Design and Feasibility of a Small NegaWatt Power Plant

Transcription

1 J. Energy Power Sources Vol. 2, No. 4, 2015, pp Received: February 27, 2015, Published: April 30, 2015 Journal of Energy and Power Sources Design and Feasibility of a Small NegaWatt Power Plant Dana Sbeity and Farid B. Chaaban Department of Electrical and Computer Engineering, American University of Beirut, Beirut, Lebanon Corresponding author: Farid B. Chaaban (fbchaban@aub.edu.lb) Abstract: There is a global concern due to the increasing demand for resources in various economic sectors, mainly the power sector. The combustion processes of various types of fuels, leading to substantial GHG emissions, have increased significantly due to the increase in population size, rapid developments in many countries and the technological boom at global scale. Numerous mitigation options are being considered, the most important of which are the deployment of renewable resources, and the wide spread use of clean and efficient technologies. Both these options have proven to be effective in reducing the GHG emissions trends in many countries. A wide range of -related research is currently targeting better sustainability and resources management. Modifying the end-users trends with respect to usage and redirecting their choices towards cleaner and renewable resources and in more efficient manners are being investigated. The aim of this paper is to introduce the NegaWatt (NW) concept through studying different conservation options as well as their effectiveness and economic feasibility. The concept is utilized for assessing the feasibility of implementing cleaner and more -efficient technologies as a measure to reduce, and hence GHG emissions, rather than continuing with the unsustainable approach of expanding the power supply capacity to meet the growing demand. In this paper, the most appropriate alternative technologies applicable for residential and office buildings are selected and options are focused on the lighting fixtures, roof insulation, double glazed windows and upgrading the HVAC systems. The paper is concluded by a feasibility study that compares the cost of clean technologies to the cost of expansion of the installed thermal power. Two scenarios are adopted, one take into consideration the CO 2 removal cost, and the other does not. The obtained results show that NW solutions are economically feasible, save resources and lead to substantial GHG. Keywords: Power sector, NegaWatt, clean technologies, feasibility study. Nomenclature: NW NegaWatt AUB American University of Beirut GHG Greenhouse gases DSM Demand side management DOE U.S. Department of Energy VFD Variable frequency drives HVAC Heating, Ventilating and Air conditioning AUBMC AUB medical center LED Light emitting diode EIA Energy Information Administration NPV Net Present Value ECM Energy conservation measures RI Roof insulation DGW Double glazed windows SGW Single glazed windows 1. Introduction The term NegaWatt is a theoretical unit that reflects the amount of power or saved or conserved as a result of technology upgrading, structural changes, or other mitigation initiatives. The term was introduced by A. Lovins in 1989, who claimed creating the NegaWatt market as a win- win solution for sustainability as it is cheaper to conserve fuel rather than burning it and as it mitigates the environmental problems by reducing the CO 2 and other emissions. He argues that the demand side customers care about the services rather than the amount of KWh of electricity. Energy services can be bought cheaply by using the electricity in a more efficient manner [1]. According to Anderson and Newell [2], the main reasons behind adopting efficient improvements are the environment, the instability in the prices

