1、Potential Energy Savings by Switching Residential Cooking and Water Heating Appliances from Electric to LPG in Saudi Arabia Faisal Al Musa, M. Eng Ayman Youssef, PE Member ASHRAE ABSTRACT Electricity consumption per capita has been gradually increasing by 8% annually during the past 10 years in the
2、Kingdom of Saudi Arabia. One of the main reasons for this above-average growth rate is the utilization of low efficiency electrical home appliances, which is encouraged by the low initial investment and the artificially low energy prices. In 2013, the residential sector consumed nearly 126 terawatt
3、hours, which represents 49% of the countrys electricity consumption. This paper investigates the potential savings in primary energy that can be achieved by switching residential water heating and cooking appliances from electricity to liquefied petroleum gas (LPG). Taking advantage of the much high
4、er source-to-site energy conversion efficiency for LPG versus electricity and the abundance of low price LPG in Saudi Arabia, this paper presents compelling evidence of the overall benefits to the Kingdom in terms of primary energy savings and CO2 emissions reductions. This paper also proposes solut
5、ions for current inhibiting factors such as the need for enabling policy and LPG safety standards, as well as consumer awareness. INTRODUCTION While the Kingdom of Saudi Arabia is considered the largest hydrocarbon producer in the world, with vast proven oil and gas reserves, it is also considered t
6、he largest energy consumer of fossil fuels in the Middle East. For example, Saudi Arabia is the worlds second-largest liquefied petroleum gas (LPG) producing country with 13% of worlds producing capacity and is the worlds largest LPG exporter with around 28% of the total world export; but it is at t
7、he same time one of the highest LPG consuming countries with nearly 5% of the worlds total consumption (UN 2010). Similarly, electricity consumption per capita has been rising rapidly with an average annual rise of 8%. In 2010, energy consumption per capita was 6.7 tonnes of oil equivalent (toe) com
8、pared to the worlds average of 1.9 toe. The building sector is considered a major energy consumer with a total of nearly 6.7 million electrically connected customers, with the bulk, 5.3 million, being residential customers (ECRA 2012). In 2013, the residential sector consumed nearly 126 TWh, which r
9、epresents 49% of the countrys electricity consumption (SEC 2013). This high residential energy demand is expected to increase in the future due to the sharp escalating population, the dynamic infrastructure expansion, the energy-intensive lifestyles and the artificially low energy prices. Policy mak
10、ers have identified energy conservation and energy efficiency as top priorities and key pillars for the national energy security. This was evident from the creation of the Saudi Energy Efficiency Center (SEEC) in October 2010 to manage the energy demands in industry, transport and buildings, and to
11、implement energy conservation initiatives that have proven effective in similar climates. To control this unrestrained demand for residential building energy, it is imperative that more energy efficiency opportunities be explored and gradually implemented. One of these opportunities is to switch res
12、idential cooking and OR-16-C004hot water heating appliances from electricity to LPG. This paper investigates the potential savings in source energy that can be achieved by switching residential cooking and hot water heating site loads from electricity to LPG, taking advantage of the more efficient L
13、PG source-to-site conversion process as opposed to electricity. The benefits would not only include reduced power consumption and summer electrical peak demand, but would also avoid costly power outages during peak hot summer months and reduce emissions of environmentally harmful greenhouse gases. A
14、PPROACH Given the special national nature of this topic, it was necessary to review literature from various countries and to understand how similar issues were dealt with internationally. The authors extensive literature reviews revealed that this subject was treated from several perspectives, namel
15、y, GHG emissions reductions, economics, societal benefits and energy policy. For example, Santos et al. (2013) investigated the risks associated with energy efficiency policies in four countries namely Brazil, China, India and Russia and concluded that decisions based solely on service technologies
16、can mislead while trying to select the best option that will help in preserving natural resources and reduce GHG emissions. Wilkenfeld et al. (2010) proposed phasing out electric water heaters in Australian homes due to their higher GHG emissions compared to gas, solar or heat pump water heaters. Th
17、e proposal to switch from GHG intensive electric water heaters to low emission options would decrease GHG emissions, reduce energy demand and lower household energy bills. Randall et al. (2002) studied the economic impact of five energy efficiency programs on consumers, utilities and society in Sout
18、h Africa. One of these programs was the switch from electricity to LPG for cooking for low-income families. It was shown that great economic and environmental benefits can be achieved as a result of the different energy conversion efficiency between electricity and LPG. Ildo et al. (2001) studied th
19、e residential sector of the metropolitan region of San Jose, Costa Rica, and identified both cooking and lighting as the two major reasons for the peak power demand. As a mitigation measure to reduce the cooking peak demand, substituting the electricity with LPG was considered due to the higher syst
20、em efficiency compared to electricity by using source to service approach in evaluating both electricity and LPG systems. Currently, electric hot water heaters are used in almost all Saudi Arabian domestic hot water heating applications, while LPG and electric stoves have an approximate equal share.
