Showing papers on "Renewable energy published in 1988"

Handbook of biomass downdraft gasifier engine systems

Abstract: This handbook has been prepared by the Solar Energy Research Institute under the US Department of Energy /bold Solar Technical Information Program/. It is intended as a guide to the design, testing, operation, and manufacture of small-scale (less than 200 kW (270 hp)) gasifiers. A great deal of the information will be useful for all levels of biomass gasification. The handbook is meant to be a practical guide to gasifier systems, and a minimum amount of space is devoted to questions of more theoretical interest.

Generation expansion planning including the renewable energy sources

Abstract: The authors study the long-term competitiveness of introducing renewable energy sources alongside the conventional generating units in a generation expansion plan by linking a short-term study and a long-term planning model. The short-term study is an extensive examination of the different combinations of the renewable energy sources which can operate with the conventional generating system for different objectives. These objectives are varied between two general strategies: the fuel-saver strategy and the peak-shaving strategy. In long-term planning, these combinations are considered as decision variables. For this purpose, a long-term generation expansion planning model is used to decide which strategy can be used and the capacity as well as the time of addition. >

The Reverse Flat Plate Collector: A Stationary, Nonevacuated, Low-Technology, Medium-Temperature Solar Collector

Abstract: The design, analysis, construction and testing of a novel solar collector is reported. The Reverse Flat Plat Collector (RFPC) is intended to be a stationary, nonevacuated, low-technology, medium temperature solar collector - a promising alternative for intermediate temperature thermal needs (100/sup 0/C

Performance of the Solar One power plant as simulated by the SOLERGY computer code

Abstract: The SOLERGY computer code is a valuable tool for the commercialization of solar central receiver power plants. SOLERGY predicts the annual energy produced by a plant and can be used in design optimization studies to evaluate alternative plant designs or operating strategies. This report validates SOLERGY by comparing its prediction of annual energy with the actual performance of the Solar One power plant during 1985. SOLERGY reliably estimates annual energy production, provided good estimates of user-supplied parameters on the plant's operation are available. The code's predictions of plant performance on clear days agree well with the actual performance. However, the code tends to overestimate the performance on partly cloudy days because of the use of 15-minute average insolation data and its failure to account for actions taken by the plant's operators. Possible applications of the code and a discussion of the sensitivity of results to uncertainty in key input parameters are presented. 28 refs., 28 figs., 19 tabs.

Process with the associated equipment for generating energy with the help of artificial energy plants

Abstract: The invention concerns a process with the associated equipment for utilising renewable sources of energy. The essence of the invention is that the energy-conversion systems are integrated into plant-like bodies; the wind energy component is converted into electrical energy with the help of the intermittent principle; and the subsystems convert solar energy, wind energy, and wave energy at sea, into electrical energy. In order to increase the efficiency of conversion, vibration-generating systems, i.e. oscillators, are also employed. The carriers of the energy conversion systems are designed to resemble stalks, flowers, branches or trees. They can be grouped into energy fields and energy forests. The availability of the overall system is increased substantially by the combination of different conversion processes to form one system. Since the systems are designed to resemble plants, and can be operated economically even in small units in the long term, consumer acceptance of this process is expected to be high. The process and its associated equipment can be applied analogously to utilising the renewable sources of energy at sea.

Impact of lower oil prices on renewable energy technologies

Abstract: The impacts of reduced oil prices on the economic viability of selected technologies which utilize solar, wind and biomass energy sources are examined The technologies include dendrothermal power plants, bagasse, fuel alcohol, wind electricity, biomass gasifiers, solar water heaters, biogas, photovoltaic pumps and wind pumps Projects in these categories which were established or planned when oil prices were above $ 28 / bbl are reviewed and their economic justifications recalculated at a range of lower oil prices The findings indicate that the economic sensitivity of renewable energy technologies to changing oil prices is mainly a function of scale and location of the project Renewable energy technologies that compete directly in the modern sector as large scale petroleum substitutes, are the most affected by falling oil prices Remote and rural applications are less affected because of their generally smaller sizes Therefore, we find a lower proportion of fuel costs to total costs in the equivalent sized conventional alternative, a reduced availability and higher cost of petroleum fuels as compared to urban areas, and a lower cost of biomass fuels in rural areas

Renewable energy: today's contribution, tomorrow's promise

Abstract: Premier volet d'une serie de trois articles generaux sur l'etat actuel de developpement et d'utilisation des energies renouvelables dans le monde. Cette premiere partie est consacree a l'energie hydroelectrique et a l'energie thermique et cinetique des mers

