Developing a sustainable plan for Hong Kong is a process that will take many decades to do effectively. The sustainable sources of energy would have to focus around tidal, wave, solar, and wind energy. Ideally, geothermal and hydroelectric power plants make for great sources that are sustainable and economically sound. However, in Hong Kong, these two sources do not possess a future and any chance of prosperity for these industries is unrealistic as discussed earlier. The rivers having don’t have sufficient flow and height; capital costs to create hydroelectric power plants would be a pointless task due to the lack of energy created.
If Hong Kong were to rely on these four sources for their energy they would be in a lot of trouble. Looking back to the green stack we can see that these four categories would provide about 17 kWh per day per person, while the red stack number clearly exceeds the energy provided. For a sustainable plan to be possible, there would have to be restrictions and limits placed on transportation, and heating/cooling for industries and private sectors. The massive amount of energy consumed in Hong Kong can be reduced but not to 17 kWh per day per person. So while it does seem impossible to rely on sustainable resources for 100 percent of the Hong Kong energy, it is very possible to create a sustainable plan for the population. If the people and the businesses keep the topic of conserving energy on their minds then change will happen. It’s tough to say where we will be at ten, twenty, or even a hundred years from now, but a sustainable plan may be the only way to preserve out planet.
Thursday, September 15, 2011
In terms of energy usage in the USA, where does it go?
Above is the United States Department of Energy treemap of energy consumption data in the U.S as of 2010[33]. This figure is beneficial because you can conceptually see the magnitude of where energy goes within each one of the four main categories: transportation, residential, commercial, and industrial.
Industrial processes make up the most of where energy goes at 32 percent. Manufacturing, chemicals, and feedstocks form the bulk of these processes.
The next highest is transportation at 29 percent, which is expected. Cars and trucks have a great significance in America in meeting our daily needs. Therefore, it is expected that gasoline and diesel make up almost all of the transportation energy usage.
Next, it is interesting to see that the residential sector uses slightly more energy than the commercial sector. Heating, air conditioning, and water heating contain the highest energy among this category. This is why there is a strong emphasis put on making HVAC systems more efficient. If these systems become highly efficient, energy usage in the U.S can drop significantly.
The commercial sector out of the four main categories is the lowest in energy usage at 18 percent. Lighting proves to be the highest energy guzzler from this sector, followed by HVAC.
Can we grow our economies but still decrease energy use?
Economies can definitely grow with decreasing energy usage, but appropriate measures need to be taken. The United States will be concentrated on in this entry; however, the principles apply to the rest of the world.
For one, in the commercial and residential sector, which make up 39 percent of total United States energy consumption, HVAC and lighting are the majority energy functions. Therefore, common sense would say that if the efficiency of HVAC systems and lighting is drastically improved, the total energy usage would decline substantially while economies increase. Making these systems very efficient is possible, but as of now requires a financial compromise. Currently, HVAC systems are more or less designed strictly to function, not worrying about the efficiency because not many businesses are willing to pay extra for higher efficiency systems. It is this financial barrier which will be hard to overcome. In terms of lighting, the switch from incandescent bulbs to florescent could make a substantial difference.
Also, the transportation sector guzzles up 29 percent of America's total energy consumption, predominantly driven by gasoline. As cars that run on batteries gain popularity and get integrated more and more in the general public, the gasoline numbers will drop severely. This would decrease energy usage and grow the renewable energy economy.
For one, in the commercial and residential sector, which make up 39 percent of total United States energy consumption, HVAC and lighting are the majority energy functions. Therefore, common sense would say that if the efficiency of HVAC systems and lighting is drastically improved, the total energy usage would decline substantially while economies increase. Making these systems very efficient is possible, but as of now requires a financial compromise. Currently, HVAC systems are more or less designed strictly to function, not worrying about the efficiency because not many businesses are willing to pay extra for higher efficiency systems. It is this financial barrier which will be hard to overcome. In terms of lighting, the switch from incandescent bulbs to florescent could make a substantial difference.
Also, the transportation sector guzzles up 29 percent of America's total energy consumption, predominantly driven by gasoline. As cars that run on batteries gain popularity and get integrated more and more in the general public, the gasoline numbers will drop severely. This would decrease energy usage and grow the renewable energy economy.
Discuss the GDP per capita versus energy efficiency figure in terms of Hong Kong?
Above is a figure showing the GDP per capita versus energy efficiency for the leading 40 countries in the world according to their GDP.
Based on the figure, it seems as if Hong Kong is in the best position out of all the 40 countries. It's close to being a highly energy efficient region, while also maintaining a highly productive GDP per capita.
It is interesting to note that the bulk of the 40 countries lie in the energy inefficient region. To cut down on total worldwide energy production, this statistic needs to change drastically.
What is the embodied energy in an apple?
When most people go and but an apple from a grocery store they do not appreciate the amount of embodied energy that’s gone into a single apple. Embodied energy is the energy invested into growing, harvesting, transporting, packaging, marketing, and selling the product. For a simple analysis of apples grown in season we will say that most of the energy is used to farm and transport them. The in season apples will need to be shipped but we will assume that the consumer can walk to the local market to get their apples. All the embodied energy comes from driving the apple from the orchard to the local market. We will say that a standard path taken by an apple starts at an orchard, then to storage where they will be graded, then transported to a wholesale market, then transported to the market, and finally picked up by the consumer. From Blanke’s calculations [34] we can estimate that the energy required to produce a local apple is about 2.8 MJ/kg.
Now we need to look at the apples when they are out of season. The Food (miles) for Thought journal [34] looks at the energy balance (or imbalance) for locally-grown apples in Germany vs. imported apples from New Zealand. They found that the imported apples only contained about 27 percent more embodied energy than those that were produced nearby. The comparison made for these German apples is probably very similar to most countries around the world when apples are out of season. The difference they found was 5.89 MJ/kg for local apples and 7.50 MJ/kg for imported apples.
We can now compare these values to a small to average apple that contains 53 calories. We will assume the apple weighs about 3.5 ounces. The energy that we get out of this one apple is only 0.4 MJ/kg.
