Category Energy Independence

After reviewing some of the details of Honda’s experimental solar-power hydrogen refueling station in Torrance, CA and its fuel cell vehicle several questions concerning efficiency and practicality come to mind. It most be noted that solar and hydrogen don’t emit harmful byproducts such as carbon dioxide or carbon monoxide so both technologies are important to our energy security. First let’s look at the efficiency of hydrogen and second the efficiency of generating hydrogen from solar.

As we learned from science class, hydrogen is the most abundant element in the universe. Hydrogen has approximately 3 times the energy per unit mass as gasoline and requires about 4 times the storage volume for a given amount of energy according to a Hydrogen Energy report from Stanford University. In further review of additional information on hydrogen we are also making some adjustments to our fuel-ranking table.

We are revising Table 1 that was used in our post of October 3, 2007 for data on the energy density for hydrogen from 2.5 kilowatt-hours (KWH) per gallon to 10.1 KWH/gal and is reflected in the revised Table 1 below. The discrepancy lies in measuring the weight of hydrogen in liquid volume. We are calculating the energy density of hydrogen using the high heat values of hydrogen of 61,000 British Thermal Units (BTUs) and a weight 0.57 pounds per gallon from the Stanford Hydrogen Report.

As a reference: 1 KWH = 3,600 kilojoules = 3,412 BTUs

Revised Table 1 Specific Energy, Energy Density & CO2

Hydrogen offers tremendous energy potential, but as we see from Table 1, hydrogen has a low energy density meaning it requires a large storage container to make it practical for use in a motor vehicle. Several car manufacturers including GM and Toyota have developed hydrogen vehicles. Hydrogen can be used in internal combustion engines replacing gasoline or in fuel cells to generate electric to power the vehicle. However, there are some limitations to the current technology that may limit the economic viability hydrogen powered vehicles in the near term. But there are no detrimental emissions with hydrogen as apposed to hydrocarbon fuels thus providing tremendous benefits as vehicle efficiency improves.

Honda’s solar-powered hydrogen fueling station takes nearly a week in sun to produce enough hydrogen to power Honda’s FCX concept hydrogen fuel cell vehicle. Honda employs a Proton Exchange Membrane Fuel Cell (PEMFC) that converts hydrogen to electric that in turn, powers the vehicle. The Honda FCX fuel cell vehicle has two fuel tanks that can be filled with up to 156.6 liters of hydrogen or about 43 gallons that offers 430km (267 miles) driving range. The hydrogen fuel cell vehicle provides a reasonable driving range, but with a fuel efficiency of 6.5 miles per gallon (MPG), suggests more research is needed.

BMW’s Hydrogen 7 can travel 125 miles on hydrogen and 300 on gasoline before refueling. In tests the BMW 745h liquid-hydrogen test vehicle has 75 kg tank has a Hydrogen Fuel Efficiency of 10 km/liter or about 25.2 MPG and cruising speed of 110 MPH. Not too bad for an internal combustion engine that is able to run on gasoline or hydrogen.

Figure 1 Specific Energy

Given the changes to hydrogen’s energy density we are also adjusting hydrogen density (Figure 2) to reflect liquid hydrogen and high-energy value as noted by Hydrogen Properties College of the Desert.

Revised Figure 2 Energy Density: KWH per Gallon

We still have more questions given hydrogen’s very high specific energy, (3 times that of gasoline) and low energy density (4 times the volume of gasoline). Hydrogen is more efficient then petroleum fuel, yet when used as a fuel cell in a vehicle Honda’s MPG of 6.5 MPG is quite low. The fuel efficiency of BMW’s Hydrogen 7 of 25.2 MPG is only at parity with gasoline.

The efficiency of using solar energy to generate hydrogen may not be the most efficient method. One report from Walt Pyle, Jim Healy, and Reynaldo Cortez Solar Hydrogen Production by Electrolysis indicated that a 1-kilowatt solar photovoltaic device could generate 1 cubic meter of hydrogen in 5.9 hours. Essentially, 5.9 KWHs from a 1KW solar cell produces 1 cubic meter of hydrogen. We know that a pound of hydrogen in liquid state equals approximately 61,000 BTUs (51,500 BTUs at low heat value) or 17.9 KWH.

Research at Caltech, suggests that photoelectrochemistry The Lewis Group may offer a more efficient means of generating hydrogen. We will continue to explore solar efficiency and hydrogen fuel cells to evaluate the economics of alternative energy.

