Optimal configuration for a
bio-solar-wind polygeneration system
in Klintehamn
Caroline Algarp
Astrid Svanfeldt
Bachelor of Science Thesis
KTH School of Industrial Engineering and Management Energy Technology EGI-2019
TRITA-ITM-EX 2019:318 SE-100 44 STOCKHOLM
Abstract
This project concentrates on the energy flows of Klintehamn and examines if it is possible for Klintehamn to be self-sufficient in the future. To reach this goal, the energy flows in Klintehamn must be analyzed. Subsequently, a new improved energy flow has been designed, where other renewable energy sources are included.
Klintehamn is an urban area on the Swedish island of Gotland. An industrial park is es-tablished in the harbour of Klintehamn, and currently a sawmill, a fodder production facility and a few wind turbines are located in the area. A program, Program Klintehamn 2030, outlines opportunities to develop Klintehamn in many areas. The goals for Klintehamn are to increase the use of renewable energy sources and decrease greenhouse gas emissions. More specifically, this includes building a biogas plant by evolving the already established sewage treatment plant, and increasing the use of renewable energy sources such as wind and solar energy.
Models of the Current Energy System and the Improved Energy System have been designed during the project. Calculations of the Current Energy System have been made and for the Improved Energy System, seven scenarios have been constructed. The calculations program, Matlab, has been used for all calculations. The following scenarios have been modeled in this project:
• Scenario 1 - Development of biogas • Scenario 2 - Increased wind power • Scenario 3 - Development of solar park • Scenario 4 - Development of solar panels
• Scenario 5 - Combination 1, scenario 1-4 added into one system • Scenario 6 - Combination 2, 100% renewable energy
• Scenario 7 - Combination 3, development of Scenario 5, with more renewable energy In the Current Energy System, the total yearly energy demand is 3.423 TWh, where 3.405 TWh is electricity and 18.2 GWh is heat. The future demand of electricity and heat will be 3.407 TWh and 265 GWh per year, respectively. Scenario 5 is the first combined scenario, where the current energy and all renewable energy sources are included. The generated elec-tricity in that scenario is not enough to satisfy the elecelec-tricity demand. Scenario 6 consists of 100% renewable energy sources. To achieve the energy demand of Klintehamn all the renew-able energy sources have been maximized in order to become self-sufficient. It generated an absurd result, which was far from realistic. Scenario 7 is an expansion of Scenario 5 but with more renewable energy. All energy sources have been expanded and Scenario 7 generates 108 GWh of electricity. Scenario 5 and Scenario 7 are two reasonable scenarios with reasonable amounts of renewable energy installed, but with different levels of ambition.
The conclusion of the project is that, it is possible to improve the current energy system. The energy system can become more sustainable and fossil energy sources can be removed and replaced by renewable energy sources. In order for Klintehamn to be self-sufficient, more energy sources must be included, for example wave power.
Sammanfattning
Det h¨ar projektet handar om energifl¨odet i Klintehamn och hur Klintehamn i framtiden ska kunna bli sj¨alvf¨ors¨orjande. F¨or att kunna g¨ora detta m˚aste dagsl¨agets energifl¨ode i Klinte-hamn utverderas. D¨arefter har ett nytt f¨orb¨attrat energifl¨ode konstruerats, d¨ar andra f¨ orny-bara energik¨allor ¨ar inkluderade.
Klintehamn ¨ar en t¨atort p˚a den svenska ¨on Gotland. En industripark ¨ar etablerad i Klinte-hamns hamnomr˚ade, och f¨or n¨arvarande ¨ar ett s˚agverk, en foderproduktionsanl¨aggning samt ett f˚atal vindkraftverk befentliga i omr˚adet. Ett program, Program Klintehamn 2030, har tagits fram, d˚a det finns m¨ojligheter att utveckla Klintehamn p˚a m˚anga omr˚aden. M˚al, f¨or att Klintehamn ska ¨oka anv¨andande av f¨ornyelsebar energi och s¨anka sina koldioxidutsl¨app i framtiden, har utvecklats. N˚agra specifika m˚al ¨ar att det ska byggas en biogasanl¨agning i anknytning till det befintliga reningsverket, samt att ut¨oka anv¨andningen av f¨ornybara en-ergik¨allor s˚a som vind och solenergi.
Modeller p˚a dagens energisystem och ett utvecklat energysystem i framtiden har konstruer-ats under projektets g˚ang. D¨arefter har ber¨akningar av dagens energisystem gjorts och f¨or framtida systemet har ett antal scenarion byggts upp och ber¨aknats p˚a. Alla ber¨akningar har gjorts med hj¨alp av ber¨akningsprogramet Matlab. Scenariona i detta projekt ¨ar f¨oljande:
• Scenario 1 - Utveckling av biogas • Scanario 2 - Ut¨okning av vindkraften • Scenario 3 - Utveckling av solpark • Scenario 4 - Utveckling av solpaneler
• Scenario 5 - Kombination 1, scenario 1-4 adderat till ett system • Scenario 6 - Kombination 2, 100% f¨ornybar energi
• Scenario 7 - Kombination 3, uteveckling av Scenario 5, med mer f¨ornyelsebar energi I det nuvarande energisystemet ¨ar den totala ˚arliga efterfr˚agan av energi 3.423 TWh, varav 3.405 TWh ¨ar elektricitet och 18.2 GWh ¨ar v¨arme. Den framtida efterfr˚agan av electricitet och v¨arme kommer vara 3.407 TWh respektive 265 GWh per ˚ar. Scenario 5 ¨ar det f¨orsta kombin-erade scenariot, d¨ar alla f¨ornybara energik¨allor ¨ar inkluderade. Den genererade elektriciteten i det scenariot ¨ar inte tillr¨aklig f¨or att n˚a efterfr˚agan. Scenario 6 best˚ar av 100% f¨ orny-bara energik¨allor. F¨or att uppn˚a Klintehamns energibehov har alla f¨ornybara energik¨allor maximerats f¨or att kunna bli sj¨alvf¨ors¨orjande. Det genererade ett absurt resultat, som var l˚angt fr˚an rimligt. Scenario 7 ¨ar en p˚abyggnad av Scenario 5, med ¨annu mer f¨ornyelsebar energi. Alla energik¨allor har ut¨okats och Scenario 7 genererar 108 GWh elektricitet. Sce-nario 5 och SceSce-nario 7 ¨ar tv˚a rimliga scenarion med rimliga m¨angder f¨ornybara energik¨allor installerade, men med olika ambitionsniv˚aer.
S˚a slutsatsen av projektet ¨ar att det g˚ar att f¨orb¨attra det nuvarande energisystemet. En-ergysystemet kan bli mer h˚allbart och fossila energik¨allor kan fasas ut och i stor utstr¨ackning ers¨attas med f¨ornybara energik¨allor. F¨or att Klintehamn ska kunna bli sj¨alvf¨ors¨orjande m˚aste fler energik¨allor inkluderas, till exempel v˚agkraft.