Now we need to look at the apples when they are out of season. The Food (miles) for Thought journal [34] looks at the energy balance (or imbalance) for locally-grown apples in Germany vs. imported apples from New Zealand. They found that the imported apples only contained about 27 percent more embodied energy than those that were produced nearby. The comparison made for these German apples is probably very similar to most countries around the world when apples are out of season. The difference they found was 5.89 MJ/kg for local apples and 7.50 MJ/kg for imported apples.
We can now compare these values to a small to average apple that contains 53 calories. We will assume the apple weighs about 3.5 ounces. The energy that we get out of this one apple is only 0.4 MJ/kg.
Compare the following sources in a well-organized table: nuclear, wind, solar, natural gas, coal, petroleum, bifuels
Below is a link to our table:
Sources:
What is the carbon footprint and embodied energy?
A carbon footprint encompasses the total amount of Greenhouse Gas emissions generated by an event, product, person, or from electricity production. Out of all the electricity sources, wind, hydroelectric, and nuclear have proven to contain the lowest carbon footprint. That is, throughout the whole life cycle from construction to operation, these energy sources give out the lowest concentration of greenhouse gases [35].
In terms of our country under study, Hong Kong contains the second highest carbon footprint per capita in the world at 29 tonnes per year. This is mainly due to the large-scale importing of energy, manufacturing, and transportation of imported goods [36].
Embodied energy consists of summing the total energy inputs throughout the whole life cycle of a product. Components of the life cycle included that are summed are as follows: extraction, transport, manufacture, assembly, installation, disassembling, deconstruction, and/or decomposition [37].
What is energy density?
Energy density is the amount of energy stored within a fuel. The energy density also helps us to realize how much waste will be produced per unit of energy extracted. Nuclear fission reactions are those that harness the potential energy of a nucleus, which contains nearly all of the energy of an atom. The element uranium is particularly useful is nuclear fission. The isotopes U-235 and U-238 are used most often to extract nearly all of the energy from an atom. The waste energy from nuclear reactions isn’t released to our atmosphere like most energy conversion processes. Instead, all of the waste can be stored and kept underground where is won’t have any negative effects on our environment.
When looking at other more common energy sources we can place propane near the top for high energy density. The next highest energy density can be found in gasoline, followed by diesel fuel, biodiesel, and then coal. Coal still has a higher energy density than a 100-ft-high dam with water spilling over by about 30,000 times.
When looking at other more common energy sources we can place propane near the top for high energy density. The next highest energy density can be found in gasoline, followed by diesel fuel, biodiesel, and then coal. Coal still has a higher energy density than a 100-ft-high dam with water spilling over by about 30,000 times.
What is the cost of energy production?
Comparing the different energy sources and their costs of production helps us to get a good grasp on what is feasible and what is not. Before the energy can be produced, the equipment that will extract the energy from its raw form needs to be built. When concerned with prices to set up the initial energy conversion process (per kWh), it should be no surprise that solar energy is the most expensive. The solar collectors are very pricey, and the amount of energy and efficiency at which the energy is extracted not overly impressive numbers. The next most expensive to construct (per kWh) is wind energy. Wind turbines are a huge capital investment, but if they are placed in strategic locations the amount of energy they produce can make up for some of that cost. The wind energy construction phase is 1/3 times as expensive (per kWh) to solar energy. Hydroelectricity is the most cost effective but is limited by the number of geographic locations needed to construct the dam. Nuclear energy and coal are the next most cost effective sources. Of these two there may be more potential for future exploration of nuclear energy. The energy extraction processes have gotten more efficient over the years for both of these sources but the potential for nuclear seems to be very high.
Petroleum and natural gas plants are used throughout most of the world and these two lie about in the middle for cost of energy production. Of course, petroleum is a limited source and in the future we may see the industry turning away from its use. The idea of sustainability has greater influence on our culture now than it ever has.
Petroleum and natural gas plants are used throughout most of the world and these two lie about in the middle for cost of energy production. Of course, petroleum is a limited source and in the future we may see the industry turning away from its use. The idea of sustainability has greater influence on our culture now than it ever has.
What is the capacity factor?
It’s important to look at the capacity factor of our resources so that we can develop a stable power grid. Energy is supplied by each grid constantly and it’s essential to get the most efficient energy that we can possibly use. The capacity factor is a measure of the performance of a power source over time as a percentage of its full potential. These factors vary substantially from one energy source to another. Nuclear power has the highest CF, followed by coal, and then renewable energy. Oil and combined cycle natural gas plants have the lower CFs and yet we still rely on these expensive fuels extensively. Coal fired plants seem to be a solid choice for generating electricity because of the high CF and fewer concerns than nuclear power plants usually present. However, the technology we use with nuclear power continues to advance and the extremely high CF will prove nuclear to be a valuable source in our future.
What is the current energy portfolio for the US and the world? Can these profiles last?
In terms of the United States, the following link is a previous blog entry explaining the current portfolio the U.S sits in and whether we can sustain the portfolio in the future: http://spencersophiedanpease.blogspot.com/2011/08/can-current-energy-consumption-profile_2725.html
In terms of the world, the current energy portfolio to meet the global demand for energy is shown below [38].
Based on the figure, it is evident that the energy portfolios between the world and US are similarly dominated by fossil fuel energy production. Whereas 83 percent of energy stemmed from fossil fuels in the United States as of 2009, 81 percent stems from fossil fuels worldwide currently.
Also, nuclear energy is not widely used in the world with only 6.30 percent energy generation from this energy source. Biomass as an energy source is more commonly accepted worldwide (10 percent) than in the United States (only 1 percent). This can largely be attributed to the large-scale burning of wood in third-world countries to meet their cooking demands.
Lastly, it is important to note that only 0.50 percent of all energy production in the world comes from the renewable sources geothermal, solar, and wind.
As with the United States, the current worldwide portfolio will definitely not be able to last for the same reasons as why the United States' energy portfolio will gradually have to transform.
For one, the fossil fuels that are used in high excess to meet the global energy demand will all run out. Projections of when these fossil fuels will run out is a relatively unknown answer. However, it can be generously said that if the current portfolio does not change, natural gas will run out in 60 years, oil will run out in less than 100 years, and the coal reserves will run out in less than 125 years.
Secondly, the high content of GHG's released from fossil fuel energy production creates hazardous and life-threatening issues. The level of carbon dioxide has already reached unprecedented levels and could cause many illnesses if the problem goes unattended. Next, there is a high probability that as the GHG concentration in the atmosphere rises, the sea level will rise. Land that was once prosperous could be underwater in the next 200 years.
