Sustainable Heat Use of Biogas Plants. Questions & Answers

Transcription

1 Sustainable Heat Use of Biogas Plants Questions & Answers

2 Author: Reviewers: Published: Ingo Wagner Ilze Dzene, Stefan Amann, Christof Amann, Željka Fištrek, Jadranka Maras Abramovic, Jørgen Hinge, Frederico De Filippi, Rita Mergner, Dominik Rutz 2014 by Euroheat & Power, Brussels, Belgium Contact: Euroheat & Power, Cours St Michel 30a Box E, Website: 1040 Brussels, Belgium, Tel , Copyright: All rights reserved. No part of this book may be reproduced in any form or by any means, in order to be used for commercial purposes, without permission in writing from the publisher. The authors do not guarantee the correctness and/or the completeness of the information and the data included or described in this handbook. Disclaimer: The sole responsibility for the content of this handbook lies with the authors. It does not necessarily reflect the opinion of the European Union. Neither the EACI nor the European Commission are responsible for any use that may be made of the information contained therein. 2

3 Acknowledgements This publication with questions and answers was elaborated in the framework of the BiogasHeat project (IEE/11/025), supported by the European Commission through the Intelligent Energy for Europe (IEE) programme operated by the Executive Agency for Small and Mediumsized Enterprises (EASME). The authors would like to thank the European Commission for the support of the BiogasHeat project as well as the reviewers and BiogasHeat partners for the preparation of and contributions to the questions and answers covered in this publication. The BiogasHeat project The BiogasHeat project addresses the problem of how to efficiently use the heat from biogas plants at the European, national and project level. Thereby a set of different policies, best practices, field tests and project implementation measures were developed and used. The specific objectives of the BiogasHeat project are: 1. to support the utilisation of otherwise wasted heat from existing and future biogas plants; 2. to increase the ability to do so in the target countries (Austria, Croatia, Czech Republic, Denmark, Germany, Italy, Latvia, and Romania) through specific analysis of technical options, feasibility studies, entrepreneurial strategy development and field testing to address key barriers; and 3. to boost capacity through training, skills enhancement, and knowledge transfer. BiogasHeat started in April 2012 and lasted 3 years. The project was supported by the Intelligent Energy for Europe Programme of the European Union (Contract No IEE/11/025). 3

4 Contents Acknowledgements 3 The BiogasHeat project 3 General Questions & Answers 5 Why should heat from biogas be utilised?... 5 How can heat from biogas plants be utilised?... 6 Where can heat from biogas plants be utilised?. 7 Operational Questions & Answers 8 Questions on various heat utilisation possibilities... 8 How can biogas plants compensate for seasonal variations in heat consumption? What are the prospects for investors? What is the role of heat as (main) source of income? Who is responsible for measuring the heat? Policy-related Questions & Answers 12 What are typical examples of incentives for facilitating the heat use from biogas plants in Europe? What are the major bottlenecks for heat utilisation? What is the future for heat utilisation from biogas without FiT, certificates? What does highly-efficient CHP mean?

5 General Questions & Answers Why should heat from biogas be utilised? The question is rather why not? Not utilising heat from incineration amounts to wasting more than 50% of the energy content of the energy carrier, in this case biogas. Wasting heat is not just illogical as it wastes energy, but also results in macroeconomic and microeconomic losses. The macroeconomic level Energy in Europe is not self-evident, as European countries are heavily dependent on energy imports, climate change is forcing the EU to decrease its CO 2 emissions, and climate change policies highlight the need for renewable resources. At the same time prices for natural resources are continuously rising due to high demand and changes in land use. Biogas represents a renewable and domestic resource that plays a role in all these fields. Therefore, the utilisation of heat from this source decreases the need for energy imports, but also substitutes non-renewable energy carriers and cuts CO 2 emissions. Its potential for efficient use, i.e. utilising the surplus heat, brings major benefits as it results in a decreased primary energy demand. Also, the more efficient use diminishes the pressure on the market for less fossil fuel resources. The microeconomic level While plant operators are under pressure due to decreasing support for electricity production, heat consumers are in continuous need of affordable energy to cover their demand. Heat utilisation from biogas addresses both their concerns. On the one hand, the revenue from heat sales add to the income of plant operators and help them substitute subsidies while ensuring continued production. On the other hand, heat from biogas is a local and affordable heat source for consumers. 5

6 How can heat from biogas plants be utilised? There are various technical options when it comes to utilising heat. A one-size-fits-all recommendation does not exist. The way to optimally use heat depends very much on the specifications and capacity of the biogas plant, the location of the plant and offset markets, and the legal framework. The following table offers an overview over the most common uses of biogas heat energy: Table 1: Heat utilisation options (Rutz 2013) Option Heating Drying Cooling Electricity production Uses District heating Heating of stables Heating of greenhouses Heating for aquaculture Heat transport in containers Drying wood, woodchips, and pellets Drying agricultural products Drying digestate and sewage sludge District cooling Cooling of buildings Cooling of stables Acclimatisation of food storage buildings Process cooling Additional electricity production with CRC, ORC or Kalina technologies Other heating options 6

