The role of energy storage in accessing remote wind resources in the Midwest

Replacing current generation with wind energy would help reduce the emissions associated with fossil fuel electricity generation. However, integrating wind into the electricity grid is not without cost. Wind power output is highly variable and average capacity factors from wind farms are often much lower than conventional generators. Further, the best wind resources with highest capacity factors are often located far away from load centers and accessing them therefore requires transmission investments. Energy storage capacity could be an alternative to some of the required transmission investment, thereby reducing capital costs for accessing remote wind farms. This work focuses on the trade-offs between energy storage and transmission. In a case study of a 200 MW wind farm in North Dakota to deliver power to Illinois, we estimate the size of transmission and energy storage capacity that yields the lowest average cost of generating and delivering electricity ($/MW h) from this farm. We find that transmission costs must be at least $600/MW-km and energy storage must cost at most $100/kW h in order for this application of energy storage to be economical.     

Induction stoves as an option for clean cooking in rural India

As part of a programme on ‘access to clean cooking alternatives in rural India’, induction stoves were introduced in nearly 4000 rural households in Himachal Pradesh, one of the few highly electrified states in India. Analysis of primary usage information from 1000 rural households revealed that electricity majorly replaced Liquid Petroleum Gas (LPG), generally used as a secondary cooking fuel, but did not influence a similar shift from traditional mud stoves as the primary cooking technology. Likewise, the shift from firewood to electricity as a primary cooking fuel was observed in only 5% of the households studied. Country level analysis indicates that rural households falling in lower monthly per capita expenditure (MPCE) classes have lesser access to electricity and clean cooking options than those falling in higher MPCE classes. Again, only three states in India with high levels of rural household electrification report consumption statuses more than 82 kWh per month (the estimated mean for electricity consumption by induction stoves). Overall, the results of the study indicate that induction stoves will have limited potential in reducing the consumption of firewood and LPG if included in energy access programmes, that too only in regions where high levels of electrification exist.     

Domestic LPG interventions in South Africa: Challenges and lessons

A majority of grid-connected households in South Africa use electricity for cooking and heating tasks. This thermal intensive use of electricity has a high load factor and is a contributory factor of electricity demand outstripping supply at peak demand periods. The government has promoted liquefied petroleum gas (LPG) as an alternative thermal energy source for household cooking and heating. This study evaluates the long-term successes, challenges and social impacts of an LPG intervention project that was piloted in Atteridgeville Township, a typical low-income suburb. The data was gathered through one-on-one household interviews with a sample of the beneficiaries. The results indicate that seven years after the LPG intervention, about 70% of the beneficiaries continue to use LPG and report that the intervention has improved their welfare. Fast cooking is cited as the key tangible benefit of LPG technology in households, followed by saving on electricity bills. The project would have achieved more success through better community engagement, including strict beneficiary selection criteria; a long-term LPG distribution and maintenance plan; and inclusion of recurring monthly LPG subsidies for indigent households. The study discusses the subset of factors necessary for successful rollouts of similar energy projects.     

Development modes analysis of renewable energy power generation in North Africa

North African countries generally have strategic demands for energy transformation and sustainable development. Renewable energy development is important to achieve this goal. Considering three typical types of renewable energies— wind, photovoltaic (PV), and concentrating solar power (CSP)—an optimal planning model is established to minimize construction costs and power curtailment losses. The levelized cost of electricity is used as an index for assessing economic feasibility. In this study, wind and PV, wind / PV / CSP, and transnational interconnection modes are designed for Morocco, Egypt, and Tunisia. The installed capacities of renewable energy power generation are planned through the time sequence production simulation method for each country. The results show that renewable energy combined with power generation, including the CSP mode, can improve reliability of the power supply and reduce the power curtailment rate. The transnational interconnection mode can help realize mutual benefits of renewable energy power, while the apportionment of electricity prices and trading mechanisms are very important and are related to economic feasibility; thus, this mode is important for the future development of renewable energy in North Africa.     