The final drastic effect that fossil fuels create is the energy dependence on one another, creating wars and economic downturns for several countries. Since oil, coal, and natural gas are only in specific locations, fluctuations in prices causes volatile economic times with a strong dependence on these energy sources. Especially as the fossil fuel sources are running out, the prices will become more and more volatile, creating more hostility and violence between nations.
With the effects of fossil fuels emphasized, the most common sense solution is to transform the world energy economy from a fossil fuel-based one to a renewable energy-based economy (geothermal, wind, solar). However, as can be seen on the figure above, only 0.50 percent of the world's energy stems from these three renewable energy sources.
The answer seems simple and solves all of the problems that arise from fossil fuel energy production. However, it is one of the most complex problems that the world faces today. What's stopping this transformation?
One of the leading forces in stopping this transformation is a lack of political will. Until governments not only locally but worldwide get on the same page and get committed to spending significant amounts of money to build renewable energy infrastructure, the current energy portfolio will not change much. In other worlds, this has to be a large-scale energy transformation.
Also, efficiency of the renewable sources have to be improved. For example, solar energy on average only has an efficiency of 15 percent.
Lastly, the building of capital for these renewable energy industries is too much money right now for large-scale adaptation. However, as the industries gain popularity and sell more, the prices will drop severely.
In terms of the world, the current energy portfolio to meet the global demand for energy is shown below [38].
Also, nuclear energy is not widely used in the world with only 6.30 percent energy generation from this energy source. Biomass as an energy source is more commonly accepted worldwide (10 percent) than in the United States (only 1 percent). This can largely be attributed to the large-scale burning of wood in third-world countries to meet their cooking demands.
Lastly, it is important to note that only 0.50 percent of all energy production in the world comes from the renewable sources geothermal, solar, and wind.
As with the United States, the current worldwide portfolio will definitely not be able to last for the same reasons as why the United States' energy portfolio will gradually have to transform.
For one, the fossil fuels that are used in high excess to meet the global energy demand will all run out. Projections of when these fossil fuels will run out is a relatively unknown answer. However, it can be generously said that if the current portfolio does not change, natural gas will run out in 60 years, oil will run out in less than 100 years, and the coal reserves will run out in less than 125 years.
Secondly, the high content of GHG's released from fossil fuel energy production creates hazardous and life-threatening issues. The level of carbon dioxide has already reached unprecedented levels and could cause many illnesses if the problem goes unattended. Next, there is a high probability that as the GHG concentration in the atmosphere rises, the sea level will rise. Land that was once prosperous could be underwater in the next 200 years.
The final drastic effect that fossil fuels create is the energy dependence on one another, creating wars and economic downturns for several countries. Since oil, coal, and natural gas are only in specific locations, fluctuations in prices causes volatile economic times with a strong dependence on these energy sources. Especially as the fossil fuel sources are running out, the prices will become more and more volatile, creating more hostility and violence between nations.
With the effects of fossil fuels emphasized, the most common sense solution is to transform the world energy economy from a fossil fuel-based one to a renewable energy-based economy (geothermal, wind, solar). However, as can be seen on the figure above, only 0.50 percent of the world's energy stems from these three renewable energy sources.
The answer seems simple and solves all of the problems that arise from fossil fuel energy production. However, it is one of the most complex problems that the world faces today. What's stopping this transformation?
One of the leading forces in stopping this transformation is a lack of political will. Until governments not only locally but worldwide get on the same page and get committed to spending significant amounts of money to build renewable energy infrastructure, the current energy portfolio will not change much. In other worlds, this has to be a large-scale energy transformation.
Also, efficiency of the renewable sources have to be improved. For example, solar energy on average only has an efficiency of 15 percent.
Lastly, the building of capital for these renewable energy industries is too much money right now for large-scale adaptation. However, as the industries gain popularity and sell more, the prices will drop severely.
Transportation and decision making. Is energy a public issue or a personal issue?
As time has passed the energy “problem” has been brought to the public eye more and more frequently. It’s safe to say that most people realize that driving around an automobile for no reason but to enjoy the fresh air is not exactly helping our planet or the atmosphere. Most people do drive or at least commute on a regular basis. This includes riding a bus, driving a car to work each day, and flying for business trips or vacations. No matter what the form of transportation may be, the consumer is always using energy when commuting (unless the consumer walks or rides a bicycle every day). Conserving energy needs to be viewed as a personal issue that has an indirect impact on the public. Transportation is just one of several examples of how the public/private issue could be discussed. The bottom line is that to create a sustainable environment for us and our kids we have to make the right decision right now. This could be anything from replacing old incandescent light bulbs with new fluorescent ones, or shutting off all power sources before leaving work for the night, or carpooling to work with a friend or co-worker. Saving energy is saving money, and with the economic and the environmental impact, it’s very important to look at the conservation of energy as a public issue.
What is feasible for the green stack analysis using only real issues?
Feasible green stack number: 28 kWh per day per person
The above figure shows the realistic future energy capacity for renewable sources in Hong Kong. These results are only 3 kWh per day per person less than the analysis performed prior. This is in large part because the first analysis performed was a drastically more realistic approach than the one first employed by McKay for the United Kingdom. Each renewable energy source in this green stack analysis is analyzed below.
Ideally, geothermal and hydroelectric power are great sources that are sustainable and economically sound. However, in Hong Kong, these two sources do not possess a future and any chance of prosperity for these industries is unrealistic. For geothermal, the land is just not suitable for drawing geothermal energy out of the Earth. Therefore, spending the large sums of money to purchase the capital for geothermal energy does not make sense. For hydroelectric, currently there is no energy production from this source in Hong Kong due to the rivers having insufficient flow and height. Once again, the high capital costs to create hydroelectric power plants would be a pointless task due to the lack of energy created.
Tidal and wave energy sources haven't been looked too far into yet for Hong Kong. These could be viable sources for small-scale energy production due to the large coast of Hong Kong. In our original analysis, tidal and wave future capacity was fairly generous in the approximation, with 3.3 kWh per day per person. This is fairly reasonable and acts as a good approximation for the potential future usage for Hong Kong.
