Meaning of Energy
Energy always means converting energy from one form into another. For instance, in space heating, we utilize energy, that is, we convert chemical energy of wood into heat. Or, in lift irrigation, a diesel engine converts chemical energy of oil into mechanical energy for powering the shaft of a pump which, in its turn, converts shaft power into potential energy of water.
Forms of energy
Energy can exist in various forms. Examples are:
- Radiation energy: the radiation from the sun contains energy, and also the radiation from a light or a fire. More solar energy is available when the radiation is more intense and when it is collected over a larger area. Light is the visible part of radiation;
- Chemical energy: wood and oil contain energy in a chemical form. The same is true for all other material that can burn. The content of chemical energy is larger the larger the heating value (calorific value) of the material is and, of course, the more material we have. Also animate energy (delivered by bodies of human beings and animals) is, in essence, chemical energy. Furthermore, batteries contain chemical energy;
- Potential energy: this is, for example, the energy of a water reservoir at a certain height. The water has the potential to fall, and therefore contains a certain amount of energy. More potential energy is available when there is more water and when it is at a higher height;
- Kinetic energy: this is energy of movement, as in wind or in a water stream. The faster the stream flows and the more water it has, the more energy it can deliver. Similarly, more wind energy is available at higher windspeeds, and more of it can be tapped by bigger windmill rotors;
- Thermal energy or heat: this is indicated by temperature. The higher the temperature, the more energy is present in the form of heat. Also, a larger body contains more heat;
- Mechanical energy, or rotational energy, also called shaft power: this is the energy of a rotating shaft. The amount of energy available depends on the flywheel of the shaft, i.e. on the power which makes the shaft rotate;
- Electrical energy: a dynamo or generator and a battery can deliver electrical energy. The higher the voltage and the current, the more electrical energy is made available.
Energy sources
- Biomass. We distinguish between: woody biomass (stems, branches, shrubs, hedges, twigs), non-woody biomass (stalks, leaves, grass, etc.), and crop residues (bagasse, husks, stalks, shells, cobs, etc.). The energy is converted through combustion (burning), gasification (transformation into gas) or anaerobic digestion (biogas production). Combustion and gasification ideally require dry biomass, whereas anaerobic digestion can very well take wet biomass. Fuel preparations can include chopping, mixing, drying, carbonizing (i.e. charcoal making) and briquetting (i.e. densification of residues of crops and other biomass).
- Dung from animals, and human excreta. The energy is converted through direct combustion or through anaerobic digestion.
- Animate energy. This is the energy which can be delivered by human beings and animals by doing work.
- Solar radiation, i.e. energy from the sun. We distinguish between direct beam radiation and diffuse (reflected) radiation. Direct radiation is only collected when the collector faces the sun. Diffuse radiation is less intense, but comes from all directions, and is also present on a cloudy day. Solar energy can be converted through thermal solar devices (generating heat) or through photovoltaic cells (generating electricity). Direct beam solar devices (whether thermal or photovoltaic) would need a tracking mechanism to have the device continuously facing the sun.
- Hydro resources, i.e. energy from water reservoirs and streams. We distinguish between: lakes with storage dams, natural heads (waterfalls), weirs, and run-of-river systems. Hydro energy can be converted by waterwheels or hydro turbines.
- Wind energy, i.e. energy from wind. Wind machines can be designed either for electricity generating or for water lifting (for irrigation and drinking water).
- Fossil fuels, like coal, oil and natural gas. Unlike the previous energy sources, the fossil energy sources are non-renewable.
- Geothermal energy, that is, the energy contained in the form of heat in the earth. A distinction is made between tectonic plates (in volcanic areas) and geo pressed reservoirs (could be anywhere). Geothermal energy is, strictly speaking, non-renewable, but the amount of heat in the earth is so large that for practical reasons geothermal energy is generally ranked with the renewable. Geothermal energy can only be tapped at places where high earth temperatures come close to the earth's surface.
Energy management
Energy management includes planning and operation of energy-related production and consumption units. Objectives are resource conservation, climate protection and cost savings, while the users have permanent access to the energy they need. It is connected closely to environmental management, production management, logistics and other established business functions.
