Archives August 2007

How to measure fuel efficiency, energy costs, and carbon emissions for home heating

To measure the efficiency of conventional hydrocarbon fuels, we need a common measure of energy. The Kilowatt-Hours (KWH), the billing quantity of electric usage, serves as a useful measure of energy because we can equate KWH to engine horsepower performance, heat energy of a fuel, and compare energy costs on a common level. KWH can be used to determine which fuel is most efficient by measuring the heat output of each fuel.

A BTU is the amount of heat necessary to raise one pound of water by one degree Fahrenheit and each fuel has its own BTU measure. For example, one ton of coal produces about 21.1 million BTUs, which would equate to 6,182 KWH. One KWH equals 3,413 BTUs.

A framework to measure energy costs is to convert each fuel type into KWH of energy. Some helpful links to common fuel conversions Energy Units and Conversions KEEP, BTU by Tree, and Fuel BTUs

We want to establish common energy measure to evaluate home heating fuel efficiency for each fuel type. Our first step is to measure the BTU value for each fuel type. The next step is to divide the BTU value for each fuel by 3,413 to arrive at its corresponding KWH energy value.

Kilowatt-Hour per Unit of Fuel
The energy value of a unit of fuel depends on its mass, carbon and hydrogen content, and the ratio of carbon to hydrogen. In general, hydrogen generates approximately 62,000 BTU per pound and carbon generates around 14,500 BTUs per pound. The combustion process is complex and while higher hydrogen content improves energy BTU levels, not all hydrogen goes to heat. Some hydrogen combines with oxygen to form water. Coal Combustion and Carbon Dioxide Emissions

Energy Comparison
1 pound of wood = 6,401 BTUs = 1.9 KWH
1 pound of coal = 13,000 BTUs = 3.8 KWH
1,000 cubic foot of natural gas = 1,000,021 BTUs = 299 KWH
1 gallon of oil = 138,095 BTUs = 40.5 KWH
1 gallon of propane = 91,500 BTUs 26.8 KWH

Figure 1a Kilowatt-Hours per Pound
KWH per Pound

As seen from figure 1, natural gas provides the highest efficiency level followed by oil. Wood offers the lowest efficiency per pound at 1.9 KWH/lb and is followed by coal with twice the efficiency at 3.8 KWH/lb. Oil offers almost a 70% efficiency improvement over coal and propane is just slightly more efficient than coal.

Fuel Energy Efficiency
Wood = 1.9 KWH per pound
Coal = 3.8 KWH per pound
Natural Gas = 6.9 KWH per pound (liquid and gas measures are calculated at 6.3 pounds per gallon)
Oil = 6.4 KWH per pound
Propane = 4.3 KWH per pound

This is not the full story. While the energy efficiency of the fuel is important, a lot depends on the fuel efficiency of the stove or furnace that is used to heat your home. The heating efficiency of your stove or furnace has a substantial impact on the overall efficiency of the fuel’s heat value. The adjusted KWH in figure 1 indicates the fuel efficiency adjusted for the efficiency of the heating system. There is also some variance in the fuel efficiency given impurities, temperature, and water presence.

Adjusted Fuel Energy Efficiency
Wood @ 1.9 KWH per pound and stove efficiency of 70% equals 1.3 KWH/lb
Coal @ 3.8 KWH /lb and stove efficiency of 70% = 2.7 KWH/lb
Natural Gas @ 6.9 KWH /lb and furnace efficiency of 95% = 6.5 KWH/lb
Oil @ 6.4 KWH /lb and furnace efficiency of 85% = 5.5 KWH/lb
Propane @ 4.3 KWH /lb and furnace efficiency of 95% = 4.0 KWH/lb

Figure 1b Kilowatt-Hours per Kilogram
KWH/kg

Figure 1b proves the same fuel types measured by liters and kilograms. While the absolute numbers are different, the relative fuel efficiency among the fuels is the same.