Like tidal and wave energy sources, the total future wind capacity was generous in nature; the total for wind power is 12.5 kWh per day per person. Although the calculations and analysis performed originally was generous, the general trends of wind power need to be taken into account. For one, popularity of wind power is growing each year. Also, China's wind capacity is increasing exponentially every year. Thus, it is reasonable that Hong Kong's wind capacity does increase up to the point of 12.5 kWh per day per person.
The result of biomass (0.0002 kWh per day per person) did not change from the original analysis to the realistic analysis. This is because biomass will never be an integral part of the Hong Kong society. The land is mostly mountainous with limited flat lands, forestry, and crop plantations. Biomass is only used for municipal organic waste.
In terms of solar energy, McKay was very unrealistic in his initial approach by giving everyone in the United Kingdom 10 meters squared of PV panels for solar farming and solar heating. For the initial approach in the Hong Kong investigation, it was assumed that 7 meters squared was given to each person in Hong Kong. However, this is not even realistic due to political and economical restraints. Thus, for the realistic approach, giving everyone in the country 5 meters squared was used. As a result, solar heating could provide 7 kWh per day per person, while both solar farming and solar PV could provide 2 kWh per day per person each.
Overall, this green stack number of 28 kWh per day per person seems very low when taken under consideration with other regions and countries. However, it has to be realized that Hong Kong imports most of their energy from China and other countries. The energy production that Hong Kong does produce for its own citizens stems mainly from coal. Therefore, for renewable energy to become an integral part of Hong Kong, not only does the whole energy production structure need to change within Hong Kong. Countries that are nearby Hong Kong need to also have a strong renewable energy foundation so that Hong Kong can receive this energy. It is also concluded that the land terrain also limits the growth of renewable energy sources in this region.
Wednesday, September 14, 2011
What are the final red stack-green stack numbers for Hong Kong?
By looking at the red stack-green stack figure above, the red stack clearly dominates the potential of the green stack, potentially creating many problems for the future. The main reason the distribution is so lopsided towards the red stack is because most of the energy production in Hong Kong is imported from China and nearby countries. Land in Hong Kong is not suitable for most renewable energy sources to develop.
The total red stack for energy production is approximately 111 kWh per day per person. The numbers that could be slightly inaccurate are airplanes and stuff. For the category of airplanes, there is no direct way to correctly find the energy production per person per day. Thus, we just made a fair assumption that each person in Hong Kong makes one flight out of the Hong Kong airport each year. In terms of stuff, 7 kWh per day per person was approximated to be the same as the United Kingdom. In reality, however, Hong Kong does not use many "stuff". The more realistic number is around 5 kWh per day per person. For the sake of this study, the difference between these two numbers is not important. What is important is the extremely low green stack number.
The total green stack number for future renewable energy capacity is only around 31 kWh per day per person. As witnessed in the next post, the more realistic future renewable energy capacity is much lower.
Overall, the difference between the red stack number and green stack number is 80 kWh per day per person.
What is the green stack number for biomass in Hong Kong?
The topography of Hong Kong includes a mountainous terrain with very limited flatland and is not suitable for crop plantation development. Therefore, there is no forestry in this region and Hong Kong does not have a big agriculture industry. As a result, biomass is very limited with the exception of municipal organic waste.
In 2000, only 34,000 metric tons of oil equivalent energy was consumed by biomass, a very small percentage of the overall energy consumption for that year (0.27 percent). A very reasonable assumption is that the level of biomass in Hong Kong has remained the same since 2000.
Thus, the calculation is as follows: (48 toe/1 year)(42 GJ/1 toe)(1,000,000 kJ/1 GJ)(1 year/365 days)(1 day/24 hours)(1 hour/60 minutes)(1 min/60 seconds)=63.9 kW
Converting this number in power per capita per day is approximately 0.0002 kWh/person/day.
In 2000, only 34,000 metric tons of oil equivalent energy was consumed by biomass, a very small percentage of the overall energy consumption for that year (0.27 percent). A very reasonable assumption is that the level of biomass in Hong Kong has remained the same since 2000.
Thus, the calculation is as follows: (48 toe/1 year)(42 GJ/1 toe)(1,000,000 kJ/1 GJ)(1 year/365 days)(1 day/24 hours)(1 hour/60 minutes)(1 min/60 seconds)=63.9 kW
Converting this number in power per capita per day is approximately 0.0002 kWh/person/day.
What is the available hydropower density in Hong Kong?
Canada, China, Brazil, the United States, and Russia have the largest energy production from hydroelectric power and they account for over 50 percent of the total capacity in the world.
Hong Kong currently does not have hydroelectric power generation and is incapable of large-scale hydroelectric generation because their rivers do not have sufficient flow and height [30]. However, there are some locations that are being looked at for small-scale hydroelectric power. Predicting that these are installed in the future but nothing that is highly successful, I give hydroelectric power a maximum of 1 kWh per day per person.
What is the theoretically available wind power density for the area 10 km out from the shore of Hong Kong? How many tons of concrete and steel would this take?
Assuming that the power per unit area of the offshore wind power in Hong Kong closely models the land-based wind power, the offshore power per unit area is approximated to be 4.05 W/m2.
Next, it is assumed that it is feasible to put wind turbines up to 10 kilometers from shore. Knowing that the coastline of Hong Kong is 733 kilometers [29], the total offshore area can be computed by multiplying 733 kilometers by 10 kilometers and converting to meters squared. The available wind power for total offshore wind availability is the same as the land-based equation: Total available offshore wind power = (.10)(Power per unit area)(Total area of offshore area). Plugging in the numbers gives a total of 269.9 kW.
Again, by using the population of Hong Kong, 7 million, the total available offshore wind energy per capita per day can be found. This number is approximately 11 kWh/day/person.
Next, it is assumed that it is feasible to put wind turbines up to 10 kilometers from shore. Knowing that the coastline of Hong Kong is 733 kilometers [29], the total offshore area can be computed by multiplying 733 kilometers by 10 kilometers and converting to meters squared. The available wind power for total offshore wind availability is the same as the land-based equation: Total available offshore wind power = (.10)(Power per unit area)(Total area of offshore area). Plugging in the numbers gives a total of 269.9 kW.
Again, by using the population of Hong Kong, 7 million, the total available offshore wind energy per capita per day can be found. This number is approximately 11 kWh/day/person.
How much area would have to be covered by PV panels to supply all the energy required by the red stack analysis?