Energy consumption pattern of a decentralized community in northern Haryana

A survey of household energy consumption pattern has been carried out in a village, Bibipur, district Jind, Haryana, India, during 2004. The households surveyed covered heterogeneous population belonging to different income groups, education groups and social groups. Studies were made on the total energy available, total energy required and energy consumption in different sectors domestic, agricultural, transport, rural industries and miscellaneous uses. The total energy available from all the sources (animate, biomass/non-conventional and inanimate sources) in the village is 468,205 MJ and the requirement for all the activities and from all the resources is 592,220 MJ. There is a big gap between energy supply and demand for the village. There is more availability of non-conventional energy resources as compared to conventional energy resources and some resources are unexploited. Therefore, to meet the balance of energy demand and supply, non-conventional resources should be exploited.In domestic sector, maximum energy is used in cooking (52.1%) and 45% of it is supplied from non-conventional energy sources and 10% from conventional energy sources. Calculations were made by considering all the energy resources for average per capita energy consumption and it was 20.02 MJ/day per capita. Electricity is used mainly for lighting and power, while gas is preferred for cooking.In agricultural sector, energy consumption for different activities was calculated and it was found that maximum energy consumption is in irrigation (41.7%) and minimum in transplanting. In agricultural sector, maximum energy comes from conventional energy sources (about 60%) and from non-conventional energy sources it is only about 30%. From the study, it was found that maximum population having good economic conditions like electricity very much as an energy source followed by LPG, biogas, coal, firewood and agricultural residues.     

Estimation of the inconvenience cost of a rolling blackout in the residential sector: The case of South Korea

South Korea is experiencing a serious imbalance in electricity supply and demand, which caused a blackout in 2011. The Korean government has planned to perform a rolling blackout to prevent large-scale blackouts when the electricity supply reserve margin reaches less than 1 million kW. This study attempts to estimate the inconvenience cost of household customers from a rolling blackout by using survey data. To this end, we apply a contingent valuation method (CVM) to measure their willingness-to-pay (WTP) in order to avoid a rolling blackout, i.e. the suspension of electricity supply. In this study, we estimate the inconvenience costs stemming from both an unannounced and an announced rolling blackout. As a result, we find that the inconvenience cost of a sudden rolling blackout is estimated at 3900.67 KRW (3.56 USD) per month per household, while that of an announced rolling blackout stands at 3102.95 KRW (2.83 USD). This difference in costs shows that people place value in receiving prior notice of a blackout, and that inconvenience costs of between 166.0 billion KRW (151.6 million USD) and 174.3 billion KRW (159.2 million USD) per year can be reduced nationwide by giving households advance notice of a planned rolling blackout.     

Consequences of a carbon tax on household electricity use and cost,carbon emissions,and economics of household solar and wind

The study was conducted to determine the consequences of a carbon tax, equal to an estimated social cost of carbon of $37.2/Mg, on household electricity cost, and to determine if a carbon tax would be sufficient to incentivize households to install either a grid-tied solar or wind system. U.S. Department of Energy hourly residential profiles for five locations, 20 years of hourly weather data, prevailing electricity pricing rate schedules, and purchase prices and solar panel and wind turbine power output response functions, were used to address the objectives. Two commercially available household solar panels (4 kW, 12 kW), two wind turbines (6 kW, 12 kW), and two price rate structures (traditional meter, smart meter) were considered. Averaged across the five households, the carbon tax is expected to reduce annual consumption by 4.4% (552 kWh/year) for traditional meter households and by 4.9% (611 kWh/year) for households charged smart meter rates. The carbon tax increases electricity cost by 19% ($202/year). For a household cost of $202/year the carbon tax is expected to reduce social costs by $11. Annual carbon tax collections of $234/household are expected. Adding the carbon tax was found to be insufficient to incentivize households to install either a solar panel or wind turbine system. Installation of a 4 kW solar system would increase the annual cost by $1546 (247%) and decrease CO₂ emissions by 38% (2526 kg) valued at $94/household. The consequence of a carbon tax would depend largely on how the proceeds of the tax are used.     

