EINSTEIN. Del.No7.3: Report on impact assessment of demonstration plants THERMAL ENERGY STORAGE SYSTEMS IN EXISTING BUILDINGS

Transcription

1 EINSTEIN Del.No7.3: Report on impact assessment of demonstration plants Project acronym: Project full title: EINSTEIN Grant agreement no.: EFFECTIVE INTEGRATION OF SEASONAL THERMAL ENERGY STORAGE SYSTEMS IN EXISTING BUILDINGS Doc. Ref.: Responsible: Author(s): Date of issue: Status: Security: EINSTEIN-<WP>-<Task>-<Type>-<Issue date>- Version 0.1 MOSTOSTAL <list of partners short names> Draft Public Change control: Version and date V0.1, 07/December/2015 V0.2, 31/03/2016 Changes <comment on the version> <comment on the version> 1/37

2 TABLE OF CONTENTS 1. INTRODUCTION COMPARISON BETWEEN CONVENTIONAL SYSTEM AND NEW EINSTEIN TECHNOLOGY IN ZABKI COMPARISON BETWEEN CONVENTIONAL SYSTEM AND NEW EINSTEIN TECHNOLOGY IN BILBAO 6 2. IMPACT ANALYSIS OF THE POLISH PILOT PLANT METHODOLOGY TECHNOLOGY IMPACT VIABILITY Reliability COST ANALYSIS CAPEX - Investment costs. 19 Operation costs - OPEX. 20 Cost-effectiveness analysis ENVIRONMENTAL IMPACT SOCIAL IMPACT IMPACT ANALYSIS OF THE SPANISH PLANT TECHNOLOGY IMPACT VIABILITY. BILBAO DEMO COST ANALYSIS. BILBAO DEMO CAPEX - Investment costs. 32 Operation costs - OPEX ENVIRONMENTAL IMPACT. BILBAO DEMO SOCIAL IMPACT. BILBAO DEMO REFERENCES 37 2/37

3 1. INTRODUCTION This report comprises the impact of the demonstrated Spanish and Polish Pilot Plant in technological, economic, environmental and social terms. The objective of this document is to demonstrate and assess the benefits from the developed EINSTEIN technology. A comparison between the use of EINSTEIN and conventional heating system in the two demonstration installation (Poland district level, Spain public building) was performed. The influence of proposed energy storage system in the overall system performance in the field of reliability, energy efficiency, power quality, costeffectiveness, environmental issues was analyzed. Non-technical views of the EINSTEIN technology were also discussed, including social end-user point of views. In chapter 1, comparison between the conventional system and new EINSTEIN technology with requirements for space heating was briefly described. The components of the proposed system and their impact on energy efficiency, reliability, power quality was shown. Chapter 2 and 3 contains the impact assessment of the EINSTEIN technology respectively for Polish and Spanish case. The analysis consists of four part: technological impact, economic feasibility study, environmental issues and social aspects. Monitoring data from one year of regular operation was used to evaluate the analysis. On that basis, power quality, energy efficiency, the savings of primary energy was discussed. Potential for optimization was provided as well. Economic analysis considers cash flows (investment and operational costs, benefits from avoided natural gas consumption) over lifetime of EINSTEIN system, and include basic factors, such as NPV and IRR. The environmental impact was evaluated as an emission reduction after modernization the conventional heating system. Emissions from all auxiliary components was also included C O M PA R I S O N B E T W E E N C O N V E N T I O N A L S Y S T E M A N D N E W E I N S T E I N T E C H N O L O G Y I N Z A B K I Conventional heating system was equipped with the modern gas-fired boiler Buderus Logano G334, with thermal power of 90 kw. Gas-fired boiler is equipped with two stage burners, without blower. The supply temperatures in the heat distribution system are controlled according to the ambient temperature. The gas boiler is switched-off at ambient temperature above 14 C. There is a constant flow in the heating circuit of 3.9 m 3 /h and no domestic water consumption is considered. Figure 1 shows monthly summary values of the load profile. January and February are the main periods with auxiliary heat demand. The long-lasting annual gas demand for heating the building is approximately 150 MWh. Considering an efficiency of 85% for the gas boiler this results in a net energy demand of the building of 130 kwh. 3/37

4 [MWh] 25 Heat demand Figure 1 Monthly values of the load profile Conventional system was retrofitting by the EINSTEIN technology. Within the scope of EINSTEIN project, the space heating system of the building was equipped with solar collector field, seasonal thermal energy storage tank and heat pump. The schematic diagram of the EINSTEIN system was shown in the picture below (Figure 2). EINSTEIN part Conventional part Figure 2 The schematic diagram of the EINSTEIN technology Solar collectors deliver heat to the system by charging the seasonal thermal energy storage (STES). Heat can be discharged from the STES either by a heat exchanger separating the STES from the heating system or by way of heat pump. If no enough solar energy is available and the STES is completely discharged the existing gas boilers operate as backup heat producers. An additional buffer 4/37