The bottom line is that our dependence on foreign oil is the biggest threat to national security and without cultivation of alternative energies we continue to endure an untenable situation. Further research into solar and hydrogen fuel cells could significantly ameliorate our dependence on oil.

Despite efforts that have enabled the U.S. to limit its demand for oil, world oil demand is up significantly. Advances in technology such as solar energy and vehicle fuel cell could help the world reduce its dependence on oil.

Figure 1 Oil and Gold Prices

The U.S. Department of Energy (DOE) and the U.S. Environmental Protection Agency (EPA) today released the Fuel Economy Guide for 2008 model year vehicles Fuel Economy Leaders: 2008 Model Year Coming in first place is the Toyota Prius (hybrid-electric) with city/highway miles per gallon (MPG) of 48/45. With higher fuel costs more people are factoring in fuel efficiency into their purchase decision. However, it is the purchase of pickup trucks and SUV that account for most of the vehicle purchases in the U.S. and these vehicles are dramatically less fuel-efficient than hybrids and small four-cylinder automobiles.

Despite the trend towards larger vehicles, the U.S is not experiencing a rapid rise in oil demand. Yet oil prices continue to climb. While geopolitical risk may account for the bulk of the recent price increase, latest information from the U.S. Energy Information Administration (EIA) Total Petroleum Consumption shows increasing oil demand from China.

Figure 2 Oil Demand: U.S. and China

Figure 2 illustrates that while oil demand in the U.S. has grown only modestly since 2000, the growth in China’s oil demand is rising rapidly. The recent data from the EIA shows oil demand through Q2/07. The demand for oil in the U.S. is up 5% from 2000 while in China oil demand is up 59% over the same period.

Improving vehicle fuel efficiency may abate rapidly rising oil demand in the U.S., but more emphasis on diesel and hybrids could take us a lot further. For example, Toyota has been slow to introduce its diesel line of pickup trucks in the U.S. while it offers a broad line of more fuel-efficient vehicle outside the U.S. Toyota offers several cars and trucks in Europe with impressively high fuel efficiencies that are not available in the U.S. Infact, the Toyota Hilux two-wheel drive pickup truck offers a four-cylinder diesel engine with an MPG of 44.8 on the highway and 29.1 in the city.

We are also seeing progress on fuel cell vehicles that could ultimately ameliorate are demand for oil, if not eliminate it entirely, all with no carbon dioxide or other emissions. We see most major automakers developing hydrogen powered fuel cell vehicles. Honda for one has the right concept in employing solar energy to make hydrogen.

Honda’s experimental hydrogen refueling station in Torrance, CA increases the solar incre3ases the efficiency of hydrogen fuel by using solar energy to produce hydrogen. The hydrogen is then used to power Honda’s Honda’s FCX concept hydrogen fuel cell vehicle with the only emission being pure water vapor. These fuel cell vehicles may not be ready for prime time, they provide a clear reality to what is achievable.

The bottom line is that supply and demand dictate price and the availability of cheap oil is on the decline. Further research into solar and hydrogen fuel cells could significantly change our dependence on oil.

The U.S. Department of Energy (DOE) is quite correct in suggesting that if every household in the U.S. substituted a 100-watt standard light bulb for a Compact Fluorescent Light bulb (CFL), it would eliminate an amount of carbon dioxide (CO2) equivalent to one million automobiles. However, it is the bigger picture that matters, – motor vehicles contribute the most to CO2 emissions. We must not forget that by focusing on CO2 emissions, they are admitting that CO2 is a real issue that potentially leads to global warming and climate change.

Let’s look at some facts about our carbon footprint. A 100-watt light in operation for 13.3 hours produces approximately one pound of CO2 when the electricity is generated by coal. Coal has significantly higher carbon emissions per kilowatt-hour (KWH) than oil or gas. Please see Carbon content of fossil fuels . Coal generates about half the electric power in the U.S. and produces roughly ¾ of a pound of CO2 for every KWH of electric. That means for every 1.3 KWH of electricity used (a 100-watt light used for 13.3 hours) we produce 1 pound of CO2. And remember it’s the oxygen in the air that contributes nearly 73% to the weight of CO2. This is why more CO2 is created than the actual weight of the fuel.

