A framework for reviewing the trade-offs between, renewable energy, food, feed and wood production at a local level

High fuel prices and concerns about energy security and anthropogenic climate change are encouraging a transition towards a low carbon economy. Although energy policy is typically set at a national level, tools are needed for people to engage with energy policy at regional and local levels, and to guide decisions regarding land use, distributed generation and energy supply and demand. The aim of this paper is to develop a per-capita approach to renewable energy demand and supply within a landscape and to illustrate the key trade-offs between renewable energy, food, (animal) feed and wood production. The chosen case study area (16,000 ha) of Marston Vale, England is anticipated to have a population density midway between that for England and the UK. The daily per capita demand for energy for heat (31 kWh), transport (34 kWh) and electricity (15 kWh) when combined (80 kWh) was seven-fold higher than the combined demand for food (2 kWh), animal feed (6 kWh), and wood (4 kWh). Using described algorithms, the combined potential energy supply from domestic wind and photovoltaic panels, solar heating, ground-source heat, and municipal waste was limited (<10 kWh p⁻¹ d⁻¹). Additional electricity could be generated from landfill gas and commercial wind turbines, but these have temporal implications. Using a geographical information system and the Yield-SAFE tree and crop yield model, the capacity to supply bioethanol, biodiesel, and biomass, food, feed and wood was calculated and illustrated for three land-use scenarios. These scenarios highlight the limits on meeting energy demands for transport (33%) and heat (53%), even if all of the arable and grassland area was planted to a high yielding crop like wheat. The described framework therefore highlights the major constraints faced in meeting current UK energy demands from land-based renewable energy and the stark choices faced by decision makers.     

Wind energy development policy and prospects in Lithuania

According to the EU Directive 2001/77/EC 7% of all electricity production is to be generated from renewable energy sources (RES) in Lithuania in 2010. Electricity production from RES is determined by hydro, biomass and wind energy resources in Lithuania. Further development of hydro power plants is limited by environmental restrictions, therefore priority is given to wind energy development. The aim of this paper is to show estimation of the maximum wind power penetration in the Lithuanian electricity system using such criteria as wind potential, possibilities of the existing electricity network, possible environmental impact, and social and economical aspects. Generalization of data from the meteorological stations and special measurements shows that the highest average wind speed in Lithuanian territory is in the coastal region and at 50 m above ground level reaches 6.4 m/s. In regard to wind resource distribution in this region, arrangement of electricity grid and environment protection requirements, six zones have been determined for wind power plant construction. Calculations have shown that the largest total installed capacity of wind farms, which could cause no significant increase in power transmission expenses, is 170 MW. The threshold, which cannot be passed without capital reconstruction of electricity network, is 500 MW of total capacity of wind farms.     

Renewable energy sources in the Egyptian electricity market: A review

This review paper presents an appraisal of renewable energy RE options in Egypt. An appraisal review of different REs is presented. The study shows that electric energy produced from REs in Egypt are very poor compared with other energy sources. The utilization of the renewable energies can also be a good opportunity to fight the desertification and dryness in Egypt which is about 60% of Egypt territory. The rapid growth of energy production and consumption is strongly affecting and being affected by the Egyptian economy in many aspects. It is evident that energy will continue to play an important role in the development of Egypt's economy in coming years. The total installed electricity generating capacity had reached around 22025 MW with a generating capacity reached 22605 MW at the end of 2007. Hydropower and coal has no significant potential increase. During the period 1981/82-2004/05 electricity generation has increased by 500% from nearly 22 TWh for the year 1981/1982 to 108.4 TWh in the year 2004/2005 at an average annual growth rate of 6.9%. Consequently, oil and gas consumed by the electricity sector has jumped during the same period from around 3.7 MTOE to nearly 21 MTOE. The planned installed capacity for the year 2011/2012 is 28813 MW and the required fuel (oil and gas) for the electricity sector is estimated to reach about 29 MTOE by the same year. The renewable energy strategy targets to supply 3% of the electricity production from renewable resources by the year 2010. Electrical Coverage Electrical energy has been provided for around 99.3% of Egypt's population, representing a positive sign for the welfare of the Egyptian citizen due to electricity relation to all development components in all walks of life. The article discusses perspectives of wind energy in Egypt with projections to generate ∼ 3.5 GWe by 2022, representing ∼9% of the total installed power at that time (40.2 GW). Total renewables (hydro + wind + solar) are expected to provide ∼7.4 GWe by 2022 representing ∼ 19% of the total installed power. Such a share would reduce dependence on depleting oil and gas resources, and hence improve country's sustainable development.     

