Residential Standby Generators for EMP
and Severe Solar Storms
by Jerry Emanuelson
This is the first draft of a page of things that you need to think about when purchasing or installing a standby electric generator with something like residential-sized capacity, especially when you have electromagnetic pulse hazards in mind. Many readers have requested that I put this page up as soon as possible, even though it is not fully complete. I will also briefly discuss portable generators.
I am going to be discussing this subject with broad generalizations. The home generator market has changed rapidly during the past few years, but a number of possible pitfalls and important considerations for buying a standby generator have remained the same. Recommending one particular brand or fuel source would be futile because models change so often, and the importance choice of a fuel supply (as discussed below) is very specific to your particular situation and location.
It is important here to once again stress the differences between nuclear EMP and the disturbances caused by solar storms.
It is difficult to fully protect a typical whole-house generator from nuclear EMP, although much can be done. A solar storm is another matter entirely. Solar storms affect mostly the electric power grids, with the most severe solar storms damaging the larger transformers in the power grid.
The main danger to residential electric power during a severe solar storm is long-term loss of electricity from the power grid. This means that having any kind of a standby generator at all provides a large amount of protection from severe solar storms as long as you have a long-term fuel supply.
The one possible source of damage to electrical powered items during a severe solar storm comes from the possibility of AC from the power grid having an extremely distorted waveform before the electric grid finally collapses. There have been severe solar storms affecting power grids in high-latitude regions. The most notable of these storms severely affected the province of Quebec in Canada in 1989, and South Africa in 2003. In both cases, sections of the power grid collapsed fairly quickly, and I have found no reports of damage to any individually-owned items.
Although some rare solar disturbances travel from the Sun to the Earth fairly quickly and catch everyone off guard (such as the March 1989 geomagnetic storm in Quebec), most severe solar storms are likely to offer you a day or two of advance warning. You can get warnings of solar storms from web sites such as:
Small solar storms often happen with great frequency (especially in the years near the peak of the sunspot cycle), and only affect small electric grids near the polar regions where the power grid operators are prepared for all but the most severe of such events. So don't start up your generator with every report of an X-class solar flare. If a once-in-a-century electromagnetic storm is on its way to the Earth, however, it would be prudent to start and transfer your generator before the grid collapses in order to supply only undistorted power to your house.
It is important to remember the 3 most important causes of generator failure:
In case some of the electronics have failed, the generator may still run, but may just not automatically start and transfer. Read your manual to learn how to manually start your generator and manually transfer the power. You don't want to learn this by flashlight while you are fumbling around in the dark. The electronics that are most likely to be damaged in your generator are those concerned with the automatic start and transfer circuits. (Of course, this doesn't apply to a portable generator.)
I'll discuss nuclear EMP protection (and protection against more common voltage spikes) near the end of this article, but first lets get started on discussing considerations for the purchase of a new generator.
Other than your budget, the first consideration will be the fuel for the generator. The fuel that you choose will be heavily dependent upon your location and the fuels that are commonly available at your location.
One important consideration for stored fuels is that they all go bad after a period of time. Modern gasoline is the worst in this regard since it can significantly deteriorate within a few months. Fuel that is continuously piped in (such as natural gas in many areas) can provide a constant fresh source of fuel, but even that source can vanish if it is pumped by electric fuel pumps.
Historically, the primary fuel used for standby generators has been diesel fuel. This is not the best choice for residential use for most people. On the other hand, if you live in a rural area (and especially if you live on a farm with diesel-powered tractors, etc.), diesel may be the perfect fuel for your situation.
Portable electric generators:
Portable electric generators are usually powered by either diesel fuel, gasoline or propane. They are not adequate for powering an entire house, but they may be very useful for powering things like critical items like electric heaters or fans, small pumps, refrigerators and (in conjunction with an uninterruptable power supply) individual medical equipment.
Although gasoline may be a convenient fuel for many people (since many people keep a can of gasoline around for things like lawn mowers), it is not the best fuel to use for a generator. The reasons are simply its short lifetime in storage, and the fact that it is more flammable than the other "household" fuels.
Diesel fuel is less dangerous to have in storage from the viewpoint of flammability. It will also last in storage for two or three years if you add the proper diesel fuel preservative. The most common diesel fuel is called diesel #2. Unless you live a climate that is fairly warm all year, it is best to buy a blend of diesel #1 and diesel #2. (Diesel #1 is somewhat similar to kerosene.) Blends of diesel #1 and diesel #2 are commonly available in cold climates.
Portable generators that run on propane are also commonly available. They are usually designed to run on the same portable tanks that are used for things like recreational vehicles. Propane tends to last longer than other fuels used in portable generators, but even stored propane doesn't last forever.
The important thing to remember about any kind of portable generator is that it will only supply standby power for periods of time measured in hours. A exception may be if you live in a rural area with a large capacity fuel tank. Even then, portable generators are not designed for continuous use during long-term power outages. You generally have to shut them down at least once a day (usually more often) for a while to check things like lubricating oil level.