Energy Economics

The final phase of our fuel efficiency exercise is to compare an economic measure of fuel cost. The market price of fuel will vary by location, usage amount, and market conditions. Our prices were quarterly average U.S. energy prices by fuel type:
Natural Gas Prices, , Oil Prices, and Propane Prices
Coal and wood prices were based on local residential delivery.

Figure 2 Cost per Kilowatt-Hours
Energy Costs

Coal and wood are among the lowest priced fuels. However, coal and wood require extensive hands-on control and cleaning which are not factored into costs. Natural gas is offered in many urban areas and is currently priced below oil or propane. Natural gas offers higher energy efficiency and is priced lower than oil or propane, but is not available in all urban markets and very limited rural availability.

The trade off between oil and propane, which can be found in most markets, is operating efficiency and maintenance. Modern oil furnaces are demonstrating higher operating efficiencies, but cost significantly more than propane. Oil does offer higher efficiency than propane, but maintenance costs are higher for oil furnaces and that cost is not reflected in these fuel costs measures.

Electric heat in some markets where utility rates are below oil or gas may offer favorable economics, but electric rates might be going higher as utilities switch to lower carbon emission fuels. The challenge is to migrate electric utilities from lower-priced coal with high CO2 emissions to natural gas with lower carbon emissions. The cost to lower CO2 emissions from coal burning utilities could force natural gas prices to rise. The bottom line is that energy prices will continue to rise with natural gas tide to oil production. Even with higher fuel prices, there is still a tremendous disparity between conventional and alternative energies with the cost of solar near $0.38 per KWH and residential electric rates of $0.11 per KWH.

Carbon Economics

Emission of CO2 from hydrocarbon fuels depends on the carbon content and hydrogen-carbon ratio. When a hydrocarbon fuel burns, the carbon and hydrogen atoms separate. Hydrogen (H) combines with oxygen (O) to form water (H2O), and carbon (C) combines with oxygen to form carbon dioxide (CO2).
How can a gallon of gas produce 20 pounds of CO2

From this example, a carbon atom has an atomic weight of 12, combines with two oxygen atoms each with a weight of 16, to produce a single molecule of CO2 an atomic weight of 44. To measure the amount of CO2 produced from a hydrocarbon fuel, the weight of the carbon in the fuel is multiplied by (44 divided 12) or 3.67.

Wood has half the carbon content than coal, but coal is twice as efficient as wood and therefore both have nearly the same high level carbon footprint. Oil benefits from having higher energy efficiency than propane giving oil 30% lower CO2 emissions pound for pound.

Figure 3 Pounds of CO2 by Fuel Type
Component Costs

Natural gas, because of its low carbon content and high fuel efficiency, achieves lower CO2 emissions than oil, propane, or coal. Natural gas produces 46% less CO2 than coal and 10% less than oil. With coal relatively abundant and cheap in comparison to oil or natural gas, energy prices may increase as electric utilities switch to lower CO2 emission natural gas or invest into emission reduction processes that add to capital costs and operating expense.

Understanding the Cost of Solar Energy

In comparison to conventional hydrocarbon fuels such as coal or oil in generating electricity, the cost of solar energy is significantly higher. To compare energy cost, a common equivalent is required. Back in our previous post, Coal: Fueling the American Industrial Revolution to Today’s Electric, we developed a framework to measure energy costs by converting costs to kilowatt-hours (KWH).

In our example, a ton of coal on the average produces approximately 6,182 KWH of electric at a cost of about $36 per short ton (2,000 pounds). Under this measure coal cost less than$0.01 per KWH. In comparison, a barrel of oil at $70/barrel produces 1,700 KWH at a cost approximately $0.05 per KWH. Let’s provide some measures to understand energy costs.
Energy Units and Conversions KEEP

Energy Comparison
1 ton of coal = 6,182 KWH
1 barrel of oil = 1,699 KWH
1 cubic foot of gas = 0.3 KWH

Energy Costs
1 ton of coal costs $36 = $0.006 per KWH
1 barrel of oil costs $70 = $0.05 per KWH
1 cubic foot of gas $0.008 = $0.03 per KWH

In comparison to solar energy, the hydrocarbon fuel costs are significantly lower without rebates, tax benefits nor the cost of carbon emissions. A two–Kilowatt (KW) solar energy system costs about $45,000 and covers roughly half of a typical American household’s energy needs. At $45,000, a solar energy system equates to $9,000 a kilowatt. The $9,000 per KW for solar is not very helpful in comparing electric generation costs to other fuels like coal or gas. Since coal, oil, and gas can be measured on a cost per KWH, we should measure solar costs on a KWH basis.