Optimization of energy consumption for soybean production using Data Envelopment Analysis (DEA) approach

In this study a non-parametric method of Data Envelopment Analysis (DEA) is used to estimate the energy efficiencies of soybean producers based on eight energy inputs including human labor, diesel fuel, machinery, fertilizers, chemicals, water for irrigation, electricity and seed energy and single output of grain yield. The study also helps to rank efficient and inefficient farmers and to identify optimal energy requirement and wasteful uses of energy. Data were collected using face-to-face surveys from 94 farms in Golestan province which is the most important center of soybean production in Iran. Based on the results, average yield and energy consumption for soybean production were 3233.15 kg ha⁻¹ and 35372.23 MJ ha⁻¹, respectively. Also, the results of DEA application showed that, the technical, pure technical and scale efficiencies of farmers were 0.853, 0.919 and 0.926, respectively. Moreover, energy saving target ratio for soybean production was calculated as 20.12%, indicating that by following the recommendations resulted from this study, about 7116.84 MJ ha⁻¹ of total input energy could be saved while holding the constant level of soybean yield. Also, electrical energy had the highest share (78.08%) from total saving energy, followed by fertilizers (10.46%) and diesel fuel (6.18%) energy inputs.     

Electricity generation from the first wind farm situated at Ras Ghareb, Egypt

Egypt is one of the Red Sea and Mediterranean countries having windy enough areas, in particular along the coasts. The coastal location Ras Ghareb on the Red Sea has been investigated in order to know the wind power density available for electricity generation. To account for the wind potential variations with height, a new simple estimating procedure was introduced. This study has explicitly demonstrated the presence of high wind power density nearly 900 kW/m² per year at 100 m of altitude for this region. Indeed, the seasonal wind powers available are comparable to and sometimes higher than the power density in many European cities for wind electricity applications like Vindeby (Denmark) and also America.New technical analysis for wind turbine characteristics have been made using three types of commercial wind turbines possessing the same rotor diameter and rated power to choice the best wind machine suitable for Ras Ghareb station. As per the decreasing the cut-in wind speed for the wind turbine used, the availability factor increases for a given generator. That it could produce more energy output throughout the year for the location.The aim of this research, was to predict the electrical energy production with the cost analysis of a wind farm 150 MW total power installed at Ras Ghareb area using 100 wind turbines model (Repower MD 77) with 1.5 MW rated power. Additionally, this paper developed the methodology for estimating the price of each kWh electricity from the wind farms. Results show that this wind park will produce maximum energy of 716 GWh/year. The expected specific cost equal to 1.5 € cent/kWh is still less than and very competitive price with that produced from the wind farms in Great Britain and Germany and at the international markets of wind power. The important result derived from this study encourages several wind parks with hundreds of megawatts can be constructed at Ras Ghareb region.     

The impact of Production Tax Credits on the profitable production of electricity from wind in the U.S.

A spatial financial model using wind data derived from assimilated meteorological condition was developed to investigate the profitability and competitiveness of onshore wind power in the contiguous U.S. It considers not only the resulting estimated capacity factors for hypothetical wind farms but also the geographically differentiated costs of local grid connection. The levelized cost of wind-generated electricity for the contiguous U.S. is evaluated assuming subsidy levels from the Production Tax Credit (PTC) varying from 0 to 4 ¢/kWh under three cost scenarios: a reference case, a high cost case, and a low cost case. The analysis indicates that in the reference scenario, current PTC subsidies of 2.1 ¢/kWh are at a critical level in determining the competitiveness of wind-generated electricity compared to conventional power generation in local power market. Results from this study suggest that the potential for profitable wind power with the current PTC subsidy amounts to more than seven times existing demand for electricity in the entire U.S. Understanding the challenges involved in scaling up wind energy requires further study of the external costs associated with improvement of the backbone transmission network and integration into the power grid of the variable electricity generated from wind.     

