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ALTENER
Biomass District Heating Plants Guidelines |
Introduction
This is one of a series of leaflets covering
biomass (wood) combustion systems in Austria, where wood provides the
greater proportion of energy for heating of domestic buildings, hotels,
etc in many regions. This may be through district heating as described
here, or smaller individual biomass boilers in the 5 to 100 kw range (see
Small Scale Biomass Boilers Guide).
Currently Austria has around 300 biomass district heating plants (generating a total of around 450 MW), operated as co-operative associations or private companies as well as by municipalities or power supply companies. This leaflet indicates the critical points concerning installation of such a plant, as well as considering aspects of marketing and customer service. The leaflet has been produced in association with a number of people (as detailed below) who provide consultancy with their services offered right from initiation of the project, through installation and commissioning and can continue the first years of operation. Hence, as indicated in the leaflet: The presentation covers only the most crucial aspects and shall not serve as a substitute for professional planning.
The leaflet defines biomass district heating plants as those that produce heat by the combustion of fuels of biological origin and supply this to their clients by means of a distribution and considers the benefits that may be summarised as follows. Larger plant overcomes criticism (efficiency and level of emissions) of smaller systems. Their efficiency is around 80 to 90 %, while emissions are similar to those from oil- and gas-fired furnaces. However, biomass does not contribute to the increase of atmospheric carbon dioxide as plants absorb and accumulate carbon dioxide during growth. This benefit will become more and more importance in the future, while use of biomass heating systems provides local employment opportunities. The fact that the fuel is produced locally and will therefore be available even in times of crisis is a comforting thought for the customers of biomass district heating plants.
Statistical Data
The leaflet provides the
following information concerning the 1993 Austrian energy supply of 1235
petajoule (PJ), as 783 PJ from imports (63.4 %), 439 PJ from national raw
material (35.6%) and 13 PJ from stored supply (1%). The two major national
energy supplies are hydro and biomass (with 110 PJ provided by fire wood,
chipped wood and bark), which is important in rural areas. In Austria, a
country where 47 % of the total area are wood, the heating of living
spaces with biomass (wood) has a very long tradition. Four fifth of the
wooded area of 3.9 million ha are privately owned, 20 % are owned by local
authorities, the provinces or the Federal Government, with an annual
increase of wooded area of 7,700 ha. Every second the Austrian forest land
grows by 1 cu m. The annual increment amounts to 31.4 million cu m of
wood. As the annual rate of felling is only 19.8 million cu m the growing
stock, which is 980 million cu m, is still increasing.
In Austria there are about 3 million dwellings of which one fifth are heated with wood, this included (in 1996), 305 plants with a total output of 434 MW, ranging from 1 to 2 MW, with an average of 1.4 MW.
Fuels
The Austrian biomass district heating
plants are fuelled by chipped wood and by-products of wood processing,
that are covered by the following Austrian standards.
ONORM M 7132: Energiewirtschaftliche Nutzung von Holz und Rinde als Brennstoff; Begriffsbestimmungen und brennstomechnologische Merk-male (1986); [Energy-economical utilisation of wood and bark as fuel; definitions and combustion properties].
ONORM M 7133: Holzhackgut fur energetische Zwecke - An-forderungen und Prufbestimmungen (1998); [Chipped wood for energetic purposes - Requirements and test specifications].
ONORM M 7135: Presslinge aus naturbelassenem Holz und naturbelassener Rinde - Pellets und Briketts -Anforderungen und Prufbestimmungen (1998); [Compressed wood and compressed bark in natural state - Pellets and briquettes - Requirements and test specifications].
Straw is used as a fuel in arable regions with a surplus of straw. Normally straw is pressed and stored in large bales. According to the technology of the plant the straw is either cut or transported in blocks into the boiler. In other systems whole bales are used. Fed into the boiler through a canal, with the bales burned at the surface.
The leaflet contains the following information concerning the costs of various biomass fuels. However, it points out that various district heating plants use very different calculation procedures. In most cases accounting for the water content of the fuel.
| Net calorific value (dry MJ/kg) |
Typical water content at delivery (%) |
Approximate price ATS/cu m fuel |
|
| Chipped wood from forestry |
18.5 | 30 -35 | 180 - 250 |
| By-products of wood processing with bark |
18.5 | 40 - 50 | 90 - 150 |
| By-products of wood processing without bark |
18.5 | 40 - 50 | 150 - 180 |
| Sawdust | 18.5 | 40 - 50 | 50 - 90 |
| Bark | 19.0 | 40 - 60 | 40 - 80 |
| Straw | 17.3 | 15 - 20 | 45 - 60 |
Project scheme
The following table is
provided in the leaflet as a 'project scheme' for the installation of a
biomass district heating plant, providing a rough indication of the
chronological order of the various parts of the project, indicating that
most of the time is invested in the planning stage, before the building
process starts.