2 Design and Feasibility of a Small NegaWatt Power Plant 145 and the national security. Several countries have adopted long term strategies to alleviate the impacts of modernization on the environment. The US National Energy Policy in the white house considers the improvement of the efficiency as a national priority in order to reduce the greenhouse gas intensity. The adopted improvements, as noted in the paper, are the one with a short payback period, low cost, that will generate high annual savings with high prices and consider as the best alternatives for accomplishing high percentage of conservation [2]. Several other nations in the EU have adopted similar objectives for combating GHG emissions. The Demand Side Management (DSM) decreases the peak demand for electricity by reducing the load at the end user side, thus avoiding the need for building more power plants and transmission lines. DSM also helps detecting the blackouts, reduces the usage of fuel, and reduces the harmful gas emissions and greenhouse gases. It also plays an important role in improving the overall system efficiency. DSM may include, amongst others, lighting retrofitting, power factor correction, motor variable-speed drives, double glazing, and taking advantage of daylight. DSM consists of collecting data, monitoring the purchase and of, identifying conservation measures followed by financial studies, implementing the projects and checking the performance of the system [3]. An audit was conducted for the Oregon State University Kerr Administration. The methodology consisted of two site visits for data collection, followed by analysis and simulations using DOE software. A baseline was formed depending on the collected data, then conservation measures were applied to the baseline scenario and the results were noted. A cost analysis based on simple calculations followed in order to estimate the payback period. After applying the conservation measures 29.5% of the total consumed were reportedly saved and the payback period was around 16 years. The suggested conservation measures included modifying the T12 lighting systems to more efficient lighting T8 alternatives, modifying the HVAC system, adding ventilation control by installing CO 2 sensors, using daylight control sensors, and adding heat recovery chillers [4]. Art Rosenfeld as a pioneer in the efficiency field and as being a member of the California Energy Commission assumes that Americans are capable of saving a minimum of 200 TWh of electricity per annum by applying efficiency standards and buying more efficient fridges over the years. The 200 TWh are a substitute for 80 typical power plants of sizes around 2500 MW each [5]. The U.S. department of Energy indicated that more than 25% of the original costs paid by the universities on can be saved by managing the usage of electricity. In order to optimize the performance a set of control applications were identified. Zone scheduling, for example, divides the building into zones and permits the HVAC and the lighting to shut down according to a certain schedule. The occupancy sensor detects the motion and turn on and off the HVAC and lighting system. Variable Frequency Drives (VFD) can reduce up to 50% if the electrical, resetting the hot water system temperature taking into consideration outside temperature can decrease the heat losses in the pipelines, ventilation on demand depending on the CO 2 level, chiller optimization, taking advantage of daylight and optimizing the cooling tower by decreasing the set point temperature. All these methods can help decreasing the without affecting the comfort [6]. Energy savings and conservation measures were applied at a school in Freiburgm Germany [7]. The methodology consisted of a feasibility study followed by conservation measures related to refurbishment of the lighting such as replacement of the luminaires to a daylight-dependent control system of the lighting, heating systems, water savings,

3 146 Design and Feasibility of a Small NegaWatt Power Plant increasing the efficiencies of the circulation pumps and the construction of two solar plants. The project capital cost was equivalent to EUR 250,000. The total saved was around 200 MWh at an annual cost of EUR 65,000, i.e., with a payback period slightly less than 4 years. In addition the NW project achieved a of 350 tons of CO 2 per year. This article will highlight the cost effectiveness of deploying the NW concept at the American University of Beirut (AUB), which has campus buildings that go back to the 19 th century. 2. The AUB Power Demand Due to the frequent load shedding in the Lebanese power system, the AUB, like most economic sectors, has opted to install standby generation units to be used during cut-off intervals which may reach around 12 hours per day in some regions. The demand for electric power in the AUB has been increasing consistently due to the growth in programs, student numbers, and facilities. AUB is mainly composed of 55 buildings including the AUB medical center, with a total power demand of around 11.6 MW [8]. To match the anticipated growth in demand, it is estimated that additional 2 MW unit will be needed, leading to higher fuel and operational costs and more fuel combustion and GHG emissions. Energy conservation, through the NW concept, if adopted properly, may reduce the and lead to increasing the system efficiency without affecting the comfort. Applying these measures will reduce the impacts on the environment, save of fuel cost, reduce fuel combustion, and reduce the CO 2 emissions. 2.1 Methodology The NegaWatt power plant project has been executed over three stages. The first stage consists of data collection and monitoring in order to estimate the consumed. The collected data includes the total annual (kwh) for the AUB buildings, the power consumed, the air-conditioning system in each building, the lighting system used in the buildings. It also includes the HVAC system, construction material used in the buildings, type of glass and the occupancy schedule of buildings. The second stage consists of building the base case model of the building using visual DOE software. Energy conservation measures will be applied on the baseline building followed by testing and analysis. When the simulations are done, the total obtained from the various sources will form the NegaWatt power plant. The third and final stage consists of developing the NW power plant. An economical study will be carried out to compare the two concepts, conventional thermal MW and clean NW taking into consideration the capital cost, the fuel cost and the CO 2 emissions. The feasibility study will take into consideration the market prices of the above suggested alternatives and calculating the expected payback period. The results will be compared to the actual cost of the MW electrical power obtained from various fossil fuel resources, such as natural gas, fuel oil, diesel and heavy fuel. 3. Audits Results Initial statistics related to this project were presented and interpreted in a paper submitted to the Energy Systems Conference [9]. A base case model of each of the considered buildings was built using visual DOE software followed by applying conservation measures where the efficient options include replacing the single glazed windows by double glazed ones, insulating the roofs using polystyrene thermal insulation with a thickness of 5 cm, replacing the installed inefficient lighting fixtures by LED and modifying the HVAC system by replacing the installed air cooled chillers by water cooled centrifugal chillers and adding variable speed drives for the fixed speed pumps. Depending on the obtained results and the cost estimates, the most appropriate alternatives were selected.

