Ninety seven percent of scientists agree that man-made climate change is a real and present danger to the health of the planet. The emissions produced by the burning of fossil fuels is causing changes in the atmosphere that are impacting upon temperature, extreme weather events and rising ocean levels. Climate change is arguably the biggest threat to life on earth we currently face.
The major contributor to the problem is our reliance on fossil fuels for energy. Burning gas, coal and oil – be it in factories to create electricity or in automobiles in the form of gasoline – releases harmful toxins such as carbon dioxide that absorb and emit thermal radiation back on the earth when they are in the atmosphere.
A secondary problem with the use of fossil fuels to meet the energy needs of the human population is that they are finite resources. Indeed, some believe that we have already passed the point of ‘peak’ production and that from now on they will become scarcer. As reserves are depleted there will be increased conflict over the scarce remainder. That is, if we don’t do something to reduce our need for these resources.
The best way to reduce the need for fossil fuels is to find ways to produce energy that do not harm the environment and are renewable. The good news is that we already have several such methods available to us; we just need the political will to make them more central to our energy plans.
Energy from the sun is free and inexhaustible. Solar panels capture sunlight and convert it into energy. There are two main ways of doing this. The first is solar thermal energy, which converts solar energy into heat. This can be used to heat water or even to drive a refrigeration system. Solar thermal energy can also be utilized to create steam, which in turn can drive turbines to produce electricity. The second method is termed photovoltaic, which converts the energy from the sun directly into electricity. This is done by the use of solar cells that can be integrated into building rooftops or placed in areas of open land.
Wind is another natural weather phenomenon that can be harnessed to produce energy. Fluctuations in temperature and air pressure combine with the rotation of the planet to make air move around the surface of the earth. Placing turbines in the path of this wind enables the production of electricity. The blades of the turbine are rotated by the wind, which drives an electrical generator. A single turbine can feasibly provide all the energy requirements of a single property depending on the local climatic conditions, while wind farms use multiple turbines to aggregate energy for a larger location, such as a town. Wind farms can be located on the land or in shallow coastal waters of the ocean.
The ocean can provide energy in other ways than simply the site for wind turbines. There are two types of ocean energy. The first is produced by the kinetic energy of water movement. Waves and tides can be harnessed to drive electrical production via turbines. The second type of energy in the ocean is that from the thermal heat the ocean has absorbed from the sun. It utilizes the temperature difference between the warmer surface waters of the sea and the cooler waters at depth to run a thermodynamic heat energy which can create electricity.
Similar to ocean power, but located on water sources on the land, hydropower harnesses the energy of falling or flowing water. The liquid is diverted onto turbine blades that rotate a shaft to drive an electricity generator. In the past hydropower was used to turn watermills on mills to rotate grain grinders. Today hydropower systems are typically incorporated into large dams.
Permaculture gardeners know how much benefit decaying plant and animal matter can bring to the soil on their plot. That’s why compost and mulch are integral parts of permaculture design. But the energy released from these materials can also be harnessed to produce power. Bioenergy production takes ‘waste’ material – be it agricultural and forestry castoffs, manure or municipal landfill waste – and captures the gases that are released as they decompose. These gases can then be used to create heat, to drive turbines to produce electricity or to produce fuels for machines and automobiles.
Decay plays a part in geothermal energy as well, although on a much longer timescale. There is a constant flow of heat from the centre of the Earth to the surface. The heat at the center – which are over 5000 degrees Celsius – is produced by the decay of radioactive elements such as uranium and thorium in the Earth’s core over millions of years. This energy is harnessed by either extracting water from below the sub surface rocks, because it has been heated by this decaying energy and can create steam to drive turbines, or by pumping cold water into those rocks, allowing it to be heated, then harnessing the resultant steam when the water is returned to the surface. Geothermal energy has the benefit of not being reliant on the time of day or weather for production, and geothermal plants can theoretically operate 24 hours a day.
Many of these methods of producing renewable energy can be combined to create hybrid systems. For instance, solar panels are often incorporated into wind turbine design, as the locations in which the turbines can be most effective are often the same that experience good levels of sunlight. The energy from the two sources is aggregated to generate more electrical energy.
Permaculturists and other citizens can certainly investigate placing solar panels or a wind turbine on their property to reduce their reliance on fossil fuel energy and lowering their fuel bills. It is also important that political parties – who are subject to concerted lobbying from fossil fuel companies – have the far-sightedness to make renewable energy a primary goal in energy policy. So let your local representative know that you favor candidates who support renewables.