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Energy Efficiency

1. Energy services

With the rising prices of traditional energy sources like oil, gas and coal, the installation and operation of technology dedicated to the efficient production and management of energy is gradually becoming more and more profitable. In general, two critical issues must be confronted: economics and financing, given the considerable sums of money required by investment in new technology; and the technical design and management of an integrated service that is optimized for the user’s needs. Public administrations represent a particular case, as they have to manage strict budgetary limitations which are usually below the overall needs and so often find themselves suffering from limited financial resources.

These difficulties can be overcome by turning to third-party funding (TPF). This involves the participation of a third party who provides the financial assets necessary to complete the work needed, provided that it is low risk and that the ensuing energy savings will result in a relatively stable cash flow. This allows the costs of installing and managing the system to be repaid within a reasonable time period. Energy Service Companies operate within this framework, raising the required funds, carrying out energy diagnoses and feasibility studies, planning the works, realizing them and then managing their maintenance and effectiveness. Some of these activities might be outsourced (for example the installation of the system and its maintenance) or be carried out by the ESCO (Energy Service Company) itself. At the end of the period required to recover the investment and repay the service company, the system has usually been paid off by the beneficiary of the works, while its management might be left to the ESCO or entrusted to other subjects.

SOURCE: FIRE - Federazione Italiana per l’uso Razionale dell’Energia (Italian federation for the rational use of energy), www.fire-italia.it

2. Cogeneration

Cogeneration (also known as combined heat and power or CHP) is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat. Conventional power plants emit the heat created as a by-product of electricity generation into the environment through cooling towers, flue gas or by other means. CHP or a bottoming cycle captures the by-product heat for domestic or industrial heating purposes, either very close to the plant, or - especially in Scandinavia and Eastern Europe – as hot water for district heating with temperatures ranging from approximately 80 to 130°C. This is also called decentralized energy.

Cogeneration is a thermodynamically efficient use of fuel. In separate production of electricity some energy must be rejected as waste heat, but in cogeneration this thermal energy is put to good use.

Thermal power plants (including those that use fissile elements or burn coal, petroleum, or natural gas), and heat engines in general, do not convert all of their available energy into electricity. In most heat engines, a bit more than half is wasted as excess heat. By capturing the excess heat, CHP uses heat that would be wasted in a conventional power plant, potentially reaching an efficiency of up to 89%, compared with 55% for the best conventional plants. This means that less fuel needs to be consumed to produce the same amount of useful energy. Also, less pollution is produced for a given economic benefit.

SOURCE: Wikipedia, http://en.wikipedia.org/wiki/Cogeneration

3. District heating

District heating (less commonly called teleheating) is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating. The heat is often obtained from a cogeneration plant burning fossil fuels or increasingly biomass, although heat-only boiler stations, geothermal heating and central solar heating are also used. District heating plants can provide higher efficiencies and better pollution control than localized boilers.

The core element of a district heating system is usually a cogeneration plant (also called combined heat and power, CHP) or a heat-only boiler station. Both have in common that they are typically based on combustion of primary energy carriers. The difference between the two systems is that, in a cogeneration plant, heat and electricity are generated simultaneously, whereas in heat-only boiler stations - as the name suggests - only heat is generated.

The combination of cogeneration and district heating is very energy efficient. A thermal power station which generates only electricity can convert less than approximately 50% of the fuel input into electricity. The major part of the energy is wasted in form of heat and dissipated to the environment. A cogeneration plant recovers that heat and can reach total energy efficiency beyond 90%.

SOURCE: Wikipedia, http://en.wikipedia.org/wiki/District_heating

Renewable Energy

1. Biomass

Biomass means every organic substance deriving directly or indirectly from photosynthesis. Through this process, plants absorb carbon dioxide (CO2) and water from the surrounding environment, and with the aid of chlorophyll, use solar energy and nutrients present in the soil to transform them into organic material which helps the plant grow. In this way around 2x1011 tons of carbon are fixed every year, with an energy content equivalent to 70 billion tons of oil.

Biofuels are solid, liquid or gaseous fuels obtained directly from biomass (e.g. firewood) or produced following the structural transformation of the organic material. The main biofuels are biodiesel, bio-ethanol, biogas, wood chips and wood pellets.

SOURCE: Italian Biomass Association, www.itabia.it

2. Photovoltaics

The solar radiation that reaches Earth can be converted into electrical energy through:

photovoltaic conversion, which allows the direct transformation of solar energy into electricity by exploiting the physical phenomenon of the photovoltaic effect, generated when light hits particular materials
thermal conversion (thermodynamics) which uses different technological systems to collect solar radiation and concentrate it on a thermo-vector fluid. The heat stored by the fluid is then transferred to the circuit of a conventional power plant for the production of electrical energy

The elementary device at the basis of photovoltaic technology is the photovoltaic cell, made up of a treated semiconductor material (generally silicon). A set of photovoltaic cells connected between themselves in series or in parallel constitutes the photovoltaic module, the commercially available base component. Several modules connected electrically between each other and mechanically installed in their operation site make up a photovoltaic array. A photovoltaic plant is made up of one or more photovoltaic arrays, inverters to convert the direct current into alternating current and the safety and monitoring components required by the relevant rules and regulations.

The main advantages of photovoltaic technology are:

absence of any kind of polluting emission during the system’s operation
saving of fossil fuels
extremely reliable, because usually there are no moving parts; service life is generally over 20 years
operation and maintenance costs reduced to the minimum
modularity of the system (all that needs to be done to increase the size is to increase the number of modules)

The following disadvantages must also be taken into consideration:

variability and unpredictability of the energy source (sunlight)
cost of the systems is currently quite high, as the market has not yet reached full technical and economic maturity

Due to the costly investment required to create a photovoltaic plant, in many European countries - Germany, France, Spain and Italy have taken the lead - the development of this technology is led and supported by government programmes and incentives, which have triggered rapid growth in the market.

SOURCE: GSE - Gestore Servizi Elettrici (Electrical services authority), www.grtn.it

3. Mini wind turbines

As with photovoltaic systems, small wind turbines with power up to a few dozen kW can be used both as autonomous systems, not connected to the mains (for isolated houses, water pumps or telecommunications), or as installations connected in parallel to the mains.

The development of this technology is still limited, but it has huge potential; in the United States, for example, the American Wind Energy Association (AWEA) has actually prepared a detailed “road map” involving the installation of 50,000 MW of small wind plants over the next six years, for an overall production of electrical energy equal to 3% of the USA’s consumption.

Italy’s potential is still limited but is growing thanks to the introduction of the possibility of net metering. This is available for plants supplied by renewable sources with a maximum power of 200 kW and allows energy produced by the wind turbine to be deducted from the electricity bill (in addition to a direct incentive per kWh produced). However the energy produced must not exceed that consumed. In that case the distributor will provide credit, on an annual basis for the following year, but the system’s owner will not be paid a monetary compensation for the surplus produced.

Advantages and costs:

small-scale wind turbine systems have many positive aspects. Above all there is a great availability of useable sites, because they take up limited space and do not require specific infrastructure for their installation
the local impact of these systems is also very low, given the small dimensions of the machines (rotors with diameters from 3 to 9 m, mounted on towers of 10 to 20 m) and the fact that special infrastructure is not needed
the costs of these systems is around 2,000-3,000 euros per kW installed, which is currently less than photovoltaic systems, and their installation can be economically advantageous in sites with an average wind speed of at least 5 m/s

SOURCE: Region of Lazio, www.regione.lazio.it