Contents
1 Introduction 1
1.1 Aim . . . 1
1.2 Providers and energy users in Klintehamn . . . 1
1.2.1 Klintehamn . . . 2
1.2.2 Fodder production plant . . . 2
1.2.3 Foodmark-Rydbergs . . . 3
1.2.4 Harbour . . . 3
1.2.5 Sawmill . . . 4
1.3 Renewable Energy Sources . . . 4
1.3.1 Polygeneration . . . 5
1.3.2 Biogas . . . 5
1.3.3 Solar . . . 5
1.3.4 Wind . . . 6
2 Methodology 7 2.1 Limitations and assumptions . . . 7
2.2 Calculations and formulas . . . 8
2.3 Model . . . 9
2.3.1 Current Energy System . . . 9
2.3.2 Improved Energy System . . . 10
2.4 Energy scenarios . . . 11
3 Results 12 3.1 Today . . . 12
3.2 Future scenarios . . . 15
3.2.1 Scenario 1: Biogas . . . 15
3.2.2 Scenario 2: Increased wind power . . . 17
3.2.3 Scenario 3: Solar park . . . 18
3.2.4 Scenario 4: Solar panels . . . 19
3.3 Combined scenarios . . . 20
3.3.1 Scenario 5: Combination 1, Scenario 1-4 added into one system . . . . 21
3.3.2 Scenario 6: Combination 2, 100 % renewable energy . . . 23
3.3.3 Scenario 7: Combination 3, an extension of Scenario 5 to achieve the energy demand of Klintehamn . . . 24
3.4 Sensitivity analysis . . . 25 4 Discussion 26 4.1 Sustainability analysis . . . 26 4.2 Scenarios . . . 26 4.2.1 Today . . . 26 4.2.2 Future . . . 27 4.2.3 Combinations . . . 27
4.3 Issues and problems . . . 28
4.4 Further research . . . 29
4.5 Conclusion . . . 29
List of Figures
1 Outgoing and incoming goods from the harbour . . . 3
2 Model of the current energy system. . . 9
3 Model of the energy system in the future. . . 10
4 Current electricity flow. . . 13
5 Current heat flow. . . 14
6 Electricity flow in Scenario 1 . . . 15
7 Heat flow in Scenario 1-7 . . . 16
8 Electricity flow in Scenario 2 . . . 17
9 Electricity flow in Scenario 3 . . . 18
10 Electricity flow in Scenario 4 . . . 19
11 Electricity flow in Scenario 5 . . . 21
12 Electricity flow without the sawmill in Scenario 5 . . . 22
13 Electricity flow in Scenario 6 . . . 23
List of Tables
1 Concluded result from the current energy system calculations . . . 12
2 Concluded result from the electricity in Scenario 1-5 . . . 20
3 Concluded result from the electricity in Scenario 6 . . . 20
Nomenclature
Abbreviations
CSP Concentrated solar power PV Photovoltaic
Other Symbols
m3f ub Real volume of timber without bark m3s External volume off chippings
1
Introduction
Gotland is the largest island of Sweden with a population of 59,249 people (SCB, 2019). The opportunity to create a sustainable energy system at the island is possible. Renewable energy production, like wind, solar and biomass, has the potential to expand on the island (Energimyndigheten, 2018). To develop the sustainable energy system, Region Gotland plans to use an already established industrial park in the harbour of Klintehamn to apply for the EU Horizon 2020 project (Project description, 2019).
To make this possible Program Klintehamn 2030 has been developed. The program con-tains strategies and several goals to facilitate the planning of the structure of Klintehamn. One of the nine main sections of the program focuses on the harbour and the industries. The program contains information about the different industries of Klintehamn and some suggestions of how the energy system will change when other technologies (e.g. biogas plant) are established in Klintehamn. To reach the goals of the program, the energy system of Klintehamn must be improved, and the degree to which the city can be self-sufficient must be examined.
1.1
Aim
The aim of the project is to analyze the energy flow of Klintehamn, Gotland, to determine whether a municipality can be self-sufficient by having the entities of the community cooper-ating. This is to decrease the costs connected to transporting energy and to reduce greenhouse gas emissions. A model for the present energy flow system will be created and ways of im-proving the system will be examined by creating a polygeneration system for Klintehamn. The questions that will be answered in this project are:
• How does the current energy system in Klintehamn look? Evaluate the energy system. • What does the energy flows look like in Klintehamn? Calculate the energy flows. • What could the energy system look like in the future?
• Is it possible for Klintehamn to be self-sufficient in the future?
• What kind of energy flows could Klintehamn have to become self-sufficient? Where would the energy come from?
1.2
Providers and energy users in Klintehamn
In order to understand how Klintehamn can be self-sufficient, information has to be gathered about Klintehamn and the industries of the city as well as how different renewable energy sources can contribute to the energy system. Especially, a quantification of how much energy can be provided by renewable energy is needed.
1.2.1 Klintehamn
Klintehamn is an urban area in western Gotland with a population of 1,535 persons. In 2015, there were 531 households in Klintehamn (SCB, 2019). AB Gotlandshem, is a housing com-pany located on Gotland, and they have 190 apartments in Klintehamn (Gotlandshem, 2019). There are four different public facilities in Klintehamn, a library, a school, a retirement home and a district health care center. There are different types of industries located in Klintehamn. In the harbour of Klintehamn, an industrial park is established (Project de-scription, 2019). The largest sawmill on Gotland produces chippings in the harbour. There is also a fodder production facility in the harbour area. Using the resources of the industries in Klintehamn, the entire energy demand of the city could be met (Program Klintehamn 2030, 2019).
1.2.2 Fodder production plant
The company Lantm¨annen is located in the harbour and most of the exports in the harbour is grain from Lantm¨annen (Program Klintehamn 2030, 2019). Lantm¨annen has several different entities in the harbour area and these are (Mikael Jokobsson, Operation Manager Klintehamn, 2019):
• Central storage: Which is supplied with goods from other Lantm¨annen facilities in Sweden. In the central storage, they store and pack goods that are distributed to customers on Gotland.
• Seed plant: Where they are receiving seed, which has been grown on Gotland, during the harvest. They dry, clean and sort the seeds before it is processed and packaged. The seeds are sold to customers on Gotland. They also received dry seeds from the farms on Gotland, and process and package it.
• Fertilizer plant: The fertilizer arrives to the harbour with ships. The fertilizer is pack-aged and is sold to costumers on Gotland.
• Silos: This facility receives 90,000 tons of grain per year from farms on Gotland. Half of the grain is sorted and dried in the harbour area, and the other half is transported to another facility on Gotland.
• Fodder plant: It produces 47,000 tons of fodder per year. Half of the fodder comes from the seed plant and the other half comes with trucks and ships. The fodder plant produces 50 varieties of fodder, and they manufacture the fodder by mixing together different ingredients and grinding them to flour. Then, they use steam to heat the raw grain to 75 degrees to kill unwanted bacteria. When they steam the grain, they get a dough and the dough goes through a machine which forms it into pellets. The pellets are cooled and dried before it is transported out to the customers.
The total energy use of Lantm¨annen in Klintehamn is 2,920,000 kWh per year, and some of the electricity comes from a windmill which Lantm¨annen owns in the harbour area. In the fodder plant they use steam, and 1,530,000 kWh goes to heat up the steam to 75 degrees. In the Seed Plant and Silo, they use two boilers to heat the air for the drying process. To heat the boilers, they use waste from the grain and the other is an oil-fired boiler. They only use the oil-fired boiler if the heat from the first boiler is insufficient. They do not generate any electricity (Mikael Jokobsson, Operation Manager Klintehamn, 2019).
1.2.3 Foodmark-Rydbergs
Rydbergs is a part of the food producer Foodmark. Rydbergs in Klintehamn produces beet-root salad, potato salad and different sauces. Both the beetbeet-roots and the potatoes are cul-tivated on Gotland (Rydbergs, 2019). The waste from the facility is planned to go to the biogas plant in the future (Helena Andersson, Eco strategist for Region Gotland, 2019). Rydbergs total electricity demand is 50,000 kWh per month and the company uses oil boilers to produce steam. 1,600 liters of oil have been used per workday, when the production is maximized, and the use during the weekend is around 1,000 liters. The currently targeted improvements for the facility is to use biogas for the steam heating once the biogas plant is built (Helena Andersson, Eco strategist for Region Gotland, 2019).
1.2.4 Harbour
The harbour of Klintehamn is important for the import and the export of Gotland because it is one of the largest harbours on the island. Region Gotland owns the harbour and it is managed by Technical committee of Gotland (Program Klintehamn 2030, 2019).
Source: Program Klintehamn 2030
Figure 1: Outgoing and incoming goods from the harbour
Figure 1 represents the incoming and outgoing goods from both internal and external com-panies, companies on and outside of Gotland. The outgoing goods from other countries, can be storage for some times or be processed in the harbour. In 2017 the grain from the fodder production plant was the most exported product, followed by the timber and wood from the sawmill. The imports consisted of fertilizers and chippings from the continent (Program Klintehamn 2030, 2019).
In the harbour, there is an industrial park and there are many different businesses estab-lished in the area. The following is a list of some of them (Program Klintehamn 2030, 2019).
• Sawmill, Gotlandsflis AB.
• Fodder production plant, Lantm¨annens foderfabrik.
• Station for measurements of how much timber and wood is exported.
• Station for weighting the vehicles for transportation of grain, to and from the fodder production plant.
• Special goods facility, for example where wind power plants and other special orders for Gotland arrives.
• Area for limestone export, Svensk mineral AB (used just for a limited time as they examine how the shipping of limestone goes).
• Traffic with tourists between the harbour of Klintehamn and the islands Stora and Lilla Karls¨on, Karls¨otrafiken.