Using the same fuel emissions data, a motor vehicle with an average fuel efficiency of 22 miles per gallon (MPG), produces approximately 90 pounds of CO2 for every 100 miles driven. A gallon of gasoline produces nearly 20 pounds of CO2. That equates to one pound of CO2 for every mile driven by an SUV with a fuel efficiency of 19 MPG. (19.9 pounds/gallon times 1 mile divided by 19 MPG)

While it makes sense to address the issue of CO2 emissions, particularly as coal accounts for half of electric power generation and has higher CO2 emissions per KWH than oil, the real issue is an energy plan that givers us energy independence. Energy independence should equate to national security.

With the rapid growth in vehicle use around the world, it would be nice to know what are the most efficiency, economic, and least carbon emitting fuels. The number of motor vehicles on the road is increasing rapidly. The number of cars and trucks in China is up over 3,600 percent in the last thirty years. Data from the U.S. Department of Energy (DOE) and Ward’s Communications, Ward’s World Motor Vehicle Data provide an interesting view of the growth in motor vehicle use.

Figure 1 China Truck and Car Registration

While the U.S. still accounts for the largest motor vehicle market, the rest of the world is quickly accelerating towards more vehicles on the road. Figure 2 shows the number of vehicle registrations over the last thirty years for China, the U.S. and the rest of the world (ROW). Vehicle registration growth in the U.S. has been growing at a 2% per year rate from 1975 to 2005. The largest growth in vehicle registration is in China and India where growth in the last ten years is up 195% and 99%, respectively.

Figure 2 World Vehicle Registration

With an explosion in motor vehicle use, what fuel should we be using to better performance and reduce emissions? Let’s go back to two basic concepts of energy: Specific Energy and Energy Density. For a quick review, (Molecular Weight Calculator) the specific energy of a fuel relates the inherent energy of the fuel relative to its weight. Specific energy is often measured in kilo-joules per gram (kj/g). One kilo-joule equals one kilowatt-second meaning one kilowatt-hour (KWH) equals to 3,600 kilo-joules. Also one British Thermal Unit (BTU) equals 1,055.05585 joules. A reference to the specific energy and energy values of most fuels can be found at Hydrogen Properties

Figure 3 Specific Energy

By specific energy hydrogen is the clear leader. However, vehicles must inherently carry their fuel supply, so to determine which fuel is best for motor vehicles, energy density of the fuel is the next measurement. While vehicle fuel efficiency is dependent upon a number of factors such as engine type and performance, make and model of vehicle, road conditions and fuel, we are focusing on fuel energy.

Figure 4 Energy Density: KWH per Gallon

Figure 4 illustrates how fuels compare with respect to energy density, that is, energy relative the container size. We again are using KWH to measure energy value. Hydrogen, because it is so light, requires 15.9 times the container volume to provide the same energy as diesel. Biodiesel provides more power per gallon than Ethanol, which requires 1.6x, the container size for the same amount of energy as diesel. Biodiesel and diesel are relatively similar with respect to energy density. While both Ethanol and Biodiesel are both form of renewable energy, Biodiesel offers more bang per gallon. Before we are able invest more into hydrogen and solar energy to bring alternative energy into parity with conventional hydrocarbon fuels, diesel and biodiesel offer better energy efficiency among hydrocarbon fuels.

Table 1 Specific Energy, Energy Density & CO2

As a final assessment of hydrocarbon fuels, let’s compare carbon dioxide (CO2) emissions among our list of fuels. CO2 emission is a function of carbon concentration and combustion process of the fuel. Fuel energy research at the Department of Environmental Protection (EPA) and DOE indicate 99% to nearly 100% combustion of with fuels used in vehicles. That means almost all of the atoms in the fuel are converted to either heat or byproducts such as CO2.

Figure 5 illustrates how much CO2 is produced per gallon of fuel. Remember the molecular weight of CO2 is about 44 with oxygen contributor nearly 73% of the weight and is taken from our atmosphere during combustion. This is why more CO2 is created than the actual weight of the fuel. A second factor needs to be considered when evaluating CO2 emission and that is how much CO2 is produced per energy value. In comparing CO2 emissions per KWH of energy, Ethanol produces about 7% less CO2 than diesel or Biodiesel and 5% less than gasoline. Neither of these estimates considers the emissions from the processing to produce Ethanol or Bioiesel.

Figure 5 CO2 per Gallon

The bottom line is Ethanol and Biodiesel provide marginal relief to our energy crisis with biodiesel offering better efficiency and Ethanol marginally less CO2 missions. The only real solution to our imminent energy crisis is alternative energies such as solar, hydrogen fuel cells, and wind.