The red stack number when adding all the sub-components together is approximately 111 kWh per day per person. Multiplying this by the population of Hong Kong, 7 million, gives 777 million kWh per day total.
Next, I assume that the average power of the sunlight per meter squared in Hong Kong is 110 W/m2 and that each one of the PV panels are 10 percent since the cheapest kind would be implemented in mass productions. By using the formula (110 W/m2)(.10)(x m2)(1 kW/1000 W)(24 hours/1 day) = 777,000,000 and solving for x, it is computed that 2.94 billion m2 area covered by PV panels are necessary to produce the red stack energy amount.
Next, I assume that the average power of the sunlight per meter squared in Hong Kong is 110 W/m2 and that each one of the PV panels are 10 percent since the cheapest kind would be implemented in mass productions. By using the formula (110 W/m2)(.10)(x m2)(1 kW/1000 W)(24 hours/1 day) = 777,000,000 and solving for x, it is computed that 2.94 billion m2 area covered by PV panels are necessary to produce the red stack energy amount.
Solar PV cells have an efficiency of about 15%. What is the collectible power density in Hong Kong?
Solar Thermal: The average power of sunshine per square meter in Hong Kong is nearly impossible to find, due to this region's area oriented towards the sun and the tilt between the sun and land being hard to find. Therefore, it is to be assumed that the average power of sunshine per square meter on roofs in Hong Kong is 110 W/m2. The average power of sunshine per square meter on the ground is also assumed to be 110 W/m2. Also, McKay informs us that if all south-facing roofs had solar thermal panels, this would be 10 meters squared. This seems very generous, so I will go 7 meters squared of roof panels per person. These panels are approximately 50 percent efficient. Thus, the potential of solar heating is (110 W/m2)(7m2)(.50). The end result for solar thermal is approximately 9 kWh/day/person.
Solar Photovoltaic: I will give each person in Hong Kong 7 meters squared of photovoltaic panels and 110 W/m2 is used again as the average power of sunshine per square meter. According to McKay, only the expensive PV panels have an efficiency of 20 percent. Most PV panels fall in between 10-20 percent. I will go in the middle and say that the PV panels are 15 percent efficient. Using this data, the total power per capita per day for solar PV is approximately 3 kWh/day/person.
Solar farming: Once again, I will use 110 W/m2 as the average power of sunshine per square meter. Like McKay, I will assume that a breakthrough occurs in the solar energy industry, both technological and economical, and will cover 5 percent of the land with PV panels that are 10 percent efficient. 10 percent is the on the low-end for efficiency, but the PV panels are assumed to be cheap, meaning this is reasonable. Also, I know that Hong Kong covers 157.5 meters squared per person. Plugging in numbers, I get 2 .0 kWh/person/day.
What is the potential wind energy availability in your country?
In order to calculate the power per day person, the first component to calculate is the power per unit area. This is done by implementing the following equation: Power per unit area = (pi/400)*pair*vuseful3. The density of air can be closely approximated as the air density standard when the pressure is 101.325 kPa and the air temperature is 15°C. Thus, pair = 1.225 kg/m3. The useful wind velocity can be found by adding 1.5 meters per second, the factor of error, to the average wind velocity of the region. Based on the figure below, which is the wind speed topology for Hong Kong, it is reasonable to believe that the average wind speed is 6 meters per second [27].
So, vuseful = vavg + 1.5 m/s = 7.5 m/s. Now, the power per unit area can be computed and the value turns out to be 4.05 W/m2.
Now, the total available power is found by using the following equation: Total available power = (.10)(Total area of Hong Kong)(Power per unit area). The 0.10 is the approximated fraction of the country covered by windmills. The total area of Hong Kong is known to be 1,098*106 meters2. After plugging in the necessary parameters, the total available wind power is 444.7*103 kW. Then, using 7 million people for the population of Hong Kong [28], the total power per day per person comes out to be around 1.50 kWh/day/person in terms of wind power on land.
What is the green stack number for geothermal power in Hong Kong?
Geothermal energy is produced constantly when the three layers of the earth shift and decay. The power available in the crust below Hong Kong is a very important topic because the geothermal power unit will produce energy regardless of the weather conditions. However, this power is not limitless. If the geothermal system sends down cold water and pulls out hot water, the heat is being taken from the rocks in the crust. The rocks in the crust won't put off near as much heat after continual usage because the heat from the core of the Earth takes so long to travel radially outward.
The geothermal capital investment is what prevents most people from choosing this option. Drilling equipment is extremely expensive and hiring a trained drilling team to operate the equipment is just as pricey. McKay says that the average optimal drilling depth is about 15 km, at which temperature an ideal heat engine could deliver 17 mW/m 2. We will assume that the power stations are operating ar perfect efficiency and that every square meter of the island is used. Since Hong Kong has a staggering population density of about 6,500 people per km 2, wide-scale geothermal power would only provide about 0.1 kWh per person per day.
What is the green stack number for wave/tidal power in Hong Kong?
Ocean energy is a fairly new source of energy so many of the processes aren't refined as well as they will be someday. With this being said, the ocean's energy can be very valuable if energy-extraction stations are placed in strategic locations. Both waves from the ocean and the changing tide can be used to produce usable energy. Since Hong Kong is surrounded by the Pacific Ocean the potential for renewable energy through the ocean is certainly there.
Wave power is measured as energy per unit length instead of per unit area since the waves can only travel on one direction. The unit length we will use is meters. The coastline of Hong Kong is 733 km long [26]. We will assume that the power of the Pacific wave, on average, is 50 kw per meter of coastline. That means that if every meter of the Hong Kong coast was set up to extract energy we could get 36.7 GW of energy! However, this is extremely unrealistic. The shoreline is not covered in these stations, and not even close to it. Wave data collected by the Hong Kong Observatory at Waglan Island in1999, showed that a 10 kW installation will take up about 35m of shoreline [31]. Because the population is so large we can assume that at most, 25 percent of the coastline is covered with these wave machines. That means that if these machines were to be 50% efficient at capturing the energy, Hong Kong could produce about 23 MW of energy. This number comes out to be about 1.3 kWh per day per person.