Co-firing biomass with coal for electricity generation—An assessment of the potential in EU27

The European Union aims to increase bioenergy use. Co-firing biomass with coal represents an attractive near-term option for electricity generation from renewable energy sources (RES-E). This study assesses the near-term technical potential for biomass co-firing with coal in the existing coal-fired power plant infrastructure in the EU27 Member States. The total technical potential for RES-E from biomass co-firing amounts to approximately 50–90 TWh/yr, which requires a biomass supply of approximately 500–900 PJ/yr. The estimated co-firing potential in EU27 amounts to 20–35% of the estimated gap between current RES-E production and the RES-E target for 2010. However, for some member states the national co-firing potential is large enough to fill the national gap. The national biomass supply potential is considerably larger than the estimated biomass demand for co-firing for all member states. About 45% of the estimated biomass demand for co-firing comes from plants located close to the sea or near main navigable rivers and indicates the possibility for biomass import by sea transport. Thus, biomass co-firing has the potential to contribute substantially to the RES-E development in EU27.     

Assessing the potential of concentrating solar photovoltaic generation in Brazil with satellite-derived direct normal irradiation

With the declining costs of flat plate and concentrating photovoltaic (PV) systems, solar PV generation in many sunny regions in Brazil will eventually become cost competitive with conventional and centralized power generation. Detailed knowledge of the local solar radiation resource becomes critical in assisting on the choice of the technology most suited for large-scale solar electricity generation. When assessing the energy generation potential of non-concentrating, fixed flat plate versus concentrating PV, sites with high levels of direct normal irradiation (DNI) can result in cost-competitive electricity generation with the use of high concentrating photovoltaic systems (HCPV). In large countries, where the transmission and distribution infrastructure costs and associated losses typical of centralized generation must be taken into account, the distributed nature of solar radiation should be perceived as a valuable asset. In this work we assess the potential of HCPV energy generation using satellite-derived DNI data for Brazil, a large and sunny country with a continental surface of 8.5 million km². The methodology used in the study involved the analysis of global horizontal, latitude-tilt, and direct normal solar irradiation data resulting from the Solar and Wind Energy Resource Assessment (SWERA) Project, and an estimate of the resulting electricity production potential, based on a review of HCPV generators operating at other sites. The satellite-derived solar irradiation data, with 10 km × 10 km spatial resolution, were analysed over the whole country, in order to identify the regions where HCPV might present a considerable advantage over fixed plate PV on an annual energy generation basis. Our results show that there is a considerable fraction of the national territory where the direct normal solar irradiation resource is up to 20% higher than the latitude-tilt irradiation availability. Furthermore, these sites are located in the most industrially-developed region of the country, and indicate that with the declining costs of this technology, distributed multi-megawatt HCPV can be a good choice of technology for solar energy generation at these sites in the near future.     

Surplus biomass through energy efficient kilns

The use of biomass in the European Union has increased since the middle of the 1990s, mostly because of high subsidies and CO₂ emission regulation through the Kyoto protocol. The sawmills are huge biomass suppliers to the market; out of the Swedish annual lumber production of 16.4 Mm³, 95% is produced by medium to large-volume sawmills with a lumber quotient of 47%. The remaining part is produced as biomass. An essential part (12%) of the entering timber is used for supply of heat in their production processes, mostly in the substantial drying process. The drying process is the most time and heat consuming process in the sawmill. This study was undertaken to determine the sawmills’ national use of energy and potential magnitude of improvements. If the drying process can be made more effective, sawmills’ own use of biomass can be decreased and allow a considerably larger supply to the biomass market through processed or unprocessed biomass, heat or electricity production. The national electricity and heat usage when drying the lumber have been analysed by theoretical evaluation and experimental validation at a batch kiln. The main conclusion is that the heat consumption for drying lumber among the Swedish sawmills is 4.9 TW h/year, and with available state-of-the-art techniques it is possible to decrease the national heat consumption by approximately 2.9 TW h. This additional amount of energy corresponds to the market’s desire for larger energy supply.     