21、 The analysis of the Saudi electricity and LPG energy conversion systems from resource to service follows Scotts concept of an energy system (Scott 1994). This concept was applied for both electricity and LPG systems components individually, including the respective associated energy efficiency comp
22、onent conversion values as shown in Figures 1 and 2. In this case, the total overall system efficiency is represented by the multiplication of the individual efficiencies of the systems components as shown in Equation 1. System=Extraction*Transportation*Transformer Technology*T&D*ServiceTechnology (
23、1) From the above equation two simple mathematical models can be developed for cooking and for water heating by multiplying the individual component energy efficiency value starting from resource-to-service technology: X1 =Y1/ (0.2021) (2) X2=Y2/ (0.2325) (3) where X1 = total resource energy for ele
24、ctrical cooking Y1 = total delivered service technology energy for electrical cooking X2 = total resource energy for electrical hot water heating Y2 = total delivered service technology energy for electrical hot water heating 2016 ASHRAE Winter ConferencePapers 2Figure 1 Electrical System Diagram (C
25、omponents and Efficiencies) Figure 2 LPG System Diagram (Components and Efficiencies) It should be noted that natural gas is the main source for electricity generation with supplemental backup of crude oil, diesel and heavy fuel oil. LPG comes from two sources, namely, oil processing refineries and
26、natural gas liquids (NGL) plants with a ratio of 76.3% to 23.7% (Saudi Aramco 2012). Therefore, the LPG mathematical model for cooking will use the following equation: LPG cooking = ( NGL NGL share) + ( oil oil share) (4) LPG cooking = (0.3831 0.237) + (0.3772 0.763) = 0.379 Similarly, the LPG cooki
27、ng model will be X3 =Y3/(0.379) and the LPG water heating model will be X4 =Y4/(0.545), where X3 and Y3 are the total resource energy and total delivered service technology energy for LPG cooking, respectively, and X4 and Y4 are the total resource energy and total delivered service technology energy
28、 for LPG hot water heating, respectively. Table 1 shows the expected percentage improvements as a result of the proposed shift from electricity to LPG for hot water heating and cooking. Table 1. Percentage Efficiency Improvements for Proposed Shift from Electricity to LPG System Electrical Efficienc
29、y, % LPG Efficiency, % Efficiency Improvement, % Stoves 20.2 37.9 88 water heaters 23.3 54.5 134 SERVICE TECHNOLOGY ENERGY ESTIMATION Due to the unavailability of the total residential delivered service technology energy consumptions data for electrical cooking and hot water heating, namely, Y1 and
30、Y2, these data had to be estimated from available information such as the total monthly residential energy consumptions, general census information, appliance specifications, in addition to launching an online end consumer survey. This survey consisted of 13 questions covering dwelling type, locatio
31、n and number of people, the number, types and hot water heaters and their usage patterns as well as the monthly energy bills information. To ensure receiving quality information, the survey contained few inter-linked questions which allowed the team to discern all reckless responses and filter them
32、out. Therefore, out of the 1,972 responses received, only 1,491 were considered. It should be noted that for the purpose of this study, only electric appliances usage was considered as current LPG users are already on the proposed track. Figure 3 shows a few additional survey results graphically. 20
33、16 ASHRAE Winter ConferencePapers 3Figure 3 Survey results showing geographical distribution, house type and appliances share by fuel type The survey results revealed some interesting information. For example, 93% of the water heaters were of the standalone type (non-central) and 99% of all water he
34、aters were electrically powered. Also, the 2.4 KW stove was found to be the most representative power rating for the purpose of cooking energy estimation, although different stove brands, types and powers ratings are available in the Saudi market. Hot water energy consumption estimation was not as s
35、traightforward as usage patterns exhibited vast variations between respondents due to many reasons such as differences in usage duration and frequency, inlet water temperatures and flow rates in addition to the availability of various appliances types such as dishwashers, clothes washers, showers he