Tidal energy is a little more complicated than wave energy since large wave basins are required. These basins contain a water-wheel that turns when the tide changes, and since the area of the basin determines the amount of water and therefore the amount of energy, tidal energy is expressed in energy per unit area. For an impounded water basin with a constant water level difference of H meters, the potential energy of the water stored in the basin for each tide is 4.91 H2 kJ per m2. This is the theoretical maximum estimation formula for tidal energy resources. With the help of seven tidal energy stations in Hong Kong taking their annual totals of tidal energy we can say that the average energy produced per station is 13.7 kJ per m2 per day [31]. This may sound like a lot at first, but again, the wave basins cannot be built all along the coast. Assuming the another 25% of the coast is covered with these wave basins (taking each wave basin to be 50 m2) then Hong Kong should be able to generate about 700 kWh per day. Since the population Hong Kong is so large this doesn't seem to be a very large part of their renewable resource potential at about 2 kWh per day per person.
Wednesday, September 7, 2011
What is the red stack number for transporting stuff in Hong Kong?
After all of the stuff is produced it then needs to be transported and distributed. The three forms of transportation are by land, by air, and by water. Since the area of land that Hong Kong covers is not very large we will neglect the energy used to transport stuff by air. The stuff that is transported by water is mostly exported out of Hong Kong and will be neglected as well. The energy used to transport stuff will then come fully from transportation over land. Freight trucks, delivery vehicles, and personal automobiles are used throughout the city to deliver all the stuff. There are about 1,140 miles of roads used for public transportation in Hong Kong. [26] Food, drink, tobacco, paper products, and merchandise are just a few of the things transported around, and with Hong Kong’s thriving market we will assume an energy usage of 10 kWh per day per person.
What is the red stack number for Stuff in Hong Kong?
Hong Kong has an enormous market for stuff. The four chunks of stuff (RPUD) need to be broken up. First the raw materials are made before anything else is done (R). Next, the raw materials are processed and changed into a certain product (P). The final products will generally require energy to operate throughout the product life (U). And finally the product will need disposed of some day in some way (D). Making and producing the various components of a product involve a lot of time, resources, and energy. When done with a drink container, many people choose to throw the item away instead of recycling. If each person throws only 2 containers out each day the energy value is equivalent to just over 1 kWh per day per person. Since we are living in the age of technology we can assume that if you have a computer you will buy a new one every four years. Since so much energy goes into the production of a computer, the red stack number comes out to 1.25 kWh per day per person. Newspapers, magazines, and junk mail are a huge part of the energy component in the “stuff” department. Since there are so many newspaper that circulate on a regular basis, we can assume that wasted energy through paper waste alone is about 2 kWh per day per person. We will guess that the density of the households is higher in Hong Kong than in most countries with about 4 people per house. From McKay’s book we can say that the estimated energy cost of a house is 2.2 kWh per day. The average energy consumed on housing comes out to be about 0.5 kWh per day per person. There aren’t near as many automobiles in Hong Kong as in New York City (per person) because people generally don’t need to travel as far on a regular basis. For the roads and cars, compared to other sources, we can assume a small impact and assign a value of 1 kWh per day per person. Totaling everything up for “stuff” we get a sum of about 7 kWh per day per person.
What is the red stack number for food, farming, and fertilizers in Hong Kong
Split into: Plants (grains/vegetable), milk, eggs, meat, fertilizers, and pet food
Food is an important area to look at in Hong Kong even though farming is not a major factor compared to other regions. The extremely localized population means that there is an extreme demand for food.
The Hong Kong region is not known for its agricultural or farming products it produces. Because much of the land is not suitable for farming (sloping terrain) and because of the urbanized population we can neglect the red stack number for farming and fertilizers. Hong Kong relies on 95 percent of its food supply from imports out of the region. [25] Energy is wasted every time consumable food is thrown out. If 7 million people discard, on average, just 200 kilocalories of consumable food energy per day, the energy wasted can be neglected compared to other red stack numbers. With the 200 kcal assumption, there would only be 0.23 kWh per day per person wasted.
What is the red stack number for heating/cooling in Hong Kong?
Domestic water heating is used every day. The volume of a tub in Hong Kong is assumed to be 29 gallons since this is standard elsewhere. The average temperature of the water taken into the house throughout the year is averaged to be 200C. For comfortable domestic uses the water need to be heated up to 500C. Using an elementary energy equation and assuming the specific heat of the water to be 4.18 kJ per kg0C, we find that 13,800 kJ are used each time the tub is filled. This amount of energy is equal to about 3.8 kWh per day per person for a bath. Assuming that one-fourth much water is used for a shower, about 1 kWh per day per person is used. The total for domestic water heating is then 4.8 kWh per day per person.
Washing both clothes and dishes generally requires hot water. A full loed of laundry uses about 21 gallons of water and about 1 kWh. To dry the same load of clothes will require about 3 kWh. Estimating that there will be a few dishes each day, and assuming that to do the dishes five gallons of water will need to be heated on average 200C, we can add up the energy and estimate it to be 10 kWh per day per person. Heating and cooling air uses more energy than any of the processes discussed to this point. McKay mentions in his book that humans need at least 12 kWh per day per person in our air. Since the people of Hong Kong like to live comfortably we can reasonably estimate that the total energy required to maintain an average temperature of 230C is 24 kWh per day per person. Cooling air to a desirable temperature is a necessity for a few of the summer months in Hong Kong. A window air conditioner in a single room uses 0.6 kWh of electricity and exchanges about 2.6 kW of cooling. We will assume that a person in Hong Kong will turn their air conditioner on for 12 hours a day two months out of the year. This puts the total energy needed up to 1.2 kWh per day per person. Refrigeration is not a huge part of the energy problem when compared to other sources. An average refrigerator/freezer combo uses about 18 kW. This comes out to about 1 kWh per day per person. When we sum all of these energy sources for heating and cooling we get a grand total of 42.9 kWh per day per person.
Cooking needs to be included in the energy accumulation since some people cook multiple times each day. Hong Kong uses 200 V outlets which operate at about 2300 Watts. We know that Hong Kong uses, on average, 2760 MJ per day for cooking. This comes out to about 46 kWh per day per person. The cooking appliances are only on for short periods of time, so we will say for one hour put of the day each day. The amount of energy consumed while cooking can be estimated to be 1.9 kWh per day per person.