5 storage is implemented into the system to facilitate the operation of the heat pump and to uncouple the energy production of the new part of the energy system from the existing part. The main components of the system concept are described in the following. 1 Solar collectors field The area of flat plate solar collectors installed in Poland is 151 m 2. The solar collectors are facing south with a slope angle of 45. Solar collectors field is connected to the rest of the system in the way which allow facilitating the solar energy in every time of the year. During the warm months, the solar energy may be used for STES charging purposes, during the heating period, for building space heating purposes. In Poland, the second option is practically not used because of the low values of solar radiation during winter months. Other subsystem components include the pipes, sensors, control equipment. 2 Solar system container station subsystem. That subsystem includes solar heat exchanger, water pumps, valves, sensors. The plate heat exchanger SWEP IC120 is designed to transfer the heat from hot glycol (working fluid in the solar collector field subsystem) to water in STES subsystem. The logarithmic mean temperature difference of heat exchanger is 4-6 K. The water and glycol pumps are activated by custom designed algorithm; the main trigger is the temperature difference between the collectors and water in the bottom of STES. 3 STES subsystem STES is built as unpressurized tank, fully insulated to prevent excessive heat losses. System is designed to work in two cycles: charging or discharging. During warm months tank is being charged and the water from the bottom of STES is heated up in the solar heat exchanger and enters in the middle or at the top of STES. During cold months the tank is being discharged what means that the heat accumulated in STES is transferred to the space heating system of the building via heat exchanger or via heat pump. The main characteristics of the tank are: - Non-pressurized - Reference volume 800 m 3 - Maximum diameter x height: 12.4 x 8 m - Operational temperature C 4 STES subsystem It is a conventional space heating system. Existing devices in a boiler room are connected to EINSTEIN system in a way allowing an easy separation of both subsystems. By closing the connection to existing subsystem it is possible to operate the same way as before project started. This feature is very important by means of maintenance and development of pilot plant virtually any changes to EINSTEIN subsystem can be done without compromising heat delivery by gas-fired boiler during heat demand. 5/37

6 5 Boiler room Einstein part subsystem It includes the equipment installed inside the boiler room. The subsystem is connected to STES tank and to the space heating system of the building. Main equipment of EINSTEIN part is: heat exchanger buffer storage of 1m 3 volume the heat pump with thermal power 90 kw pipes automation equipment sensors The role of the heat exchanger is to hydraulically separate the poor water in STES circuit from water in space heating system circuit. Hot water from STES flows into the heat exchanger or into the heat pump. It depends on the climate conditions, the temperature of water in STES and the current building user s needs. In Ząbki a heat pump is integrated into the system that has been developed by University of Ulster. It is operated with the refrigerant R245fa and thus achieves a maximum temperature of about 75 C at the condenser for heating. The maximum thermal capacity is about 90 kwth C O M PA R I S O N B E T W E E N C O N V E N T I O N A L S Y S T E M A N D N E W E I N S T E I N T E C H N O L O G Y I N B I L B A O The existing heating conventional system of the Bilbao demo before installing the STES installation consisted on a conventional natural gas boiler (190 kw) used to provide heat to the underfloor heating system of a facility of m 2 surface used for cultural activities. The facility is a retrofitted paper industry that performed its activity about one hundred years ago. Within the scope of EINSTEIN project, the space heating system of the building was equipped with solar collector field (on the roof of an existing building), seasonal thermal energy storage tank (next to the building) and heat pump (on the roof of an existing building). Those are the main parts of the Einstein system which are described in the next chapter. The schematic diagram of the whole EINSTEIN system was shown in the picture below (Figure 3). On the right of the Scheme is indicated the conventional part, while on the left of the scheme is indicated the part of the Einstein system. 6/37

7 EINSTEIN part Conventional part New part added in Einstein project Figure 3: The schematic diagram of the Einstein system Scheme of the conventional system before Einstein plant installation in Bilbao: Figure 4: Diagram conventional system Bilbao 7/37

8 The main components of the Bilbao Einstein demo concept are described as follows. 1 Solar collectors field Solar collector primary circuit has as thermal fluid water with 30% ethylenglycol in a copper pipeline. The area of 27 flat plate solar collector installed in Bilbao is 62 m 2. The solar collectors are installed with a slope angle of 45 oriented exactly to the South. Solar energy can be used for charging purposes along the whole year although during winter, the underfloor heating system can be directly heated with heat obtained from solar collectors. The circuit is feed with a water ethylenglycol solution that allows working between 30 C and C. Stagnation problems are prevented by oversizing of the expansion tank of the circuit: when temperature of collectors is higher than 120 C, the expansion tank absorbs the increase of volume and avoids any damage to the collectors. When temperature of the collectors goes back to working level again, the expansion tank sends ethylenglycol to the collectors automatically. 2 Hydraulic system The primary circuit is isolated from the secondary circuit which uses just water as thermal fluid (this secondary circuit is always inside the building so it has not freezing problems). The secondary circuit, with isolated polypropylene piping, is composed by the STES tank, the 2 m 3 buffer, heat pump, the natural gas boiler and the space heating system (underfloor heating and air handling unit). The secondary circuit shows a big volume because comprises the hot water storage. Both primary and secondary circuits are separated by a plate heat exchanger to transfer harvested heat from solar collectors into the secondary circuit water to accumulate heat in the STES tank. The logarithmic mean temperature difference of heat exchanger is about 5 K so the efficiency of it is high. Pumps of the primary and secondary circuits are automatically switched on when temperature of the primary circuit increases due to the solar radiation. Heat exchanger has four temperature sensors in the inlet and outlet of both circuits and all these temperature data can be seen by connection to the Scada system. Temperatures from the solar collector plates and from the STES tank are also included in the Scada system which allows monitoring of the whole installation (see 3 STES subsystem STES is built as unpressurized tank, insulated on the top, bottom and side part of the cylindrical tank. There is a double tank, the inner one, with 6m diameter which contains up to C water, and the external one with 7.2 m diameter. Space between both cylinders, 0,6 m, is filled with recycled polyurethane as insulation material. During warm months tank is being charged and the water from the bottom of STES is heated up in the solar heat exchanger and enters in the middle or at the top of STES depending on the temperature of the tank. During cold months the tank is being discharged what means that the heat accumulated in STES is transferred to the underfloor heating circuit. Hot water from the tank is directly circulated in the underfloor heating circuit of the building (or mixed with colder water from the system) but when temperature of the STES tank is under 40 C approx. the heat 8/37