The value of supply security: The costs of power outages to Austrian households,firms and the public sector

This paper presents a model for assessing economic losses caused by electricity cuts as well as Willingness-to-Pay to avoid these power outages as an approximation to the value of supply security. The economic effects for simulated power cuts from 1 to 48 h, which take the affected provinces, the day of the week and the time of day into consideration, can be calculated using the assessment tool APOSTEL. The costs due to power cuts are computed separately for all sectors of the economy and for households. The average value of lost load for Austrian households and non-household consumers in the case of a power cut of 1 h on a summer workday morning was calculated to be 17.1 € per kWh of electricity not supplied.     

Thermoeconomic analysis of a power/water cogeneration plant

Cogeneration plants for simultaneous production of water and electricity are widely used in the Arabian Gulf region. They have proven to be more thermodynamically efficient and economically feasible than single purpose power generation and water production plants. Yet, there is no standard or universally applied methodology for determining unit cost of electric power generation and desalinated water production by dual purpose plants.A comprehensive literature survey to critically assess and evaluate different methods for cost application in power/water cogeneration plants is reported in this paper. Based on this analysis, an in-depth thermoeconomic study is carried out on a selected power/water cogeneration plant that employs a regenerative Rankine cycle. The system incorporates a boiler, back pressure turbine (supplying steam to two MSF distillers), a deaerator and two feed water heaters. The turbine generation is rated at 118 MW, while MSF distiller is rated at 7.7 MIGD at a top brine temperature of 105 °C. An appropriate costing procedure based on the available energy accounting method which divides benefits of the cogeneration configuration equitably between electricity generation and water production is used to determine the unit costs of electricity and water. Capital charges of common equipment such as the boiler, deaerator and feed water heaters as well as boiler fuel costs are distributed between power generated and desalinated water according to available energy consumption of the major subsystems. A detailed sensitivity analysis was performed to examine the impact of the variation of fuel cost, load and availability factors in addition to capital recovery factor on electricity and water production costs.     

Financial analysis of cooking energy options for India

A financial analysis of cooking energy options is attempted for India using data from a field study and real costs and prices. The fuels considered are; fuelwood, kerosene, biogas, liquid petroleum gas (LPG) and electricity. Traditional and efficient devices and different discount rates are used in the analysis. Financial analysis for rural areas shows that the efficient Astra-stove using wood is the least cost option and biogas, which is the only quality fuel option for rural areas, is the most expensive option. The subsidised kerosene option is cheaper than wood in the traditional stove. The ranking of options from low to high costs is from fuelwood to kerosene to LPG to biogas. In the urban situation, the subsidy on kerosene distorts the energy ladder. Kerosene is the low cost fuel option, and fuelwood in the traditional stove is among the most expensive options. The existing subsidies on kerosene, LPG and electricity seem to benefit middle and high income groups, particularly in urban areas. Low income households in urban and rural areas are forced to use fuelwood in traditional stoves, which is not only a low quality fuel but is also a high cost cooking energy option. The efficiency of the device is shown to be a crucial factor in determining the cost of using a fuel. Low income households are disadvantaged, as they use traditional low efficiency wood stoves. A need to alter energy policies to promote quality fuels and efficient devices in an accessible way to low income households is highlighted.     