4 Design and Feasibility of a Small NegaWatt Power Plant The Obtained Results Tables 1-4 show the results of the simulation for the different conservation measures that were applied for the selected buildings. In Table 4 modifying the HVAC system consisted of replacing the existing air cooled chillers by water cooled chillers and substituting the fixed-speed pumps Table 1 Energy by switching to DGW. Engineering Chemistry Health science 1, , Biology Math Physics AUBMC 17, Agriculture Not applicable Table 2 Energy by applying RI. Engineering Chemistry Health science 1, , Biology Math Physics AUBMC 17, Agriculture Not applicable Table 3 Energy by switching to LED lighting. Engineering Chemistry Health science 1, , Biology Math Physics AUBMC 17,330 16, Agriculture that circulate water through the chiller by a variable speed ones. In the case of the AUBMC 2 cases were considered, the first is increasing the set point temperature and the second is replacing air cooled chillers by water cooled alternatives. Table 5 shows the cost of new equipment and the replacement cost of the new fixtures. As shown in Table 6, the proposed conservation Table 4 Energy by modifying the HVAC system. Engineering Chemistry Health science 1, , Biology Math Physics AUBMC (a) 17,327 15, AUBMC (b) 17,327 16, Agriculture Not applicable Table 5 Cost of new equipment and replacement cost. Cost of new Replacement equipment ($) cost ($) Engineering 143,203 62,720 Chemistry 37,336 21,408 Health science 48,511 28,361 Biology 45,900 26,710 Math 19,931 7,840 Physics 24,659 14,891 AUBMC 522,220 67,981 Agriculture 43,190 31,584 Table 6 Results of the simulations of selected buildings. power (KW) power (KW) Engineering Chemistry Health science Biology Math Physics AUBMC 1,978 1, Agriculture Total 3,391 2,

