Extreme Energy Inefficiency from Generator Conversion
I've been looking into an emergency backup energy source for my home. Over the past several days, I've explored various websites, read books and pamphlets, and visited local stores that specialize in backup home power. In the process, I seem to have discovered something about how much energy is wasted in converting chemical energy to electrical energy.
Take for instance a single gallon of gasoline. In this one gallon, purchased today for $3.29 US, there is an energy content around 112,500 British Thermal Units (BTU) (1). BTU is but one of any number of different measures of energy. Food Calories are a very familiar measure of energy, as is Kilowatt-Hour (KWH) which is used to measure electrical energy.
Let's see how these measures of energy relate to a gallon of gasoline.
One U.S. Gallon of Gasoline
The energy content of a gallon of gasoline is 33.0 KWH. The energy loss in the process of releasing the chemical energy in the gasoline and converting it into alternating (AC) electrical energy is about 83%.
I'll say that again, 83% of the energy in the gasoline is NOT converted to electricity. Only 17% is used for the desired purpose.
I find that shocking. It is like going to the grocery store to get some food, taking out $100 at the ATM, and only having $17 left by the time I get to the cash register.
Let's look at another example, this time with another fuel, liquid propane gas (LPG).
One U.S. Gallon of Propane LPG
Compare this produced to the 26.7 KWH content of the fuel. Again, the loss is about 83% of the energy content, leaving on 17% actually converted into electricity.
With peak oil near upon us, I wonder, is that the best we can do? I suspect that the conversion rate in automobiles is about the same (4), and it is probably similar when we burn coal to generate our electricity.
Is there another method or technology that would allow us to convert the energy more completely into the form we want?
The worst part about generators is that most are unable to reduce their fuel comsumption below a certain mark amount, so even if the electrical demand is only 1.5 watts from an LED reading lamp, the generator still burn a gallon of gasoline in 14 hours. That is to say that 14 hours X 1.5 watts = 21 watt-hours of energy used by consuming 33,000 watt-hours of gasoline energy. In this case, the energy loss is more on the range of 99.9%, with only 0.01% being used.
In order to avoid this level of inefficiency, the generator can be used to charge deep cycle batteries, which are the primary energy source for the house. (This is very similar to the full hybrid technology used on vehicles such as the Toyota Prius and the Ford Escape Hybrid.) The advantage of the battery is that if it only needs to provide the home with 1.5 watts, then it will only use that much energy. While this does not avoid the initial 83% loss, it does help to ensure that the losses do not exceed this already large percentage.
Let's be honest, we have past the era of increasing energy supplies, and are now beginning the gradual, or perhaps rapid, decline. It is essential that we focus on exploring new ways to convert energy from one form to another with improved efficiency, so we can make a smooth transition from this era to the next.
.....
Endnotes:
1. The EIA of the US-DOE states up to 125,000 BTU, but the formulation and ethanol mix can decrease the BTU.
2. When generating between 25% and 100% of rated load of 1600 watts.
3. When generating between 50% and 100% of rated load of 7000 watts.
4. One source claims that 20% efficiency is achieved in automobiles.
References:
http://www.onlineconversion.com/energy.htm
http://www.uwsp.edu/cnr/wcee/keep/Mod1/Whatis/energyresourcetables.htm
http://mb-soft.com/public2/engine.html
Take for instance a single gallon of gasoline. In this one gallon, purchased today for $3.29 US, there is an energy content around 112,500 British Thermal Units (BTU) (1). BTU is but one of any number of different measures of energy. Food Calories are a very familiar measure of energy, as is Kilowatt-Hour (KWH) which is used to measure electrical energy.
Let's see how these measures of energy relate to a gallon of gasoline.
One U.S. Gallon of Gasoline
- BTU = 112,500
- Calorie = 28,350
- KWH = 33.0
The energy content of a gallon of gasoline is 33.0 KWH. The energy loss in the process of releasing the chemical energy in the gasoline and converting it into alternating (AC) electrical energy is about 83%.
I'll say that again, 83% of the energy in the gasoline is NOT converted to electricity. Only 17% is used for the desired purpose.
I find that shocking. It is like going to the grocery store to get some food, taking out $100 at the ATM, and only having $17 left by the time I get to the cash register.
Let's look at another example, this time with another fuel, liquid propane gas (LPG).
One U.S. Gallon of Propane LPG
- BTU = 91,000
- Calorie = 22,900
- KWH = 26.7
Compare this produced to the 26.7 KWH content of the fuel. Again, the loss is about 83% of the energy content, leaving on 17% actually converted into electricity.
With peak oil near upon us, I wonder, is that the best we can do? I suspect that the conversion rate in automobiles is about the same (4), and it is probably similar when we burn coal to generate our electricity.
Is there another method or technology that would allow us to convert the energy more completely into the form we want?
The worst part about generators is that most are unable to reduce their fuel comsumption below a certain mark amount, so even if the electrical demand is only 1.5 watts from an LED reading lamp, the generator still burn a gallon of gasoline in 14 hours. That is to say that 14 hours X 1.5 watts = 21 watt-hours of energy used by consuming 33,000 watt-hours of gasoline energy. In this case, the energy loss is more on the range of 99.9%, with only 0.01% being used.
In order to avoid this level of inefficiency, the generator can be used to charge deep cycle batteries, which are the primary energy source for the house. (This is very similar to the full hybrid technology used on vehicles such as the Toyota Prius and the Ford Escape Hybrid.) The advantage of the battery is that if it only needs to provide the home with 1.5 watts, then it will only use that much energy. While this does not avoid the initial 83% loss, it does help to ensure that the losses do not exceed this already large percentage.
Let's be honest, we have past the era of increasing energy supplies, and are now beginning the gradual, or perhaps rapid, decline. It is essential that we focus on exploring new ways to convert energy from one form to another with improved efficiency, so we can make a smooth transition from this era to the next.
.....
Endnotes:
1. The EIA of the US-DOE states up to 125,000 BTU, but the formulation and ethanol mix can decrease the BTU.
2. When generating between 25% and 100% of rated load of 1600 watts.
3. When generating between 50% and 100% of rated load of 7000 watts.
4. One source claims that 20% efficiency is achieved in automobiles.
References:
http://www.onlineconversion.com/energy.htm
http://www.uwsp.edu/cnr/wcee/keep/Mod1/Whatis/energyresourcetables.htm
http://mb-soft.com/public2/engine.html