A false sense of security
19 Nov 08 | Conservation, EnvironmentI continue to watch in amazement as fuel oil prices (and energy prices in general) plumet from there summer time record highs. Home heating oil has decreased by nearly 38%, from $4.80/gallon to the current price of $3.018/gallon.
The reason given on most news channels is the demand dropping off due to the bad economy. Maybe, but I have another theory. Demand is off by roughtly 5.2% over the same period last year. The price per barrel of oil has dropped from a high of $147/bbl to about $56/bbl today, or a decrease of 62%.
Something doesn’t quite add up here. Perhaps it has something to do with the less than transparent oil hedge fund speculation. In fact, the hedge funds came to light last summer, when congress considered banning the practice, but choose not to. So what is a hedge fund?
That is an investment that is betting on the price of some comodity will go up. The idea is to buy low, sell high. With oil, that was a pretty safe bet until recently. Some hedge funds completely collapsed, leaving investors holding the bag.
As oil prices began to fall toward the middle of July, these funds began to dump there crude holdings, thus, the market became very soft for crude which lead to the price collapse. So, was the the end of high oil/gas prices?
No, most experts agree that oil prices will go back up, even before the economy begins to recover. Indeed, OPEC has already cut production once to prop up prices. That effort was ineffective, so no doubt they will try again at their next meeting.
In the grand scheme of life, spending money, especially large amounts of hard earned cash, is always somewhat difficult. The exact perfect time to invest in a renewable energy system may never arrive. After all, there are many other things to spend money on, a new car, a new bathroom or kitchen, that trip the the Bahamas that you always wanted to take. However, wouldn’t it be nice to know that you are not being manipulated out of your money by wealthy hedge fund operators? Wouldn’t it be nice to know that you are not dependent on buying oil from people who don’t like us? Wouldn’t it be nice to know that you have lessend your impact on the environment, even if it did cost a little more in the short run?
In the coming months, we may be called upon to sacrifice for the good of our country. The time has never been better to install a renewable energy system, what better way to support the local economy, create jobs, reduce imports, reduce the trade deficite, improve the environment and take back control of your life.
Related posts
Tags: Commentary, energy costs, Environment
Do solar panels increase global warming?
01 Aug 08 | EnvironmentI have had several people tell me that solar panels, both photovoltaic and thermal, increase climate change, aka global warming due to the local “Heat Islanding” effect.
Others have said the cost (in CO2) of manufacturing and shipping solar panels is more than there subsequent use would eliminate.
Solar panel Heat Islanding
There is some validity to the first concern. If you take an area that was normally light reflective and put a solar panel in it, less light is being reflected and thus more heat is being generated. However, in the case of a solar thermal panel, most of that heat is then conducted away by Heat Transfer Fluid (HTF) for use or storage. A typical solar thermal panel is 65-70% efficient at converting and removing the energy striking it. The remaining 30-35% of the energy is either reflected off of the glazing or the absorber plate or it is lost due to heat transfer inefficiencies, insulation losses, etc. In short, a solar thermal panel is very efficient at collecting energy and removing it. Having a solar thermal panel on the roof of your house would reduce the solar gain because most of the heat energy is being removed to another location and the panel shades the roof it is attached to.
Photovoltaics however, are not as efficient as solar thermal. The average PV panel in use today is around 15% efficient. Some of the energy passes through the panel and some of it is reflected. Therefore, about 80% the energy striking the panel is converted to heat. The average insolation on earth at mean sea level is 1,000 watts per square meter per hour.
A 4.3 KW grid tied solar system has 24 Sanyo HIP190BA3 PV modules. Each Module is 1.16 M2. The total area is 26.78 M2. Therefore the total energy striking this array is 26.78 KW/hr. The total heat being generated by this array on a sunny day is about 22 KW/hr or about 75,000 BTU/hr. In the mean time, it is producing 4.3 KW of electricity. The average peak sun hours in the Hudson Valley is 4.5 per day so this system can be expected to produce an average of 19.35 kWh per day or 7063 kWh per year. Electricity production in the United States is about 32% efficient. Therefore, that 19.35 kWh if purchased from the power company, would have produced 60.41 KW of waste heat and 32.9 pounds of CO2 vs 99 KW of waste heat and zero pounds of CO2. This system will save 12,000 pounds of CO2 per year or 150 tons of CO2 over a 25 year life.
This should trigger two questions; How much of the sun’s energy would have been absorbed by the surface of the earth and turned into heat regardless of the solar panel and what importance does CO2 have on climate change. To answer the first question is rather complicated. It depends on the color of the surface, the angle of the sun striking the surface and the atmospheric insulative effect. The second question is a little easier to answer
CO2 in the production of solar panels
It takes about 3.6 years (in average insolation) for a PV cell to make the energy used in its production. Therefore, over a PV cell’s 25 year life, it will produce electricity and contribute 86% less CO2 than electricity generated by fossil fuels. This reducing in CO2, a known Green House Gas (GHG) which is thought to be significantly contributing to the global rising in temperatures more than off sets the local heat island effect that PV panels have.
