial, and industrial property demand. Brownfield sites have the potential for rapid renewable energy deployment if state and national interests in this area materialize. This study investigates the application of renewable energy production on brownfield sites using Michigan as a case study. Wind and solar resource maps of Michigan were overlaid with the brownfield locations based on estimates of brownfield land capacity. The total estimated energy potential available on Michigan’s brownfield sites is 4320 megawatts (MW) of plate capacity for wind and 1535for solar, equating to 43% of Michigan’s residential electricity consumption (using 30% capacity factor). Estimated economic impacts include over $15 billion in investments and 17,500 in construction and long-term jobs.     

Energy production and sustainable energy policies in Turkey

Turkey's demand for energy and electricity is increasing rapidly. Turkey is heavily dependent on expensive imported energy resources that place a big burden on the economy and air pollution is becoming a great environmental concern in the country. Turkey's energy production meets nearly 28% of its total primary energy consumption. As would be expected, the rapid expansion of energy production and consumption has brought with it a wide range of environmental issues at the local, regional and global levels. With respect to global environmental issues, Turkey's carbon dioxide (CO₂) emissions have grown along with its energy consumption. States have played a leading role in protecting the environment by reducing emissions of greenhouse gases (GHGs). In this regard, renewable energy resources appear to be the one of the most efficient and effective solutions for clean and sustainable energy development in Turkey. Turkey presently has considerable renewable energy sources. The most important renewable sources are hydropower, biomass, geothermal, solar and wind. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. Turkey has a great and ever-intensifying need for power and water supplies and they also have the greatest remaining hydro potential. Hydropower and especially small hydropower are emphasized as Turkey's renewable energy sources. Turkey's hydro electric potential can meet 33–46% of its electric energy demand in 2020 and this potential may easily and economically be developed. This paper presents a review of the potential and utilization of the renewable energy sources in Turkey.     

Current status of renewable energy in Nepal: Opportunities and challenges

Energy is indispensible in modern society and is one of the most important components of socio-economic development. Nepal is one of the least developed countries with more than 80% of its population residing in rural communities. Per capita energy usage – often viewed as a key index of the development – in the country is far less than the global average per capita energy usage. The energy sector is dominated by the traditional energy sources such as fuel woods, crop residues and animal dung mainly for domestic usage contributing to about 86% of the national energy consumption. Currently 40% of the population has access to electricity, and the rural electrification accounts for only 29%. The majority of rural populations are meeting their energy needs by burning biomass in traditional stoves which has several environmental and public health issues. Nearly all fossil-derived fuels consumed in the country are imported in a refined form, and the perpetual increase in petroleum imports has adversely impacted the existing fragile economy of the country. Despite a huge potential in harnessing various renewable energy resources such as hydropower, solar power, wind energy and biofuels/bioenergy, these resources have not been sustainably captured due to geographical, technical, political and economical reasons. This paper presents a brief account of Nepal's renewable energy resources and the current status of various renewable energy technologies (RETs) such as micro-hydro, solar power, wind energy, biofuel/bioenergy, improved cook stoves, and improved water mill. It also highlights the opportunities and barriers for the development of RETs. Finally this paper presents some recommendations for the promotion, development and implementation of RETs in the country.     

Cyprus energy system and the use of renewable energy sources

Cyprus is an island state whose energy production is almost completely dependent on imported hydrocarbon fuels. Its electricity production sector is more than 90% dependent on oil products while the remaining 9% are covered by imports of coal (4.5%) and by solar energy (4.5%). Because Cyprus will become a full member of the European Union (EU), it becomes essential to follow the EU white paper rules and insert renewable energy sources (RES) as part of its energy production system. Solar, wind energy and biomass are the three available forms of RES. This paper will examine and analyze the energy system of Cyprus. It will examine the RES available and the extent of the energy needs could be satisfied by them.     

Optimizing 100%‐renewable grids through shifting residential water‐heater load

A low‐carbon electricity supply for Australia was simulated, and the installed capacity of the electrical grid was optimized by shifting the electricity demand of residential electric water heaters (EWHs). The load‐shifting potential of Australia was estimated for each hour of the simulation period using a nationwide aggregate EWH load model on a 90 × 110 raster grid. The electricity demand of water heaters was shifted from periods of low renewable resource and high demand to periods of high renewable resource and low demand, enabling us to effectively reduce the installed capacity requirements of a 100%‐renewable electricity grid. It was found that by shifting the EWH load by just 1 hour, the electricity demand of Australia could be met using purely renewable electricity at an installed capacity of 145 GW with a capacity factor of 30%, an electricity spillage of 20%, and a generation cost of 15.2 ¢/kWh. A breakdown of the primary energy sources used in our scenario is as follows: 43% wind, 29% concentrated solar thermal power, and 20% utility photovoltaic. Sensitivity analysis suggested that further reduction in installed capacity is possible by increasing the load‐shifting duration as well as the volume and insulation level of the EWH tank.     