Washing both clothes and dishes generally requires hot water. A full loed of laundry uses about 21 gallons of water and about 1 kWh. To dry the same load of clothes will require about 3 kWh. Estimating that there will be a few dishes each day, and assuming that to do the dishes five gallons of water will need to be heated on average 200C, we can add up the energy and estimate it to be 10 kWh per day per person. Heating and cooling air uses more energy than any of the processes discussed to this point. McKay mentions in his book that humans need at least 12 kWh per day per person in our air. Since the people of Hong Kong like to live comfortably we can reasonably estimate that the total energy required to maintain an average temperature of 230C is 24 kWh per day per person. Cooling air to a desirable temperature is a necessity for a few of the summer months in Hong Kong. A window air conditioner in a single room uses 0.6 kWh of electricity and exchanges about 2.6 kW of cooling. We will assume that a person in Hong Kong will turn their air conditioner on for 12 hours a day two months out of the year. This puts the total energy needed up to 1.2 kWh per day per person. Refrigeration is not a huge part of the energy problem when compared to other sources. An average refrigerator/freezer combo uses about 18 kW. This comes out to about 1 kWh per day per person. When we sum all of these energy sources for heating and cooling we get a grand total of 42.9 kWh per day per person.
What is the red stack number for airplanes in Hong Kong?
Taking a single airplane trip consumes an incredible amount of energy. Since the Boeing 747-400 is a common choice for flights we will use it to get a rough estimate. We will estimate that the aircraft holds 63,500 gallons of fuel and carries 415 passengers about 5,000 miles. Assuming that the fuel will get 38 kWh per gallon, it has been calculated that each passenger will consume 11,630 kWh on a full round trip. It’s reasonable to say that each person will take a flight once a year, and so we can come up with the value of about 32 kWh per day per person.
What is the red stack number for cars in Hong Kong?
Energy is consumed at every level of human interaction, and one of the most common ways we use energy is through transportation. Since Hong Kong has a population of nearly 7 million people, it’s important to look at their energy consumption via automobiles. Assuming the fuel they use gets on average 25 miles per gallon, and also assuming that the fuel gets approximately 24 kWh per gallon, we only need to know how many miles per day the people of Hong Kong drive each day. We will take the amount of energy used each year to be 91 Tera-Joules[24] The calculation has been done to show people living in Hong Kong travel on average 10.2 miles per day. We need the energy consumption so we will use the miles per gallon average along with the energy per gallon to get 9.9 kWh per day per person.
What is the red stack number for gadgets in Hong Kong?
To calculate the total power per capita per day for gadgets is not feasible with the time constraint. But, we do not want to leave this value out of the green stack completely. It will be assumed that the gadgets for Hong Kong can be closely modeled to the United Kingdom's gadgets. Therefore, the power for gadgets in Hong Kong is taken to be 5kWh per day per person.
What is the red stack number for lighting?
For lighting in Hong Kong, it is assumed that it is modeled fairly closely to the United Kingdom's approximation. Between large and active regions like these, the difference would not be drastic unlike the power for cars and airplanes. Therefore, the power for lighting in Hong Kong is assumed to be 4 kWh per day per person.
Tuesday, September 6, 2011
Comparison of Manufacturing Energy and Energy Usage for Infiniti I35
Where does the energy go for Hong Kong?
According to the Energy Efficiency Office of Hong Kong, the breakdown of the distribution of energy can be seen in the figure below [24]. The data is from the year 2008, so the data is fairly recent.
Based on the figure, as of 2008, taxi usage is the highest percentage of where the energy goes (20 percent), followed by space conditioning (14 percent) and goods vehicles (11 percent). The next highest energy usage to the lowest energy usage is then listed: refrigeration (10 percent), lighting (9 percent), buses (7 percent), cooking (6 percent), cars and motorcycles (6 percent), others (5 percent), hot water (5 percent), industrial processes (3 percent), marine (3 percent), and lastly rail (1 percent).
Based on the figure, as of 2008, taxi usage is the highest percentage of where the energy goes (20 percent), followed by space conditioning (14 percent) and goods vehicles (11 percent). The next highest energy usage to the lowest energy usage is then listed: refrigeration (10 percent), lighting (9 percent), buses (7 percent), cooking (6 percent), cars and motorcycles (6 percent), others (5 percent), hot water (5 percent), industrial processes (3 percent), marine (3 percent), and lastly rail (1 percent).
What is the power consumption per capita and GDP per capita for Hong Kong?
Shown in the figure below are several regions and how they compare to each other in terms of power consumption per capita and GDP per capita [3]. Based on the figure, Hong Kong’s power consumption per capita is approximately 80 kWh per day per person while its GDP per capita is approximately $35,000 per person.
In terms of the 8 regions in the figure below, why is the figure of the greenhouse gas pollution per capita vs. population the way it is?
According to the McKay, as of the year 2000, the world’s total greenhouse gas emissions were approximately 34 tons of carbon dioxide-equivalent per year [3]. Shown below is a figure that resembles the breakdown of the world’s total greenhouse gas emissions in 2000 [3]. It contains the greenhouse gas emissions per year per person versus the population for eight regions of the earth. The width of each rectangle is population of the region, while the height is the average per-capita emissions in the region.
As can be seen, North America has the largest per-capita greenhouse gas emissions, followed by Oceania and Europe. In fact, North America’s per-capita greenhouse gas emissions are four times the world average while Europe’s per-capita greenhouse gas emissions are twice the world average. Also, Asia has small per-capita greenhouse gas emissions, but since it has by far and large the biggest population, this region possesses the most total greenhouse gas emissions.
The belief that energy is a measure for the quality of life is the reason the distribution of per-capita greenhouse gas emissions is the way it is. Energy contributes 75 percent of all greenhouse gases and most energy comes from fossil fuels [3]. Thus, the higher the quality of life in the region, the more energy the region needs to power the quality of life, and the consequences are a higher carbon dioxide concentration in that region. Especially as of 2000, a very high percentage of energy was due to the burning of fossil fuels since renewables were relatively new. So, as can be seen, North America, Oceania, and Europe contain the highest qualities of life while Asia and the Sub-Saharan Africa have the lowest. This seems like the most reasonable explanation.