Solar thermal panels take much less time to payback because they are made mainly from copper (absorber plate and piping), aluminum (frame and mounting), insulation and glass. These materials are readily recyclable which greatly reduced the energy required for extraction and refining. Additionally, a solar thermal panel is much more efficient at collecting energy, so the energy payback comes in about 1.5 years. Most solar HW systems have some type of AC pump. Taking that into consideration, the Energy Returned on Energy Invested (EROEI) while the system is operational is about 15, or for every 1 watt of electricity used, 15 watts of energy are gained. In the Hudson Valley, a two panel SDHW system can expect to save about 3,350 kWh per year. That equals about 5,690 pounds of CO2 per year or 71 tons of CO2 over a 25 year life span.
Related posts
Tags: climate change, Environment, photovoltaics, solar thermal
How long do Solar Systems last?
26 Jul 08 | Solar Electric, Solar Hot WaterThat is a very common question. The answer is, it depends. Solar systems, like all other mechanical systems require some maintenance. Last week, I came across a solar hot water drain back system that was 28 years old. The great thing is, it was still working just like the day it was installed. The only problem the home owner had encountered was a bad circulator pump, which the plumber replaced.
Properly installed drain back solar hot water systems using distilled water could, in theory, last almost indefinitely. Solar Hot water systems that use antifreeze will likely last only 30 years or so. Still, that is a great payback. For either system, over the course of its operational life, it should easily pay for it self 4 to 5 times over.
Photovoltaics are said to last 25 years however, their output slowly declines over time. After 25 years, most current photovoltaic panels will be producing about 80% of their rated power. Still, that is not bad, and a well designed photovoltaic system should pay for itself at least two to three times over its operational life (with current incentives).
The advantages of renewable energy systems, for those that are in it for the long haul, are:
- Stabilizes energy prices at or below their current levels, gives the property owner more control over expenses.
- Increases the property value of the residence or building they are installed on.
- Reduces emissions and environmental pollutants from nearby electrical plants.
- Reduces overall electrical load on grid, thus reducing the need for more power plants and high tension distribution lines.
- Spreads out electrical generation capacity, thus making it more difficult for any one catastrophic event to cause a regional blackout (distributed generation).
- Reduces the use of fossil fuels and thus dependence on other countries to provide energy for us.
As you can see, there are many advantages to a solar thermal, photovoltaic, wind, or microhydro system
Related posts
Tags: distributed generation, Environment, photovoltaics, Solar Hot Water
Gravity Film Heat Exchangers or GFX
29 Dec 07 | Conservation, Environment, Solar Hot WaterUpdate: Sun Volt Solar is now an authorized dealer of ECO-GFX gravity film heat exhangers! For more information, check out our GFX web page.
I am always looking for ways to improve efficiency, especially in energy use. I came across something called a Gravity Film Heat Exchanger or GFX system. These units recover heat from waste water and return it to the hot water tank. Since 80-90 percent of household hot water heat goes down the drain, literally, what a great way to recover some of that energy and reuse it.
Here is how they work: Hot water from a shower or sink runs down the drain and out into the sewer. If there is a vertical run of pipe, the water, because of adhesion, runs down the wall of the pipe (and not the center). If the pipe is metal, heat is transfered from the water to the metal pipe wall until the pipe is the same temperature as the water. All of this happens in any sewer line. If the vertical section of pipe has a heat exchanger attached to the outside of it, the heat from the metal pipe is conducted away to be reused. Most often cold water feed into the hot water tank is run through the heat exchanger. The system efficiency depends on the difference in temperature between the waste water and the incoming cold water. The greater the difference, the higher the efficiency.
This system only works where there is simultaneous hot water use and immediate drainage, say a show or sink. Something like a bath or laundry would not work well because the hot water is drawn off, used, then drained away.
It appears that the system is around 45-50 percent efficient. Therefore, if you use 70 percent of your hot water in showers or sink use, you would recover 30-35 percent of your total hot water energy. Not too bad.
These systems would work very well with solar hot water systems. I am contemplating installing one at my house to see if they work as advertised. The only requirement is that they be installed vertically. In fact, in order to work properly, great care should be taken to make sure the unit is perfectly vertical. For more information, see the NREL website on waste water heat recovery or this .pdf file called Heat Recovery from waste water using Gravity Film Heat Exchangers.
Related posts
Tags: Environment, GFX, SDHW, Solar Hot Water
Filibuster!
13 Dec 07 | CommentaryIn the second procedural vote, the Senate has voted 59-40 for the 2007 Energy Bill. This is not the 60 vote majority needed to prevent a Senate Filibuster by the mostly Republican minority that opposes this legislation. So what, let them filibuster.
From the Energy Smart Blog:
Senator Reid should not be so quick to cave in front of 40 Senators willing to put their fossil-fuel friends before the nation. 40 Senators willing to put their fossil fuel friends before the future of all humanity.
Senator Reid: KEEP THE SENATE OPEN for the weekend. Make the 40 read the phone book in support of tax subsidies for the oil and gas companies. Make this “CALLOUS MINORITY” explain themselves to the nation.
I agree, let Senator McCain, who is attempting a presidential run stand in front of the country and explain why he does not see the need to encourage development of alternate energy. Let the rest of the minority opposition explain why, when oil is trading at $94.00 per barrel, it is not important to invest in renewable energy. Let them explain why, when oil companies are reaping record profits never before heard of in the history of US business, they need huge tax payer subsides. I for one, would look forward to such an explaination.