• The public area where private boats are moored.
The harbour does not generate any electricity (Mats Eriksson, Harbour Manager Klintehamn, 2019).
1.2.5 Sawmill
The sawmill is located in the harbour. The company who owns the sawmill is Gotlandsflis AB and they have 34 employees. Gotlandsflis AB produces timber, wood of several qualities and chippings. Sawdust and other waste goes to districts heating boilers. Almost all chippings and wood are shipped from the harbour of Klintehamn to the continent (Gotlandsflis AB, 2019).
Gotlandsflis AB have a timber requirement of 185,000 m3f ub and the saw capacity for timber
is 45,000 m3s sawn goods. 25,000 m3s of the timber turns into wood of several qualities and
205,000 m3s turns into wood chips of different kinds (Gotlandsflis AB, 2019).
The annual heat usage of the sawmill is 6-7 MWh and the annual electricity usage is 3 TWh. The boiler of the sawmill produces 9 GWh of heat for district heating (Lars Ahlby, Purchaser of forest 2019)
1.3
Renewable Energy Sources
The municipality of Klintehamn strives to use more renewable energy. They have concrete plans of implementing a biogas plant to make use of waste and residues from other parts of the system. They also strive to increase the use of other kinds of renewable energy, like solar and wind power by actively fostering the development of renewable energies (Energi 2020, 2013).
The system to be created aims for the municipality to supply energy in a self-sufficient way to the different end-users, including households. More than one energy source will be used for the most efficient and flexible solution. To obtain an optimized system, a polygeneration system will be created.
1.3.1 Polygeneration
The concept of polygeneration combines different energy sources and produces several energy services, within one enclosed system, in a lucrative, sustainable and efficient way. With one output, or energy service, of the system, for example electricity, the result is called generation. With two and three outputs the result are called cogeneration and trigeneration. With more energy services the result is called a polygeneration system (Moritz Wegener & Anders Malmquist, 2018).
The purpose of polygeneration is for entities of a society to cooperate for optimization of the system. The intention is to decrease greenhouse gas emissions and improve the efficiency, by for example turning waste energy into useful energy. The system is flexible but complex and is more complicated to create. It is difficult to envision how it will transpire in reality and the theory of a polygeneration system may differ more from reality than with a plain system (Moritz Wegener & Anders Malmquist, 2018).
Typical outputs of polygeneration systems are energy services like electricity, heat, cooling and purified water. The polygeneration system model that is to be created for Klintehamn will use the energy sources, solar, wind and biogas and the energy services it will provide are electricity and heat. Cooling will probably not be needed due to the weather conditions of Klintehamn.
1.3.2 Biogas
Biogas plants create biogas from biomass. The byproducts of the process are greenhouse gases, but when the the whole life circulation of the plants are accounted for the net emis-sions are zero. Biogas therefore can be considered as a renewable energy source.
Biogas can be produced in two different ways and produce two different kinds of gases, syn-thetic gas, or syngas, and biomethane, or biogas. The production of biogas occurs through the bio-logical process of anaerobic digestion of organic materials. Syngas is produced when cel-lulosic materials are gasified. Both syngas and biogas may be converted into liquid advanced biofuels (ETIP Bioenergy, 2019). Biogas can be produced in anaerobic digestion facilities, where different kinds of organic materials, e.g. food and agriculture residues, decomposes (Biog¨odsel, 2014).
The municipality is planning on developing a biogas plant. Their plan is to rebuild and modernize an old treatment plant. The modernization of the plant includes both for the plant to cover a larger area of Klintehamn and to convert to renewable energies. They are planning to built a biogas facility similar to the one already in use in Visby. The biogas facility in Visby is an anaerobic digester and produces 5 GWh of biogas annually (Region Gotland, 2019).
1.3.3 Solar
Solar Energy is a renewable energy source that uses the sun to produce electricity. Solar power can be generated in two ways; Photovoltaic (PV) and Concentrated Solar Power (CSP). PV cells convert the sun directly into electricity. PV are often used as panels on houses or as roof tiles (Irena, 2019).
the fluid. Then steam is created which drives a turbine and generates electricity. CSP is usually used for larger solar power plants where, often, fields of mirrors direct the rays to a thin tall tower. With CSP it is possible to generate electricity even after the sun has set, by storing heat in molten salts. This is not possible with PV (Irena, 2019).
In Sweden, solar panels annually generate 50-150 kWh of electricity per square meter (Svensk Solenergi, 2015). An example of solar panels on apartment houses is in Fru¨angsporten in Stockholm, with 366 solar panels with an approximate size of 1.6 square meters each (Utellus AB, 2018), which adds up to a solar panel area of 585.6 square meters.
The amount of energy generated from solar parks is different due to different sizes of the parks and different weather conditions. Two examples of solar parks in Sweden are the one in Varberg and the one in Gothenburg. The solar park in Varberg, which has been running since 2016, consists of 9,300 solar panels and generates around 3 GWh per year (NyTeknik, 2018). The solar park in Gothenburg, which was built in late 2018, consists of 20,000 solar panels and annually generates 5.5 GWh (NyTeknik, 2018).
Solar heat systems generate heat, both for heating and cooling of buildings and for heat-ing of warm water. Solar heat systems collect solar radiation and the resultheat-ing heat is then transferred into a heat transfer medium. The heated medium then either directly heats water or indirectly transfers heat to e.g. a room, by using heat exchangers. The most common use of solar heat is on buildings (Solar Heat Europe, 2019). Solar heat systems annually generate 2-6 MWh, on average sized single family houses (Energimyndigheten, 2015).
Solar heat for industrial processes and solar district heating are under development. It is not as widely spread as solar heat for buildings but it has promising future. Solar district heat is solar thermal technology in large scale application. Development in large scale district heating allows energy to be stored in the summer and used in the winter, which leads to that solar district heat can meet the heat demand all year around. There are currently plans on developing large scale solar heat in Sweden, among other countries (Solar Heat Europe, 2019).
1.3.4 Wind
Wind power is a renewable energy source which uses the kinetic energy of wind to produce electricity. The wind causes the blades of the wind turbine to rotate and the kinetic energy transforms into rotational energy. This then causes a shaft, connected to a generator, to move. Thus, through electromagnetism, electrical energy is produced (Irena, 2019).
The harvested power from the wind turbines depends on the dimensions of the rotor and the wind speed. Wind turbines offshore have much larger capacity than wind turbines on-shore. The average capacity of wind turbines is 2 MW but there are also wind turbines with capacities of 8 MW (Irena, 2019).
Today there are 6 wind turbines south of Klintehamn and one in the harbour. The one in the harbour is owned by Lantm¨annen and the energy it produces goes directly to the fodder production plant. All wind turbines in Klintehamn have a rotor diameter of 40 meters (Medvind p˚a bygden, 2015).
2
Methodology
This project is of descriptive character, and the literature study resulted in descriptions of polygeneration, energy sources, e.g. biogas, solar and wind, and the municipality of Klinte-hamn. The methods used are collecting of data and statistics from electronic sources and from telephone and email contacts with the representatives of the entities in the municipality. It has been difficult to find information about the different entities and to receive answers from the companies which have delayed the project. Therefore, a study visit in Klintehamn was necessary to collect the final information. In this project many assumptions have been made. Another method in order to avoid assumptions is to make experiments and observations of e.g. renewable energy sources. Unfortunately, that would have taken too much time. This project includes calculations of the energy flow in Klintehamn. All the calculations of this project have been made using the calculation program Matlab. Other programs, e.g. OSEMOSyS, have been considered, but the choice ended up being Matlab. The calculations have been easier to adapt to the project and the results have been easier to understand as the code was written for this project. This would not have been the same if another energy flow program would have been used. Also, many inputs have been varied to fit the the scenarios and several results have been generated, which also has been easier because the calculations were made in Matlab.
2.1
Limitations and assumptions
The project covers a social change, which affects many different factors in the community. Therefore limitations and assumptions have been made to limit the extent of the project. Costs are an important part when planning and performing for social changes in a com-munity. However, this project has not taken costs into account, because of the purpose of the project. The purpose is to define the existing energy flows and change the system to a theoretical polygeneration system, where Klintehamn is self-sufficient. The costs to build the solar park, the costs to put PV panels on the houses of the municipality, the costs to build more wind turbines and the costs to develop the biogas plant have, therefore, not been accounted for.