9 pump starts automatically until temperature of the STES tank arrives up to 15 C. Then the natural gas boiler is used for space heating. The main characteristics of the tank are: 1. The choice that meets all the requirements is a double metallic tank, built over a foundation slab enough strong to homogeneously distribute the loads and weight of the tank. The tanks are formed of galvanized steel parts bolted, and using an epoxy board in each junction. 2. At the bottom, it has an EPDM sheet confirming the impermeability of the deposit. In side part and the top of the container, metallic pieces are in contact with water; these surfaces are painted and the union between pieces is sealed with epoxy resins glue. The top of the tank is isolated by using recycled PolyUrethan foam between both cylindrical containers. The inner tank contains the water to be used as storage media, and have the in and out connections. 3. The external tank has the function of contain the insulation of the tank, by filling with a granular recycled PU insulation the cylindrical ring between the two tanks. Also in the covering, the insulation is made by filling the space between the two covers. For the bottom part, insulation is made by using a rigid insulation over the insulation slab, and under the waterproofing liner The main characteristics of the tank are: Non-pressurized Useful volume 160 m 3 Maximum diameter x height: 6 x 7 m Operational temperature o C Five Pt 1000 temperature sensors are submerged into the tank. Besides, temperature sensors are in the insulation material: three on the top part of the tank, three in the side part and one on the bottom part of the STES tank. 4 Main technical data of the circuit The equipment installed includes: heat exchanger buffer storage of 2m3 volume Supply/return temperatures: 45/35ºC of the underfloor heating circuit (existing circuit), 69 kwth heat pump (commercial equipment). The heat pump selected for the installation can operate between 28 and 10 C with a COP of Conventional 190 kw natural gas boiler, air handling unit (existing installation before STES), Scada system to visualize temperatures, running of pumps, solar irradiation and discharge data from the system to monitor it Sensors (mainly temperature but also one pressure-level sensor in the tank and solar radiation sensor). 9/37

10 The lay-out of the installation is shown in the picture: Figure 5: Lay-out of Bilbao STES and solar collector installation 10/37

11 2. IMPA CT A NALYSIS O F T H E P OL I SH P I LOT PLAN T The main principle of EINSTEIN technology is to renovate the conventional heating system in terms of energy efficiency, environmental and economic issues. Thermal energy stored in STES provide solar energy and allow to reduce natural gas demand. It results in primary energy savings, emission reduction and economic savings from reducing natural gas consumption. However, retrofitting requires a significant capital and operational cost. The purpose of this analysis is to determine feasibility study to evaluate potential economic and operational benefits with comparison to conventional heating system. Economic benefits includes lower operational energy cost and potential construction cost savings. Operational benefit may include the ability to serve a load for a period of time without the operation of a conventional heating. The summarized benefits that can be obtained when implementing thermal storage are: - Reducing operational costs - Achieving a more efficient use of energy - More flexible plant operations and added backup capacity - Less pollution of the environment and less CO2 emission - Better system performance and reliability M E T H O D O L O G Y Impact analysis for the polish system was performed based on the monitoring data from one year of regular operation of the demonstrated plant (from January to December 2015). The acquired data from monitoring system was processed and used to evaluate an analysis. The feasibility study scope of work was presented in the figure below (Figure 6). In order to determine the potential benefits, the required parameters are related to energy and CO2 emission. Within the energy field energy savings should be determined. The energy savings simply refer to the heat that is stored and may be reutilized. The reduction in CO2 emissions is achieved as a result of reusing stored energy, therefore not consuming fossil fuels. The parameters of EINSTEIN technology that was assumed in impact assessment are summarized in the table 1. Impact assessment was performed for two cases: for the data obtained from monitoring system during one year of a regular operation (from January to December 2015) and after planned optimization, since in 2015 the system operated in non-optimal conditions and potential improvements can be achieved (explained later). 11/37

12 Technological impact Solar fraction Energy balance in the system Reliability INPUT Load profile Solar yield Heat charged to the STES Heat discharged from the STES COP of the heat pump Capital and investment costs, lifetime of components Energy prices over lifetime of the project Environmental impact Primary Energy savings CO2 emission reduction Economic impact NPV, IRR indicators Structure of operational cost Cost effectivess Heat costs Social impact Figure 6 Input for impact assessment of demonstration plant in Ząbki End-user point of view Maintance issues Lower energy costs Social benefits Table 1 EINSTEN technology parameters EINSTEIN (monitoring data 2015 year) EINSTEIN after improvement (assumption) Heat demand in building Heating demand [MWh/a] Solar collector Solar collector field [m 2 ] Solar collector utilization rate [%] 43.62% 43.62% Specific solar irradiation [kwh/m 2 *a] Solar irradiation [MWh/a] Specific solar yield [kwh/m 2 *a] Solar yield [MWh/a] STES parameters heat charged to STES [MWh/a] heat discharged from STES [MWh/a] Solar heat Direct discharging STES [MWh/a] Heat pump solar heat [MWh/a] Heat pump COP [-] Solar fraction [%] 18.54% 38.87% 12/37