An outdoor test facility for the large-scale production of microalgae

Abstract: The goal of the US Department of EnergySolar Energy Research Institute's Aquatic Species Program is to develop the technology base to produce liquid fuels from microalgae. This technology is being initially developed for the desert Southwest. As part of this program an outdoor test facility has been designed and constructed in Roswell, New Mexico. The site has a large existing infrastructure, a suitable climate, and abundant saline groundwater. This facility will be used to evaluate productivity of microalgae strains and conduct large-scale experiments to increase biomass productivity while decreasing production costs. Six 3-m/sup 2/ fiberglass raceways were constructed. Several microalgae strains were screened for growth, one of which had a short-term productivity rate of greater than 50 g dry wt m/sup /minus/2/ d/sup /minus/1/. Two large-scale, 0.1-ha raceways have also been built. These are being used to evaluate the performance trade-offs between low-cost earthen liners and higher cost plastic liners. A series of hydraulic measurements is also being carried out to evaluate future improved pond designs. Future plans include a 0.5-ha pond, which will be built in approximately 2 years to test a scaled-up system. This unique facility will be available to other researchers and industry for studies on microalgae more » productivity. 6 refs., 9 figs., 1 tab. « less

Gearing for small wind and water power plants

Abstract: The object of the invention serves for more efficient acquisition and conversion of renewable forms of energy, such as wind and water power, into electricity, in particular for supplying independent supply districts (isolated operation) and for minimising plant costs. The gear train as designed in the invention divides the power path coming from the prime mover into two power paths for two separate supply systems: - a power path with automatic speed control for driving a small a.c. generator, for priority supply of a base-load system with clean, constant-frequency current; - and a power path for driving a larger generator without automatic speed control for converting the energy arising that exceeds the base demand, for example for heating, producing hydrogen electrolytically, or for other forms of storage. Apart from the advantage of low losses, and thus efficient energy conversion, when only small amounts of energy are available, the construction effort and costs of the supply path with automatic speed control can be kept modest, and the components for converting sporadically occurring excess amounts of energy can be constructed in a robust, inexpensive and reliable manner.

Power from the people. Innovation, user participation, and forest energy development.

Abstract: Through the example of the analysis of forest energy technology development the author illustrates the importance of user participation in developing technologies, and discusses the management of technological change.

Geothermal direct use developments in the United States

Abstract: Direct heat use of geothermal energy in the United States is recognized as one of the alternative energy resources that has proven itself technically and economically, and is commercially available. Developments include space conditioning of buildings, district heating, groundwater heat pumps, greenhouse heating, industrial processing, aquaculture, and swimming pool heating. Forty-four states have experienced significant geothermal direct use development in the last ten years. The total installed capacity is 5.7 billion Btu/hr (1700 MW/sub t/), with an annual energy use of nearly 17,000 billion Btu/yr (4.5 million barrels of oil energy equivalent). In this report we provide an overview of how and where geothermal energy is used, the extent of that use, the economics and growth trends. The data is based on an extensive site data gathering effort by the Geo-Heat Center in the spring of 1988, under contract to the US Department of Energy. 100 refs., 4 figs., 4 tabs.

Combined battery/hydrogen storage for autonomous wind/solar systems

Abstract: We have analyzed total wind/solar electrical energy systems using time step simulation. The systems investigated here are a combination of the following components: - Photovoltaic array (PV) - Wind energy converter (WEC) - Pb batteries - Hydrogen storage system, consisting of electrolyser, H 2 /O 2 storages and fuel cell. The investigations are focussed on: - the determination of system configurations yielding renewable fractions of 1 (autonomous systems) - the analysis of the influence of the hydrogen systems cycle efficiency on the storage configuration - the system optimization with respect to energy investment.

Power to the outback (remote-area power generation)

Abstract: Continuous electricity supply for people in remote areas has always presented a problem. This has certainly been the case in the geographically diverse continent of Australia, where central grid electricity supply to all consumers is economically impossible. The author shows that the alternative source of electricity is small-scale private generation. He demonstrates that, with capital costs falling, remote power generation is progressing beyond the traditional unsupported diesel set, with renewable sources (including solar, wind and hydroelectric power) becoming economically viable. >

Further Studies on the Thermal Performance of a Low Energy Greenhouse

Abstract: Thermal performance of the Burnley Low Energy Greenhouse is studied by estimating solar air heater efficiency, rockpile time-temperature response and the overall contribution of solar energy in heating the greenhouse.

Application of solar technology to fuel ppoduction chemical processing, and thermochemical energy transport: status and future

Abstract: A number of research efforts in the United States, Germany, Israel, Australia, Russia, Spain and Switzerland are pursuing the possibility of applying solar thermal technology to chemical processes Potential applications include thermochemical energy transport, hydrogen production, oil shale retorting, coal gasification, destruction of hazardous wastes, solar-pumped lasers for production of exotic chemicals, carbothermic reduction of metal oxides, and the pyrolysis of biomass These efforts and their relationships to the various national programs are discussed The concept of a direct catalytic absorption receiver (DCAR) for application to solar-driven chemical processes is also presented The future of non-electric applications of solar thermal technology appears to be bright

A technoeconomic assessment of solar-assisted biogas systems

Abstract: Biogas has been recognized as one of the best available renewable and decentralized sources of energy and organic fertilizer for a country like India. There is enough evidence to prove that temperature has a profound influence on the rate of biogas production. In temperate climates, where the winters are mild, solar energy systems can be effectively used to increase the temperature of the biogas digester to the desired level. This paper examines various techniques, such as a solar greenhouse on the biogas digester, a shallow solar pond water heater, insulation, and a heat exchanger, and their technoeconomic viability.