Because the climate in Sweden varies greatly during the year, the need for heat in the country is different, depending on the season. These variations have not been accounted for in this project, because of the missing data in this field.
Cooling of households has been neglected, in this project. The Swedish climate is overall cold and cooling of households is therefore not necessary and not used. The technical aspects of processes of water purification have not been accounted for in this project, mainly because of the purpose of the project to evaluate the energy flow. Assumptions have also been made that water treatment plants would not affect the energy flow significantly.
The monthly distribution of solar power during the year has been assumed to be propor-tional to the amount of solar radiation each month (SMHI, 2006). Two solar parks have been considered when assuming the electricity generation of the solar park. The sizes of the solar parks are information that has not been found, an assumption has been made that the sizes of the solar panels are 1 square meter. One of the solar parks have an annual generation of 3 GWh and its size is 9,300 m2. The other solar park has a generation of 5.5 GWh and a
size of 20,000 m2. Therefore an average generation of 4.25 GWh and average size of 14,650
m2 have been assumed in the calculations. This has then been divided between the months
according to the calculated distribution.
An average solar panel annually generate 50-150 kWh/m2(SMHI, 2019) and in this project an assumption have been made that the new solar panels developed will generate 150 kWh/m2. This value is based on the assumption that new solar panels will have a higher energy effi-ciency due to advanced technical development. The maximum area dedicated for solar panels on apartment buildings has been assumed to be equal to the one described for Fru¨angen, which is 585.6 m2. This has also been converted into monthly variations by using the
calcu-lated distributions.
To calculate the power from wind, the wind velocity ha to be known, as can be seen in Formula 1. Monthly average wind velocities from measuring stations in Visby have been used for the calculations (SMHI, 2006). The measuring station in Visby is the station nearest Klintehamn. The distance between Visby and Klintehamn are 30 kilometers and that makes the wind data relevant for this project.
Energy storage, e.g. batteries, of the generated electricity enables distribution of electric-ity throughout the year. This makes it possible to use the redundant electricelectric-ity, from periods of the year with more energy generation, during other periods of the year, when the energy generation is lower. However, storage has not been used in this project, as sufficient informa-tion has not been found.
Solar heat systems annually generate 2-6 MWh, on average sized single family houses (En-ergimyndigheten, 2015). Solar heat on apartment buildings is assumed to be 7 MWh. The apartment houses are larger than the typical houses, and therefore a larger energy amount is assumed.
The value for the wind power coefficient, cp, lies between 0.35 and 0.45, according to the
literature study. This range is for the best designed wind turbines (Subhamoy Bhattacharya, 2019). The wind turbines of Klintehamn are built in 2005 after which the technology of wind turbines have been improved. Therefore, the calculations of this project used a cp of 0.35.
The first estimation of biogas made for the Program Klintehamn 2030 was an annual elec-tricity generation of 5 GWh. After consideration and inputs, second calculations have been made. Unfortunately, the second estimation was not received in time to be included in the project.
2.2
Calculations and formulas
The energy generated of a wind mill can be calculated with the following formula. Ein“
1 2ρr
2πv3 and E
out“ Eincp (1)
Where Einrepresents the wind energy in the wind mill and Eoutis the generated energy. ρ is
the density of the air, v is the velocity of the wind, which varies during the year (Subhamoy Bhattacharya, 2019).
2.3
Model
Two models have been produced, one of the models represents the Current Energy System and the other the Improved Energy System of Klintehamn. The current model is created by information from the different entities, which are described in the section Introduction. The Improved Energy System is created by information from the program Program Klintehamn 2030. The Improved Energy System is more developed and sustainable, in the context of energy flows between the different entities.
2.3.1 Current Energy System
Figure 2: Model of the current energy system.
The Current Energy System, as shown in Figure 2, is simple and lacks connections between the entities. The sawmill produces wood and chippings and requires heat and electricity. Sawdust, chippings and other waste go to district heating boilers to heat the households and public buildings. Foodmark require heat and electricity and they produce food. The fodder production require electricity and large quantities of heat. One of the windmills in the harbour supplies electricity to the fodder production, and they sell grain and fertilizers to the agriculture on the island. There are other windmills in Klintehamn, which generate electricity to the city. To reach the electricity demand of Klintehamn and all its entities, external electricity is required. Fuel for vehicles is also external.
2.3.2 Improved Energy System
Figure 3: Model of the energy system in the future.
The Improved Energy System of Klintehamn as shown in Figure 3, is an advanced polygener-ation system. Some of the main differences of the improved energy system compared to the Current Energy System are that the external fuel and electricity have been removed. A biogas plant has been built instead. The biomass is intended to come from households, Foodmark and the fodder production plant. The biogas will be used as fuel for vehicles and in prime movers to generate heat and electricity. Another energy source, PV, has been included in the new system. Both the energy from PV and windmill go to a converter. The process for the fodder production, in the Improved Energy System, is similar to the process in the Current Energy System. The difference is that fertilizer also goes to a fertilizer production residues and further to the biogas plant, in this improved model. The only difference for the sawmill is that its energy is connected to the local power grid.
2.4
Energy scenarios
The Current Energy System will be calculated from the collected data from the different entities and other relevant data (e.g. households energy demand). Most of the electricity is external in Klintehamn today. To be able to determine a suitable way to get Klintehamn self-sufficient, different scenarios have been developed. The scenarios are:
• Scenario 1 - Development of biogas • Scenario 2 - Increased wind power • Scenario 3 - Development of solar park • Scenario 4 - Development of solar panels
• Scenario 5 - Combination 1, Scenario 1-4 added into one system • Scenario 6 - Combination 2, 100% renewable energy
• Scenario 7 - Combination 3, Development of Scenario 5, with more renewable energy In the first scenario, Scenario 1, the energy demand will be increased, because of the already planned development of Klintehamn. More buildings will be built and more people will move there, although it is hard to estimate how many exactly. A biogas plant will be built and it has been added to the calculations. The same energy sources from the Current Energy System are included in this scenario as well. In Scenario 1, along with all the following scenarios, solar heating systems will be added on 145 on the newly built houses.
In each of the Scenarios 2-4, one renewable energy source will be added to Scenarios 1. In Scenario 2 the wind power will be increased with 24 extra wind turbines, along the already existing 6 ones. In the solar park scenario, Scenario 3, a solar park will be added into the system and in Scenario 4 solar panels will be put on the newly built houses. The amounts of the added renewable energies were chosen to what was estimated to be a reasonable increase, compared to how it is today.
Then, three scenarios of combinations of the renewable energy sources will be constructed. The first combination, Scenario 5 will be a merging of Scenario 1-4. After which, it will be shown if the energy demand will be achieved when the renewable energy sources are included. The second combination, Scenario 6, will be a scenario where the energy demand is achieved with 100% renewable energy sources. The last scenario, Scenario 7, will be a development of Scenario 5, but with increased amount of renewable energy.
3
Results
Each of the 7 scenarios have been calculated using the computation engine Matlab. The current electricity demand of Klintehamn is 3.405 TWh and it is expected to increase to 3.407 TWh in the future. The heat demand has been calculated to 18.2 GWh today and in the future it will increase to 265 GWh. Electricity and heat graphs have been produced for each scenario, which have been developed in Matlab.
3.1
Today
Table 1: Concluded result from the current energy system calculations Today Jan-Mar Apr-Jun Jul-Sep Oct-Nov Electricity generation 1.3 GWh 631 MWh 529 MWh 967 MWh Heat generation 1.33 GWh 1.33 GWh 1.33 GWh 1.33 GWh Electricity demand 284 GWh 284 GWh 284 GWh 284 GWh Heat demand 1.52 GWh 1.52 GWh 1.52 GWh 1.52 GWh Imported electricity 282 GWh 282 GWh 282 GWh 282 GWh
Table 3.1 illustrates the concluded result of the current energy system from the Matlab cal-culations. The values are monthly averages of the four different quarters. Heat generation, electricity demand and heat demand are the same during the year but the electricity gen-eration vary over the year. The imported electricity does also vary but the differences are negligible, which makes it appear as it does not vary. As the heat demand is smaller than the generation, there is no need for imported heat.
Figure 4: Current electricity flow.
