A blog by Mel Riser about LifeBoat Permaculture and Solar Villages

Thursday, May 25, 2006

Peak Oil and Solar energy

Living off the Grid
A while back, it was susggested that I write up a small post about the things to think about in regards to living off-the-grid. By this I am referencing the ability to not need connection to the electric company for your house.

Now this is a wide subject that can fill volumes, so what I present here is just a brief overview, to give you some thoughts about what is available along with some books and publications on the matter.

So without further ado,

Once we start thinking through the problems of peak oil, it quickly becomes apparent that a change in lifestyle will be necessary. With oil such an integral part of every sector of our economy, yet getting more and more expensive every day, we soon will not be able to afford to use the amounts of oil we are accustomed to. As the oil gets more expensive, corporations and utilities struggle to make ends meet. The cost of natural gas goes up along with the oil, since transportation costs go up. There is also greater demand from industry attempting to find cheaper fuels, driving the costs up further. Greater demand occurs for electricity as some switch to using electric, forcing electric companies to switch on the natural gas fired generating plants held in reserve. The electric companies pass on their increased costs, and your rates skyrocket.

If the system gets overloaded, due to a heat wave, or a cold snap in winter, a blackout occurs. There is even a possibility that in the near future, utility companies may not be able to afford to run some of their reserve generators due to high prices, or even due to not having the fuel to feed them. All of a sudden, the unbelievably dependable electric serve that we take for granted in the United States starts to deteriorate in service, and blackouts could become a common occurrence.

Think about what would happen should you go to turn on the light, and although the switch works, the lights do not. The food in your refrigerator quickly warms up and goes bad. You turn on the water. If you are lucky, there is enough pressure in the lines to push it out of the tap. If you are really lucky, you use a gas water heater, and have hot water. But most likely, even if you have gas hot water, it won’t do you much good, as there is no water pressure from where the pumps used by the local water company use run off of electricity. Quickly, the import of having no electricity sinks in. Doing with out the lights is one thing; doing without water is another.

If you do not live in the city and are lucky, you live in an area where you are on well water. But this is by no means a sure thing either. Most private wells use an electric pump. Needless to say, no electricity, no water.

Your well may be shallow enough that you can retrofit a hand pump onto it. The traditional hand pump that we know from movies, TV shows and the like, only works for a maximum depth of about 16-25 feet depending on brand name. There are larger pumps that can draw from deeper, but you may run into troubles with the well not being large enough in diameter for a larger pump.

In flatlands, farmers have traditionally used windmills to pump their water. Wind power has been used for ages in Europe. The Dutch windmills of Don Quixote fame were used to pump out the lowlands behind the dikes keeping the North Atlantic at bay. In North America it was the only (mostly) reliable way to get water in the rural parts of the nation. Wind power is at the behest of the wind. When the wind blows, the water pumps; when the air is still, the pump is too. This necessitates the use of a cistern in conjunction with the windmill to store the water until it is needed. The cistern acts as a battery of sorts, being charged or refilled as it were when the wind blows, and providing a continuous water supply. The owner puts his faith in the wind not stopping for a longer period of time than it takes for the cistern to be drained, and that once it starts up again, it continues to blow for a long enough period of time that the cistern is refilled.

But not all areas of the country or world are suitable for windmills. The terrain may be unfavorable, with mountains, trees or buildings blocking the wind, or keeping the wind high enough up that it is unpractical to get a windmill’s blades up into the air stream. In this case, a rainwater cistern is often a viable solution.
Essentially, a rainfall cistern uses the rain runoff from the roof of your house or building, channeling the gutters into a cistern through a filter of some sort. Of course, this is only useful in the areas of the world that get regular amounts of rainfall.

Both rainfall and windmill cisterns will need to be completely sealed from the outside, as you want to minimize contaminants. There is also the need for a filtration system, especially on rainfall cisterns. Well water typically does not require filtration, as the ground provides a natural filter.

It is to remove the need for a cistern that American well users went universally to electric pumps once electric service reached them thanks to the Rural Electrification Administration.

In the 1930’s, only 10 percent of U.S farms were served by central-station electric power. But, thanks to good marketing strategies by Zenith Radio promoting the Windcharger brand of small wind powered charging systems as a solution to powering their new radios, the American homesteader had their appetite for electricity whetted, and demanded more power. Windcharger and other manufacturers such as Jacob Wind Electric of course ramped up production and power generating capacity, with 14 feet diameter, 1.5 Kilowatt capacity windmills being produced by the 1940’s and 1950’s.