13 Solar yield of the collector field [MWh] T E C H N O L O G Y I M PA C T V I A B I L I T Y In this paragraph technology impact was discussed. Solar yield from collector field, STES heat balance by means of charged and discharged energy, annual energy balance in space heating system was analyzed. An important element of the whole system is solar collector field. The obtained input-output diagram for solar collector field is given in the Figure 7. Diagram present mean solar irradiation on the solar collector field and mean solar yield (output) on monthly basis. Annual solar yield from the field of MWh/a was measured, which corresponds to a specific yield of kwh/(m 2 *year). The annual specific solar irradiation measured on the side was kwh/(m 2 *a) table 1. This value can be increased in the future, since the solar collectors was shaded by surrounding bushes and trees. Mean solar specific solar irradiation in this region is estimated at 1055 kwh/(m 2 *a). This means that solar yield could be increased. Assuming that annual collector utilization ratio of 43.62% expected solar yield is approximately 70 MWh/a. 12,00 10,00 [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] 8,00 [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] 6,00 4,00 2,00 [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] [ZAKRES KOMÓREK] 0,00 0,00 2,00 4,00 6,00 8,00 10,00 12,00 14,00 16,00 18,00 20,00 Solar irradiation on the collector field [MWh] measured data utilization ratio 50% utilization 25% Figure 7. Utilization ratio of solar energy The measured STES heat balance (heat charged and discharged) and mean temperature of the STES on monthly basis was shown in the Figure 8. Amount of heat charged to the STES can be increased by reducing shading for solar collector. Heat discharged from STES for heating purpose can also be enhanced. During one year of operation the heat pump was not operated as expected, due to several test runs. Expected heat balance after optimization is presented on the figure 9. 13/37

14 Heat [MWh] mean STES temp. [C] Heat [MWh] mean STES temp. [C] 15,00 60,00 10,00 40,00 5,00 20,00 0,00-5, ,00-20,00-10,00-40,00-15,00 Month -60,00 Heat charged to STES [MWh] Heat discharged from STES [MWh] STES mean temp [C] Figure 8. STES heat balance on monthly basis and mean temperature of STES (monitoring data) 20,00 15,00 10,00 5,00 0,00-5,00-10,00-15,00-20, Month 70,00 50,00 30,00 10,00-10,00-30,00-50,00-70,00 Heat charged to STES [MWh] Heat discharged from STES [MWh] STES mean temp [C] Figure 9. STES heat balance on monthly basis and mean temperature of STES (after modernization) In figure below (Figure 10) monthly energy balance for the demonstration plant is shown from January to December In winter most of the heat was provided by the existing gas boiler. This is due to the fact that the STES was rarely charged and the share of thermal energy from heat pump was very low so far as the operating conditions for a regular operation was not given so far. It is expected that heat pump will contribute significantly to the heating in the forthcoming winter 2015/2016 (Figure 11). 14/37

15 Heat [MWh] Heat [MWh] 30,00 25,00 20,00 15,00 10,00 5,00 0,00 Heat charged to STES [MWh] Heat pump solar heat [MWh] Heat pump electricity [MWh] Direct discharging STES Gas boiler [MWh] Control/monitoring system electricity [MWh] Figure 10 Monthly energy balance in the system (monitoring data) 25,00 20,00 15,00 10,00 5,00 0,00 Heat charged to STES [MWh] Heat pump solar heat [MWh] Heat pump electricity [MWh] Direct discharging STES [MWh] Gas boiler [MWh] Control/monitoring system electricity [MWh] Figure 11 Monthly energy balance in the system (after modernization) Summarized energy balance of the EINSTEIN technology on an annual basis was shown and compared with conventional system in the Figure 12. Solar fraction of 18.54% was achieved. It is expected that this value can be increased in the future to more than 40% if the heat pump is in proper operation. However, this requires purchase of additional electricity, what should be taking account in 15/37

16 Annual energy balance [MWh] primary energy savings calculation. Natural gas has a primary factor of 1.1. As the heat pump is consuming electricity this amount of energy must be regarded as well taking the primary energy factor for electricity of 3.0 in Poland into consideration. In 2015 the primary energy savings of MWh was obtained. Supposing that EINSTEN technology will be optimized the primary energy savings are estimated at MWh which correspond to 33.29% of savings (Figure 13). 160,00 140,00 120,00 100,00 80,00 60,00 40,00 20,00 0,00 Conventional EINSTEIN EINSTEIN after modernization Natural gas Electricity - heat pump [MWh] Solar heat used Electricity - control system and other [MWh] Figure 12. Annual energy balance in the EINSTEIN system with comparison to conventional 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Conventional EINSTEIN EINSTEIN after modernization 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Natural gas Heat pump solar heat Direct discharging from STES PRIMARY ENERGY SAVINGS Figure 13. Annual fuel structure in heating demand and primary energy savings achieved by EINSTEIN technology 16/37