Figure 4 is a graph that represents the the current electricity flow in Klintehamn. The electricity demand, the generated electricity from the different entities and the imported elec-tricity are included in the graph. The total annual elecelec-tricity demand is 3.405 TWh, and the annually generated electricity today, which comes from wind turbines, is 10.3 GWh. The remaining electricity is imported and it is of 3.395 TWh, which is very large, because of the small contribution, to the energy generation, of the wind turbines.
Figure 5: Current heat flow.
The current heat demand is shown in Figure 5. The heat demand curves are district heating, heat demand of industries and heat demand of public places. The annual district heating of houses is 900 MWh, the industries annually require 8 GWh of heat and the public places require 9.3 GWh. The total heat demand is 18.2 GWh per year and the generated heat from the sawmill is 16 GWh. The largest part of energy from district heating goes to public places. The curve representing Other heating households include the households that require heat from oil boilers, wood, pellets or other fuels. This heating is not accounted for in the system as they acquire their energy on their own.
3.2
Future scenarios
7 future scenarios have been made. Scenario 1 introduces bio energy to the system. Scenario 2-4 are expansions of Scenario 1, with additions of a solar park, solar panels and increased wind power. Scenario 5-7 are different combinations of Scenario 1-4, with different levels of generated energy.
3.2.1 Scenario 1: Biogas
Figure 6: Electricity flow in Scenario 1
In Figure 6 biogas is added to the electricity generation curve. The biogas plant annually produce 5 GWh of electricity and the the remaining electricity in the curve is the same as today. The electricity demand has been increased a bit, because of the growth of the city and the changed number of inhabitants, so in the future it is 3.407 TWh. The electricity generation does not reach the demand and therefore there is still a need for imported electricity. In this scenario 3.392 TWh of electricity is imported. The generated electricity for each quarter of the year, is shown in Table 2, in Section 3.3.
Figure 7: Heat flow in Scenario 1-7
Figure 7 illustrates the future heat flow of the system and this figure applies to all scenarios. The differences between the heat demand today and in the future are because of the growth of the city. More inhabitants and more buildings lead to larger heat demand, which now is 265 GWh per year. All new buildings are assumed to be heated by district heating, therefore Other heating households, remain the same as today. No new public buildings are planned and therefore this curve also remains the same. District heating households increases greatly because of the city growth, to 14.2 GWh per year. Heat generation increases, with a maximum of 1.52 GWh in June, because of the development of solar heat on 145 of the new apartment buildings.
3.2.2 Scenario 2: Increased wind power
Figure 8: Electricity flow in Scenario 2
In Scenario 2 wind power is increased by installation of 24 extra wind turbines, in addition to the existing 6 ones. That increases the generated electricity with 41.1 GWh per year, which results in a total of 51.4 GWh per year. The imported electricity is 3.351 TWh per year. The heat is the same as in the previous scenario. The generated electricity for each quarter of the year, is shown in Table 2, in Section 3.3.
3.2.3 Scenario 3: Solar park
Figure 9: Electricity flow in Scenario 3
Scenario 3 is an expansion of Scenario 1 and in this scenario one solar park has been installed in Klintehamn. Figure 9 represents the electricity flow for this scenario. The solar park annually generates 4.25 GWh which gives a total of 19.5 GWh of generated electricity. The demand is the same as in Scenario 2. The imported electricity is now 3.388 TWh. The generated electricity for each quarter of the year, is shown in Table 2, in Section 3.3.
3.2.4 Scenario 4: Solar panels
Figure 10: Electricity flow in Scenario 4
Like Scenario 3, scenario Scenario 4, is an expansion of Scenario 1. Instead of a solar park, PV panels have been installed on the rooftops of the new building. Figure 10 represent the electricity generation for this scenario. The calculations are based on solar panels on 100 of the new houses, which gives an increase in electricity generation of 8.78 GWh. This results in the imported electricity being 3.383 TWh. The generated electricity for each quarter of the year, is shown in Table 2, in Section 3.3.
3.3
Combined scenarios
To create a polygeneration system, combinations of the energy sources have been made. One combination, Combination 1 is a combination of Scenario 1-4, Combination 2 is a scenario where the electricity demand of the city has been met and Combination 3 is a development of Combination 1, with increased amount of renewable energy.
Table 2: Concluded result from the electricity in Scenario 1-5
Electricity Jan-Mar Apr-Jun Jul-Sep Oct-Dec Biogas 417 MWh 417 MWh 417 MWh 417 MWh Wind power 6.5 GWh 3.16 GWh 2.65 GWh 4.84 GWh Solar park 152 MWh 646 MWh 531 MWh 87.6 MWh Solar panels 314 MWh 1.33 GWh 1.1 GWh 181 MWh Total electricity generation 7.23 GWh 4.91 GWh 4.16 GWh 5.43 GWh Imported electricity 277 GWh 279 GWh 280 GWh 279 GWh
Table 3: Concluded result from the electricity in Scenario 6
Electricity Jan-Mar Apr-Jun Jul-Sep Oct-Dec Biogas 417 MWh 417 MWh 417 MWh 417 MWh Wind power 403 GWh 196 GWh 164 GWh 300 GWh Solar park 41.7 GWh 177 GWh 145 GWh 24 GWh Solar panels 2.48 GWh 10.6 GWh 8.67 MWh 1.43 GWh Total electricity generation 447 GWh 384 GWh 319 GWh 326 GWh Exported electricity 163 GWh 99.7 GWh 34.7 GWh 41.8 GWh
Table 4: Concluded result from the electricity in Scenario 7
Electricity Jan-Mar Apr-Jun Jul-Sep Oct-Dec Biogas 417 MWh 417 MWh 417 MWh 417 MWh Wind power 10.8 GWh 5.26 GWh 4.41 GWh 8.06 GWh Solar park 304 MWh 1.29 GWh 1.06 GWh 175 MWh Solar panels 628 MWh 2.67 GWh 2.19 GWh 362 MWh Total electricity generation 11.9 GWh 8.35 GWh 7.02 GWh 8.84 GWh Imported electricity 272 GWh 276 GWh 277 GWh 275 GWh Table 2 illustrates the generated electricity from bio, wind, solar park and solar panels from Scenario 1-4. It also illustrates the total electricity demand of Scenario 5, Combination 1. The imported electricity is also for Scenario 5. The values are monthly averages of each quarter of the year. Table 3 and Table 4 illustrates the same as Table 2 but for Combination 2 and Combination 3. The biogas energy for Combination 2 and Combination 3 is the same as for Combination 1.
3.3.1 Scenario 5: Combination 1, Scenario 1-4 added into one system
Figure 11: Electricity flow in Scenario 5
Figure 11 represents the first combination of all renewable energy sources in the same graph. The electricity demand has not changed and the external electricity still exist. The imported electricity is 3.342 TWh. The electricity generation, which includes biogas, wind power, solar park and panels, is 65.2 GWh. In the calculations, one solar park has been included, with a capacity of 4.25 GWh, 100 solar panels on newly built houses and 30 wind turbines with a rotor diameter of 40 meters. The largest contribution to the electricity generation is from the wind turbines, which is shown in Table 2.
Figure 12: Electricity flow without the sawmill in Scenario 5
Figure 12 represents the same as Figure 11 but only a part of the demand is included in the curve for electricity demand. The difference is that the electricity demand of the sawmill is excluded. The sawmill constitutes an enormous part of the electricity demand, which can be seen when comparing Figure 12 with Figure 11.
3.3.2 Scenario 6: Combination 2, 100 % renewable energy
Figure 13: Electricity flow in Scenario 6
To reach the electricity demand with renewable energy sources this scenario has been con-structed. In Figure 13, the electricity generation is higher than the demand during the year. There is no imported electricity in this scenario. There are three curves that represent the different energy sources, wind power and solar power from solar parks and solar panels. Wind power are generate most of the electricity, followed by the solar park and then solar panels. In this scenario there are solar panels on all 525 new buildings and all 531 already built houses and there are 274 solar parks, or a total solar park area of approximately 4.01 square kilome-ters. There are also 824 newly built wind turbines with a rotor diameter of 60 meter, along with the already existing 6 wind turbines with rotor diameter of 40 meter. The generated electricity from the different energy sources and the total generated electricity is found in Table 3.
