We know that coal is the enemy of the human race, what with carbon emissions, deadly air pollution, and unsafe and destructive mining practices. The supply of coal is becoming more problematic as well: recently, a Wall Street Journal article described a “coal-price surge,” and Richard Heinberg has warned that coal may peak much sooner than most people expect. So what’s to like? Not much.

But since coal-fired plants provide almost half of our electricity, we can’t get rid of coal unless we find either a way to replace it or a way to reduce the use of electricity. Recently, Gar Lipow has discussed how friggin’ cheap it would be to replace coal, and Bill Becker has pointed to several studies that show how renewables could replace coal.

I will argue in this post that if buildings could produce all the space and water heating, air conditioning, and ventilation that they need, we wouldn’t need any coal. Heating and cooling buildings and water now consume 30 percent of our electricity and 32 percent of our natural gas.

If, for instance, geothermal exchange units (also known as geothermal heat pumps) were installed under every building, and an appropriate amount of solar photovoltaics were installed on roofs in order to power those units, we wouldn’t need to burn 60 percent of our coal because we would not need 30 percent of our electricity. And because we could redirect our natural gas from warming and cooling into electricity generation, we could get rid of the remaining coal, replacing it with natural gas.

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In other words, the buildings would both destroy electrical demand and free up natural gas, until renewables come online and replaced natural gas in turn. If we did this within a 10-year timeframe, we could generate millions of green-collar jobs, create new industries, and help the rest of the world kill off the rest of coal.

All of the data that I use in this post is available online in a spreadsheet I created called “EnergyUse.” It has tabs for electrical use, natural gas use, my calculations concerning coal, and some notes on the data, all of which comes from the Department of Energy’s Energy Information Administration (EIA).

So let’s get electricity literate, and take a look at how electricity (and natural gas) are used in this country, so that we can figure out how to kill coal:

Heating and cooling: The EIA divides energy reality into four main areas of use, residential, commercial (which seems to include government), industrial, and transportation. As you can see in more detail on my spreadsheet, residential air conditioning, space heating, and water heating use up about 14 percent of all electricity and about 18 percent of natural gas; for commercial buildings such as malls and schools, 13 percent of our electricity is needed for heating and cooling and about 11 percent of our natural gas. Industry only uses a few percent of each for heating and cooling the buildings.

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Buildings can provide this heating and cooling if geothermal heat pumps are installed below them. Depending on the building, pipes can be installed from 10 feet or so to 400 feet below the surface, because the temperature at a certain depth stays very constant, even in very hot or very cold climates. The geothermal units can take advantage of this heat constancy to heat or cool the building, depending on the need. Geoexchange does use some electricity, so in order to make the building self-reliant for heating and cooling, some solar photovoltaics would have to be installed on the roof, with some storage also available.

There are other heating and cooling needs that take up quite a bit of electricity, and as far as I know, the possibilities of using geothermal heat pumps to replace electricity for these other uses has not been investigated. Refrigeration, for instance, is a huge consumer of electricity, taking up 6 percent of all electricity in homes, 3 percent in commercial buildings, and even 1 percent in industry. The problem, I assume, is that the refrigeration equipment would have to be converted from being powered by electricity to working with heat pumps, which would seem to make sense since refrigerators are also heat pumps.

Another couple of large users of electricity are household washing and drying, at over 2 percent, and process heating in industry, at almost 3 percent. Again, these would probably have to be redesigned to accommodate heat pumps, but it would seem to me to be more efficient to use heat pumps than to create the electricity that then is used to mimic heat pumps.

Electricity for heat pumps: if we didn’t want to use solar photovoltaics to power geothermal units, wouldn’t we need to add back coal? Not necessarily. First of all, retrofitting buildings to retain as much heat as practical would probably cut down on the size of the geothermal unit needed. Second, if we could cut the remaining uses of electricity and natural gas down, we could use the extra natural gas and noncoal electrical capacity to power the geothermal units. In any case, it’s to our advantage to decrease electrical use as much as possible. So let’s look at the other parts of the electrical and natural gas landscape:

Lighting: There seems to be a certain amount of confusion concerning lighting, and my estimates will be on the low end of what you may encounter, because I’m using EIA numbers. With that caveat, we can see that residential lighting accounts for 3 percent of total electrical use — and commercial lighting almost 9 percent. So Wal-Mart might be offering compact fluorescent lightbulbs, but they’re probably wasting all of the saved electricity by lighting the huge buildings that they sell the CFLs in.

