Thursday, February 15, 2007

Conservation is #1, Don't get the cart before the horse.

Because of posted comments, I fear we may have put the cart before the horse. Many want to jump to sexy alternative energy sources, but as I mentioned in a previous post, the most viable alternatives for meeting our energy objectives are actually conservation rather that alternative energy sources.

I'm going to mix energy with investments here, so if you are interested in both, as I am, you may want to check out my other blogs.

Probably the most viable energy alternative, as well as the best investment available anywhere, is the compact flourscent light bulb. A compact flourscent light bulb used 2 hours per day will pay for itself in 6-12 months depending in your electric rate. That means an investment in replacing an incandescent bulb with a flourscent yields an investment return over 100% per year. The return shoots to 200% for a bulb used 4 hours per day and to 300% for one used 6 hours, as many are. In warm climates where a/c is predominant you will gain even more by reducing your a/c usage. And rather than speculative, this return is virtually risk free. I dare you to find a better investment of any kind. As a bonus you'll be decreasing our dependence on foreign supplies of energy and decreasing greenhouse gases and other pollution. Not only are you a top flight investor, but you are helping save the earth in the process.

Other conservation may be a bit harder to define, but you can be pretty sure there are great investments all around your house. Examples:
  1. Insulation. The value of insulation has to be evaluated on a case by case basis, since it is subject to the law of diminishing returns. That means that the more insulation you currently have, the less viable it is to add more. But if your house is insulated below the established standards for your area and you plan to be in your house for a while, you can be sure insulation will be a great investment.
  2. Weatherstripping, caulking and niche insulation. If your house is well insulated, most of your heating and a/c bill is vanishing either through your windows or through gaps around your doors, electrical outlets or other openings. While improved windows are rather expensive and a bit hard to justify for retrofitting, other efforts such as weatherstripping, caulking and niche insulating are not. If the weatherstripping around doors and windows is not preventing a breeze when the wind blows, replacing it will be a great investment as is caulking any source of air intrusion. As for niche insulation...odds are good that even if your attic is well insulated, the pulldown steps into the attic are both unweatherstripped and uninsulated. There is a good chance the ductwork in the attic is insulated by less than an inch of insulation and the ducts are leaking like a sieve. A roll of duct tape and some strategically placed insulation will work wonders. If your water heater feels warm to the touch or if the pipe on the top of it is uninsulated, a $10-15 insulating kit will pay big dividends, especially if it is electric. And don't forget any electrical outlets or switches on ourside walls. Since the box takes up most of the depth of the wall, the outlets are frequently poorly insulated. Foam inserts that fit neatly behind the cover are just a few cents apiece at your local hardware store.
  3. Set back thermostat. One of the best ways to save energy is to set the thermostat warmer in summer and cooler in winter, but of course there may be a comfort tradeoff. You can make these adjustments when you leave and return with less effect on your comfort, but a better way is to automate the process. A set back thermostat can be an investment with triple digit returns, particularly if everyone is away from the house on a regular basis.

I could go on and on, but you get the picture. Improve your financial health and help solve some of the world's most pressing problems by taking some time to look for conservation measures you can take a small bite at a time. Many can be financed with the loose change that collects in your pocket in a few weeks time.

Tuesday, February 13, 2007

Intense commentary plus a/c from heat

Wow!, while I admit that my intention is to promote discussion, I am surprised (and delighted)by the intensity of the comments on my last post. So, where do I begin to respond?

First, let me say I sincerely appreciate the comments, despite...No, because of, their intensity and diversity.

Jay, you make some excellent points. For example, with my comments in red:

  • Energy drives our entire economy. Quite correct, energy supply is a serious matter which has wide reaching effects on our way of life.
  • Solar energy is the source of all energy on the earth. Wind, wave and fossil fuels all get their energy from the sun. Fossil fuels are only a battery which will eventually run out. There may be a few other exceptions, such as nuclear and tidal energies, but the point is well taken. Many do not recognize that even fossil fuels are essentially just a capture and storage mechanism for past solar energy.
  • the direct conversion of sunlight with solar cells, either into electricity or hydrogen, faces cost hurdles independent of their intrinsic efficiency. Ways must be found to lower production costs and design better conversion and storage systems. Agreed, hence my comments that photovoltaics are far from viable economic alternatives to the grid in the current environment.
  • Mandate net metering. Since utilities are generally government sanctioned monopolies, government has the right and obligation to mandate appropriate controls on the monopoly.

However, before I retreat to my area of expertise (technical), let me be perfectly clear. I believe very strongly that free enterprise will produce the best solutions at the appropriate time. In general, neither the federal government nor big business has either the mandate or the ability to solve these problems by edicts outside those demanded by free enterprise. Both government and business will effect solutions when, and only when, their customers demand it. Regulations and actions outside those demanded by free markets divert valuable resources and decrease the efficiency of the system in solving problems.

Only education about the possibilities, the science, the technologies available can improve the efficiency of the free market, hence this blog.

Now, off the soapbox and on to the issue of cooling with heat.

Jeremy, thanks for your question about using solar heat to generate air conditioning. As I mentioned in my previous post, this area is one of the least understood and therefore least recognized alternative energy resources. And, of course, it seems contradictory. At the same time, the technology is well proven. Most RVs have propane refrigerators which use the propane to generate heat, and thereby refrigeration by a process known as adsorption. You may remember natural gas powered air conditioning systems, although they are pretty rare now. They work on the same process. Variations of both this and other cooling process, such as steam vacuum are widely used in industrial processes to provide cooling through application of heat.

Very simply, the process looks like this:

  • Use desiccants (materials that naturally attract water vapor) to attract moisture.
  • Evaporate water to supply the moisture demand created. Cooling results from the water evaporation.
  • Regenerate the desiccant by using heat to drive moisture out.