5 148 Design and Feasibility of a Small NegaWatt Power Plant Fig. 1 Reduction in power. measures have led to substantial of around 13.4% in the total power where the electricity of the eight buildings dropped by 454 KW from 3,391 MW to 2,937 MW. The buildings under consideration account for 53% of the total AUB buildings (27,241 MWh out of 51,380 MWh for the year 2012). If we generalize the results for all the buildings assuming they operate at a uniform level the total NegaWatt capacity will be set to 0.86 MW. Fig. 1 shows the difference between the original business- as- usual power levels of the eight buildings that accommodate the main academic units at the institute, and the reduced after applying the pre-set conservation measures. 4. Environmental Cost The main purpose of the carbon tax is to mitigate the problems facing our societies nowadays by increasing the expenses associated with fossil fuels and thus motivating the power utilities, corporates and even individuals to reduce their actual by switching to cleaner and less emitting technologies such as renewable or by increasing the efficiency [10]. Carbon tax is a pollution tax imposed on the industries that burn various types of fuels in their production operations. The tax is based mainly on the carbon content of each burnt fuel type. Countries of the European Union have imposed carbon taxes in the range of 4~30 tons -1 CO 2 where 17 tons -1 CO 2 which is equal to 21.5 $ being the average tax proposal [11]. This is almost the same like the US carbon taxes of 20 $ tons -1 CO 2 [12]. For fuel types such as diesel, fuel oil, heavy fuel and even natural gas, the avoided tons of CO 2 were calculated as: Avoided Tons of CO 2 = CO 2 emission coefficient (tons KWh -1 (1) ) reduced (kwh) Thus the environmental cost will be calculated as: Environmental cost = Tons of CO 2 avoided (2) carbon tax ($) 5. Calculating the Cost of a NegaWatt The cost of a NegaWatt was calculated with and without considering the environmental cost. The calculations without environmental cost were carried out by dividing the replacement cost of the new fixtures by the power (KW). For the second case the environmental cost were reduced from the replacement cost of the new fixtures and then divided by the total power. 6. The Payback Period The payback period of the NegaWatt power plant is calculated taking into consideration the replacement cost of the applied measures as the investment cost and the annual saved cost is equal to the amount of KW saved multiplied by the cost of KW with and without environmental cost. The results of the calculations are shown in Table Comparing the NegaWatt to the Megawatt According to the Lebanese Ministry of Energy and Water: The levelized cost of production for combined cycle gas turbine for the available liquid fuels is as follows:

6 Design and Feasibility of a Small NegaWatt Power Plant 149 Diesel oil: 21.7 kwh -1 ; Heavy fuel oil: kwh -1 ; Natural gas: 9.1 kwh -1. Based on 60% load factor the electricity cost is obtained by dividing the levelized cost of production of each of the type of fuel ($) by the load factor. The obtained results were as follows: The electricity cost of the diesel oil is $1.14 Million, for the heavy fuel oil equal to $0.86 Million and the natural gas equal to $0.48 Million. Table 8 and Fig. 2 show the comparison between the cost of megawatt for different types of fossil fuels to the cost of NegaWatt. As shown in Table 8 and Fig. 1, the price of a NegaWatt as estimated based on Lebanese market is half of the price of a megawatt of diesel fuel oil without taking into consideration the environmental cost and is even lower when substituting the environmental cost from the replacement cost which allows a major of around 5.7% in the price of the NegaWatt. In the case of the fuel oil, the price of a NegaWatt is 42% lower than the actual cost of a megawatt without considering the environmental cost which allows a Table 7 Summary of the results. Replacement cost ($) Total (KW) Cost of KW Annual saved cost ($) Payback period Without env. cost 880, , With env. cost Diesel 880, , Fuel oil 880, , Natural gas 880, , Heavy fuel 880, , Table 8 Comparison between megawatt and NegaWatt costs. Type of fuel MW cost (Million $) NW without env. NW with env. cost Cost in % Cost in % cost (Million $) (Million $) (without env.) (with env.) Diesel Fuel oil Natural gas Heavy fuel higher of around 5.8% in the price of the NegaWatt. In the case of the heavy fuel oil, the price of the installed NegaWatt is 33% lower than the actual cost of a megawatt power plant. The environmental cost allows an additional of around 6.16% in the price of the NegaWatt. However in the case of a natural gas the NegaWatt price was higher than the price of a megawatt due to the lower carbon content of the natural gas. 7.1 Fuel Consumption Reduction Consideration Fig. 2 Megawatt versus NegaWatt costs. The annual fuel for all AUB buildings and AUBMC is around 5,643,655 liters of diesel fuel at an annual cost of $4,690,000. The total