7 Where can heat from biogas plants be utilised? Spatially, heat from biogas plants can be used for industry or in houses or buildings in the area of the production plant. The heat energy is transferred through (underground) pipe connections. For heat as a final product, experience indicates that reasonable distances can be 1 to 5 kilometres away from the plant, depending on the local circumstances. A typical proposal can be seen in Figure 1. In order to better inform the business cases and project planning processes for biogas plants, the project consortium is documenting and summarising all experience gained from field testing. Figure 1: Possible piping in Zamberk, Czech Republic. 7

8 Operational Questions & Answers Questions on various heat utilisation possibilities a) What is the value of the heat sold from district heating systems compared to heat used at the farm (when talking about farm biogas plants)? The monetary value of the heat produced depends heavily on the end-use of the heat, and national policies, especially tax regulations. For example, in Denmark, the value of the heat delivered to private households through district heating grids is substantially higher than heat used for industrial/process purposes. This is because tax is higher for heating used for private purposes than heat used for industrial purposes. As such the value of the heat sold can best be assessed through feasibility studies and business case development on a case by case basis. b) Is it more feasible to upgrade biogas for natural gas grid injection than to use it in CHP units? Once again, this differs per case and depends on a number of factors. The most important determinants are the size of the biogas plant (annual production), the distance to the nearest natural gas grid, the feed-in tariff for electricity production, the availability of support for biomethane injection or use in transport, and the possibilities of using heat from cogeneration. A feasibility study must be completed to tell decisively. c) At what size of biogas plant does it become economically feasible to upgrade biogas to biomethane? Technically it is feasible to upgrade biogas to biomethane at nearly any size biogas plant. However, on a commercial level it is only feasible for larger plants. Thereby, the costs for the production of the raw biogas are a crucial factor. Currently, in Germany, only facilities with a capacity of about 250 m³ to 500 m³ of upgraded biomethane per hour are economically feasible. 8

9 d) Can heat be used to generate extra electrical energy? An example is the organic Rankin cycle (ORC). ORC allows generation of an electrical output power of 125 kwhel from 980 kwth. If the use of ORC generates an increase of the electrical power which decreases the FiT value, then it can be better to avoid working at full power. Similarly, if the feed represents a cost, it would be better to reduce the feed. If the feedstock does not represent a cost (for example waste) and the power increase generates a loss in the FiT, the ORC option should not be considered. e) What is the status of mobile heat transport in containers? The use of mobile heat storage containers is not yet widely implemented. Only a few technology providers exist and some pilot projects have been realised. An example is the German company LaTherm which has implemented mobile biogas heat storage containers in Berlin and Leipzig. Containers are used for landfill gas and waste incineration plants. However, most installations are not set up in connection with heat from biogas plants. f) How could the digestate in waste water treatment plants be used? Utilising heat to reduce the quantity of digestate is often not a viable solution due to various difficulties, which include the reduction of nitrogen content. In waste water treatment the potential to use heat is difficult due to the chemical composition of the digestate. Waste water digestate could contain harmful chemical compounds, and as such the only available treatment is to store the digestate and thus abate environmental risks. However, if reduction for storage is the aim, excess heat can be used to reduce the water content and make proper storage easier and cheaper. 9

10 How can biogas plants compensate for seasonal variations in heat consumption? Depending on the type and availability of substrates, it is possible to regulate biogas production on a seasonal basis. However, in many situations it is more feasible to optimise the biogas production to ensure maximum electricity production, especially for farm biogas plants. If large quantities of excess heat are available, alternative applications focusing on the utilisation of excess heat should be examined. For example, using heat to dry wood products or agricultural commodities would allow for heat utilisation in summer. Alternatively, during the summer heat can be used for cooling purposes. The BiogasHeat project is describing and evaluating all alternatives in terms of optimisation of heat use. What are the prospects for investors? The prospects for investors are positive, for two different reasons. The use of CHP is becoming increasingly attractive as energy efficiency and decentralised production gain more traction in Europe and become increasingly incentivised. The use of biogas as a fuel is becoming more important and relatively cheaper as non-fossil fuels are valued higher and natural gas supplies become less reliable and more expensive. Together, this provides a positive outlook for potential biogas heat investors. 10

11 What is the role of heat as (main) source of income? Generally the income from heat sales is seen as an additional income to the profit from electricity sales. The sale of biogas heat can be achieved at a relatively low marginal cost for relatively high marginal benefit, but only once the whole installation is there and in conjunction with electricity production. Who is responsible for measuring the heat? The measurement of heat at production and consumption level is the responsibility of the provider. Generally providers place converter substations at the household or building level, which convert the heat from the (closed) production system to the heat supply unit, and simultaneously measure consumption so producers can charge appropriately. 11