As a renewable energy hydropower for sustainable development in Turkey

The most important renewable sources are hydropower, biomass, geothermal, solar and wind. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. In recently, electricity has demand increased significantly; it is the fastest growing end-use of energy. Therefore, technical, economic and environmental benefits of hydroelectric power make it an important contributor to the future world energy mix. In the world, particularly in the developing countries renewable energy resources appear to be one of the most efficient and effective solutions for sustainable energy development in Turkey. Turkey's geographical location has several advantages for extensive use of most of the renewable energy sources. This paper deals with policies to meet increasing energy and electricity demand for sustainable energy development in Turkey. Turkey has a total gross hydropower potential of 433 GWh/year, but only 125 GWh/year of the total hydroelectric potential of Turkey can be economically used.     

Overview of renewable energy sources in the Republic of the Sudan

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources and agricultural residues. An overview of the energy situation in Sudan is introduced with reference to the end uses and regional distribution. Energy sources are divided into two main types: conventional energy (biomass, petroleum products and electricity) and non-conventional energy (solar, wind, hydro, etc.). Sudan possesses a relatively high abundance of solar radiation, moderate wind speeds, hydro and biomass energy resources. Application of new and renewable sources of energy available in Sudan is now a major issue in strategic planning for alternatives to fossil fuels to provide part of local energy demand. Sudan is an important case study in the context of renewable energy. It has a long history of meeting its energy needs through renewables. Sudan’s renewables portfolio is broad and diverse, due in part to the country’s wide range of climates and landscapes. Like many of the African leaders in renewable energy utilisation, Sudan has a well-defined commitment to continue research, development and implementation of new technologies. Sustainable low-carbon energy scenarios for the new century emphasise the untapped potential of renewable resources. Rural areas of Sudan can benefit from this transition. The increased availability of reliable and efficient energy services stimulates new development alternatives. Renewable environmentally friendly energy must be encouraged, promoted, implemented and demonstrated, for use in the Republic of the Sudan.     

Renewable energy resources as an alternative to modify the load curve in Northern Cyprus

The average annual increase in electricity consumption and peak demand in Northern Cyprus (N. Cyprus) during the past 20 years have been 7.1 and 5.5%, respectively. In recent years, the demand for electricity has been stretched to its limits in winter. This raised the question of whether renewable energy resources could be utilized to reduce the level of peak demand. Indeed, Cyprus being a Mediterranean island, enjoys an abundance of solar energy, and preliminary studies showed that a considerable potential of wind energy is also available. Utilization of renewable energy for space heating, water heating, pumping and power generation would increase electrical reserve margins, raise system load factor, improve load following capabilities, and reduce the need for capacity expansion. Currently, solar water heating which leads to a saving of at least 72 GWh energy per annum and a significant reduction in CO₂ emission has been extensively used in N. Cyprus. In N. Cyprus, despite the availability of renewable energy resources constructing renewable base-load, electrical power stations has not been found feasible. However, constructing such systems is recommended for two reasons: firstly, as a supplement to saving fuel and secondly, expanding capacity. In this context, the economic analysis for both solar and wind energy systems, has shown a reasonable internal rate of return (IRR). Although, the IRR is higher for wind energy systems, the availability of wind is limited to a few locations and therefore energy distribution is required.     

Potential of renewable energy sources and its applications in Yakushima Island

A study was carried out to see if the potential of renewable energy sources other than hy droelectric power, such as wind, photovoltaic, solar thermal, biomass and waste energy sources, can meet the current energy consumption in Yakushima. The current electricity consumption can be covered by wind and photovoltaic energy sources. The total potential of wind and photovoltaic energy sources is 5.4 times as much as the current electricity consumption. LP gas and kerosene can be replaced by solar thermal and biogas energy. The potential of plant biomass and municipal waste is not sufficient (approximately one third) to cover the rest of the fossil fuels (gasoline, diesel oil and heavy oil). Also, plant biomass and municipal waste must be converted into fluid form. This shortage can be covered by the po tential of wind and photovoltaic energy sources. We also investigated the possibility of tourism expansion using the potential of wind and photovoltaic energy sources. Taking into account three types of capacity (energy, accommodation and transportation), Yakushima can accept approximately four times as many tourists as the current number of tourists.     

Estimation of electrolytic hydrogen production potential in Venezuela from renewable energies

An initial estimation of the potential for hydrogen (H₂) production in Venezuela is made, obtained by water electrolysis using electricity from renewable sources, taking advantage of the great potential of the country for solar, wind and mini hydro energies. For the first two, its potential maps is obtained from insolation and wind speed maps, respectively, prepared from satellite data, and for mini-hydro, the potential is obtained from documentary information. To calculate the amount of H₂ to produce is used the Higher Heating Value, considering the electrolytic system overall efficiency of 75%, including power requirements of the electrolyzer, auxiliary equipment, and system losses. In addition, in the calculation of usable renewable potential are excluded land areas under special administration, marine, lake and urban areas, and other limitations are considered concerning energy conversion efficiencies and useful areas available for the location of the different renewable technologies.     