17 Likelihood of component failure R e l i a b i l i t y In this paragraph reliability of conventional system and new EINSTEIN technology was discussed. The potentially unreliable equipment in EINSTEN system was listed in the table below (table 2). It can be noticed that EINSTEIN contain more equipment thus the system is much more complex. Conventional system is a proven technology and there is relatively low risk of system failure. Overall system, design, construction and maintenance is quite simple. The reliability of the system was evaluated as a reliability matrix tool. The results are presented in the figure 14, where likelihood of failure of each component has been estimated. Failure of system components may cause the interruption in the heat delivery to the building users. It includes the events like the damages of the heat pump, water pump, errors of control system, leakages etc.). In the figure 15 expected lifetime and costs of the components was presented. Near certainty Highly likely Likely Low likelihood Electric connections; Heat exchangers Heat pump; Monitoring & controls Solar collectors field Not likely Hydraulic connections Buffer storage; Water pumps Gas boiler; STES tank Figure 14. Reliability matrix tool Negligible Minor Moderate Serious Critical The impact of component failure 17/37

18 year Cost of component Table 2 Potentially unreliable equipment Conventional system Gas fired boiler Potentially unreliable equipment EINSTEIN system Gas fired boiler 1 x controller (simple automation) 5 x controller (complex automation) 1 x water pump 3 x control cabinets 1 x mixing valve 5 x water pumps 2 x temperature sensors 2 x mixing valves 1 x expansion vessel 5 x switch valves 1 x safety valve 2 x on/off valves 50+ temperature sensors 9 x flow meters 3 x pressure sensors 1 x weather stations Heat pump s electrical compressor Heat pump s expansion valve 2 x heat exchangers 3 x expansion vessels 4 x safety valve 65 x solar collectors Conventional - lifetime EINSTEIN - cost of component EINSTEIN - lifetime Conventional - cost of component Figure 15. Expected lifetime of the system components and its costs. 18/37

19 2. 3. C O S T A N A LY S I S C A P E X - I n v e s t m e n t c o s t s. CAPEX (capital expenditures) is calculated by summing up each cost associated with capital expenditure. In Table 3 estimated investment costs of conventional system are shown. In case of EINSTEIN system, the total required investment, without considering any subsidy, has been estimated at This estimate considers the cost of STES and solar field construction, its integration into the conventional system, purchase cost of the pieces of equipment. In Table 4 are shown in detail the considered investment costs of EINSTEIN system. Major investment cost in EINSTEIN technology is STES tank - estimated at approximately 50% of total investment (including engineering project, project management, etc.) figure 16. Table 3. Investment costs of the conventional Conventional system Component Cost per Number of unit unit Cost Gas boiler Water pumps Monitoring/control system Hydraulic connections Electrical connections SUM Table 4. Investment costs of the EINSTEIN system EINSTEIN technology Component Cost per unit Number of unit Cost STES tank Solar collectors field Heat exchanger Heat pump Water pumps Buffer storage Monitoring/control system Hydraulic connections Electrical connections Gas boiler SUM /37

20 Heat pump 12% Gas boiler 2% Solar collectors field 29% STES tank 51% Figure 16. Investment cost in EINSTEIN technology O p e r a t i o n c o s t s - O P E X. OPEX (operational expenditure) is an ongoing cost for running the system. Typical maintenance costs include: - Preventative/periodic maintenance of equipment - Repair of equipment - Rebuilding/overhaul equipment during the life of the analysis In the table 5 operational cost involved with inspection and replacement of component are listed. The requirements for the gas boiler servicing are the same for both systems but in EINSTEIN system the qualified worker have to check also solar collector installation, heat pump and monitoring/control system. The maintenance of EINSTEIN system is more complex than in case of conventional heating systems. The suggested number of inspection per year for particular EINSTEIN system components was shown in the table 6. Table 5. Operational costs conventional Component COST OF INSPECTION Inspection per year Cost of inspection Cost per year Lifetime [year] COST OF REPLACEMENT Number of replacement in project lifetime Cost of replacement during lifetime Gas boiler 2 50,00 100, ,00 Water pumps - - Monitoring/control system Hydraulic connections Electrical connections , SUM 100,00 SUM ,00 20/37

21 Table 6. Operational costs EINSTEIN Component COST OF INSPECTION Inspection per year Cost of inspection Cost per year Lifetime [year] COST OF REPLACEMENT Number of replacement in project lifetime Cost of replacement during lifetime STES tank Solar collectors field 1 70, ,00 Heat exchanger ,00 Heat pump 1 50, ,00 Water pumps ,00 Buffer storage Monitoring/contro l system Hydraulic connections Electrical connections Gas boiler 2 50, ,00 SUM 220,00 SUM ,00 An important part of operational maintenance costs is purchased energy cost. Conventional and EINSTEIN technology require natural gas and electricity. In EINSTEIN project STES system is extended by a heat pump consuming electric power. Monitoring and control system is much more complex and thus consume more energy. The annual energy cost between two systems was compared in the figure 17. It can be seen that conventional system consumes less electricity than EINSTEIN system. The main equipment responsible for additional electricity consumption is the heat pump and in lesser extent the auxiliary devices: water pumps, monitoring and automation systems. Energy costs in 2015 year [EUR] 8.000, , , , , , , ,00 0,00 Conventional EINSTEIN EINSTEIN after modernization Natural gas [EUR] Electricity - monitoring/control Electricity - heat pump Figure 17 Annual costs of purchased energy (natural gas and electricity). 21/37