Some of the considerations for a solar energy system include the 20-to-30 year lifespan of the system and the hours of available sunlight. The hours of available sunlight depends on latitude, climate, unblocked exposure to the sun, ability to tilt panels towards the sun, seasonality, and temperature. On the average, approximately 3.6 peak sunlight hours per day serves as a reasonable proxy to calculate the average annual output of electric from solar energy panels.

Solar Energy Costs
Average system costs = $95 per square foot
Average solar panel output = 10.6 watts per square foot
Average solar energy system costs = $8.95 per watt

In order to compare the solar energy costs to conventional hydrocarbon fuels, we must covert the $8.95 per into KWH. Let’s make two calculations to measure the total electric energy output over the lifespan of the solar energy system. The first adjustment is to convert solar direct-current (DC) power to alternating current (AC) power that can be used for household appliances. The conversion of DC to AC power results in an energy loss of 10 percent for a solar energy system. The second calculation is to approximate total electric output by multiplying the average peak hours of sunlight (about 3.63 hours per day) times 365 days times 20 years (the product lifespan).

For our 5-KW solar energy system costing $45,000, the conversion to KWH is as follows:

5 KW times 90% = 4.5 KW – (Conversion of DC to AC power)
4.5 KW times 3.63 hours = 16 KWH per Day
16 KWH x 365 = 5,962 KWH – (Average Annual Output)
5,962 KWH x 20 years = 119,246 KWH – (Total output over 20 year lifespan)

So a $45,000 5KW solar energy system produces about 119,246 KWH of electric over its lifespan meaning the average cost equals $0.38 per KWH. ($45,000 divided by 119,246 KWH)

Figure 1 Cost of Energy
Energy Costs

The relatively high solar energy costs in comparison to conventional fuels should improve with utility rebates and government tax incentives. In addition, solar panel prices should continue to decline as volume production increases. Solar cell manufacturers employ similar production methods as semiconductor suppliers and benefit from economies of scale.

There are several components of a solar energy system. Solarbuzz provides some detailed information on solar industry pricing. Solarbuzz
The single largest cost is the solar panels themselves. The following figure provides an overview of the components of a solar energy system. Sharp Solar provides a very useful calculator for system costs and electric generation by geographical location along with utility rebates for your area. Sharp Solar Energy

Figure 2 Solar Energy Component Costs
Component Costs

We will explore the some of the advances in thin-film technologies, the declining costs of solar panels, and the improving solar conversion efficiencies that should continue to bring solar energy costs on par with hydrocarbon fuels. With the improving cost structure of solar and a better understanding of the cost of carbon emissions from hydrocarbon fuels, we may find a more level playing field in comparing energy costs.

Coal: Fueling the American Industrial Revolution to Today’s Electric

Why the economics of coal helps us better understand the benefits of wind and solar energy

On August 8, 1829, the Stourbridge Lion made entry as the first American steam locomotive in Honesdale, PA initiating the American Railroad. The steam locomotive railroad was the first developed to transport Anthracite coal mined in nearby Carbondale, PA to a canal in Honesdale, linking to the Hudson River in New York.

Coal as fuel energy has had an early use in American history with the 50 tons dug in 1748. Coal 1748 The history of coal dates backs to 2,000 BC and for oil it is even longer. Coal was cheaper and more efficient than wood. Coal was also more efficient to run most steam-powered engines, but was costly to transport and mine.