Contribution of renewable energy sources to electricity production in the La Rioja Autonomous Community,Spain. A review

The implementation of the emissions market should imbue renewable energies with a greater degree of competitiveness regarding conventional generation. In order to comply with the Kyoto protocol, utilities are going to begin to factor in the cost of CO₂ (environmental costs) in their overall generating costs, whereby there will be an increase in the marginal prices of the electricity pool.This article reviews the progress made in the La Rioja Autonomous Community (LRAC) in terms of the introduction of renewable energy technologies since 1996, where renewable energy represents approximately only 10% of the final energy consumption of the LRAC. Nonetheless, the expected exploitation of renewable energies and the recent implementation of a combined cycle facility mean that the electricity scenario in La Rioja will undergo spectacular change over the coming years: we examine the possibility of meeting a target of practical electrical self-sufficiency by 2010.In 2004, power consumption amounted to 1494 GWh, with an installed power of 1029.0 MW of electricity. By 2010, the Arrúbal combined cycle facility will produce around 9600 GWh/year, thereby providing a power generation output in La Rioja of close to 2044.7 MW, which will involve almost doubling the present output, and multiplying by 8.9 that recorded in this Autonomous Community in 2001.     

Exploration of regional and global cost–supply curves of biomass energy from short-rotation crops at abandoned cropland and rest land under four IPCC SRES land-use scenarios

We explored the production cost of energy crops at abandoned agricultural land and at rest land at a regional and a global level to the year 2050 using four different land-use scenarios. The estimations were based on grid cell data on the productivity of short-rotation crops on the available land over time and assumptions regarding the capital and the labour input required to reach these productivity levels. It was concluded that large amounts of grown biomass at abandoned agricultural land and rest land, 130–270 EJ yr^?1 (about 40–70% of the present energy consumption) may be produced at costs below $2 GJ^?1 by 2050 (present lower limit of cost of coal). Interesting regions because of their low production cost and significant potentials are the Former USSR, Oceania, Eastern and Western Africa and East Asia. Such low costs presume significant land productivity improvements over time and cost reductions due to learning and capital-labour substitution. An assessment of biomass fuel cost, using the primary biomass energy costs, showed that the future costs of biomass liquid fuels may be in the same order of the present diesel production costs, although this may change in the long term. Biomass-derived electricity costs are at present slightly higher than electricity baseload costs and may directly compete with estimated future production costs of fossil fuel electricity with CO₂ sequestration. The present world electricity consumption of around 20 PWh yr^?1 may be generated in 2050 at costs below $45 MWh^?1 in A1 and B1 and below $55 MWh^?1 in A2 and B2. At costs of $60 MWh^?1, about 18 (A2) to 53 (A1) PWh yr^?1 can be produced.     

Providing electricity access to remote areas in India: Niche areas for decentralized electricity supply

This paper presents the results of a study undertaken for identifying niche areas in India where renewable energy based decentralized generation options can be financially more attractive as compared to grid extension for providing electricity. The cost of delivering electricity in remote areas considering cost of generation of electricity and also cost of its transmission and distribution in the country have been estimated. Considering electricity generated from coal thermal power plants, the delivered cost of electricity in remote areas, located in the distance range of 5–25 km is found to vary from Rs. 3.18/kWh to Rs. 231.14/kWh depending on peak electrical load up to 100 kW and load factor. The paper concludes that micro-hydro, dual fuel biomass gasifier systems, small wind electric generators and photovoltaic systems could be financially attractive as compared to grid extension for providing access to electricity in small remote villages.     

A solar-powered traveling-wave thermoacoustic electricity generator

Traveling-wave thermoacoustic electricity generator is a new external-combustion type device capable of converting heat such as solar energy into electric power. In this paper, a 1 kW solar-powered traveling-wave thermoacoustic electricity generation system is designed and fabricated. The system consists of a traveling-wave thermoacoustic electricity generator, a solar dish collector and a heat receiver. In the preliminary tests, using electric cartridge heaters to simulate the solar energy, a maximum electric power of 481 W and a maximum thermal-to-electric efficiency of 15.0% were achieved with 3.5 MPa pressurized helium and 74 Hz working frequency. Then, after integrating the traveling-wave thermoacoustic electricity generator with the solar dish collector and the heat receiver, the solar-powered experiments were performed. In the experiments, a maximum electric power of about 200 W was obtained. However, due to the solar dish collector problems, the heating temperature of the receiver was much lower than expected. Optimizations of the collector and the heat receiver are under way.     

