To fit in with the Carbon Futures Challenge, I thought I’d look at some types of energy for electricity and fuel that aren’t based on fossil fuels. These are a problem because they are basically converted wood and plankton so they are very high in carbon. Burning them creates carbon dioxide, which contributes to the greenhouse effect. Most of the alternative energy sources will only work in particular areas so we are going to need to shift the way we think about generating power, from one large station supplying the whole grid to many different stations that all feed in and take the load at different times.
Generating electricity is all about movement – moving magnets around a coil of wire (or vice versa) produces an electric current, this is how power stations work. Something, generally steam, is forced past a turbine that has the magnets and coils in it, et voila. So the search for alternative power supplies is a search for things that can move the turbines or things that can make steam to move the turbines.
Fuels are different, the internal combustion engine runs on explosions. Fuel is compressed in a piston and a tiny explosion is set off which pushes the piston back up the cylinder. Repeat on alternating sides and it will start going around in circles, which can then be transferred to the wheels.
- Wind power – one of the oldest power sources it is still used throughout the world. Windmills for pumps and to grind flour and especially wind powered sails have been important for thousands of years. Today’s wind farms have a few differences, but they are one of the most advanced types of alternative energy.
- Hydro generation – Water power is as old as wind with different types of water wheels. Hydro generators use dams or strong rivers to create a current and move the turbine directly. While water sounds lovely and natural, dams can have major environmental consequences.
- Tidal power – This works very similarly to hydro generation, the tide is forced through narrow channels to turn the turbines. Unfortunately it will only work where there are very large tides, and there can be consequences to blocking off the mouths of inlets.
- Wave power – There are some obvious difficulties here because of the irregularity, but some very inventive designs are coming out and being trialled.
- Geothermal – this usually applies to areas that are volcanically active and are naturally producing steam that can be directed to the power plant.
- Hot rocks – very similar to geothermal energy but it uses deeper rocks that are hot through natural radiation. Water is pumped down under high pressure and turned to steam which comes back up to a plant above.
- Solar power – This is the solar cells that you know of from pocket calculators. They don’t actually work with turbines but reactions in the cells themselves. There are groups looking at putting them into roads, given the number of roads there are it would supply more than enough power for the US.
- Solar furnaces – There are a few different types of these working in desert areas. Basically they use ranks of mirrors to focus the sun onto something that carries the heat and produces steam. There is a proposal to use these in the Sahara, a fraction of a percent of the desert would produce enough electricity for all of Europe. Unfortunately there are political as well as practical implications in having all of Europe dependent on only a few connections across the Mediterranean.
- Nuclear fission – This is the one that powers nuclear power plants using Uranium. Radioactivity is completely natural, in power plants it is concentrated far more than normal (although there was a set of low power natural fission reactors at Oklo a couple of billion years ago) and turned into self sustaining reaction. Once again, the heat from the reaction heats water to make steam and turn the turbines. There are two main problems with fission reactors – in the short term, keeping the reaction under control so it doesn’t turn into a nuclear bomb, and in the long term finding a place to store the waste which is highly radioactive.
- Nuclear fusion – This is the reaction that fuels the sun. It would be a wonderful way of producing energy, extremely efficient if we can only keep from blowing ourselves up. Part of the problem is that it requires incredibly high temperatures (like the sun!) and has to be contained within very strong magnetic shields. There are some small experimental reactors but we are nowhere near actually using it.
- Methane from landfill –Think of them as giant compost heaps, busily producing all sorts of useful gases that can be harvested and then burnt. I’ve seen theoretical pipe systems but don’t know if there are any actually working. It is a good way of recycling and can in some ways be a carbon gain – methane is a far more potent greenhouse gas than carbon dioxide. If you are burning the methane then that is better than it being released on its own. However if it is safely locked away and not being released, the carbon is a problem.
- Bioethanol – Good old fashioned alcohol made from grains. Alcohol burns well and a percentage can be put into a normal petrol engine with no modifications, reducing the need for oil refining (although it still produces carbon dioxide). Unfortunately there are other good uses for grains, like eating, or the land, which could be growing food. My opinion is that this is a short term solution that can be used now to make what we already have work a little better while we are looking for a long term solution.
- Renewable diesel – this is similar to bioethanol, diesel can be produced from a number of oils including cooking oils. It is a good way of recycling or using things that otherwise wouldn’t have been used, but will not ultimately solve the problem of carbon dioxide emissions.
This isn’t a type of energy per se, which is why I haven’t added it to the list. It is more a style of energy supply. Rather than having a massive power station somewhere, or even several, many people have a small generator of some sort on their property. The type of generator would depend on what is appropriate to your area, many places already have solar panels on roofs or ones that burn a variety of fuels. All houses are connected to the grid in a two way link, putting power in when they are producing more than they need and taking it out when they aren’t producing enough. This is already working all over Australia in a small way, in my personal opinion it would be a great answer to the problems currently facing us. Empowering because people could choose the solution that suited their needs rather than being dependent on a company or government and promoting a community solution.
What are your thoughts on alternative energy?
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