I chalk up the obsession with CFLs to the fact that it is one of the few places that individuals can easily make a difference. In fact, except for appliances, it can be about the only way to decrease electrical use through individual action, particularly if you rent. Everything else requires some form of social action — and commercial lighting is certainly a good example. Which leads us to:

Electronic/Electrical equipment: Excluding refrigerators, washers and dryers (which are really heat-related devices), kitchen appliances, home electronics, and that researcher’s nightmare, “Other”, account for almost 10 percent of American electrical use. Most of these items could be made more efficient, saving probably a few percent of electrical use.

In the commercial sector, office equipment uses up 6 percent of our electricity. The industrial equivalent, machinery, uses up a whopping 14 percent; no doubt much electricity is wasted in both sectors. Finally, we have:

Industrial heating and processing, which uses up 23 percent of the natural gas consumption, and 5 percent of electricity. Much of this energy is concentrated in just a few industries, in particular, chemicals, plastics, petroleum, primary metals, glass, and some food processing — these industries use almost 20 percent of all electricity (and 80 percent of industry use). Petroleum and chemicals use nearly 15 percent of all of the natural gas; so if we stopped using petroleum, cut back on chemicals and plastics, and recycled our metals, glass, and paper, we could reap a huge reward in electricity and natural gas saved and ensure that coal was not needed.

And what about the cost? There are about one million installations of geothermal heat pumps, but there are still many unknowns concerning the cost of carpeting the entire country in them. From my reading, for instance in this San Francisco Chronicle article, a 2,000-square-foot home would require $20,000 for a geothermal installation. And how much electricity would that take? I found one government document (PDF) that found that a 25,000-square-foot building required about 33,000 kWh to operate for a year; if the typical household uses 2,500 square feet, then 3,300 kWh/year would be needed, or about 9 kWh per day. If “1 kilowatt [of solar photovoltaic] will produce about 1800 kilowatt-hours a year,” then we would need about 2 kWs for a typical household, or about $10,000 worth of photovoltaics.

With 100 million households, times $10,000 for photovoltaics and $20,000 for geothermal, that runs to about $3 trillion dollars for the whole country; if we assume commercial buildings use about the same amount of electricity for geothermal, then we would have to double the national bill to $6 trillion. Over 10 years, this would take $600 billion, which as I explained in my previous post, is most of the disposable military budget. No problem!

But the situation should be much better than that, because geothermal units pay for themselves within at most 10 years, so we could nationalize the Berkeley policy of loaning homeowners the upfront cost of installing equipment, paying the government back with the savings. The entire program could incur only the governmental cost of interest lost.

But I think we could do much better than that, for a few reasons. First, not all households need so much space, and multifamily dwellings are much more efficient than single-family homes because there is only one roof for many households. There should also be economies of scale for larger buildings in terms of insulating them. Second, our commercial buildings are often much larger than they need to be, with all of the attendant heating, cooling, and lighting. Finally, the way we lay out our cities and towns will be very important, both for efficiency of residential buildings and perhaps even more so, for commercial buildings, which should be much more energy efficient in walkable communities — which leads to …

Transportation: How would plug-in hybrids, or better yet, all-electric vehicles impact a coal-less economy? There were about 3 trillion vehicle miles driven in 2005 (PDF); if we assume one third of a kWh per mile, then we would need 1,000 billion kWh, or an additional 25 percent added to our electrical output.

On the other hand, the NYC subway system uses 1.8 billion kWh per year for about 8 million people, but that doesn’t include the bus system; in order to figure out a minimal amount of electricity for the country as a whole for transportation, we would need to multiply that 8 million people by 40, and double the resulting number to include the bus system, yielding about 160 billion kWh, as opposed to 1,000 billion for an all-electric automobile society. So the range for passenger transportation, at least, would be from 160 to 1,000 billion kWh (I’ll go into details on petroleum use in the near future, never fear!).

Resilience: Natural gas is certainly not a renewable commodity, although there may be some possibilities for generating methane in a renewable manner, but using natural gas for most of our electricity needs would have to be temporary. We should work towards a renewable energy infrastructure with many different scales: continental-sized, using high-voltage DC transmission lines; city-sized, using local solar thermal and wind farms; neighborhood scale, using some forms of cogeneration and smaller sets of solar and wind systems; and finally the building itself. The resulting system might not maximize electrical and energy output; but it would surely make society much more resilient, and help it start to make peace with the planet.

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