22 C o s t - e f f e c t i v e n e s s a n a l y s i s Economic analysis is the process by which the financial viability can be determined. The conducted feasibility study contain: - Estimation of the investment, annual costs (energy, maintenance) - Net cash flow (income from natural gas savings vs annual costs) - Calculation of the resultant NPV Net Present Value (NPV) is the difference between the present value of cash inflows and the present value of cash outflows. NPV is used in capital budgeting to analyze the profitability of a projected investment or project. The following is the formula for calculating NPV: T C t NPV = (1 + r) t C 0 t=1 Where: Ct - net cash inflow during the period t, Co - total initial investment costs, r - discount rate, t - number of time periods. The analysis was carried out for discount rate of 3% and assuming that lifetime of the EINSTEIN project is 50 year. Given a collection of pairs (time, cash flow) involved in a project, the internal rate of return follows from the net present value as a function of the rate of return. A rate of return for which this function is zero is an internal rate of return. The internal rate is given by r in following equation: T C t NPV = (1 + r) t = 0 t=1 Energy price is a key aspect, as it will be one of the main influencing factor on the cost-effectiveness of the proposed system. A forecast of the energy prices has been done, fixing attention on natural gas and electricity. As starting point, a compilation of statistical data has been performed. The historical prices and on this basis estimated forecast of natural gas and electricity price was shown respectively in the figure 18 and 19. Two scenarios (high and low were performed). Prices was 22/37

23 presented excluding VAT and other recoverable taxes and levies. The aim of the analysis for two scenarios is to shown energy price sensitivity on the NPV parameter. 40,00 35,00 30,00 25,00 20,00 15,00 10,00 5, EU (27 countries) [EUR/GJ] FORECAST - HIGH SCENARIO Poland [EUR/GJ] FORECAST - LOW SCENARIO Figure 18. Natural gas price: historic data (source: Eurostat) and forecast 0,64 0,54 0,44 0,34 0,24 0,14 0, EU (27 countries) [EUR/kWh] FORECAST - HIGH SCENARIO Poland [EUR/kWh] FORECAST - LOW SCENARIO Figure 19. Electricity price: historic data (source: Eurostat) and forecast In the figure 20 the results from NPV analysis for two energy price scenario was presented. The discount rate is 3%. NPV parameter is ,83 and ,09 over 50 years for high and low scenario, respectively. It can be seen that during the project that STES systems are not yet 23/37

24 Net Cash Flow [EUR] NPV [EUR] economically feasible. The main reason is that the economic value of the energy saved is very low at current fossil energy prices (gas prices) against the great investment and later cost of replacement of equipment effort to perform (figure 21). The IRR indicator equal -3.08% and -6.98% for high and low scenario respectively. It means that capital expenditure for the project will not be equal to the value of updated cash inflows. The structure of maintenance cost over lifetime of the project was shown on the figure ,00 0,00 0, , , , , , , , , , , , , ,00 Period Net Cash Flow [EUR] - High prices Net Cash Flow [EUR] - Low prices NPV [EUR] - High prices ,00 Figure 20. NPV analysis and net cash flow over lifetime of the project 24/37

25 Cost [EUR] EUR Cash flow (High scenario) ,00 0, , , , , , , ,00 Reduction in natural gas consumption [EUR] Net Cash Flow [EUR] - High prices Figure 21. Savings from natural gas reduction (income) and net cash flow over project lifetime ,00 Operational cost - High scenario , , , , , ,00 0, Period Operational - purchased electricity cost [EUR] Operational - inspection cost [EUR] Operational - replacement cost [EUR] Figure 22. Structure of operational cost Heat cost refers to the cost of producing all the heat delivered to the buildings, including therefore solar heat as well as the heat produced by the boiler. It has been calculated according to the following formulas: 25/37

26 Heat cost = I a + O&M Q load I a = z coll + z STES + z HP + z aux Where: Ia: annual investment cost O&M: operational and maintenance costs zi: for each element (solar collectors, STES, heat pump and auxiliary equipment): i (1 + i) ni Z i = Inv i (1 + i) ni 1 Where: Invi: investment cost of component i (collectors, STES, heat pump and auxiliary equipment), i: annual interest rate (3%), ni: equipment lifetime (25, 50, 20 and 15 years for solar collectors, STES, heat pump and auxiliary equipment, respectively. By decreasing demand for natural gas consumption, the primary energy is reduced. The cost associated with total primary energy saved after retrofitting conventional technology is given by following equation: Cost effectiveness = I a + O&M Total Primary Energy Saved The result from heat cost and cost effectiveness are presented in the table 6 and figure 23. Table 6. Heat cost and cost effectiveness for conventional and EINSTEIN technology in Zabki Conventional system EINSTEIN technology Heat cost [EUR/MWh] COST effectiveness [EUR/MWh] /37