Projected costs of a grid-connected domestic PV system under different scenarios in Ireland,using measured data from a trial installation

This paper presents results of a study of projected costs for a grid-connected PV system for domestic application in Ireland. The study is based on results from a 1.72 kWp PV system installed on a flat rooftop in Dublin, Ireland. During its first year of operation a total of 885.1 kWh/kWp of electricity was generated with a performance ratio of 81.5%. The scenarios employed in this study consider: a range of capital costs; cost dynamics based on a PV module learning rate of 20±5%; projections for global annual installed PV capacity under an advanced and moderate market growth conditions; domestic electricity cost growth of 4.5% based on historic data; and a reduction of 25% or 50% in the CO₂ intensity of national electricity production by 2055. These scenarios are used to predict when system life cycle production costs fall to grid prices (grid parity).     

Possibilities and consequences of deregulation of the European electricity market for connection of heat sparse areas to district heating systems

The objective of the study is to analyse the conditions for connection of residential buildings in heat sparse areas to district heating systems in order to increase electricity production in municipal combined heat and power plants. The European electricity market has been assumed to be fully deregulated. The relation between connection of heat sparse areas, increased electricity and heat production as well as electricity prices, fuel prices and emissions rights is investigated. The results of the study show that there is potential to expand the district heating market to areas with lower heat concentrations in the cities of Gävle, Sandviken and Borlänge in Sweden, with both economic and environmental benefits. The expansion provides a substantial heat demand of approximately 181 GWh/year, which results in an electricity power production of approximately 43 GWh/year. Since the detached and stand-alone houses in the studied heat sparse areas have been heated either by oil boiler or by direct electricity, connection to district heating also provides a substantial reduction in emissions of CO₂. The largest reductions in CO₂ emissions are found to be 211 ktonnes/year assuming coal-fired condensing power as marginal electricity production. Connection of heat sparse areas to district heating decrease the system costs and provide a profitability by approximately 22 million EURO/year for the studied municipalities if the price of electricity is at a European level, i.e. 110 EURO/MWh. Sensitivity analysis shows, among other things, that a strong relation exists between the price of electricity and the profitability of connecting heat sparse areas to district heating systems.     

Energy use, cost and CO2 emissions of electric cars

We examine efficiency, costs and greenhouse gas emissions of current and future electric cars (EV), including the impact from charging EV on electricity demand and infrastructure for generation and distribution.Uncoordinated charging would increase national peak load by 7% at 30% penetration rate of EV and household peak load by 54%, which may exceed the capacity of existing electricity distribution infrastructure. At 30% penetration of EV, off-peak charging would result in a 20% higher, more stable base load and no additional peak load at the national level and up to 7% higher peak load at the household level. Therefore, if off-peak charging is successfully introduced, electric driving need not require additional generation capacity, even in case of 100% switch to electric vehicles.GHG emissions from electric driving depend most on the fuel type (coal or natural gas) used in the generation of electricity for charging, and range between 0 g km⁻¹ (using renewables) and 155 g km⁻¹ (using electricity from an old coal-based plant). Based on the generation capacity projected for the Netherlands in 2015, electricity for EV charging would largely be generated using natural gas, emitting 35-77 g CO_2 eq km⁻¹.We find that total cost of ownership (TCO) of current EV are uncompetitive with regular cars and series hybrid cars by more than 800 € year⁻¹. TCO of future wheel motor PHEV may become competitive when batteries cost 400 € kWh⁻¹, even without tax incentives, as long as one battery pack can last for the lifespan of the vehicle. However, TCO of future battery powered cars is at least 25% higher than of series hybrid or regular cars. This cost gap remains unless cost of batteries drops to 150 € kWh⁻¹ in the future. Variations in driving cost from charging patterns have negligible influence on TCO.GHG abatement costs using plug-in hybrid cars are currently 400-1400 € tonne⁻¹ CO_2 eq and may come down to −100 to 300 € tonne⁻¹. Abatement cost using battery powered cars are currently above 1900 € tonne⁻¹ and are not projected to drop below 300-800 € tonne⁻¹.     