Production possibility frontier analysis of biodiesel from waste cooking oil

This paper presents an assessment of the productive efficiency of an advanced biodiesel plant in Japan using Data Envelopment Analysis (DEA). The empirical analysis uses monthly input data (waste cooking oil, methanol, potassium hydroxide, power consumption, and the truck diesel fuel used for the procurement of waste cooking oil) and output data (biodiesel) of a biodiesel fuel plant for August 2008–July 2010. The results of this study show that the production activity with the lowest cost on the biodiesel production possibility frontier occurred in March 2010 (production activity used 1.41 kL of waste cooking oil, 0.18 kL of MeOH, 16.33 kg of KOH, and 5.45 kW h of power), and the unit production cost in that month was 18,517 yen/kL. Comparing this efficient production cost to the mean unit production cost on the production possibility frontier at 19,712 yen/kL, revealed that the cost of producing 1 kL of biodiesel could be reduced by as much as 1195 yen. We also find that the efficiency improvement will contribute to decreasing the cost ratio (cost per sale) of the biodiesel production by approximately 1% during the study period (24 months) between August 2008 and July 2010.     

Assessment of environmental and economic costs of rural household energy consumption in Loess Hilly Region,Gansu Province,China

Due to poverty, serious soil erosion and shortage of rural household energy in Loess Hilly Region, Gansu Province, China, excessive consumption of biofuel has become a critical factor underlying eco-environment degeneration. Data on rural household energy use was obtained by questionnaires, and based on substitutable analysis, environmental and economic costs under different energy consumption structures were estimated using a quantitative model. The results show that annual energy consumption per household is 2112.44 kgce and per capita 428.59 kgce, a low level. The total annual energy consumption cost per household is 1925.25 yuan, of which environmental cost is 621.13 yuan and economic cost 1304.52 yuan. Commercial energy has been used widely. The per household annual cash payment for commercial energy is 536.51 yuan, 8.69% of household net income. Exclusive use of solar energy and biogas obviously decreases energy consumption cost, cash payout and energy source availability being the main criteria for household energy choice. To compare with the actual structure of energy usage, there are clear differences in the total cost, environment cost, economic cost and cash payout for households among the four substitutable structures. All costs are lower when biogas and solar energy are used, so this structure is the primary direction that rural energy should adopt in the future.     

Experimental studying of a small combined cold and power system driven by a micro gas turbine

A small combined cold and power (SCCP) system is presented. An experimental study of the performance of the SCCP system is described. The gas fuelled SCCP system uses a micro gas turbine generator set and an absorption chiller. The test facility designed and built is also described. The rated electricity power of the micro gas turbine generator is about 24.5 kW at the experimental conditions. When exhaust gas from the micro gas turbine is used to drive the absorption chiller, the rated cooling capacity is 52.7 kW without supplying fuel to burn in the absorption chiller and 136.2 kW with supplying about 78.9 kW LPG fuel to burn in the absorption chiller, respectively. Primary energy rate (PER) and comparative saving of primary energy demand are used to evaluate the performance of the SCCP system. PER of the SCCP system decreases rapidly with the decrease of electric power output when the electric power output is less than 10 kW. The calculated results also show that comparative saving of primary energy demand of the SCCP system decreases with the decrease of electric power output and the SCCP system do not save primary energy comparing to conventional energy system when the electric power output is less than 10 kW.     