In terms of heating efficiency, coal offers almost double the energy, pound for pound, in comparison to wood. Energy Units and Conversions KEEP
Coal was difficult to mine and transport so engineers in America during the Industrial Revolution faced many challenges. Anthracite coal commanded a premium price because it emitted less smoke, was harder and contained more carbon giving it more fuel content than softer Bituminous or Lignite coals. There are several types of coal along a hard-to-soft classification. The makeup of coal changes according to compounds of lower hydrogen content and higher carbon – types of coal. Coal Ash Research Center University of North Dakota
The Anthracite coal deposits in Northeastern, PA are the largest deposit in the U.S. The gravity railroad linking Carbondale to Honesdale was an example of capital, knowledge, and technology meeting the growing need for energy.

Figure 1 Gravity Railroad
Gravity Railroad

Coal was an important component for commerce and heating. With access to the large Anthracite coal deposits in Northeastern, PA, New York City gained an advantage over competing port cities like Boston and Philadelphia. It was the energy infrastructure of the railroad and canal transportation network that enabled New York to access coal. Essentially, coal provided the fuel for the Industrial Revolution and New York City’s ability to access coal to meet the needs of its growing population and commerce was critical to the city’s success. Honesdale, PA was named in honor of then mayor of New York. Wayne County Historical Society

To understand the economics of coal let’s start with a measurement of energy. One ton of coal is equal to 16.2-to-26 million BTUs (British thermal units) of energy. A BTU is the amount of heat necessary to raise one pound of water by one degree Fahrenheit.

What is the economical value of a BTU? A common metric we should understand, particularly when we pay our utility bills is the kilowatt-hour – the amount of electricity consumed per hour. The KWH can be used to compare the efficiency and cost of wood, coal, oil, and gas. Also we can equate KWH to horsepower and have a common measure between energy usage and costs for our home and car.

Let’s convert fuel energy into a common equivalent. One-kilowatt hour (KWH) equals 3,413 BTUs. One ton of coal produces, on the average, 21.1 million BTUs, which equals 6,182 KWH of electric at a cost of about $36 per short ton (2,000 pounds). That means coal cost less than$0.01 per KWH. To put that into perspective, a barrel of oil at $77/barrel produces 1,700 KWH of electric equating to 60% higher efficiency pound for pound than coal. However, on a cost per KWH basis, oil cost about $0.05 per KWH. Coal’s lower cost per KWH is why it is still used today to generate electric.

Today, the Moosic Mountains who’s 1,940 foot pass became a formidable engineering challenge for transporting coal from Carbondale to Honesdale is adorned with wind mills from Florida Power & Light providing 64.5 megawatts of electric, enough to power 22,000 homes. Florida Power & Light
(FPL) is the largest generator of wind energy in the U.S. The irony is the mountain range with the largest deposits of Anthracite coal in the world and first used to provide electric to New York City, is now hosting windmills to generate electricity for homes and businesses.

Figure 2 Wind Energy
Waymart Wind Energy Center

FPL is one of the growing list of utilities that are adopting alternative energy including wind energy programs in 15 states and offering rebates up to $20,000 for solar photovoltaic residential systems and up to $100,000 for commercial systems. The windmills atop Moosic Mountains produce electric replacing 3,800 tons of coal a year. A ton of coal produces 746 kg (1,644 lb.) carbon, so the windmills save our atmosphere from about 3,131 tons of CO2. The incremental increase in CO2 emissions should be added to the cost of coal because it has significantly higher carbon byproduct per KWH than oil or gas. Carbon content of fossil fuels

The coalmines are closed today along with the railroads and canals. Changes in the economic value of coal impacted numerous towns and villages across the region. Anthracite coal production in Pennsylvania reached its peak in 1917 when more than 100 million tons of coal was mined with the anthracite industry employment reaching its peak in 1914 with about 181,000 workers. Anthracite Coal

The value of coal diminished as demand shifted towards coke for iron and steel and oil became an energy substitute. The Carbondale region with its vast Anthracite coal deposits suffered as a result of falling demand for Anthracite coal. According the World Coal Institute, Anthracite coal has high carbon and energy content, but Bituminous coal accounts for majority of the world coal consumption because it is more abundant while coke is used in the iron and steel industry. World Coal Institute

The Northeastern, PA region experienced an economic shock as Anthracite coal lost its appeal. Demand shifted towards oil at the high end for transportation and the more abundant Bituminous coal at the low end. Anthracite represents only 8% of coal production today with Bituminous accounting for 76% and Lignite 16%. Those communities in Northeastern, PA that were more tightly linked to coal mining fell deeper into financial turmoil as the demand for Anthracite coal declined.