Simultaneous processes of electricity generation and ceftriaxone sodium degradation in an air-cathode single chamber microbial fuel cell

A single chamber microbial fuel cell (MFC) with an air-cathode is successfully demonstrated using glucose-ceftriaxone sodium mixtures or ceftriaxone sodium as fuel. Results show that the ceftriaxone sodium can be biodegraded and produce electricity simultaneously. Interestingly, these ceftriaxone sodium-glucose mixtures play an active role in production of electricity. The maximum power density is increased in comparison to 1000 mg L⁻¹ glucose (19 W m⁻³) by 495% for 50 mg L⁻¹ ceftriaxone sodium + 1000 mg L⁻¹ glucose (113 W m⁻³), while the maximum power density is 11 W m⁻³ using 50 mg L⁻¹ ceftriaxone sodium as the sole fuel. Moreover, ceftriaxone sodium biodegradation rate reaches 91% within 24 h using the MFC in comparison with 51% using the traditional anaerobic reactor. These results indicate that some toxic and bio-refractory organics such as antibiotic wastewater might be suitable resources for electricity generation using the MFC technology.     

Electricity tariffs based on long-run marginal costs for central grid system of Oman

The electricity tariffs in Oman are subsidized and are based on a cost accounting approach and do not reflect the true cost incurred in generating, transmitting and distributing a kilowatt-hour of electricity at the consumer end. This paper presents the electricity tariff based on the estimation of long-run marginal cost at generation, 33 kV, and 415 voltage level for Ministry of Housing, Electricity & Water (MHEW) interconnected power system of Oman. The result shows that at the generation level a marginal kW costs US$ 75 per year and a marginal kWh costs 2.07 ¢/kWh. These costs increase as we move downstream from generation to consumer end. The average cost of electricity at the consumer end connected at 415 V is 6.52 ¢/kWh or 25.17 Bz/kWh.     

Potential impacts assessment of plug-in electric vehicles on the Portuguese energy market

Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), which obtain their fuel from the grid by charging a battery, are set to be introduced into the mass market and expected to contribute to oil consumption reduction. In this research, scenarios for 2020 EVs penetration and charging profiles are studied integrated with different hypotheses for electricity production mix. The impacts in load profiles, spot electricity prices and emissions are obtained for the Portuguese case study. Simulations for year 2020, in a scenario of low hydro production and high prices, resulted in energy costs for EVs recharge of 20 cents/kWh, with 2 million EVs charging mainly at evening peak hours. On the other hand, in an off-peak recharge, a high hydro production and low wholesale prices' scenario, recharge costs could be reduced to 5.6 cents/kWh. In these extreme cases, EV's energy prices were between 0.9€ to 3.2€ per 100 km. Reductions in primary energy consumption, fossil fuels use and CO₂ emissions of up to 3%, 14% and 10%, respectively, were verified (for a 2 million EVs' penetration and a dry year's off-peak recharge scenario) from the transportation and electricity sectors together when compared with a BAU scenario without EVs.     

The use of cost-generation curves for the analysis of wind electricity costs in Spain

The cost of the electricity generated from onshore wind is assessed through a method based on an estimation of the geographical distribution of the technical potential and a cost structure for the estimation of the local unit cost. Generation-cost curves are then employed to portray the evolution of the specific generating cost with the increase of the generated energy, until the limit of the technical potential is reached. The study also relates the energy cost to the land occupancy, the installed power and the capacity factor, and includes an assessment of the interplay between land usage and the cost of wind electricity. An analysis is presented to determine the uncertainty in the costs of the several model parameters. The method is applied to Spain, and allows to establish that, for an electricity-generation level of 300 TW h/y (roughly equal to the overall demand in Spain in 2008), the specific marginal cost is around 8.5 c€/kW h.     