12 Policy-related Questions & Answers What are typical examples of incentives for facilitating the heat use from biogas plants in Europe? In order for biogas plants to produce electricity under cogeneration regulations, they must comply with the highefficiency CHP requirements of the EU (see page 15). These requirements have been transposed from the Cogeneration Directive (2004/8/EC) and other related Directives into national legislation. In order to reach such high-efficiency CHP requirements, biogas plants must have useful heat use. In some European countries heat use from biogas plants is facilitated by CHP bonuses. For example, in Germany the introduction of the so-called CHP bonus in the 2004 amendment of the Renewable Energy Act (EEG) resulted in a significant increase of heat utilisation in biogas plants. In addition to the basic feed-in tariff, the law had foreseen an additional payment of 2 c/kwh if the waste heat of the CHP plant was also used. With the increase of the CHP bonus in the new version of the EEG in 2009, the incentive to expand the use of the waste heat was further strengthened. This law introduced a CHP bonus ranging from 2.94 Ct/kWh to 3 Ct/kWh for waste heat use. The amended EEG introduced a so called positive list for heat recovery. By using a solution on this list an increased CHP bonus could be obtained. With the amendment of the EEG in 2012, the CHP bonus of the old feed-in tariff system of 2009 was replaced by an obligation to use the heat of biogas plants. As of 1 January 2012, biogas operators of newly installed biogas plants in Germany are required to use at least 25% waste heat during the first year of operation and at least 60% heat in the following years from the CHP plant. 12

13 What are the major bottlenecks for heat utilisation? Heat utilisation from biogas faces a broad variety of bottlenecks, including issues of awareness, capacity, social acceptance, legal and political questions. Table 2 gives an overview of bottlenecks in various project countries. Table 2: Bottlenecks in BiogasHeat project countries Country Austria Bottleneck Injection of heat into DHN is almost exhausted, many plants are in rural areas with little local heat markets, uncertainty for producers with respect to demand changes. Croatia Czech Republic Denmark Lack of awareness, lack of knowledge, lack of incentives, lack of transparency of legislation. Missing specifications of reasonable heat utilisation options, lack of incentives. On-site utilisation creates wasted heat surpluses in summer, local resistance against centralised plants, industrial utilisation unattractive because of Danish legislation Germany Distance/placement, under 60% obligation, uncertainty for producers when heat demand changes, lack of continuity and financing in DH support programmes, only new plants Italy Latvia Lacking recognition of heat as primary energy source, heat utilisation not obligatory RES feed-in tariff competes with heat utilisation tariff, positive list excludes self-consumption, lack of control, DH operators do not benefit Romania Lack of clarity in green certificate legislation, biogas not part of national energy policy, lack of measures designed to encourage heat utilisation from biogas (district heating development procedures, drivers, etc.). Financing of the biogas projects still remains a bottleneck. 13

14 What is the future for heat utilisation from biogas without FiTs and certificates? In the future, electricity production will be increasingly flexible. This means that biogas plants will be important when it comes to stabilising power grids as the shares of (fluctuating) power production from other renewables such as photovoltaics and wind energy increase. The flexibilisation of the power production from biogas has impacts on the heat production, which may require investments in storage or buffer tanks and additional biogas boilers. However, as has been displayed by some European governments, there are also strong arguments for subsidising biogas: as a possible reduction tool for GHG emissions, as a solution for pathogens in animal sludge, as a solution for poor nutrient soils, or as a solution for electricity and heat problems. In many countries the production of biogas has been seen also as a way of increasing the revenue of farmers. Biogas production received very important support directed especially towards its potential for electricity production and not towards the use of bio waste for different products. It is very difficult to predict the future of biogas without FiT or Green Certificates. In many cases biogas could prove to be economically unsustainable, as the price of biogas will be closely connected to the price of corn and may exceed the revenue that can be made from biogas production. However, using the heat from biogas plants can bring supplementary revenue, and as such cogeneration could prove to be part of the solution when it comes to keeping biogas economically viable. 14

15 What does highly-efficient CHP mean? In Directive 2004/8/EC (the CHP Directive) high efficiency cogeneration is defined as cogeneration with primary every savings of at least 10% compared with the references for separate production of heat and electricity, which can include small scale and micro unit production, More information of calculation methods of energy savings and reference values can be found in Annex III of the CPH Directive, Directive 2012/27/EU and implementing decisions No. 2008/952/ES and No. 2011/877/EU. By the time this brochure was written the reference values were under scrutiny and thus subject to change. 15

16 Project Consortium and National Contact Points: Ekodoma, Latvia (Project coordinator) Ilze Dzene WIP Renewable Energies, Germany Dominik Rutz Rita Mergner Energy Institute Hrvoje Požar, Croatia Željka Fištrek Jadranka Maras Abramović Energy Efficiency Center SEVEn, Czech Republic Tomáš Voříšek Sogesca Srl, Italy Federico De Filippi e7 Energie Markt Analyse GmbH, Austria Christof Amann Stefan Amann Danish Technological Institute, Denmark Jørgen Hinge SC Mangus Sol Srl, Romania Mihai Adamescu Euroheat & Power, Belgium Ingo Wagner