Solar and wind opportunities for water desalination in the Arab regions

Despite the abundance of renewable energy resources in the Arab region, the use of solar thermal, solar photovoltaics, and wind is still in its technological and economic infancy. Great potential exists, but economic constraints have impeded more rapid growth for many applications. These technologies have certainly advanced technically over the last quarter century to the point where they should now be considered clean-energy alternatives to fossil fuels. For the Arab countries and many other regions of the world, potable water is becoming as critical a commodity as electricity. As renewable energy technologies advance and environmental concerns rise, these technologies are becoming more interesting partners for powering water desalination projects. We evaluate the current potential and viability of solar and wind, emphasizing the strict mandate for accurate, reliable site-specific resource data. Water desalination can be achieved through either thermal energy (using phase-change processes) or electricity (driving membrane processes), and these sources are best matched to the particular desalination technology. Desalination using solar thermal can be accomplished by multistage flash distillation, multi-effect distillation, vapor compression, freeze separation, and solar still methods. Concentrating solar power offers the best match to large-scale plants that require both high-temperature fluids and electricity. Solar and wind electricity can be effective energy sources for reverse osmosis, electrodialysis, and ultra- and nano-filtration. All these water desalination processes have special operational and high energy requirements that put additional requisites on the use of solar and wind to power these applications. We summarize the characteristics of the various desalination technologies. The effective match of solar thermal, solar photovoltaics, and wind to each of these is discussed in detail. An economic analysis is provided that incorporates energy consumption, water production levels, and environmental benefits in its model. Finally, the expected evolution of the renewable technologies over the near- to mid-term is discussed with the implications for desalination applications over these timeframes.     

Renewable energy in Taiwan: Its developing status and strategy

With limited indigenous conventional energy resources, Taiwan imports over 97% of its energy supply from foreign countries, mostly from the Middle East. Developing independent renewable energy resources is thus of priority concern for the Taiwanese government. A medium subtropical island surrounded by the Pacific Ocean, Taiwan has enormous potential to develop various renewable energies, such as solar energy, biomass energy, wind power, geothermal energy, hydropower, etc. However, owing to the importance of conventional fossil energy in generating exceptionally cheap electricity, renewable energy has not yet fully developed in Taiwan, resulting from a lack of market competition. Consequently, numerous promotional and subsidy programs have recently been proclaimed by the Taiwanese government, focused on the development of various renewables. This study reviews the achievements, polices and future plans in this area.     

Enhancing information for solar and wind energy technology deployment in Brazil

Brazil's primary energy matrix is based on more than 47% of renewables, and more than 85% of its electricity is generated by hydro power sources. Despite this large fraction of renewable energy resources, less than 0.3% of the national energy supply comes from solar or wind sources. This paper presents a diagnostic review on the penetration of the solar and wind energy technologies in Brazil. It also includes a survey of the latest government policies and incentives for renewable energies deployment by entrepreneurs, industry and commercial and residential consumers. In addition, the paper analyses how to best meet the requirements for policy support and information technology to boost the deployment of solar technology and wind energy in Brazil. This study was mostly based on results of a widely distributed survey covering key issues, and also by personal interviews carried out with key stakeholders in order to better understand the issues highlighted in the survey responses. The study pointed out some of the main obstacles to effectively promote and improve government policies and actions for investment in solar and wind energy market in Brazil.     

Intermittent renewable energy: The only future source of hydrogen?

In this paper we assess the feasibility of various future energy production pathways for hydrogen. We argue that neither nuclear energy, nor coal gasification with carbon collection and storage can provide sufficient climate-neutral energy to be probable routes to a hydrogen future. Their contributions are likely to be too little and too late to be of much help. Hydroelectricity, geothermal and biomass energy can all provide base-load power, but even combined have limited potential, and are not always climate-neutral in operation. On the other hand, the high-potential renewable energy (RE) sources, particularly wind and direct solar energy, are intermittent. Further, wind resources are poorly matched to the existing distribution of world population. Wind power's high potential compared with present electricity demand, high return on energy invested, intermittency, and mismatch with load centres all favour hydrogen conversion and transmission to load centres.     

Renewable-energy clusters for remote communities

Remote rural communities are especially vulnerable to the reliability of conventional electricity supply methods and many of these communities are post-industrial and therefore suffer from fuel poverty. In this study, the potential contribution to electricity supply to a remote community based on emerging technologies for embedded solar and wind renewable energy, is investigated using simulation modelling. The technologies focus on photovoltaic “slate” roof coverings and micro-vertical-axis wind-turbines. A new model for photovoltaic energy-supply is developed and combined with an existing method for modelling wind-turbine energy. These supply-side models are matched to an existing model of domestic electricity-demand for a whole village community. Results show that in excess of 40% of annual electricity-demand can be relied upon from these sources, provided that a mechanism for surplus power export is available. In the absence of surplus power management, however, only 8% of the annual electricity demand could be met by these sources.