Diesel generator | EPFL Graph Search

A diesel generator (DG) (also known as a diesel genset) is the combination of a diesel engine with an electric generator (often an alternator) to generate electrical energy. This is a specific case of engine generator. A diesel compression-ignition engine is usually designed to run on diesel fuel, but some types are adapted for other liquid fuels or natural gas. Diesel generating sets are used in places without connection to a power grid, or as an emergency power supply if the grid fails, as well as for more complex applications such as peak-lopping, grid support, and export to the power grid. Diesel generator size is crucial to minimize low load or power shortages. Sizing is complicated by the characteristics of modern electronics, specifically non-linear loads. In size ranges around 50 MW and above, an open cycle gas turbine is more efficient at full load than an array of diesel engines, and far more compact, with comparable capital costs; but for regular part-loading, even at these power levels, diesel arrays are sometimes preferred to open cycle gas turbines, due to their superior efficiencies. The packaged combination of a diesel engine, a generator, and various ancillary devices (such as base, canopy, sound attenuation, control systems, circuit breakers, jacket water heaters, and starting system) is referred to as a "generating set" or a "genset" for short. Set sizes range from 8 to 30 kW (also 8 to 30 kVA single phase) for homes, small shops, and offices, with the larger industrial generators from 8 kW (11 kVA) up to 2,000 kW (2,500 kVA three phase) used for office complexes, factories, and other industrial facilities. A 2,000 kW set can be housed in a ISO container with a fuel tank, controls, power distribution equipment and all other equipment needed to operate as a standalone power station or as a standby backup to grid power. These units, referred to as power modules, are gensets on large triple axle trailers weighing or more.

Comparative Assessment of Electrical Generating Systems for a Greek Island

Lucas Mosca

This master thesis is the last part of the master studies in the department of Energy Management and Sustainability, at the Swiss Federal Institute of Technology (EPFL) in Lausanne. This work has been performed in collaboration with the company Renenig Energy, in Athens. The reader should note that the report is an academical work. Results and conclusion are influenced by hypothesis and should not be taken as general truths. The case study is a fictive project but it is composed of values adapted from another real but confidential project, which makes the analysis plausible. The owner of a private island in Greece wants to build a luxury resort on his island. Therefore, he will also need an electrical generating system that must cover the future electricity demand. Usually, diesel generators are used in remote areas in order to produce electricity. However, this technology is very expensive, and harmful for the environment. This master thesis covers the estimation of the electricity demand and the technico-economical assessment of different energy systems. The objective is to evaluate the potential of a microgrid composed of different renewable energy technologies and compare it to the a baseline system composed of generators only. The hourly electricity demand of the entire island has been modeled using a bottom-up approach with a list of representative types of locals. The consumption of these locals have been divided into three categories : The appliances, the lighting and the heating/cooling. For the energy system which must produce electricity, supply strategies have been defined based on the type of technology. For all strategies, an optimization of the technology installed capacities is performed with the software HOMERPro. It is used as a tool to minimize the net present cost of the energy system and analyze the microgrid energetic behavior. The yearly electricity demand of the island has been estimated to around 11 GWh, with a peak load of 2,5 MW during the summer. The cost of serving this load with generators is

63 million with a levelized cost of electricity of 0.467

/kWh. When integrating solar panels, the system cost decreases to

51.3 million with a LCOE of 0.378

/kWh. Moreover, wind turbines and a battery storage system are also economically viable. The last strategy consists of distributed PV panels on building roofs, wind turbines and a battery storage system. Results show that this energy system can decrease the cost to $ 39.8 million while emitting half of the carbon dioxide compared with the baseline system. However, the battery bank has a large impact on CO2 emissions due to its manufacturing processes. Further work can be done for this case study, especially on the network stability assessment, which was not part of this master thesis. Moreover, the potential of implementing hydrogen in the microgrid could be interesting. This could bring a good storage alternative to batteries.

2019

A review of sustainable energy access and technologies for healthcare facilities in the Global South

Silvia Hostettler, Andrea Franco, Marjan Shaker, Dikolela Kalubi

Access to reliable, affordable and sustainable energy is essential for improving living standards, development and economic growth. From a healthcare perspective, energy is a critical parameter for delivering and improving healthcare services and life-saving interventions in the Global South. This review provides an estimation of the energy needs of different healthcare facilities as a function of patient capacity and services provided. It also presents the strengths and limitations of several energy sources that can be used to meet these needs. The review focuses on energy provision in off-grid scenarios and for satisfying peak demands of grid-connected hospitals. The initial key observations are that fossil-fuel generators are the main energy source because of their low investment costs. However, this technology can no longer compete with the energy produced from renewable sources in terms of levelized cost of electricity (LCOE). Photovoltaics (PV) has an LCOE of 0.09 USD/kWh, versus an average 0.25 USD/kWh for diesel generators. Moreover, PV is a modular technology that can efficiently meet energy demands in an environment-friendly way. Wind turbines share many strengths of PV and yet both technologies suffer from intermittent energy sources. They must therefore be coupled with a storage system that provides continuous and stable electricity. Today, energy is mainly stored electrochemically, in the form of lead-acid batteries. However, this review shows that nickel-metal hydride (NiMH) should be used when possible for their higher energy density (200 Wh/l versus 80 Wh/l), non-toxicity, safety and simple maintenance. Alternatively, lithium-based batteries should be used when the energy density and number of cycles is a priority. Other energy production means (e.g., hydropower) and storage technologies (e.g., flywheels) are reviewed as well. In conclusion, the optimal energy solution for medium-to-large healthcare facilities, especially for those in off-grid settings, is a hybrid system wherein the strengths of a renewable energy source coupled with efficient batteries is combined with a diesel generator to minimize the LCOE.

Elsevier Science Bv2017

The Energy and Water Emergency Module; A containerized solution for meeting the energy and water needs in protracted displacement situations

Govinda Upadhyay, Anish Modi

The world has faced many natural and man-made disasters in the past few years, resulting in millions of people living in temporary camps across the globe. The energy and clean water needs of the relief operators in such emergency situations are primarily satisfied by diesel engine based generators and importing clean water to the site, in certain cases even for several years after the emergency. This approach results in problems such as low security of supply and high costs. Especially targeting the prolonged displacement situations, this paper presents an alternative solution – the Energy and Water Emergency Module. The proposed solution aims towards reducing the dependency on fossil fuel in prolonged emergency situations to a minimum while including local energy sources in the energy supply in a flexible and reliable way. The proposed module is built in a standard 20 ft container, and encompasses hybrid generation from solar, wind and biomass, with the possibility of using fossil sources too thanks to a dual fuel gas engine. The module can work both in grid connected and stand-alone mode. In addition the module includes a water purification unit to meet the water needs of displaced population. A demonstration unit was assembled at the Royal Institute of Technology in Stockholm during the year 2012 as a ‘concept proof’, and is now being tested and optimized for future deployment on the field. Preliminary testing and modelling shows that the proposed solution can reliably support emergency situations, and is already cost competitive with the current water and energy supply solutions for emergency situations.

Elsevier2015