| actors. | actions, documents | |
| IDEA | private consumers, fuel providers, residential building co-operatives, local authorities, others | discussion, basic considerations, search for supporters |
| INFORMATION ROUGH SKETCH | local authorities, information centres, planner, interested parties | inspection tours, first calculations of economic efficiency, data recording, examples, assistance |
| PRELIMINARY PROJECT, DETAILED STUDY | information centres, planners, others | layout plan, stages of construction, potential locations, prognosis, consumption, rough cost estimate, determination of finance opportunities, calculations of economic efficiency, canvassing of customers |
| BUSINESS FOUNDATION | committee of proponents, plant operators | foundation procedures, notarial procedures |
| CALL FOR TENDERS and ASSIGNMENT of the PLANNING | plant operators, information centres | test call for tenders, planning requirements |
| OFFICIAL PROCEDURE | trade authority, building authority, others, plant operators | requirements, negotiations |
| DETAILED PLANNING | planners | individual parts of the project, time schedule, preparation of the tender documents |
| CALL FOR TENDERS | planners | call for tenders |
| AWARD OF CONTRACTS | planners, plant operators | examination of tenders, decision on the award of contracts |
| CONSTRUCTION | companies, plant operators | construction, building inspection, own contribution to the project |
| OPENING, TRAINING | providers, plant operators | trial operation, authorised testing, opening |
| OPERATION | plant operators | supply of fuel, customers' service, economic matters, controlling |
A more detailed description of the various parts of the project are also given. These include the following comments.
IDEA The idea to install a biomass district heating plant is considered by single persons, discussed among various groups of persons, debated in a pub, spread among friends, . . The actors are interested customers, fuel providers,...In the end the idea very often can hardly be traced back to its origins. However, it is only important that the idea originated and that a group of project proponents took it up. The final success of the project depends on every single participant, the providers of fuel and heat, the consumers, the local authorities, sponsors, planners and building companies.
INFORMATION. ROUGH SKETCH During this stage of the project various district heating plants are inspected and information is exchanged. Know-how, records and pictures are collected in an inspection folder. After the first inspection of the area to be supplied with heat a rough sketch is developed in co-operation with consulting centres and companies. This should contain the potential route of the pipes, locations, forms of company and existing barriers to construction. The determination of the potential amount of heat to be supplied by the plant is a basic requirement. The data is collected and the feasibility of construction is examined. A first reference point for calculation of the potential heat requirements is the relationship between length of the pipes and the consumers' demand of heat. In ideal circumstances the range of 1 to 1.5 should not be exceeded. This means that a minimum energy demand of 1 kW per 1 metre pipe length should be achieved. The whole region potentially supplied with heat can be divided into profitable and non-profitable areas. For a rough evaluation of the economic efficiency estimated values concerning the costs for the construction of the furnace room, storeroom, boiler and network are used. These values are divided by the estimated profits in order to calculate the time of amortisation. There are no clear boundaries between the rough scheme and the preliminary project.
PRELIMINARY PROJECT. DETAILED STUDY. FINANCING After a rough assessment of whether the project can be realised, a detailed study is prepared. The basic data of the rough scheme is completed in detail and a plan for the first stage of construction is drawn up. Apart from the detailed recording of data a general idea of financial opportunities and subsidies has to be obtained. As it is impossible to wait for calls for tenders in order to be accepted for assistance programmes, the collected material will serve as a basis for the authorisation of financial assistance. In order to evaluate the demand it is absolutely essential to establish contact with potential consumers and to prepare meetings, leaflets and forms for those who intend to be connected to the network, during the preliminary project. Basically financing is divided into own resources, freely financed credits, assisted credits and direct financial support. The financial means depend on the form of the company and includes initiatives such as credit for agricultural investments, direct support from the Federal Ministry of Agriculture and Forestry, Austrian Communal Credit and financial support for the renovation of houses.
FOUNDATION OF A COMPANY The decision on the form of the company has to be taken during the planning stage, as it will influence financing decisively. Depending on the circumstances it is recommended to found unincorporated firms and joint-stock companies. However, general partnerships, limited partnerships, private companies and co-operatives lie within the range of possibility. In Austria most district heating plants are co-operatives and private companies.
CALL FOR TENDERS AND ASSIGNMENT FOR THE PLANNING The planning does not only include a detailed technical planning,, but also preparatory contracts, organisation of information meetings, drawing up of contracts for the supply of heat, sale organisation, application for and obtaining of permissions, organisation of administration and clearing procedure, setting up of schedules an schemes, training, etc. Above all the operators have to decide on their own contribution to the project. A call for tenders allows for the comparison of different tenders. The description of performances has to be formulated in such a way that it can be used both for the tender and for the contract. It has proven appropriate to agree on fixed prices and not on percentages of the building costs.
OFFICIAL PROCEDURE For the official procedure a number of documents have to be prepared. The first centres of information are the local authorities and district administration authorities. During the negotiations concerning trade law and building matters the submitted documents are examined, objections are considered and emission limits are determined.