27 Primary Energy consumption [MWh] Heat cost [EUR/MWh] 180, ,00 140,00 120,00 100, ,00 60,00 40,00 20, ,00 Conventional EINSTEIN 0 Primary energy consumption - electricity natural gas cons. [MWh] Primary energy consumption - natural gas natural gas cons. [MWh] Heat cost [EUR/MWh] Figure 23. Heat cost and primary energy consumption for conventional and EINSTEN technology E N V I R O N M E N TA L I M PA C T Reduction in the gas consumption brings not only energy savings, but also has positive environmental impact. The environmental impact has been assessed as an emission reduction after retrofitting the conventional heating system. In table 7 emissions per unit of produced energy from natural gas was presented. Auxiliary components in EINSTEIN techonology should be taken into account in emission calculation, since additional electricity consumption is needed. CO2 emission factor for electricity generation in Poland is about of 812 kg/mwh, however it is expected that in the future this factor will be decreased to about 400 kg/mwh. A possible annual reduction of CO2 emission was presented in the figure 24. As can be seen, possible reduction from natural gas savings is estimated at kg per year. Table 7. Emission from natural gas Emissions from natural gas CO 2 [kg/gj] SO 2 [kg/gj] NO X [kg/gj] CO [kg/gj] particles [kg/gj] /37

28 CO 2 emission [kg/a] 35000, , , , , , ,00 0,00 Conventional EINSTEIN EINSTEIN after modernization (Emission factor in 2015) EINSTEIN after modernization (Emission factor in 2020) CO2 [kg] Natural gas CO2 [kg] Heat pump CO2 [kg] Monitoring Figure 24. Structure of CO2 emission from one year of operation S O C I A L I M PA C T In this paragraph social effects of EINSTEIN project was reviewed. Thermal energy storage have the potential to provide positive social impact through the provision of heat. The staff attitude was analyzed by questionnaire asking for the feedback on the building personnel satisfaction and working conditions. End users are generally satisfied and no negative effects of integration of EINSTEIN technology was identified. In the table below social impacts was summarized and described (table 8). Table 8. Social impacts. Type of social impacts Innovation / research Employment EINSTEIN project stimulate research and development. Academic and industrial research are promoted. In Zabki there is no specific impact in terms of jobs created or lost. No negative consequences for particular profession, groups of worker were identified. Administration EINSTEIN techonology does not impose additional administrative requirements. The use of energy The option affect positively on fuel mix used for heating purpose. There is a 28/37

29 Environmental issues Building integration Visual impact Noise intrusion Land use reduction in fossil fuel (natural gas) consumption through the use of solar energy. Decreasing emission of air pollutant. The option does not affect on the likelihood or prevention of fire, explosions, accidental emissions. EINSTEIN part was integrated with conventional heating system. There are no negative issues regarding with integration. The main visual intrusion come from the STES tank. The noise is generated primarily by heat pump compressor. Trees and bushes were cut in order to avoid shading of the solar collector field. 29/37

30 3. IMPA CT A NALYSIS O F T H E SPA N IS H PLANT TEC H N O L O G Y I M PA C T V I A B I L I T Y. B I L B A O D E M O Thermal energy stored in STES provides solar energy and reduces natural gas demand. It results in primary energy savings, CO2 emission reduction and economic savings from reducing natural gas consumption. However, installing STES tank, solar collectors and the heat pump mainly together with a more complex system to control installation coupled to the existing natural gas boiler requires a significant capital and operational cost. The purpose of this analysis is to provide feasibility study to evaluate potential benefits with comparison to conventional heating system. The parameters of EINSTEIN technology that was assumed for Bilbao demo with impact assessment are listed in the following table. Table 9: EINSTEN technology parameters for Bilbao demo EINSTEIN (monitoring data 2015 year) Heating demand [MWh/a] 83 Solar collector field [m 2 ] 62 Solar collector utilization rate [%] 40-70% Specific solar irradiation [kwh/m 2 *a] 1,100 Solar irradiation [MWh/a] 68.2 Specific solar yield [kwh/m 2 *a] 529 Solar yield [MWh/a] 32.8 heat charged to STES [MWh/a] 30.8 heat discharged from STES [MWh/a] 9.7 Direct discharging STES [MWh/a] 8.2 Heat pump solar heat [MWh/a] 1.3 Heat pump COP [-] Solar fraction [%] 97.6% Annual solar yield from the field of 32.8 MWh/a was measured, which corresponds to a specific yield of 529 kwh/(m 2 *year). The annual specific solar irradiation measured on the side was 1,100 kwh/(m 2 *a). The overall system performance was shown in the following figure. During one year of operation the heat pump has been in operation only for testing purposes as there is low heating demand because the building has scarcely being used. Use of boiler has also very low due low current use of the building. 30/37

31 Figure 25: Solar yield and heat from solar, heat pump and boiler sources on monthly basis. Bilbao demo The following picture shows the STES monthly balance for Bilbao demo (charging and discharging of STES) and the average temperature in the Bilbao STES tank. Figure 26: STES heat balance on monthly basis and mean temperature of STES. Bilbao demo. Summarized energy balance of the EINSTEIN technology on an annual basis was shown and compared with conventional system Solar fraction of 97.6% was obtained. The primary energy savings are estimated at 32.8 MWh of a total of 83 MWh which correspond to 39.5% of fossil fuels savings. 31/37

