Low-Density Nickel Iron Batteries?
We have been continuing our research and work with Nickel-Iron (NiFe) batteries. NiFe batteries are non-toxic, extremely durable, and very tough. Lead-acid batteries are fragile, toxic, and short-lived. Lead-acid batteries dominate the off-grid market, and have largely destroyed it because they die so quickly.
All of the research and development of batteries, NiFes included, has focused on power density- storing a lot of energy in a small space. Thomas Edison made and sold NiFe batteries, intending them for use in electric vehicles and other portable uses where high power density is very desirable. For such uses, short recharge times are also desirable. NiFe batteries have lower power density and longer recharge times than lead-acid. Modern research on NiFe technology has continued to focus on these issues. (There is one substantial research project underway at Stanford University.)
From the perspective of how we do things at LEF, power density and recharge time are irrelevant. At LEF, we store energy in various ways that allow us to minimize the need for stored electricity. We store water in pressurized tanks, so we don’t have to run a water pump at night. Our buildings have massive thermal mass, so we don’t have to run a heating system at night. We will pump irrigation water through the house while the sun is shining, getting free air-conditioning in the summer from solar pumped irrigation water. We use high voltage DC motors when the sun is out. We use stored electricity for lighting, nothing else. Our NiFe batteries charge all day long from our solar electric panels. It would not matter if their recharge times were slow or if their power density was abysmally low. Big, cheap batteries would be just fine.
A few people have tried “out in the garage” experiments with homemade NiFe batteries. The basic ingredients — nickel, iron, potassium hydroxide (aka potash) — are easily available. We have been looking over Edison’s original manufacturing processes, as well as the documentation of various homemade NiFe attempts. From his shop in Pittsburgh, Eddie is going to continue the research and try to build low-density NiFes in mason jars. We are not so presumptuous as to imagine that we could outsmart the many well-endowed entities that have worked on high-tech batteries over the years. But it is very possible that low-density NiFes have been ignored simply because there is no immediate profit to be made.
If we can make cheap, low-density NiFes, it would be revolutionary. A very small solar electric panel could be wired straight to the batteries. Small houses in villages all over the world could have light with small LED flashlight bulbs designed to run on low voltage. That could be a cheap, very durable way to provide lighting to millions and millions of the world’s poorest peoples. Wish us luck. If the mason jar NiFes fail, we will continue our overseas efforts using purchased NiFes.
Finding a clean, sustainable way to cook food each and every day has proven to be the most challenging aspect of our project. A defining characteristic of LEF is that everything we do has to be as cheap and simple as possible. That is embedded
in our definition of sustainability. Finding tools and machines that are accessible to most of humanity is not easy. At LEF, we are using a combination of solar cookers (parabolic and ovens), and wood stoves. Our rocket stoves are very efficient, using about one-tenth of the wood of an old-fashioned wood cook stove. There are numerous organizations working to spread rocket stoves around the world. That’s a good thing.
The rocket stoves work, but they are an outdoor technology. They are a fire hazard. They mean that some ash and soot get into the food, and some smoke gets in the face of the cook. We built a biogas system at LEF a few years ago. (Biogas = methane = natural gas.) It worked, but there are limitations. The gasifier needs to be kept warm. In cold climates, sometimes they are buried. It needs to be of considerable size. It needs to be fed biomass each and every day.
Seeing the limitations of biogas, we have built a prototype solar boiler. We designed a tracking collector that followed the sun, but decided to use a simpler trough system that needs no tracking. The collector reflects light onto a pipe which contains water. The water boils and the steam collects in a storage tank. The steam could be then piped into a steam-jacket kettle in the kitchen to cook our food. Cooking would be as simple as opening a valve leading to the kettle.
We have been making solar steam, but so far, not enough to make it an effective heat source for cooking. We have some design modifications under way that should improve performance substantially. At LEF, we live with these technologies. We are currently eating small amounts of ash and soot in our food almost every day. Such is unavoidable when cooking with wood, and unacceptable in the long run, especially for our kids. The fact that we live with the technologies we espouse gives us a very different perspective than just experimenting with them.
Another advantage of developing the solar boiler is that we need the exact same parabolic trough setup for a solar ammonia ice maker, a super low-tech refrigeration system. We have thus given ourselves a head-start on that project. And we decided we are also going to look at biogas again. It could be a good bridge fuel for times when the weather does not support the solar boiler. Can we do it and still keep it simple and economical? Methane is a potent greenhouse gas. Can we control leakage? What is the impact of that on a larger scale? We will be seeking to answer these questions in the coming months.