3.3.3 Scenario 7: Combination 3, an extension of Scenario 5 to achieve the energy demand of Klintehamn
Figure 14: Electricity flow in Scenario 7
Figure 14 represents Scenario 7 which is a enhancement of Scenario 5. Instead of one solar park, this scenario has two solar parks. Instead of solar panels on 100 of the new buildings there are solar panels of 200 of the rooftops. Instead of 24 new wind turbines, there are 44 new wind turbines which gives a total of 50 wind turbines. The generated electricity from the different energy sources and the total generated electricity is found in Table 4. The generated electricity is 108 GWh per year and the imported electricity is 3.299 TWh.
3.4
Sensitivity analysis
There are uncertainty factors that will affect the energy system, therefore, a sensitivity anal-ysis has been carried out. One factor that can affect the energy system is the number of people who move to Klintehamn. If more people move there, more houses need to be built. If every newly built house has solar panels, the electricity from solar panels increases. However, there can be a counter effect. If fewer people move in, the number of houses being built will decrease. That leads to fewer solar panels and a decreasing electricity generation. If a lot of people move in to Klintehamn without the ambition of solar panels on there houses, the electricity demand will increase a lot. As the energy generation is lower than the demand already, this would increase that problem.
If more people move to Klintehamn, another factor will be affected, public places. Health care centers, schools, after school care center and sport centers (e.g. public swimming baths) would have more reason to be built. If these facilities are connected to the district heating network, the district heating demand would increase greatly. If, for example, a duplication of public places would occur, the heat demand would presumably increase by 100%. Today the heat demand is almost as big as the generation, therefore an increase of public places would make it even more difficult to generate enough heat. If the current public places, on the other hand would be shut down, the heat demand would decrease and it would be easier to meet the demand. However, it is not an alternative.
The third factor that can make a large change in the result is if the sawmill would be shut down or separated from the system. The sawmill requires a lot of electricity and generates a lot of heat. When the sawmill is removed, the electricity demand decreases immensely and the total generated electricity reaches the electricity demand of Klintehamn easily. The heat is more critical. If the sawmill is removed the heat generation decreases immensely as well. The heat demand is probably too high to reach with only new solar power systems on houses.
4
Discussion
This discussion focuses on both the energy system today and all of the 7 scenarios. To evaluate the results, a sustainability analysis have been made, and problems and issues with the project have been analyzed, along with examples of further research. Finally a conclusion have been made.
4.1
Sustainability analysis
To be able to evaluate the results a sustainability analysis has been made, on environmental, social and economical aspects. There are both positive and negative outcomes from each aspect. The positive outcome from the environmental perspective is that there are lower emissions, because more green energy is used in the energy system. Negative aspects are that the wind turbines obscure views of nature and the coast and another aspect is that large areas of nature disappear, for wind turbines and solar parks.
When it comes to the social aspects, something positive is that more people can move to Klintehamn, which leads to greater prerequisites for social life and companies locating in the area, which in turn leads to more job opportunities. When the city grows, the familiar feeling may disappear. This may lead to exclusion in the community, which may increase the crime rate.
The economy is affected by people moving to Klintehamn. When more people move to a city, more companies will establish there, which is positive for the city and the economical development. Something negative is that the costs for building new energy power plants are high. Exact numbers of the costs have not been calculated in this project but the as-sumptions is that they are large. To be able to make Klintehamn more sustainable financial contributions, e.g. government grants, are important.
4.2
Scenarios
Some of the curves are horizontally straight which represents that there are small alterations during the year. The y-axis of the graphs are logarithmic and because there are small relative differences and all values are of the same order of magnitude, the curves appear very straight. The main entities have the largest demand of energy which is something that does not change. If the graph would have a numerical scale, it will look like most of the values are zero, which is not correct.
4.2.1 Today
A small part of the energy today comes from sustainable energy sources and this is something that needs to be improved. Table 3.1 represents the energy today. The electricity demand is high and the generated electricity is insufficient. There are not enough energy sources for production of electricity in Klintehamn today. Therefore, most of the electricity is imported. Most of the generated electricity today comes from two windmills in the harbour of Klinte-hamn and six windmills south of KlinteKlinte-hamn. The heat generation is redundant because of the sawmill which makes it possible to develop the district heating network in Klintehamn.
4.2.2 Future
In Scenario 1, the electricity demand is increased, because of the growing city. That is a positive development for the community, for environmental reasons. A biogas plant was also added to the system in Scenario 1, but unfortunately, the electricity demand still is too high. If another biogas plant were to be built the demand still would be too low, and other complica-tions would arise (e.g. hard to find waste and fertilizer). The total predicted heat demand of the future is 265 GWh, which is a rise, and it is because of the growth of the city. The district heating has increased because of the conjecture that the new houses will use this kind of en-ergy instead of e.g. oil. This increases the efficiency of the system and decreases the emissions. The wind power generates most of the electricity in the current energy system. In Scenario 2, more wind turbines have been added to the system and the wind turbines now generate 51.4 GWh. The electricity generation still is too far from reaching the demand. To reach the demand an absurd amount of wind turbines have to be installed, as can be seen in Scenario 6. Some negative factors with wind turbines is that they take a lot of space, and in different areas they generate different amounts of electricity. Therefore, is it difficult to estimate the number of wind turbines which can be built in the area of Klintehamn and the amount of electricity they will generate. The heat generation or demand are not affected by the devel-opment of wind turbines.
When the solar park was added, in Scenario 3, instead of increasing the number of wind turbines, there were only a small increase compared to how it was in Scenario 1. This means that the solar park energy does not affect the generated electricity in the range of what the city needs. However, there are potential areas on Gotland on which solar parks can be built. If every household in Klintehamn uses solar panels on their roofs the generated electric-ity generation increases most during the summer. There is a larger amount of solar radiation during the summer than during the winter. During November and December the electricity generation is almost the same as Scenario 1, because of low amount of solar radiation. This scenario is more difficult to change because the solar hours will not drastically change. The number of houses with solar panels on their rooftops can be increased but only as much as so many houses there are. Many houses in Klintehamn are old, though, and have to refurbish in the future which means there are fewer rooftops to put solar panels on.
4.2.3 Combinations
The first combination of the renewable energy sources was Scenario 5. In this scenario the biogas plant, 24 new wind turbines, one solar park and 100 solar panels on newly built houses, from Scenario 1-4 were added to this system. The result was that the electricity generation is still to low to reach the demand in this scenario, which means that the need for imported electricity still exists.
As seen in Figure 12, the largest electricity contributions, in Scenario 2-4, is from the wind turbines, followed by the solar panels and the smallest contributions comes from the solar park. So the best, or with largest energy generation, scenario of 2, 3 and 4, therefore is Scenario 2. The wind turbines generate the most electricity and it is most likely that the wind turbines will be built. The area where the wind turbines should stand, is not in the calculations. An alternative is that they build them at the sea, which would increase the generated electricity. A problem with putting wind turbines off shore is that they will be in
the way of the path of boats going to the harbour. There are also ecological factors that can be affected by the wind turbines, both in water and on land.
For Klintehamn to be self-sufficient, and for the system to have no imported energy, Sce-nario 6 has been constructed. The calculations were made much like SceSce-nario 5 but with differences in wind and solar power. 824 new wind turbines with a rotor diameter of 60 meters, 274 times the size of the solar park in Scenario 2, and solar panels on every newly built houses and on all already built houses, were added. These quantifications are extreme and far from realistic. But it is the only scenario where the demand is reached.
The third combination of the renewable energy sources, resulted in a qualified suggestion. Two solar parks were installed, 200 houses has solar panels on their roof tops and 44 new wind turbines are built. This gives a total electricity generation of 108 GWh per year.This is a scenario that is far more realistic than Scenario 6, although this scenario does not reach demand. This scenario requires 3.299 TWh of external electricity. The imported energy may come from other places on Gotland, instead of just from Klintehamn, for the electricity to still be relatively local.
Figure 12 is based on Scenario 5. In this plot the electricity demand of the sawmill has been excluded. It can be seen that the sawmill constitutes a huge part of the electricity demand. It can also be seen that, when not having the demand of the sawmill in mind, the electricity generation reaches demand with a significant margin. The sawmill is the reason for the high electricity demand in all scenarios, as it is 3.4 TWh. The sawmill runs machines which require large amounts of electricity.
Of all the combinations, Scenario 5 and Scenario 7 represent two realistic situations and Scenario 6 represents a scenario that is far from realistic. Scenario 7 is a more ambitious scenario than Scenario 5, as the amount of renewable electricity has been increased in that scenario. The municipality also has plans on making the newer buildings far more energy efficient than the older buildings, therefore, the demand may be lower than what is in the calculations.