As I said, this is a well proven process. I realize that, to most, the term desiccant is foreign, but it simply means materials which attract or have an affinity for water, and there are many well known examples. Salt is a've seen water extracted from the air into salt to create a wet mixture in a humid area. Popcorn becomes less crisp when exposed to humidity for the same reason. Ethylene Glycol (antifreeze) is added to your radiator because it attracts water and therefore makes the water mixture less inclined to boil and escape the radiator. Ethylene Glycol and ammonia are dessicants widely used in industrial processes for drying and/or cooling. And there are desiccant pellets such as silica gel manufactured specifically for drying air and natural gas to eliminate freezing, corrosion and other negative effects in processing. These are also used to remove moisture from packaging. You've probably seen the small packets of silica inside packaging. They are there because they absorb moisture from the air and therefore prevent moisture related problems.

So, all that remains is to select the appropriate desiccant and to generate sufficient temperatures with solar heat to apply the process to solar air conditioning. Importantly, this process has synergy with solar heating which makes both more attractive. Everyone knows, of course, about solar heating. But one of the problems is that heating demands are high, but short lived. A solar heating system designed to meet a significant portion of heat demands in a home sits idle much of the year. And, even worse, the highest heating demands occur when there is the least sunshine, ie at night or cloudy days. If the same heat collector and storage mechanisms can be used for air conditioning, the economic viability of both solar heat and air conditioning can be significantly improved. And the highest air conditioning demand largely corresponds to the periods of maximum sunshine.

So, what does this collector look like? You've seen them and could probably do a pretty good job of building one yourself, but here is where I get most excited. I believe that with relatively minor modifications you could collect enough energy in your attic to supply most of your air conditioning and heating requirements. And you would further improve the efficiency of your house in the process by increasing ventilation and temperature in the attic.

I'll leave you with that, although I know some may want more details. If there is a demand, perhaps I'll get smart enough to post sketches and schematics in the blogs and explain further.

Monday, February 12, 2007

But what alternatives?

I love it when a plan comes together. Jon asks, what are the most viable alternatives?

That is not such an easy question to answer, but I'm anxious to give it a shot.

First, what are not viable alternative energy sources? Hydrogen!! I know you've all heard the hype. Hydrogen is the most plentiful element on earth. The only exhaust from its burning or conversion in a fuel cell is water. Both quite true, but very misleading.

This is because there is no readily available source of hydrogen in its pure form. Most hydrogen is either combined with carbon in hydrocarbons such as oil and gas, or is combined with oxygen as water. That means that a significant amount of conventional energy is required to generate hydrogen which is useful. If generated directly from hydrocarbons, the hydrocarbons are consumed, requiring a large source of conventional petroleum and leaving the carbon to enter the atmosphere, primarily as the potent greenhouse gas, carbon dioxide. If the hydrogen is generated from water, electricity is generally used in a process called electrolysis. And, you guessed it, the process requires considerable energy, largely supplied by hydrocarbons today.

All of this means that hydrogen really should be thought of as energy storage similar to a rechargeable battery, rather than an energy source. With any technology generally on the horizon today, generation of hydrogen is both polluting and conventional energy intensive.

So, what are the alternatives closest to being viable? I'll exclude coal, nuclear and heavy oils, even though there is considerable potential for increasing production of these fuels with oil prices above $50/bbl. I consider them to be proven, conventional sources. Beyond that, the most viable way of reducing conventional energy use is conservation. We're talking compact flourescent bulbs, insulation and weather stripping, lighter vehicles, computer control of processes ranging from air conditioning to refineries. Conventional energy use could be significantly reduced with highly attractive investments in these technologies, assuming prices above $50/bbl. And more good news... these technologies can and should be invested in by individuals at the lowest income levels and will decrease the release of greenhouses gases in the process. You and I can make a difference.

Ok, so you wanted to know about the most promising alternative energy sources? Wind, solar heat and low grade geothermal. Let me take them one at a time.

Wind. There is enough energy blowing in the wind to satisfy all the world's demands several times over. We just have to capture it. Unfortunately, that is not necessarily so simple. Most of the wind energy is in remote locations and/or at high elevations. That means a robust electricity transportation system is required. Wind energy is also highly variable. That means either batteries or interconnection of widely varied regions to even out the supply. There is a lot of investment in battery technology today, but for the foreseeable future energy storage in batteries looks like a marginal investment unless grid power is not available. All that said, I think wind energy is currently the most viable alternative energy source.

Solar heat. Notice I'm not talking about generation of electricity by photovoltaic cells, the technology most touted today. In general, photovoltaic cells are not viable alternatives to grid electricity at anything approaching today's energy prices despite the fact that many times world demand is available for the capture cost. This is true because of the high cost and low efficiency of today's cells, as well as because of the variability issue discussed in the section on wind. Solar heat, however, is one of the best, but least recognized alternative energy sources, particularly where electricity is utilized for these purposes. A large part of our energy consumption is for heat and cooling, both of which can be supplied through solar heat. The variability issue can largely be overcome by energy storage in mass such as water, earth and concrete. And, in the case of air conditioning, the largest loads correspond to high solar energy supply periods, ie sunny days.

Low grade geothermal. Again, I'm not talking about the few locations where high grade geothermal is easily accessible to generate steam. These areas are too sparse and protected to generate significant energy supplies. But just a few feet in the ground is an energy supply at nearly constant temperatures which can be tapped for heating and cooling. This applies nearly everywhere there are major populations. A heat pump can extract either heat or cooling (or both at the same time) from this source at substantially higher efficiencies than from the more variable ambient air temperatures.

So there you have it. I realize I've been rather cryptic in my explanations, but perhaps I can go further into the details in the future. So, keep those questions and comments coming.