The Bottom Line: the economics of energy determines its use – coal still accounts for approximately half of our electric generation because it has a lower cost than other fuels. However, there are two factors to consider 1) the cost of carbon is not calculated into the full price of coal or other hydrocarbon fuels and 2) the cost of conventional fuel is calculated on a marginal basis while alternative fuel costs are calculated on a fixed cost basis. Meaning the cost of roads, trucks, and mining equipment is not factored into the price of each piece of coal, only the marginal cost of producing each ton of coal. For solar and wind energy systems, the cost to construct the system is factored into the total cost while the marginal cost of producing electric is virtually free. We need a framework to better measure the economics of alternative energy.

Despite the carbon issues surrounding coal, (coal has higher carbon-to-hydrogen ratio in comparison to oil or gas) coal is more abundant and therefore is cheaper than oil. Utilities could migrate to natural gas to reduce carbon emissions, but with a cost of $0.03 per KWH, there is no economic incentive. Alternative energies such as wind and solar could provide a longer economic benefit to users, our environment, and the economy.

Our next step is to develop a framework to measure the fixed and marginal costs of alternative energy.

FSLR – Leading Growth in Thin-Film Solar


First Solar, Inc. Announces 2007 Second Quarter Financial Results

(FLSR) is leading market growth in thin-film solar with revenues increasing 177% year/year.A day after the dust settles on FSLR’s earnings call, let’s look at what’s doing well and maybe not so well.

Revenues increased 177% y/y in Q2/07 demonstrating that FLSR has a leadership position in the emerging thin-film solar energy market. Thin-film solar panels cost significantly less than crystalline solar panels which makes thin-film feasible for large solar array projects such as for electric utilities.

Please review the following pdf file
FSLR Financial Analysis

FSLR reported earnings of $0.58 per share for Q2/07 with a one time tax treatment benefit of $0.51 per share. Wall Street was expecting earnings of $0.03, so even factoring out the extra $0.51 from the tax benefit, FSLR produced $0.07 which is still more than double what analysts were expecting.

FSLR is also giving investors comfort with its ability to collect on its accounts receivable balance. Accounts receivable declined from $27 million in December 2006 to $14 million in June 2007 which together with strong revenues, pushed Days Sales Outstanding (DSO) to a low of 16 days from 149 days for 2006. Low DSO provide a level of comfort for investors because faster collection of cash assures the sustainability of cash flows – the most important factor in a company’s valuation.

In the not so well area, or at least what some investors viewed as negative in taking the stock price down from over $120 before FSLR’s earnings release to $107.50 the day after the release, we see that gross margins are lower and the incremental revenues growth is lower. Investors become nervous over any perception of weaker financial performance especially stocks with high PE ratios.

FSLR’s gross margins in Q2/07 were 37% versus 48% in Q4/06 and 45% in Q1/07. FSLR is in the process of adding to its solar panel production capacity. Production facilities need to operate close to full capacity to lower cost per unit and thereby, achieve higher gross margins. FSLR is significantly adding to its production capacity which adds costs ahead of production and detracts from profit potential.

FSLR’s incremental quarter over quarter revenue growth was an increase of $10.3 million in Q2/07 over Q1/07. Incremental revenue growth was however, $14.3 million in Q1/07 and $14.2 million in Q2/06. Investor are willing to pay a high multiple for a stock with strong growth potential. Any sign of weakness and investors flee. Given the long lead times in solar projects there is variability in revenues on a quarterly basis. So why it may be important to look at incremental growth, the trend for solar is just emerging and should provide future growth opportunities.