DETAILED PLANNING The detailed planning has to be carried out and co-ordinated by a chief planner. Even if the operator wants to work on certain planning stages on its own the coordination and timing should be carried out by a professional planner. The detailed planning consists of the dimensioning of the different parts of the project, the drawing up of forms for calls for tenders, the examination and comparison of tenders, the negotiations and the award of contracts.
CALLS FOR TENDERS The calls for tenders for a biomass district heating plant project include data about the type of fuel used in the plant and detail the requirements of various authorities (e.g.: emission limits). The calls for tenders can be divided into:
The detailed specification indicates the importance of the effort and the value of a well elaborated call for tender.
AWARD OF CONTRACTS Tenders for the individual parts of the project submitted in due time are examined according to their completeness and correctness and compared with the tenders of the competitors. The best tender and not the cheapest one shall be awarded the contract. Furthermore, it is recommendable to check the company concerning its management and its ability to solve problems.
CONSTRUCTION As soon as the construction is started most of the preliminary work will be finished. Now, the most intensive phase of the project will begin. Intense activity does not only dominate at the building site itself, but also at excavation sites, where the installation of the pipes may lead to many problems with the population. During the construction period the schedule and the quality shall be checked and the target and the actual achievements shall be compared continuously. For this purpose supervising staff may be trained Quality control is essential if the pipes are, for example, partly installed by the operator.
OPENING. TRAINING If in the end the plan is finally put into effect, surely the time has come to celebrate the success with all those who have participated in the project. However, some final activities still have to be carried out. The opening of the plant ready for operation and the testing of performance and emissions has to take place according to the contract. In the presence of the manufacturer the results are recorded and deadlines for the elimination of potential shortcomings are determined. The operators of the plant have to be trained in the best possible way so that they are able to cope with any problems occurring in future. For serious problems and defects plans of proceeding shall be elaborated (hot line to the manufacturer, etc.). The pipes, the combustion and the network have to be adjusted. An audit of accounts has to be carried out and included in the test report.
OPERATION, MARKETING. CUSTOMER SERVICE After many weeks of hard work still some small problems are likely to occur. And very often the heating season has already started. The future economic management will require to keep records right from the beginning. It does not have to be a very complicated system of recording. The most simple way will be to write down in an operational journal the meter readings, fuel deliveries and possible operating troubles. If the distributing system is equipped with an operating remote control reading and the plant is automatically recording the operational condition the data obtained can be read and checked by the computer. A special software available on the computer market records the amount of heat delivered to every single customer and bills them automatically according to the calculations. These data will be used as the basic information to draw up the balance sheet. Fur-thermore the data will serve for possible changes of the structure of business, the organisation or the balance.
Whether the customers of district heating plants are satisfied with the plant or not does not only depend on the price. In a survey among customers of various district heating plants it became clear that good information and service on part of the op-erator are much more important for the decision in favour of district heating than low prices. The consumers expect the plant to react immediately if problems occur. Moreover, it is desirable to involve a very broad range of the population in the proj-ect "district heating". Invite the children of the local schools to visit the plant and to have a snack, or to create paintings and produce some group work concerning the topic of district heating. Organise an audio-visual show about the installation or a tour through the plant for groups of pensioners. Let your imagination flow, but do not forget: all activities have to be well prepared and carried out with commitment and enthusiasm.
In the beginning it will be of major importance to attract consumers. Once they have signed the contract the service of the operator should not be limited to the reading of the meter and the distribution of bills. Information may also be disseminated through periodic circulars, local newspapers, etc. and will therefore also be available for other persons than the consumers. Some operators also provide additional service: they regulate the distribution of heat in the dwellings of their customers. By means of the remote control the room temperature may be regulated during the absence of the consumer.
GENERAL DATA. CHARACTERISTIC DATA: The installation of a continuous output of 1 MW will cost 11 to 12 million schillings. This amount includes the building, the combustion and other technical installations like flue gas purification, controller device, pumps, pipes, the planning and additional costs. The losses from the pipes (the difference between the heat meter and the amount of heat balanced) should not exceed 20 % if the plant is operated the whole year round. If the hydraulic system of the network works efficiently the temperature may differ by as much as 40°C between the flow temperature and the return temperature. The proportion between the consumption of electricity and the generated heat will at its best be 1 %, i.e. 10 kWh electricity are needed for the generation and distribution of 1 Mwh heat. Another important parameter is the amount of water pumped through the network, compared with the amount of heat required. The minimal value lies at 30 m'/MWh heat required by the consumers.
In Austria there are 12 biomass district heating plants which are operated in combination with a system of solar cells. Part of the energy required for the preparation of hot water can be generated by means of the solar system. During the summer month 90 % can be covered by solar energy.
Developed in cooperation with:Contacts
Editor
Participant
© Copyright 2006 Policy Statements
Updated
by CPL Press:
03/07/2007
- biomatnet@biomatnet.org
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