4.3
Issues and problems
A problem with the project is the uncertainty regarding the heat demand. Precise numbers on the heat demand from public spaces came in too late and were much higher than assumed. The calculations did not account for such a high heat demand and hence the results are to be studied with caution.
Another problem with the project are the laws and rules that apply to communal facili-ties. For example the sewage treatment plant, which will be made into a biogas facility, has restrictions of where the generated energy can be transported and from where the biomass can be received. The calculations were made with the impression that the energy could go wherever it needed to, in the system of the municipality. This is not correct, as they are only allowed to produce energy for Foodmark. The sewage treatment plant also has their core activity of cleaning water. They are not allowed to abstain from this, which means they can not start producing bio energy on a larger scale.
How-ever the main goal is to decrease the carbon dioxide emissions and making Klintehamn 100% renewable is still possible. For this to happen it is important that the electricity that is im-ported to Klintehamn is renewable. Gotland has the opportunity to increase the generation of renewable energy by e.g. utilizing fields for building solar parks and wind turbines.
4.4
Further research
Today, PV panels are more widely used than CSP, in Sweden. CSP has the capacity to store electricity, which is something that PV panels need e.g. batteries to do. CSP would therefore be the better choice when the goal is a more effective system. Perhaps there is a future for CSP, even in Sweden.
Because of the climate changes in the world, the last summers in Sweden have been warm. Therefore, the energy consumption for cooling may be an interesting and relevant part of further research. Do the households today have any kind of a cooling system and do people request a cooling system? How will the cooling affect the energy system?
To take this project further in the future, cost is an interesting factor. An estimation of the most cost-effective suggestion of the improved energy system would be relevant. Another interesting energy source is wave power. Is wave power possible in the area of Klintehamn and how much will that energy source generate?
4.5
Conclusion
We conclude that the current energy system can be improved. There are possibilities to increase the use of sustainable and renewable energy sources as shown in Scenario 7. It is difficult to generate electricity to the extent that Klintehamn can be self-sufficient, it is almost an impossibility, because of the high electricity demand of the sawmill. To make Klintehamn self-sufficient a larger area needed to be turned into energy effective buildings and facilities for different renewable energy sources.
References
[1] Statistiska centralbyr˚an (SCB). 2019. Folkm¨angd Gotland.
https://www.scb.se/(Retrieved 2019-05-11)
[2] Energimyndigheterna. 2018. Smart och f¨ornybart energisystem p˚a Gotland.
http://www.energimyndigheten.se/contentassets/5227e291e81645f3b75bcf21bfa88ef8/smart-och-fornybart-energisystem-pa-gotland—final.pdf(Retrieved 2019-03-16)
[3] Hagstr¨om, Peter. 2019. KTH, Porject desqription: Kurs-PM MJ146X VT 2019
https://kth.instructure.com/courses/7936/files/?preview=1652165(Retrieved 2019-01-30) [4] Statistiska centralbyr˚an (SCB). 2019. Hush˚all Klintehamn.
https://www.scb.se/(Retrieved 2019-02-25)
[5] Gotlandshem. 2019. Klintehamn, Lugn och harmoni vid havet.
https://www.gotlandshem.se/vara-omraden/klintehamn/(Retrieved 2019-04-28) [6] Region Gotland. 2019, Program Klintehamn 2030 Samr˚adsf¨orlag.
https://gotland.maps.arcgis.com/apps/MapSeries/index.html?appid=fe7395c2c949411fb78e1b5e12518a54
(Retrieved 2019-02-20)
[7] Gotlandsflis AB. 2019. Gotlandsflis AB.
http://www.gotlandsflis.se/(Retrieved 2019-03-10) [8] Region Gotland. 2013. Energi 2020.
https://www.gotland.se/67446(Retrieved 2019-02-22)
[9] ETIP Bioenergy. 2019. Bio-SNG (Synthetic Natural Gas) and Gasification Technologies.
http://www.etipbioenergy.eu/?option=comcontentview “ articleid “ 280
(Retrieved 2019-03-22)
[10] Biog¨odsel. 2014. Basfakta om biog¨odsel.
http://www.biogodsel.se/vad-ar-biogodsel/basfakta-om-biogodsel/(Retrieved 2019-03-22) [11] Irena. 2019. Solar energy.
https://www.irena.org/solar(Retrieved 2019-02-15) [12] Svensk solenergi. 2015. Fakta om solenergi.
https://www.svensksolenergi.se/fakta-om-solenergi(Retrieved 2019-02-19) [13] Utellus AB. 2018. Solceller fr˚an SunPower, Mono 350W
https://www.utellus.se/product/sunpower/(Retrieved 2019-02-26) [14] Solar Heat Europe. 2019. About solar heat
http://solarheateurope.eu/(Retrieved 2019-02-13) [15] Energimyndigheterna. 2015. Solar heat.
http://www.energimyndigheten.se/en/sustainability/households/heating-your-home/solar-heat/(Retrieved 2019-05-09)
[16] Irena. 2019. Wind energy.
[17] Medvind f¨or bygden. 2015. H ¨ANG MED UPP I ETT VINDKRAFTVERK.
http://www.medvindforbygden.se/2015/06/15/hang-med-upp-i-ett-vindkraftverk/
(Retrieved 2019-04-28)
[18] ETC El. 2018. S˚a lagrar vi solenergi i batterier.
https://www.etcel.se/energi/sa-lagrar-vi-solenergi-i-batterier(Retrieved 2019-03-13) [19] SMHI. 2006. SMHI Meteorologi.
http://www.smhi.se/polopolyfs{1.1895!meteorologi121 ´ 06%5B1%5D.pdf
(Retrieved 2019-03-25)
[20] Campanello, Simon. 2018. Sveriges st¨orsta solcellspark invigd – klar p˚a rekordtid. Time: 14 December.
https://www.nyteknik.se/energi/sveriges-storsta-solcellspark-invigd-klar-pa-rekordtid-6942563(Retrieved 2019-03-01)
[21] Nohrstedt, Linda. 2017. Sverige beh¨over 4 700 solcellsparker Time: 30 October.
https://www.nyteknik.se/energi/sverige-behover-4-700-solcellsparker-6879360
(Retrieved 2019-02-19)
[22] Bhattacharya, Subhamoy. 2019. Design of Foundations for Offshore Wind Turbines. Hoboken: John Wiley Sons ltd.
https://books.google.se/books?id=51yHDwAAQBAJpg=PA11lpg=PA11dq=power+coefficient+0.35-0.45source=blots=mZcJ2u0NDVsig=ACfU3U2q7QVYcVkfUC48z0rzGYDCAvSa5ghl=svsa=Xved=2ah UKEwj584GmqpPhAhUjwMQBHSsEDaUQ6AEwA3oECAcQAQv=onepageqf=false
(Retrieved 2019-04-15)
[23] Wegener, Moritz & Malmquist, Anders, 2018. Polygeneration Concept, A General Overview. Power point (Retrieved 2019-02-27)
[24] Jakobsson, Mikael; Operation Manager Klintehamn. 2019. E-mail 24 April. [25] Andersson, Helena; Eco strategist for Region Gotland. 2019. E-mail 3 May. [26] Eriksson, Mats; Port Manager Klintehamn. 2019. Interview 9 April
Appendix
Appendix 1. Infromation about the fodder production,
e-mail from Mikael Jakobsson
Hej Caroline
F¨or att du skall f¨orst˚a svaren jag ger m˚aste jag f¨orst ge lite bakgrundsinformation om Lantm¨annens verksamhet i Klintehamn.
I Klintehamn har Lantm¨annen vi administrativ verksamhet som bland annat innefattar Lantm¨annens s¨aljare som ¨ar stationerade p˚a Gotland. Vi har ¨aven en lagercentral som f¨orses med varor fr˚an Lantm¨annens ¨ovriga anl¨aggningar i Sverige d¨ar vi lagrar och packar om varor som sen distribueras ut till v˚ara gotl¨andska kunder.
Vi har en uts¨adesanl¨aggning som till stor del tar emot uts¨ade under sk¨ord som har odlats p˚a Gotland. Den torkar vi och lagerf¨or f¨or att sedan rensa och sortera innan den behandlas och paketeras f¨or att s¨aljas till v˚ara kunder. Vi tar ¨aven emot en del uts¨ade som lagrats och torkats ute p˚a g˚ardar f¨or att sedan rensa och sortera den innan den slutligen paketeras f¨or f¨ors¨aljning. Det finns ¨aven en g¨odselanl¨aggning d¨ar vi tar emot handelsg¨odsel i l¨osvikt som kommer med b˚at f¨or att paketera den h¨ar f¨or f¨ors¨aljning till v˚ara kunder.