With oil prices over $80 per barrel, the National Energy Assistance Directors’ Association in its press release today Record Home Heating Prices for Heating is expecting the average home heating cost for the ’08-’08 season to rise 9.9%. For homeowners using oil heat, heating costs are expected to increase 28% and for homes using propane, a 30% increase is expected.

With rising energy costs driven by costly oil extraction, the potential impact from carbon emissions with our continuing use of oil on climate change and rising sea levels, as well as the potential for fuel supply disruptions, could exacerbate our tenuous relationship with energy.

Eventually, as price rise dramatically, alternative energy becomes more compelling. The problem is our economy is so inextricably link to oil, that our energy security is based on securing foreign oil.

Figure 1 Oil Prices and Home Heating Costs

Without support and research on alternative energies such as solar and fuel cell technologies, we are hostage to oil. The U.S. economy is facing one of the most crises since the Oil Embargo of the 1973. Inflation driven by escalating oil prices is impacting the cost of home heating, transportation, production, materials, and food, particularly as corn is diverted to ethanol production. The housing market is in turmoil with falling home values, rising foreclosures, and a credit crisis that is making it more difficult to secure a mortgage may lead to slower consumer spending. With rising inflation and slower growth we may find ourselves in an economic world described as stagflation that was coined in the ’70’s to describe the bleak environment when gas stations rationed fuel, unemployment grew and the Federal Reserve raised rates dramatically to quell inflation.If we could limit our dependence on foreign oil through investment into solar energy and fuel cell technologies, we would not be impacted by the exogenous events in oil producing nations.

We believe there are a number of catalyst that could serve to dramatically lower the cost of alternative energies. It takes initiatives from all of us to change the balance. After all, oil is becoming more costly to extract, new oil discoveries are in difficult and challenging environments, and oil will eventually run out – it is finite. If we wait to long, our ability to make a difference may not be available.

Without greater investment into solar and hydrogen energies, we are held hostage to rising oil prices. Alternative energies such as solar and hydrogen fuel cells offer tremendous potential to provide energy independence and energy security. The dependence of the U.S. upon imported foreign oil raises inflation, weakens our currency, exacerbates the trade deficit, and forces consumers to pay higher prices for home heating and transportation. With oil exceeding $80 a barrel in late September 2007, the only beneficiaries are countries exporting oil and oil conglomerates. I guess when countries such as Dubai, after accumulating a large trade surplus based on inflated oil prices, decides to diversify away from oil and buy a non-voting stake in the NASDAQ market, it’s a wake-up call.

To better understand the potential of alternative energy, we should try to understand two basic concepts of energy: Specific Energy and Energy Density. Without digressing into chemistry 101, (Molecular Weight Calculator) the specific energy of a fuel relates the inherent energy of the fuel relative to its weight. Typically, specific energy is measured in kilo-joules (kj) per gram. A joule is a measure of kinetic energy – one joule is the amount of energy needed to move two kilograms at a velocity of one meter per second. Or a kilo-joule equals one kilowatt-second meaning one kilowatt-hour (KWH) equals to 3,600 kilo-joules. Your local electric utility bills you by the KWH, which according to the US Department of Energy Average Retail Price of Electricity in 2007 is approximately $0.11 per KWH.

Table 1 Specific Energy and Energy Density

The specific energy of a fuel tells us how much energy can be derived from a measured amount fuel by weight. By ranking each fuel by its specific energy, one can determine how efficient each fuel is. Specific energy and fuel density are often proportional to the ratio of carbon and hydrogen atoms in the fuel. A reference to the specific energy and energy values of most fuels can be found at Hydrogen Properties

Figure 1 Specific Energy
Figure 1 illustrates how fuels compare according to their specific energy. As we can see, hydrogen, because it’s extremely light, has the highest specific energy in comparison to hydrocarbon fuels.

This however, is not the full story because volume or energy storage requirement becomes a significant factor for gaseous fuels. Specific energy is important to analyze fuel efficiency by weight, but for hydrogen that must be pressurized and cooled to bring to a liquid state, the energy density become more relevant to fuel efficiency.

Figure 2 Energy Density: KWH per Gallon

Figure 2 illustrates how fuels compare according to their energy density, that is, energy relative the container size. As we can see from figure 2, hydrogen, because it is so light, requires 15.9 times the container volume to provide the energy of diesel or oil. In comparison to diesel, ethanol requires 1.6x the container size for the same amount of energy.