Improvement of the cogeneration plant economy by using heat accumulator

The optimisation code ACOM (Advanced Cogeneration Optimisation Model) is used with purpose of assessing influence of the district heat accumulator on the Elektrana-Toplana (EL-TO) Zagreb cogeneration plant economic performance. The plant supplies hot water for district heating, steam for industry and electric power. It is possible to achieve economic benefits by charging the accumulator during the day time, when the electricity price is high, and by releasing district heat during cheap night hours, when other parts of equipment may be shut down. The consequences of this strategy are the decrease of total annual electricity production and fuel consumption, whereby the savings of some 1.8 mil Euro/a are achieved with the reduction of CO₂ emission by about 23,000 t/a or 6.4% and SO_x by about 200 t/a or 16.9%.     

Economics of wind power when national grids are unreliable

Power interruptions are a typical characteristic of national grids in developing countries. Manufacturing, processing, refrigeration and other facilities that require a dependable supply of power, and might be considered a small grid within the larger national grid, employ diesel generators for backup. In this study, we develop a stochastic simulation model of a very small grid connected to an unreliable national grid to show that the introduction of wind-generated power can, despite its intermittency, reduce costs significantly. For a small grid with a peak load of 2.85 MW and diesel generating capacity of 3.75 MW provided by two diesel generators, the savings from using wind energy (based on wind data for Mekelle, Ethiopia) can amount to millions of dollars for a typical July month, or some 5.5–17.5% of total electricity costs. While wind power can lead to significant savings, the variability of wind prevents elimination of the smaller of two diesel units, although this peaking unit operates less frequently than in the absence of wind power.     

Air conditioning in the region of Madrid, Spain: An approach to electricity consumption, economics and CO2 emissions

An understanding of electricity consumption due to residential air conditioning (AC) may improve production and environmental impact strategy design. This article reports on a study of peak and seasonal electricity consumption for residential air conditioning in the region of Madrid, Spain. Consumption was assessed by simulating the operation of AC units at the outdoor summer temperature characteristics of central Spain. AC unit performance when operating under part load conditions in keeping with weather conditions was also studied to find cooling demand and energy efficiency. Likewise final electricity consumption was computed and used to calculate energy costs and greenhouse gas emissions (GHGs). Cooling demand, when family holidays outside the region were factored into the calculations, came to 1.46 × 10⁹ kWh. Associated seasonal electricity demand was 617 × 10⁶ kWh and seasonal performance of AC units around 2.4. Electricity consumption in the whole region was observed to peak on 30 June 2008 at 5.44 × 10⁶ kW, being the load attributable to residential AC 1.79 × 10⁶ kW, resulting about 33% of the total peak consumption. The seasonal cost per household was about €156 and the total equivalent warming impact was 572 × 10³ t CO₂. The method proposed can be adapted for use in other regions.     

Electricity market participation of wind farms: the success story of the Spanish pragmatism

In the last 10 years, more than 15 GW of wind power (Asociación Empresarial Eólica (Spanish Wind Energy Association), Nota de prensa (Press release) 17 de enero de 2008. http://www.aeeolica.org/doc/NP_080117_Espana_supera_los_15000_MW_eolicos.pdf) have been installed in Spain, of which more than 3.5 GW in 2007. Furthermore, plans are to reach 20 GW by 2010 and there are expectations of an installed capacity exceeding 40 GW by 2020. This article will present the innovative solutions for technical and economical integration that allow to reach such high level wind penetration objectives (the system peaks at around 44 GW and is almost isolated). It will be described how the regulation has evolved from a pure Feed-in-Tariff to a market+premium option, where technical and economic integration has been a priority. Today, approximately 97% of installed wind capacity accesses the Spanish wholesale electricity market. Market integration has been crucial, sending the correct signals to participants to look for the optimum technical solutions. Technical improvements have come from both wind power producers (fault-ride-through capabilities, visibility and controllability of wind power, power production forecasting, reactive power control) and the system operator (specific control centre dedicated to Renewable Energy Sources (RES), new security analysis tools, gaining technical confidence of wind capabilities).