Sen har vi ¨aven en silo anl¨aggning som normal˚ar tar emot ca 90 000 ton spannm˚al som odlats p˚a Gotland. H¨alften av den spannm˚alen rensas och torkas samt lagras i v˚ar anl¨ aggn-ing, resterande transporteras med b˚at till n˚agon av Lantm¨annens anl¨aggningar p˚a fastlandet f¨or att d¨ar torkas, rensas och lagras.
Slutligen har vi v˚ar foderfabrik som producerar ca 47 000 ton foder per ˚ar. Ca h¨alften av de r˚avaror som g˚ar ˚at f¨or den produktionen ¨ar spannm˚al som kommer fr˚an v˚ar spannm˚alsanl¨ aggn-ing. Av resterande m¨angd kommer ungef¨ar lika mycket hit med b˚at som med lastbil. Vi producerar ca 65 olika sorters foder till n¨otkreatur, f˚ar, grisar och fj¨aderf¨a och till det anv¨ander vi ca 50 olika r˚avaror.
Man tillverkar foder genom att blanda samman olika ingredienser och sen mala dem till mj¨ol. Slutligen tills¨atter man ˚anga f¨or att baka ihop blandningen till en deg som pressas genom en j¨arnring med h˚al i f¨or att det skall bli pellets som sedan kyls och torkas innan den transporteras iv¨ag till kund. Man tills¨atter ¨aven ˚anga f¨or att v¨arma upp r˚avarorna till 75 grader f¨or att avd¨oda o¨onskade bakterier (fr¨amst salmonella).
Den enda energi k¨alla vi anv¨ander i foderfabriken ¨ar el och vi f¨orbrukar ca 2 920 000 kWh per ˚ar var av ca 1 530 000 kWh g˚ar ˚at att producera den ˚anga vi beh¨over.
Foderfabriken genererar inte n˚agon energi.
Lantm¨annen ¨ager ett av vindkraftverken i hamnen och det mesta av den el den produc-erar anv¨ands i v˚ar anl¨aggning.
Vi har inga andra energi fl¨oden i v˚ar foderfabrik men i v˚ar uts¨ades och spannm˚alsanl¨aggning anv¨ander vi stora spannm˚alstorkar som f¨orses med v¨arme av 2 v¨armepannor. En av pan-norna ¨ar en fastbr¨ansle panna d¨ar vi eldar avfall fr˚an spannm˚alshanteringen, den andra ¨ar en oljepanna som vi anv¨ander n¨ar v¨armen fr˚an den f¨orsta pannan inte r¨acker till.
Hoppas det var svaret p˚a dina fr˚agor.
H¨or g¨arna av dig om du beh¨over n˚agot f¨ortydligande eller ytterligare uppgifter. Med v¨anlig h¨alsning
Appendix 2. Infromation about biogas plant, e-mail from
Helena Andersson
Hej Caroline och Astrid!
Vad roligt att ni valt att jobba med Klintehamn och kommer p˚a bes¨ok
Om biogas fr˚an Reningsverket i Klintehamn, I det gamla reningsverket anv¨andes ca 100 m3 eldningsolja per ˚ar, nu byggs det om till att betj¨ana ett st¨orre omr˚ade och f˚a mod-ernare drift: Ur teknikf¨orvaltningens ¨arendebeskrivning: ”Som huvudman f¨or vatten- och avloppsf¨ors¨orjningen p˚a Gotland och ansvarar Region Gotland f¨or ombyggnation av avlopp-sanl¨aggningen i Klintehamn. Syftet ¨ar att modernisera anl¨aggningen och d¨ar ing˚ar ¨aven konvertering till f¨ornybara energik¨allor. Det kommer att byggas en samr¨otningsanl¨agging Foodmark AB ¨ager och driver livsmedelsproduktion 4 km fr˚an Klintehamns avloppsren-ingsverk. Verksamheten har f¨or avsikt att byta ut eldningsolja f¨or produktion av processv¨arme till f¨ornybar energik¨alla. Verksamheten har ¨aven ett behov av att behandla eget r¨otbart avfall och avloppsvatten som idag hanteras i egen reningsanl¨aggning. .... Sammantaget ¨ar m¨angden slam fr˚an VA-verksamheten och avfall fr˚an Foodmark tillr¨ackliga f¨or att genom slamr¨otning f¨or biogasproduktion m¨ota verksamheternas behov av f¨ornybar energi. En investering skulle m¨ojligg¨ora ¨aven behandling av organiska avfall fr˚an andra verksamheter. Enligt VA-lagen f˚ar merkostnader i drift till f¨oljd av detta ej tillf¨oras VA-kollektivet och ska d¨armed t¨ackas av avgifter f¨or utf¨ord tj¨anst. I det nya milj¨otillst˚andet villkoras det att avloppsslammet skall r¨otas samt att om r¨otning sker p˚a annan plats f˚ar ej slam fr˚an enskilda avlopp l¨amnas till Klintehamns reningsverk. Konsekvensen om r¨otning ej byggs i Klintehamn blir att slam fr˚an reningsverket beh¨over transporteras till Visby f¨or r¨otning. Visby avloppsreningsverk ¨ar redan idag ¨ar ¨overbelastat. Milj¨odomens villkor f¨oreskriver att hantering av slam fr˚an en-skilda avlopp ej kan ske i Klintehamn utan att en r¨otgaskammare finns. Etableras r¨otning i Klintehamn bidrar det till l¨osning f¨or ovan samt om det sker i samband med ombyggnaden av reningsverket ges samordningsvinster. Den totala investeringsutgiften f¨or projektet uppg˚ar till 29 mnkr kronor varav 12, 34 mn kr finansieras med st¨od fr˚an Klimatklivet.”
Det ¨ar s˚avitt jag vet inte helt f¨ardig-projat ¨an, allts˚a inte angivet vad det kommer att handla om f¨or gasm¨amngder
Utvecklingsm¨ojligheter enligt teknikf¨orvaltningens tj¨ansteskrivelse: ”Ett ¨onskem˚al fr˚an Food-mark ¨ar att kunna leda avloppsvatten fr˚an industrin till reningsverket. En s˚adan l¨osning kan med f¨ordel g¨oras i samband med f¨orl¨aggning av gasledning och substratledning. Detta ger en ¨okad belastning p˚a reningsverket och regleras via en industritaxa. Avloppsvattnet bidrar ocks˚a med ytterligare potentiella r¨otbara substrat som ¨ar positivt f¨or aff¨aren. Det finns vilja att ytterligare ¨oka fordonsgasproduktionen p˚a Gotland. Etableras ytterligare samarbeten kring substrat med andra intressenter kan st¨orre m¨angder gas produceras, vilket g¨or det ekonomiskt intressant att producera biogas av fordonsgaskvalitet. Detta f¨orenklar distribu-tionen till Foodmark och m¨ojligg¨or lagring av biogas som beh¨ovs f¨or livsmedelsproduktionens produktionsvariationer. Flexibiliteten ger besparingar i Foodmarks processv¨armef¨ors¨orjning som annars beh¨over kompletteras med andra br¨anslen. Biogas av fordonsgaskvalitet ¨ar l¨attare att lagra och distribuera, och ger flera avs¨attningsm¨ojligheter. Andra akt¨orer som ocks˚a har visat intresse av biogas ¨ar Lantm¨annen, S˚agen, GEAB och lokala lantbruk. Flera av dessa verksamheter har ¨aven organiska avfall som kan vara l¨ampliga f¨or processen. Ytterligarare
en utvecklingsm¨ojlighet ¨ar lantbruket d¨ar efterfr˚agan p˚a f¨ornybara n¨arings¨amnen v¨axer” Det byggs inte f¨or att ge gas till fj¨arrv¨armen eller ens till en mack i f¨orsta skedet, det blir f¨or lite gas f¨or uppgradering.just nu bed¨oms det bli ca 5 GWh per ˚ar, Foodmark vill egentligen f˚a mer gas. Betr vindkraftverken ber jag att f˚a ˚aterkomma,
