Distributed Generation Holds Promise, Faces Challenges
Those of us who maintain optimism for a future than includes sustainable practices in energy generation place a great deal of hope in “distributed generation” – the concept in which the model of buying electricity from huge utilities becomes increasingly irrelevant, and in which individual users generate more – or all — of their own. Such a schema has many obvious advantages, especially that it encourages renewables; users will not be building their own coal-fired power plants, for example, but they will deploy solar and wind power.
Yet there are equally obvious challenges. Though distributed generation has been with us since the dawn of time, it is just now coming back into the mainstream after a century in which centralized generation had become the norm, at least in the developed world. That means a great deal of inertia that needs to be overcome, in several different forms, one of which is legal.
Suppose my friends at Continental Wind Power, for example, want to lease one of their 400 kilowatt wind turbines to a factory, or a farm, or a school. Can the transaction be based on a standard lease agreement? Not in today’s world. A gaggle of lawyers is going to be involved on both sides for quite some time. That’s not how established businesses and industries work; can you imagine telling a car salesman that you’ll have your lawyer redraft the lease agreement on that new Buick?
Distributed generation has a long journey ahead of it, but the destination will be more than worth the trip.
Let us suppose that a few people lease such a wind generator, supplement it with PV power, and disconnect themselves from the grid. From where will their power come when the wind is not blowing and the sun is not shining? When only minimal amounts of power are required such as for operating a few LED lights, a radio, and recharging cell ‘phones, battery power may solve the problem especially if people are willing to accept interruptions from time to time. But where total reliability and large amounts of power are absolutely required, that scheme simply is not practical.
I suppose that they could use Diesel generators for back up power, but that would add additional cost and require burning fossil fuels.
I have been a fan of distributed generation for a long time. I believe every house and building should generate at least some if not all of it’s own power. If it does nothing else it at least reduces the load on an aging electrical infrastructure especially during what is typically peak demand periods. It also increases efficiency because power is used at the point of generation or within the immediate vicinity of where it is generated instead of having to be shipped in from distant power plants at a loss of efficiency. My nearest power plant is about 40 miles away. That’s a lot of wire and power is lost. It also reduces the amount of power that must be “imported” from commercial generation facilities and helps to level the load.
Storage of power for when it is not being generated is a major need. I have FLA deep cycle batteries that I use to keep me going for a period of hours but they are not adequate for extended periods of time. These batteries are also not terribly robust and require care in their use. There are limits as to how hard and deep they can be charged and discharged without hurting them and they typically will last only 7 years or so. Edison nickel iron batteries are very much more robust and better suited for this type of use and will last 50 years before the fluid must be replenished and then will last another 50 years but are a little less efficient than FLA batteries. They can be charged and discharged harder and discharged completely and left dead for years and will still come back and hold a charge like the day they were made with no damage. An FLA battery is dead forever once it is run out like that. If the zinc/air battery can be perfected it may prove to be a useful alternative to the FLA battery. It will be interesting to see if these batteries can withstand the rigors of this type of use.
Having a backup generator in the typical sense is not really the correct alternative. In order for a typical gas or diesel generator to replace grid power it must run at 3600RPM in order to generate 60Hz. This means if is consuming a lot of fuel all the time. I have a car alternator hooked to a lawnmower engine for backup power. Since I have an inverter generating my AC and I am not directly generating AC at 60Hz from the generator I can run it much slower. The speed becomes based on how much air I need to move through the alternator to keep it cool based on how much power I need. Typically I can run it at 1/3 the speed of a regular generator. My engine is also not as big as a regular generator engine is.
As an example of this type of arrangement I relate the story of a recent power outage which lasted 2 days. Most of the residents of my 110 house neighborhood abandoned the neighborhood entirely for the duration. Those that stayed had gas generators and had to run them at full speed all day and night until they shut them off to go to bed at which time they had no power at all. The neighbors I talked to about this were using about 5 gallons of gas a day.
I had four 175watt solar panels and a small wind turbine and my little generator. During the day I could run all that I needed to from the panels and wind turbine using the battery storage as needed. When night came I fired up my little generator and used it to keep the batteries up. We ran the microwave to heat up dinner and watched movies on the entertainment system and I used the computer room as if all was normal. The generator made power at a steady pace. When more power was required the batteries provided and when less was required the batteries were recharged. When it came time to go to bed I would shut my generator down but still had the batteries and my emergency lighting tied to the batteries throughout the house so I could operate with decent lighting after shutting the generator down while preparing for bed. My neighbors had to resort immediately to flashlights once they shut their generators down. During the entire 2 day outage I used a total of 1.5 gallons of gas. My neighbors used at least 10 gallons and had to make trips to the gas station to fill their only 5 gallon jug. Essentially I have a hybrid power system for my house.
Having a more efficient house that uses less power generally is very advantageous in this situation. My entire house runs on about 13 kWh/day. Paying attention to power usage so it can be used when it is being generated is also a plus. You can’t just willy nilly use power whenever the whim hits you. The old adage “make hay while the sun is shining” definitely applies here in a most literal sense.
The bottom line here for me though is that distributed generation can and should be done. It is a change in habit and better storage needs to be developed but these things are both doable and should be done. It reduces the amount of fossil fuels that need to be consumed at least while power is being generated at each house. Any reduction in the use of fossil fuels is a good thing.
“Having a backup generator in the typical sense is not really the correct alternative. In order for a typical gas or diesel generator to replace grid power it must run at 3600RPM in order to generate 60Hz. This means if is consuming a lot of fuel all the time. I have a car alternator hooked to a lawnmower engine for backup power.”
Actually, it’s not quite that bad.
Generator systems are readily available that incorporate an inverter. They maintain efficiency over a wide range of loads by varying the speed so that it is always as low as possible to produce the power being used. The inverter maintains a constant 60 Hz regardless of the speed at which the engine and generator are operating. The system comes in a variety of sizes and is used in motor homes and other places.
Automotive generators are not very efficient, nor are lawn mower engines. Thus the combination of a generator and lawn more engine is very inefficient.
Having to back up a solar system with either the grid or home engine-generator increases the investment cost. In fact, the solar system does not decrease the grid and power plant investment since they still have to be able to provide adequate power when the sun is not shining. The solar system can, however, reduce the amount of fossil fuel used, but not by enough to solve global warming problems. What is needed is a system that is available 24 hours per day 365 days per year that does not use fossil fuel at all ever. The only system that can do that is nuclear.
The problem with nuclear power is that we have chosen the wrong nuclear technology. There are numerous type of nuclear reactors and we have chosen a bad one partly because it fits in very well with the desire to build nuclear warheads. We should be implementing a project on the scale of the Manhattan project to develop a better, safer, and more economical nuclear power system. The liquid fluoride thorium reactor (LFTR) seems particularly promising; a prototype was successfully operated a few decades ago then abandoned partly because it could not contribute to nuclear arms.
People should not be condemning nuclear power unless they have educated themselves on multiple nuclear technologies. I highly recommend reading the book Super Fuel: Thorium, the Green Energy Source for the Future by Richard Martin. It is readily available from the usual sources.