But Franklin Roosevelt caused that market to disappear, as he created the Rural Electrification Administration as one of his Public Works departments used to put the depression era unemployed to work. It had the express purpose of subsidizing the wiring up of the nation’s rural areas, and providing cheap centrally supplied electricity to everyone. This program took a while to implement, as some areas did not receive electricity until the late 1950’s.
With electric power readily available at the flick of a switch for pumping duties, cisterns were no longer needed for times when the wind did not blow, and small generators fell into disuse. Cheap readily available electricity in the intervening years caused our appetite for electricity to explode exponentially.

Stop and consider the number of electric devices you use on a daily basis. Alarm clocks, light bulbs, electric razors and toothbrushes, radios, televisions, computers, air conditioning, coffee pots, crock pots, electric stoves, toasters, refrigerators, freezers, garage door openers, security systems, computers, cordless phones, cell phones, video games, VCRs, DVD players, cassette players, CD players, vacuums, electric weed eaters, electric lawn mowers, electric hedge trimmers, the list goes on and on.

And all of these become useless when the power goes out. It boils down to reassessing what you truly need, as opposed to what you want. Learn to conserve. Replace electric powered items with manual or mechanical powered ones wherever possible. Yes, you can come up with an alternative power system that can replace your current usage of grid supplied electricity, but you need to stop and consider a simple fact.

The more you need to power, the higher the cost of the system. Why pay more for higher capacity when you can reduce your consumption with a few simple changes in lifestyle?

Replace incandescent light bulbs with compact fluorescents. They fit into the same bulb sockets, and provide the same amount of light for less electrical usage. For instance, a compact fluorescent with the equivalent light output of a 100 watt incandescent bulb only uses 17 watts. It also has a longer lifespan, resulting in very high savings that more than make up for the additional up front costs. And for those who don’t like the quality of fluorescent lighting due to its cold harsh nature, compact fluorescents are now available in color corrected versions that give off a soft white glow.

But the best way to conserve electricity with lights is to turn them off when they are not in use. If you walk out of a room, go ahead and turn off the light. If you can do what you need to using just the daylight coming in through the windows, do so. Rather than lighting up the entire room for one person, use task lighting.

This sort of conservation thinking can be extrapolated into all aspects of your household, and in doing so will reduce the electrical needs to the necessities, as opposed to typical usage patterns. A normal American household should be able to cut their energy usage in half, down to about 3,600 kilowatt-hours a year without going to a truly Spartan lifestyle. For comparison, most European households live comfortably on this amount or less.

Once you have reduced the amount of energy you consume, you are ready to determine what sort of alternative energy system is right for you, as one size does NOT fit all. All power systems consist of 3 parts: generation, storage and loads. The loads are the actual energy used as discussed above, and drive the sizing of the system. Storage is typically done via batteries. Generation is typically done through harnessing the sun, wind or water.

All stand alone power systems produce and store energy in direct current (DC). Photovoltaic arrays produce DC directly, whereas Wind and water generators typically produce alternating current (AC) which must be rectified to DC for storage. This is due to the typical storage medium being the battery. Relatively unchanged for over a hundred years, the typical battery bank used for off the grid applications consists of nothing more than heavy duty, deep cycle batteries, similar to automotive batteries, wired up to provide a storage bank of energy. For the stored power to be used, it must them be rectified back to AC for most applications through the use of an inverter.

For homes, it is generally recommended that you wire the house for AC, just as if you were going to connect to the grid. This is due to most codes not recognizing DC wiring as being satisfactory, and their being a wider pool of equipment and appliances that can be used. Banks are also unwilling to finance anything other than AC, as they look at what it would take to make it sellable to the next person who may not be into off-the-grid living. There are appliances and equipment designed for 12 volt systems however, as an industry has grown up around supplying them for RV and marine applications. Ultimately it is up to you to determine what is best suited for your needs. Again, one size does not fit all.

The power systems and battery arrays come in 12, 24 and 48 volt systems, which is a function of how the batteries are wired together, and what voltage runs through the wires. A general rule of thumb is as follows: Systems requiring less than 2 kilowatt-hours a day should use 12 volt, systems requiring up to 6 kilowatt-hours a day should use 24 volt, and systems requiring more than 6 kilowatt-hours a day should use 48 volt. Of course, as the voltage goes up, the price follows. See why learning to conserve is so important?

The actual sizing and configuration of a system is beyond the scope of this entry, and should be customized for each application. I will link to good resources both print and online at the end of this essay.

As for choosing what sort of generation capacity to use, many elements come into play. Is there a location available that gets direct sun for most of the day? How much sun does your location normally get? Is the weather typically cloudy and rainy? Is there a source of running water? Are you in an area with a near constant wind? Are you in the city? The suburbs? The country? Again, Individual situations will need to be assessed and will inform the choices made. However, I will briefly touch upon some of the different choices available.