36、ads and taps. This finding was confirmed by previous work where the variance in average hot water usage for households was found to be between 50 liter/day (13 gallons/day) to 500 liter/day (132 gallons/day) (Hendron and Burch 2007). Therefore, an average value of 60 liter (16 gallons) per capita pe
37、r day was assumed. This value was gathered from previously published paper in Florida, which has similar weather conditions as Saudi Arabia (Tim and Parker 1994). Additional literature review revealed that a design value of 120 Liter (32 gallon) per capita per day was used for sizing thermal solar s
38、ystems for the city of Dubai during the mild 6 months period (Epp 2010). And since during the other hot 6 months the water is heated naturally, the 60 Liter (16 gallon) per capita per day could be assumed as the annual average usage for Dubai which confirms the suitability of our assumed figure. COO
39、KING ENERGY ESTIMATION The average monthly household stove consumption was estimated by multiplying the power input of 2.4 KW by the average monthly use time of 34.447 hours obtained from the survey. The total monthly household energy consumption was calculated by dividing the total residential mont
40、hly consumption by 5,347,126, which is the total number of residential households (ECRA 2012). Therefore, the percentage of monthly household stove energy consumption was estimated by dividing the monthly stove consumption by the total household consumption. The total monthly residential stove energ
41、y consumption was obtained by multiplying this percentage by the total number of residential homes. The results of this methodology are tabulated in Table 1. It should be noted that the energy consumption obtained until this point was before the stove without considering its conversion efficiency. T
42、he final sought after value, Y1, was obtained by multiplying the total electrical stoves consumption of 5,330,313 MWh (18,187,711 million Btu) by the average stove efficiency of 73.7% resulting in a final value of 3,929,445 MWh (13,407,770 million Btu) as shown in the table 2. 2016 ASHRAE Winter Con
43、ferencePapers 4Table 2. Annual Cooking Consumption Details Month Monthly Residential Consumption, MWh Monthly Home Consumption, MWh Monthly Stove Share of Home Consumption, % Monthly Stoves Consumption, MWh January 5,976,055 1.11762 7% 418,323.85 February 6,242,780 1.16750 7% 436,994.60 March 5,728,
44、386 1.07130 8% 458,270.88 April 7,318,394 1.36866 6% 439,103.64 May 11,418,241 2.13540 4% 456,729.64 June 15,251,805 2.85234 3% 457,554.15 July 13,520,128 2.52849 3% 405,603.84 August 16,083,358 3.00785 3% 482,500.74 September 14,169,941 2.65001 3% 425,098.23 October 11,621,089 2.17333 4% 464,843.56
45、 November 7,397,452 1.38344 6% 443,847.12 December 5,518,043 1.03196 8% 441,443.44 Total Residential Consumption, MWh 120,245,672 Total Electrical Stoves Consumption, MWh 5,330,313 Total Stoves Share from residential Consumption, % 4% Total Stoves Energy after the Appliance, MWh 3,928,441 Total Stov
46、es Energy after the Appliance, Million Btu 13,407,770 HOT WATER ENERGY ESTIMATION The energy consumption of the average value of 60 Liter (16 gallons) per capita per day was found to be 8.3 kWh/day (28,321 Btu/day), based on a family size of 3.6 persons (Tim and Parker 1994). This energy consumption
47、 value needed to be corrected to reflect the average family size in Saudi Arabia. The total population of Saudi Arabia is around 27.1 million, whereby 18.7 million are Saudi nationals and 8.4 million are expatriates, 2 million of which are living with Saudi families as housemaids and drivers. To sim
48、plify the analysis, those 2 million expatriates will be considered as part of the Saudi families (SAMA 2011). Since the average size of a Saudi and an expatriate family are 5.7 and 2 persns respectively, the weighted average family size was calculated along with the associated number of families as
49、shown in Table 3 (Sfakianakis et al. 2011). Table 3. Weighted Average Family Size and Number of Families Description Saudis Expatriate Population (million) 20.7 6.4 Average Family Size (person) 5.7 2 Weighted Average from Total Population 0.76384 0.23616 Weighted Average Family Size (person) 4.8 Number of Families 5,615,184 Assuming a linear relationship between the family size and the hot water energy consumption, the daily and annual consumptions for the corrected family size was found to be 11.07 kWh