The container size becomes a significant detriment for housing hydrogen. Energy density is usually measured in kilo-joules per cubic meter (kj/m3). As kilo-joules are readily translated into KWH by multiplying by the number of seconds in an hour (3,600) and the College of the Deserts’ computation into gallons, we are converting the data into KWH per gallon for those of us in the U.S.

Hydrogen fares poorly relative to energy density. However, technology offers an approach to enhance the benefits of hydrogen with fuel cells. Fuel cell enable hydrogen molecules to interact with oxygen through a membrane that allows transmission in only one direction to convert H2 into an electric current to power your automobile. Fuel Cell Basics Fuel cells often capture the hydrogen electron from hydrocarbon fuel such as methane allow convention fuels to generate hydrogen for electric generation.

In a hydrogen-based economy, solar energy can provide electric to generate hydrogen through electrolysis and vice versa. Jeremy Rifkin’s The Hydrogen Economy eloquently illustrated the hydrogen economy where fuel cell act as mini power plants and the electric network resembles the Internet where cars plug into an electrical grid supplemented by solar cells at your home and work. Electric power generation moves from large utility generation to a distributed generation – everyone plugged in can generate power to the grid. The key benefit of hydrogen is that it democratizes the energy economy bringing power to all countries in the world.

An interesting technical analysis of hydrogen energy is provided by Ulf Bossel and Baldur Eliasson Energy and the Hydrogen Economy The bottom line is that solar and hydrogen energies offer tremendous potential to low long-term fuel costs and improve our environment and climate. More research is required to lower costs and improve feasibility.

There is considerable variance in calculating the cost of solar energy. Using U.S. Solar Radiation Resource Maps from the National Solar Radiation Data BaseThe (NSRDB) we found the amount of kilowatt-hours (KWH) per days of solar radiation per square-meter varies from less than two for Northern Alaska to six KWH/m2 per day for parts of Arizona. Using these maps we found that the cost of solar varies from $0.23-to-$0.68 per KWH with a mean of approximately $0.45 per KWH. The cost of $0.23 per KWH equates to Arizona and $0.68 per KWH reflects the cost of the lower solar radiation in Anchorage, Alaska. These cost are based on data from solar photovoltaic (PV) supplies before tax benefits or rebates. Please see SunPower (SPWR) and Sharp Solar.

Green Econometrics provided a normalized solar energy cost per KWH of $0.38-to-$0.57 with a mean cost of $0.45 as reference for what most of the U.S. would expect for solar energy. We have referred to the Lewis Group at Caltech which has provided estimates of $0.25-to-$0.50 per KWH for the cost of electric production from solar with a mean of $0.38 per KWH. According to Solarbuzz the average price of solar electric is approximately $0.38 per KWH. The Solarbuzz index is based upon an average of 5.5 hours of sunshine per day over a year, which relates to locations such as the US Sunbelt, Latin America, Africa, the Middle East, India and Australia. With large U.S. populations still residing in the North, we would still expect the average home in the U.S. to be paying closer to $0.45 per KWH.

There are a number of factors to consider such as total system cost, the use of concentrators and tracking systems to align the solar panel to be perpendicular with the sun during the day and the property location. There are factors to consider with property location such as whether the roof is facing south or towards the east or west. If the system rests on the ground, shading from building or trees becomes a factor. Other considerations include latitude, climate, weather, and time of day, season, local landscape, and temperature. The Department of Energy provides some information for home owners considering a solar energy system Small Solar Electric Systems

The cost for solar energy systems refers to the average efficiency of solar photovoltaic (PV) panels. The average efficiency for PV devices is between 15%-to-16%. According to SunPower, which has the leading PV device efficiency of 22% there is a practical limit to solar efficiencies of approximately 30%. SunPower is targeting a 23% solar efficiency as a goal to reduce its solar energy system cost by 50% by 2012. Sanyo is second with solar efficiency of 18%. SunPower claims to have patented solar PV architecture and production processes that enable the company to command a lead in solar efficiency.

For solar energy systems below 5 kilowatts, the cost of the inverters represents a substantial part of the system cost. An inverter is used to convert the direct current (DC) from the solar panels to alternating current (AC) used in your home. Inverters can cost from $400-to-$700 per 1000 watt adding to the total cost of deploying small solar energy systems. See Wholesale Solar