Definition
- Energy management is the discipline and measures executed to achieve the minimum possible energy use and cost while meeting the true needs of the activities occurring within a facility. Actions intended to achieve this energy efficiency focus on reducing necessary end-use, increasing efficiency, reducing wasted energy, and finding superior energy alternatives.
- Energy management is the proactive, organized and systematic coordination of procurement, conversion, distribution and use of energy to meet the requirements, taking into account environmental and economic objectives.
- The strategy of adjusting and optimizing energy, using systems and procedures so as to reduce energy requirements per unit of output while holding constant or reducing total costs of producing the output from these systems
Why is energy management important?
Energy management is the key to saving energy in your organization. Much of the importance of energy saving stems from the global need to save energy - this global need affects energy prices, emissions targets, and legislation, all of which lead to several compelling reasons why you should save energy at your organization specifically.
- The global need to save energy - If it wasn't for the global need to save energy, the term "energy management" might never have even been coined... Globally we need to save energy in order to:
- Reduce the damage that we're doing to our planet, Earth. As a human race we would probably find things rather difficult without the Earth, so it makes good sense to try to make it last.
- Reduce our dependence on the fossil fuels that are becoming increasingly limited in supply.
- Controlling and reducing energy consumption at your organization - Energy management is the means to controlling and reducing your organization's energy consumption... And controlling and reducing your organization's energy consumption is important because it enables you to:
- Reduce costs – this is becoming increasingly important as energy costs rise.
- Reduce carbon emissions and the environmental damage that they cause - as well as the cost-related implications of carbon taxes and the like, your organization may be keen to reduce its carbon footprint to promote a green, sustainable image. Not least because promoting such an image is often good for the bottom line.
- Reduce risk – the more energy you consume, the greater the risk that energy price increases or supply shortages could seriously affect your profitability, or even make it impossible for your business/organization to continue. With energy management you can reduce this risk by reducing your demand for energy and by controlling it so as to make it more predictable.
On top of these reasons, it's quite likely that you have some rather aggressive energy-consumption-reduction targets that you're supposed to be meeting at some worrying point in the near future... Your understanding of effective energy management will hopefully be the secret weapon that will enable you to meet those aggressive targets...
How best to manage your energy consumption?
We identified four steps to the energy-management process above. We'll cover each of them in turn:
- Metering your energy consumption and collecting the data - Detailed interval energy consumption data makes it possible to see patterns of energy waste that it would be impossible to see otherwise. For example, there's simply no way that weekly or monthly meter readings can show you how much energy you're using at different times of the day, or on different days of the week. And seeing these patterns makes it much easier to find the routine waste in your building.
- Finding and quantifying opportunities to save energy - The detailed meter data that you are collecting will be invaluable for helping you to find and quantify energy-saving opportunities. We've written an article that explains more about how to analyze your meter data to find energy waste. The easiest and most cost-effective energy-saving opportunities typically require little or no capital investment. For example, an unbelievable number of buildings have advanced control systems that could, and should, be controlling HVAC well, but, unbeknown to the facilities-management staff, are faulty or miss configured, and consequently committing such sins as heating or cooling an empty building every night and every weekend
- Targeting the opportunities to save energy - Just finding the opportunities to save energy won't help you to save energy - you have to take action to target them. For those energy-saving opportunities that require you to motivate the people in your building, our article on energy awareness should be useful. It can be hard work, but, if you can get the people on your side, you can make some seriously big energy savings without investing anything other than time.
- Tracking your progress at saving energy
- Energy savings that come from behavioural changes (e.g. getting people to switch off their computers before going home) need ongoing attention to ensure that they remain effective and achieve their maximum potential.
- If you've invested money into new equipment, you'll probably want to prove that you've achieved the energy savings you predicted.
- If you've been given energy-saving targets from above, you'll need to provide evidence that you're meeting them, or at least making progress towards that goal...
- And occasionally you might need to prove that progress isn't being made (e.g. if you're at your wits' end trying to convince the decision makers to invest some money into your energy-management drive).
0 Comments