Biomass and central receiver system (CRS) hybridization: Volumetric air CRS and integration of a biomass waste direct burning boiler on steam cycle

Concentrated solar power (CSP) plants generate an almost continuous flow of fully dispatchable “renewable” electricity and can replace the present fossil fuel power plants for base load electricity generation. Nevertheless, actual CSP plants have moderate electricity costs, in most cases quite low capacity factors and transient problems due to high inertia. Hybridization can help solve these problems and, if done with the integration of forest waste biomass, the “renewable” goal can be maintained, with positive impact on forest fire reduction. Local conditions, resources and feed in tariffs have great impact on the economical and technical evaluation of hybrid solutions; one of the premium European locations for this type of power plants is the Portuguese Algarve region.Due to the concept innovation level, conservative approaches were considered to be the best solutions. In this perspective, for a lower capital investment 4 MWe power plant scale, the best technical/economical solution is the hybrid CRS/biomass power plant HVIB3S4s with CS3 control strategy. It results in a levelized electricity cost (LEC) of 0.146 €/kWh, with higher efficiency and capacity factor than a conventional 4 MWe CRS. A larger 10 MWe hybrid power plant HVIB3S10s could generate electricity with positive economical indicators (LEC of 0.108 €/kWh and IRR of 11.0%), with twice the annual efficiency (feedstock to electricity) and lower costs than a conventional 4 MWe CRS. It would also lead to a 17% reduction in biomass consumption (approximately 12,000 tons less per year) when compared with a typical 10 MWe biomass power plant – FRB10; this would be significant in the case of continuous biomass price increase.     

The prospective of coal power in China: Will it reach a plateau in the coming decade?

Coal power holds the king position in China's generation mix and has resulted in ever-increasing ecological and environmental issues; hence, the development of the electric power sector is confronted with a series of new challenges. China has recently adopted a new economic principle of the “new economic normal,” which has a large effect on the projection electricity demand and power generation planning through 2020. This paper measures electricity demand based upon China's social and economic structure. The 2020 roadmap presents China's developing targets for allocating energy resources to meet new demands, and the 2030 roadmap is compiled based upon an ambitious expansion of clean energy sources. Results show that electricity demand is expected to reach 7500 TWh in 2020 and 9730 TWh in 2030. Coal power is expected to reach its peak in 2020 at around 970 GW, and will then enter a plateau, even with a pathway of active electricity substitution in place.     

Realistic generation cost of solar photovoltaic electricity

Solar photovoltaic (SPV) power plants have long working life with zero fuel cost and negligible maintenance cost but requires huge initial investment. The generation cost of the solar electricity is mainly the cost of financing the initial investment. Therefore, the generation cost of solar electricity in different years depends on the method of returning the loan. Currently levelized cost based on equated payment loan is being used. The static levelized generation cost of solar electricity is compared with the current value of variable generation cost of grid electricity. This improper cost comparison is inhibiting the growth of SPV electricity by creating wrong perception that solar electricity is very expensive. In this paper a new method of loan repayment has been developed resulting in generation cost of SPV electricity that increases with time like that of grid electricity. A generalized capital recovery factor has been developed for graduated payment loan in which capital and interest payment in each installment are calculated by treating each loan installment as an independent loan for the relevant years. Generalized results have been calculated which can be used to determine the cost of SPV electricity for a given system at different places. Results show that for SPV system with specific initial investment of 5.00 $/kWh/year, loan period of 30 years and loan interest rate of 4% the levelized generation cost of SPV electricity with equated payment loan turns out to be 28.92 ¢/kWh, while the corresponding generation cost with graduated payment loan with escalation in annual installment of 8% varies from 9.51 ¢/kWh in base year to 88.63 ¢/kWh in 30th year. So, in this case, the realistic current generation cost of SPV electricity is 9.51 ¢/kWh and not 28.92 ¢/kWh. Further, with graduated payment loan, extension in loan period results in sharp decline in cost of SPV electricity in base year. Hence, a policy change is required regarding the loan repayment method. It is proposed that to arrive at realistic cost of SPV electricity long-term graduated payment loans may be given for installing SPV power plants such that the escalation in annual loan installments be equal to the estimated inflation in the price of grid electricity with loan period close to working life of SPV system.