Sun power consists of two general means of capturing energy, electricity via Photo-Voltaic cells or PV, and heat capture via solar water heaters, modified stirling engines and using proper design and material choices to let the sun carry the bulk of your heating requirements. Of these types, the modified stirling engines are still in their infancy for power generation. In a nutshell, they utilize the heat from the sun to vaporize a liquid (typically water) which causes the water to expand. The design of the vents on the container cause the container to rotate, driving a generator.

Retrofitting for solar heating is an expensive route, and is not economically viable for the average homeowner. This is something that is relatively inexpensive to do on the front end as the home or building is being designed, but absurdly expensive to retrofit. The basic idea is to utilize the heat of the sun to warm a solid surface over the course of the day. After night falls, this heat sink then releases the stored heat back into the structure keeping it warm through the night time hours, depleting its stored heat by the morning when the cycle begins again. There are many ways this can be done, and a good architect should be able to advise you on how best to tailor your building for this.

Solar hot water heaters are a retrofit item, typically installed on a roof and tied into the hot water system of the structure. They are nothing more than gloried camp showers, those black plastic bags that you hang in the sun in the morning, allowing the sun to heat up the couple of gallons inside the bag, providing you with hot water for a shower that evening. For building applications, this concept is merely enlarged, and made a bit more permanent and rugged. They can either pre-heat the water in your existing hot water tank, reducing the amount of energy paid for in heating the water, or serve as the sole hot water source. Again, this system must be custom sized for each application
Photovoltaics are also a retrofit item, and are used to generate electricity from the sun. They are fairly expensive to purchase, as the silicone used in their creation is also in demand for circuit boards in electronics and computers. There is some argument as to truly how “green” of a product they are, as there are a number of hazardous materials used in creation of a solar cell, not to mention the large amounts of energy expended in their manufacture.

Even so, they are a tried and proven technology that is commonly accepted as the number one way to get off the grid. To be most effective, they require a south facing location in full sun for the majority of the day. They can be mounted on a swivel which follows the sun throughout the day, or fixed in one position. They need to be tilted such that the sun’s rays fall as close to perpendicular to the surface as possible. A typical lifespan of a PV cell is about 15-20 years, though improvements are constantly being made to the technology.

As mentioned earlier, the wind has been used to directly pump water for ages, and to generate electricity for decades. It is a fairly mature field, with the Germans and Dutch taking the lead in developing the technology. Wind systems range in size from a miniscule 1.7 foot diameter blade generating 20 watts in a stiff wind, all the way up to a massive 330 foot diameter monster capable of producing 3 Megawatts or 3,000,000 watts. Wind power is limited in location, as the local terrain and structures must be conducive for capturing wind. Quite simply, some places have more wind than others.

If you are in a relatively open area, with good winds year round, then wind generation is a definite possibility.

Water power, or hydroelectric, is also a terrain limited source of electricity generation. Quite simply, hydroelectric uses the force of falling water to turn a generator. Most people think of massive dams and reservoirs when they think of hydro power, but smaller applications have been around for years. These smaller, household sized hydro systems tend to be lumped together under the heading of micro-hydro.

Hydro consists of a water wheel of some sort driving a generator. This can be accomplished by merely dipping a wheel into a running stream, or damming up a river and pouring a set amount across the wheel, or somewhere in between. The cost of the systems typically force their being used in locations where there is a constant supply of water to power a hydro system obviating the need for batteries for power storage, however, one could consider a reservoir to be a giant battery of sorts, as it stores water lessening the impact of a short term lack of rainfall.

As you have seen, I have merely touched upon the various means of going off the grid. The reasons to do so are compelling, namely to ensure access to water and needed electricity in the event that the grid fails. How much you need to produce is in direct correlation to your conservation habits, and learning to live with less is something you can do now as opposed to after you have no choice. Choosing which system is best suited for your needs is best done on an individual basis, and is highly dependent on your personal circumstances.
I will leave you with the following list of further resources:

Wind Power: Renewable Energy for Home, Farm and Business by Paul Gipe copyright 2004 ISBN – 1-931498-14-8

The Solar Electric House by Steven J. Strong with William G. Scheller copyright 1993 ISBN – 0-9637383-2-1

The Solar House: Passive Heating and Cooling by Daniel D. Chiras copyright 2002 ISBN – 1-931498-12-1

Layman’s Guide for Developing Microhydro (Second Edition) by Celso Penche for the European Small Hydro Association (Adobe PDF – 1998 edition)


Post a Comment

Subscribe to Post Comments [Atom]

<< Home