Whole house generators:
Whole house generators have been available for decades, but it has only been in very recent years that they have become more widely available, and at a more reasonable price that has put them within reach of large numbers of homeowners.
The most popular whole-house generators in recent years have been those that run on natural gas or propane. Natural gas generators have the advantage that many people have fresh natural gas piped into their house already, so they don't have to worry about a fuel supply for ordinary power outages. Large-scale disasters, which includes any scenario where a large part of the power grid is down for days or weeks, may mean that there is inadequate pressure in the natural gas lines, as well.
Fortunately, all whole-house natural gas generators that I have seen will run on propane as well. Although the change-over from natural gas to propane is usually quite straightforward, you do have to follow the proper procedure. It can be dangerous to feed a mix of natural gas and propane to your generator. At a minimum, the changeover usually involves shutting down the generator, moving a fuel lever on your generator to the alternative fuel position, and opening the fuel valve on your emergency supply tank (propane tank).
Natural gas generators usually come set up for natural gas only, and require an adapter kit to accommodate the use of propane. (Your chances of finding the proper adapter kit and propane tanks during a very long-term power outage of any kind are virtually zero.)
For those who live in rural areas, these natural gas/propane generators can be set up to run from the propane in a large propane tank.
During any sort of a long-term power outage, most of the home generators (unlike industrial standby generators) must be shut down once a day or so for brief maintenance for things like checking the oil level. Other than these brief maintenance periods, the run time is generally limited only by the fuel supply.
The most popular whole-house generators currently being sold are all set to automatically start and run once a week or so. This is a form of automatic self-maintenance. Alarm lights will come on if the generator fails to start and run at the preset time. The alarm lights won't do any good if you don't check them occasionally. You cannot just buy a standby generator, and then forget about it. Usually, very little maintenance is required; but you should look for alarm lights and check things like the oil level every week or so. This only takes a minute or so. Unless you have a small pull-to-start portable generator, the starting batteries will have to be replaced every few years.
Unless the battery comes with the generator package, get a battery with a larger capacity (in both amp-hours and cold-cranking-amperes) than what is recommended. Having a large enough battery will greatly increase the chances of the generator starting when you need it to start.
About EMP and other transient protection for your generator:
Most portable generators are in pretty good shape, even for nuclear EMP, as long as no external wires are connected to them. This means don't plug in extension cords or other items into a portable generator until you actually need them. Leaving an unused portable generator with an extension cord plugged into it is just like connecting an EMP antenna to the interior.
For whole-house generators: At a minimum, you should have a voltage transient suppressor at the input (electric power grid side) of your transfer switch. If you don't have the time or money to search for and purchase a suppressor that is fast enough for EMP, at least have the electrician install a lightning protector on the input to your transfer switch.
Voltage transient protectors that are fast enough for nuclear EMP are made by Transtector and SOLA. These will only block the EMP coming in on the power line, but this is the most important part of the pulse. Voltage spikes coming in from the main power lines from a nuclear EMP would range from many thousands to a million volts or more. In addition, if you live in a lightning-prone area, then lightning-induced power line spikes are likely to destroy unprotected generator electronics sometime within the normal lifetime of your generator. There is always good transient protection built into the generator electronics, but that "good" transient protection is nearly always inadequate, even under normal conditions.
The excellent EMP power line transient suppressors by Transtector have gotten very expensive in recent years. Most Transtector transient suppressors are now more than a thousand dollars each. SOLA makes good transient protectors for half the price of the Transtector units. The SOLA model STV 100K-10S is an excellent unit made for the 120/240-volt systems that are the most common for U.S. residential use. It costs around $570. This model will also work on residential systems in many other countries. It will have to be wired in by an electrician.
Ideally, in addition to the power line input side of the transfer switch, there should also be one on the load side (the output going to your house). This one is less important that the power line side transient suppressor. I've been looking for a good place for readers of this page to buy the SOLA or Transtector units, but for now, you will either have to look around on the web, or ask your electrician if he is able to purchase it.
In addition to voltage transient protection for your generator, especially if you have a whole-house stationary generator, it is important to have transient protection for the critical and more sensitive electrical and electronic items in your house. Every time that your transfer switch switches the power either to the generator or back to the main power, it will create a voltage spike in your entire house. Put at least an inexpensive consumer-type "surge suppressor" on every piece of important electrical device in your home. Inexpensive surge suppressors have gotten much better in the past few years, and every one of them that you use will eventually pay for its cost. (You won't realize that the surge suppressors are paying for themselves because you won't know about the electronics that you would have been replacing due to premature failure.) Try to get an outlet surge protector that is rated at at least 3000 joules, but any surge suppressor is better than nothing. Even the electrical outlets that you use for charging things like laptop computers and cell phones should have a surge suppressor.