32 3. 2. C O S T A N A LY S I S. B I L B A O D E M O C A P E X - I n v e s t m e n t c o s t s. It has been estimated in the same way that indicated for Zabki demo. Below there are two tables summary of costs: 1. The conventional system investment costs to provide service to the area. They have caught approximate values 2. Investment costs incurred to carry out the Einstein system. So, costs without receiving any subsidy or help. This last estimate considers all costs which have been required for this deployment and which would be required considered to replicate this same installation elsewhere. There hasn t been considered any indirect costs or the costs associated with each of the special features of the place. The existing thermal system is based on a natural gal boiler system: Low T gas boiler, ground floor heating system and Air Handling Unit Supply/return temperatures: 45/35ºC Boiler and load side hydraulically separated by a collector Gas boiler: 190 kw nominal capacity (can be reduced up to 30%) Following this scheme: Figure 27: Existing Thermal System Bilbao site. The investment cost associated to this conventional space heating system are shown in the following table: 32/37

33 Table 10: Investment Costs Thermal existing for natural gas boiler of Bilbao Conventional natural gas boiler system Component Cost per unit, Units Cost, Gas boiler, 190 kw Water pumps Monitoring/control system Hydraulic connections Electrical box, connections TOTAL However, the Einstein STES system scheme is much more complicated and also the installation includes more equipment and much more sophisticated control system of the plant which means a high increase in investment cost: Figure 28: Einstein STES System Scheme Bilbao demo Next table shows the main costs associated to the Einstein STES of Bilbao that the highest cost corresponds to the STES tank, 34% of the total required investment (including insulation, concrete...) and the second main cost is due to hydraulic connections, pumps, heat exchanger, etc. The cost of electrical connections is rather high because of the high number of sensors of the installation. Costs of civil works performed for installation of the demo have not been included because they were specific of this installation (asbestos roof removal, beams removal, reinforcement of the structure of buffer tank, etc). 33/37

34 Table 11: Investment Costs of the Einstein STES system of Bilbao EINSTEIN Technology Bilbao Component Cost per unit Number of unit Cost STES tank Solar Collectors Heat Pump Pumps, pipping Spare pumps Control and monitorization Electrical connections TOTAL Figure 29: Cost division Einstein STES System Bilbao demo O p e r a t i o n c o s t s - O P E X. OPEX (operational expenditure) is an ongoing cost for running the system. In the table 5 operational cost involved with inspection and replacement of component are listed. The requirements for the gas boiler servicing are the same for both systems but in EINSTEIN system the qualified worker have to check also the solar collector s installation, the heat pump and control system. The maintenance of EINSTEIN system is more complex than in case of conventional heating systems. The suggested number of inspection per year for particular EINSTEIN system components is showed in the table 6. 34/37

35 Table 12: Operational costs conventional Component COST OF INSPECTION Inspection per year Cost of inspection Cost per year Lifetime [year] COST OF REPLACEMENT Number of replacement in project lifetime Cost of replacement during lifetime Gas boiler 2 200,00 400, ,00 Water pumps ,00 Monitoring/co ntrol system Hydraulic connections Electrical connections SUM 400,00 SUM ,00 Table 13: Operational costs EINSTEIN Component COST OF INSPECTION Inspection per year Cost of inspection Cost per year Lifetime [year] COST OF REPLACEMENT Number of replacement in project lifetime Cost of replacement during lifetime STES tank Solar collectors field Heat exchanger , ,00 Heat pump ,00 Water pumps ,00 Buffer storage Monitoring/co ntrol system Hydraulic connections Electrical connections Gas boiler 2 200, ,00 SUM 1 700,00 SUM ,00 An important part of operational costs is purchased energy cost. Conventional and EINSTEIN technology require natural gas and electricity. In EINSTEIN project STES system is extended by a heat pump consuming electric power. Conventional system consumes less electricity than EINSTEIN system. The main equipment responsible for additional electricity consumption is the heat pump and in lesser extent the auxiliary devices: water pumps, monitoring and automation systems. 35/37

36 3. 3. E N V I R O N M E N TA L I M PA C T. B I L B A O D E M O Reduction in the gas consumption brings not only energy savings, but also has positive environmental impact (CO2 emissions reduction). The environmental impact has been assessed as an emission reduction after retrofitting the conventional heating system. CO2 emission factor for electricity generation in Spain is about 225 kg/mwh (data of 2015 of Iberdrola, main Spanish utility), quite low because of the low use of coal in thermal power plants and quite a lot use of renewable energies as solar, hydropower and wind. A possible reduction from natural gas savings is estimated at 7,380 kg per year in Bilbao demo site due to the reduction of natural gas consumption S O C I A L I M PA C T. B I L B A O D E M O Social impact due to the installation of a STES system which uses solar energy substituting partially natural gas consumption has not been able to measure it because the building is still suffering retrofitting works and is not being regularly used but it is expected to be used for cultural activities. Anyway, the building has been visited by several groups (European project partners, local authorities, attendees to energy events performed in Bilbao, etc.) and all of them have considered that the STES system offers high potential to reduce fossil fuel consumption. Tecnalia is trying to promote STES installations in Central Spain due to its higher solar irradiation and also higher heat demand than in the region of Bilbao. STES technology offers a positive social impact due to the promotion of solar energy and can be an alternative system for space heating of shopping centers, sport centers, hospitals etc. not located in the center of a town and with enough place for solar collectors and STES tank. 36/37