The belief that energy is a measure for the quality of life is the reason the distribution of per-capita greenhouse gas emissions is the way it is. Energy contributes 75 percent of all greenhouse gases and most energy comes from fossil fuels [3]. Thus, the higher the quality of life in the region, the more energy the region needs to power the quality of life, and the consequences are a higher carbon dioxide concentration in that region. Especially as of 2000, a very high percentage of energy was due to the burning of fossil fuels since renewables were relatively new. So, as can be seen, North America, Oceania, and Europe contain the highest qualities of life while Asia and the Sub-Saharan Africa have the lowest. This seems like the most reasonable explanation.
What is "albedo" of the earth?
The “albedo” of the Earth refers to the reflectivity of Earth, most commonly measured by implementing an average reflection coefficient. What the average reflection coefficient of Earth describes is the visual brightness of the planet when seen with reflected sunlight. Numerically, the average reflection coefficient is known to be 0.39 [22].
The main effect of the magnitude of the albedo of Earth is the equilibrium temperature on Earth’s surface. Several effects can affect the albedo. The effects serve to either lower the albedo and cause warming of the Earth or raise the albedo and cause cooling of the Earth. The greenhouse effect, for example, traps infrared radiation and lowers the reflectivity (albedo) of the Earth, likely causing global warming [22]. On the other hand, a decrease in sunlight causes an increase in albedo and the effect cools Earth’s surface.
The main effect of the magnitude of the albedo of Earth is the equilibrium temperature on Earth’s surface. Several effects can affect the albedo. The effects serve to either lower the albedo and cause warming of the Earth or raise the albedo and cause cooling of the Earth. The greenhouse effect, for example, traps infrared radiation and lowers the reflectivity (albedo) of the Earth, likely causing global warming [22]. On the other hand, a decrease in sunlight causes an increase in albedo and the effect cools Earth’s surface.
Could the increase in carbon dioxide be due to the reduction of biomass?
On one hand, there is an argument that could be made that the increase of carbon dioxide concentration in the atmosphere is solely due to the decrease in biomass. For one, biomass is known to take in carbon dioxide and give out oxygen. Thus, cutting down forests and decreasing the amount of biomass would logically increase the amount of carbon dioxide in the atmosphere. Also, land use change accounts for the highest uncertainty in terms of the amount of carbon dioxide emissions from the global carbon market. Therefore, any approximation to the increase in carbon dioxide due to a decrease in biomass is going to have some percentage of uncertainty.
Although there could be an argument that the rise in carbon dioxide is solely due to the deduction of biomass, it is extremely likely that the rise in carbon dioxide emissions is mainly due to the burning of fossil fuels. The figure below demonstrates this belief [23].
It is evident from the figure that the carbon dioxide emissions that can be attributed to fossil fuel burning has increased steadily from the years 1960-2009, while emissions attributed to land use change has remained relatively constant. Even though there is some noted uncertainty in the land use change numbers, it is safe to conclude that most of the emissions are due to fossil fuel burning since the magnitude of carbon dioxide emissions is overwhelmingly larger for fossil fuel burning than the approximate land use change. Also, the Global Carbon Project predicted that in 2009 only 10 percent of global carbon dioxide emissions stemmed from land use change [23]. Lastly, the percentage of global carbon dioxide concentration that is attributed to land use change has decreased in recent years and will continue to decrease due to new federal policies limiting deforestation [23].
What are positive forcings and negative forcings?
Other than the classification of natural or human-made for climate forcings, another common classification is a positive forcing or a negative forcing. Positive forcings change the Earth’s energy balance and the effects are a warmer surface on Earth. Negative forcings are the opposite; they change the Earth’s energy balance but act to cool the surface on Earth [21].
An example of a positive forcing is a spontaneous increase in the sun’s brightness, leading to a warmer surface temperature on Earth. On the other hand, a negative forcing that cools the Earth is a volcano. Volocanos shoot out aerosols at high speeds into the atmosphere and the aerosols act to reflect light from earth; this causes a cooling of the earth’s surface [21].
The central problem recently is that climate sensitivity relative to positive forcings has begun to outweigh the sensitivity due to negative forcings. This has led to a very slight increase in recent years in the Earth’s surface temperature. If the problem is not solved, drastic consequences may ensue, such as the sea level rising due to thermal expansion.
An example of a positive forcing is a spontaneous increase in the sun’s brightness, leading to a warmer surface temperature on Earth. On the other hand, a negative forcing that cools the Earth is a volcano. Volocanos shoot out aerosols at high speeds into the atmosphere and the aerosols act to reflect light from earth; this causes a cooling of the earth’s surface [21].
The central problem recently is that climate sensitivity relative to positive forcings has begun to outweigh the sensitivity due to negative forcings. This has led to a very slight increase in recent years in the Earth’s surface temperature. If the problem is not solved, drastic consequences may ensue, such as the sea level rising due to thermal expansion.
What are climate forcings?
A climate forcing can be defined as an event that changes and disturbs the Earth’s energy balance [21]. A common classification of climate forcings is whether the forcings are natural or human-made. An example of a natural climate forcing for Earth is a sudden change of brightness from the sun, while an example of a human-made forcing is a human-made gas. One of these human-made gases is the added concentration of carbon dioxide in the atmosphere due to the burning of fossil fuels. Both of these examples change the Earth’s energy balance.
What event occurred in the year 1769, causing carbon dioxide concentrations to skyrocket?
As can be seen from the previous blog entry, the figure below shows the level of carbon dioxide in the atmosphere, measured in terms of parts per million [3]. It is evident from the figure that before 1769, the carbon dioxide concentration was relatively constant.
In the year 1769, James Watt invented and patented the first ever steam engine, sparking the start to the Industrial Revolution [3]. It is also in this year that the level of carbon dioxide emissions rose drastically and has not stopped growing ever since.
Although the connection between the growing carbon dioxide emissions and the start of the Industrial Revolution is not 100 percent known, it is extremely likely that the start of the Industrial Revolution and the introduction of burning fossil fuels have led to the growing concentration of carbon dioxide [3]. Until the day where energy stems from solely renewable sources, the carbon dioxide concentration will keep rising.
Although the connection between the growing carbon dioxide emissions and the start of the Industrial Revolution is not 100 percent known, it is extremely likely that the start of the Industrial Revolution and the introduction of burning fossil fuels have led to the growing concentration of carbon dioxide [3]. Until the day where energy stems from solely renewable sources, the carbon dioxide concentration will keep rising.
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