7 150 Design and Feasibility of a Small NegaWatt Power Plant Table 9 NegaWatt price for diesel fuel. NW without env. NW with env. cost Cost in % Cost in % Type of fuel MW cost (Million $) cost (Million $) (Million $) (without env.) (with env.) Diesel for all the buildings is equal to 51,380,179 MWh. The total power is around MW. The cost of a MW of fuel is equal to $462,479. For the 0.86 MW savings, the total cost of the fuel saved will be equal to $397,732. It should be noted that in the case of a NegaWatt power plant less fuel are being burnt to supply the same load demand. Reducing the fuel cost from the previously calculated costs for the diesel fuel will result in a higher in the price of the NegaWatt and the results are shown in Table 9. The results have shown that the NegaWatt solutions save resources and are economically feasible. 8. Conclusions The goal of the NegaWatt project is to utilize recent developments in clean and more efficient technologies to provide a solution for the power deficiency problem at AUB, by modifying the usage of electricity at the end user side with low or without additional costs and without affecting the comfort in general. This paper showed that building a NegaWatt (NW) power plant is more cost-effective than building a new thermal power plant or installing standby generation units in order to cover the shortage of electricity in the AUB campus. In addition, the NW power plant is a clean and combustion-free technology that will assure of overall greenhouse gas emissions and specially CO 2 gas, since less fuel are being used to supply the load demand of electricity. Data were used from the audit that was conducted for various AUB buildings in order to upgrade selected the electrical appliances to reduce the. The buildings were modeled and simulated using visual DOE 4.0 software taking into consideration all the collected data. Energy conservation measures were applied and the best alternatives were chosen such as roof insulation, HVAC system modifications (replacing air cooled chillers by water cooled and adding variable speed drives to the fixed speed pumps), more efficient LED lighting, and double glazed windows. The simulations showed that a of around 13.4% can be achieved in the total power of the buildings where the electricity of the 8 selected buildings dropped by 454 KW, from MW to MW. In the second part, the cost of the NegaWatt was calculated taking into consideration the cost of the upgraded appliances, their replacement cost in addition to the environmental cost. Four scenarios were considered for different types of fuels. The addition of the environmental cost has achieved a valuable in the price of a NW, and considering the diesel fuel cost in the calculations achieved a higher in the price of a NW. In addition the payback period of the built NegaWatt plant has been estimated taking into consideration the cost of the new appliances as investment cost and the reduced cost as annual savings. The calculations have proven that the price of a NegaWatt is much lower than the actual price of a conventional thermal Megawatt for different types of classical power plants (diesel, fuel oil and heavy fuel) however it is higher than the price of a megawatt associated with natural gas. The results have also shown that the NegaWatt is considered as an important and economically-feasible option that leads to efficiency improvements, fuel savings, and deployment of cleaner and more efficient technologies. References [1] A.B. Lovins, The Negawatt revolution, Across the Board 27 (9) (1990)

8 Design and Feasibility of a Small NegaWatt Power Plant 151 [2] S.T. Anderson, R.G. Newell, Information programs for technology adoption: The case of -efficiency audits, Resource and Energy Economics 26 (1) (2004) [3] Demand side management [Online], reeep.org/modules/module14.pdf. [4] J. He, D. Gilles, Energy audit report for Oregon state university Kerr administration building [Online], s/kerr_sep audit_2012.pdf. [5] The Elusive Negawatt [Online], The Economist, May 10, 2008, [6] Leading Techniques for Energy Savings in Colleges and Universities [Online], 2007, r savings_in_colleges_and_universities.pdf. [7] D. Seifried, B. O-quadrat, The ECO-watt project: a negawatt power plant in school [Online], pp eceee/2001/panel_5/p5_12/paper. [8] S. Karaki, N. Ghaddar, F. Moukalled, F.B. Chaaban, Energy analysis of AUB buildings, 2008, pp [9] D. Sbeity, F.B. Chaaban, Feasibility and cost analysis of a small negawatt power plant, in: Energy Systems Conference, London, UK, [10] R. Dowdey, How carbon tax works [Online], cience/carbon-tax.htm. [11] J. Kanter, Europe considers new taxes to promote clean, The New York Times, June 22, [12] B. Plumer, Seven thrilling facts about carbon taxes from the CBO, The Washington Post, 2013.