Nerve 14 - Technical Solutions to Climate Change

Most people now know that the atmosphere and the Earth’s surface is slowly warming up, known as ‘global warming’. If this continues much longer, there will be large-scale effects on the earth’s climate. Deserts will spread, there will be shortages of drinking water, there will be a rise in the level of oceans that will flood coastal areas, and the frequency of violent storms will increase. There will also be indirect effects, such as the spread of disease and the elimination of many biological species. In fact, some of these changes have already begun!

Technical Solutions to Climate Change

What is causing this global warming? There is now almost universal agreement (99% of professional climate scientists) that global warming is the result of human activity. Certain gases such as carbon dioxide (CO2) and methane released into the atmosphere cause the atmosphere to behave like greenhouse glass, and are therefore called ‘greenhouse gases’.

The most important cause is that we are burning fossil fuels which release CO2 into the atmosphere. We are also cutting down rainforests which help to absorb the CO2 from the atmosphere. Clearing rainforests also releases CO2 – both from the soil and from burning the resulting wood waste. This destruction of rainforests therefore has a double effect and causes about 25-30% of the annual CO2 net increase.

What can be done to stop further global warming? We must do at least two things. One: immediately stop cutting down rainforests. Two: stop using fossil fuels for our supply of energy. The first is clearly possible, but would require an international agreement with teeth, that is, the ability to enforce it against vested logging interests. The second is also equally possible over time, but also would require political determination to confront and defeat powerful vested interests such as the oil and gas companies, and the road and car lobbies. There are no technical or scientific reasons why all of the present requirements for fossil fuel-based energy cannot be replaced by so-called ‘renewable’ energy sources that do not emit any significant amount of greenhouse gases, over a period of ten to twenty years.

What is meant by ‘renewable energies’? They are forms of energy that will not run out in any meaningful time-scale, say, hundreds of thousands or even millions of years. Most forms of renewable energy are derived from the energy of the sun, either by directly converting sunlight into electricity using photocells (this is called photovoltaic conversion or PV for short), or else into heat for hot water and heating of our houses. The latter is called ‘solar thermal’ conversion. Another form of solar power can be obtained by focussing solar energy using mirrors on to a boiler containing water or a molten salt. In both cases steam is produced which can create electrical energy just as it does in power stations today. This is called concentrated solar power or CSP.

Other forms of indirect solar energy are those derived from wind or waves. The sun heats the atmosphere in some places more than others, and this creates pressure differences, which causes winds. Some wind energy can be turned into electricity using wind turbines, or else used to create waves, which can also be turned into electricity using suitable turbines. Another form of indirect solar energy is hydroelectric power. The sunlight evaporates water into the atmosphere, which then falls as rain and is collected in reservoirs. The water in the reservoir can then be used to drive a turbine generator. There is another indirect form of solar energy that is also referred to as ‘renewable’, that derived from biomass, which uses sun energy to grow. Some people believe that this form of stored energy places long-term stresses on the environment, which might not be sustainable.

There are two other forms of renewable energy that are not derived from sunlight. They are geothermal and tidal energy. Geothermal energy uses the heat that flows up from deep inside the Earth to create steam. Tidal power mostly comes from gravity forces due to the moon that cause the tidal movements which can be used to drive turbine generators.

There is approximately 10,000 times more sunlight energy falling on the earth in a single day than is required by all human beings to have a decent standard of living during that day. So only a small fraction - 0.01% - needs to be captured. There is thus no need for the dangerous, polluting, and very expensive nuclear energy. The usual claim by those who oppose renewable energy is that it is too expensive and also intermittent. The latter means that the energy is not always available because the sun is not always shining or the wind blowing. The so-called intermittency problem does not apply to hydropower, geothermal, biomass, and tidal power, and there are several ways of solving it for other renewable sources. The solar energy from PV can be used to create hydrogen, which can be stored and then converted back to electricity in a fuel cell, which is a kind of battery. Hydrogen can also be used to power aircraft. Engineers have carried out detailed design studies on High Voltage Direct Current (HVDC) grids for Europe and North Africa. Many different sources of renewable energy can be connected to this grid thus largely smoothing out the supply and thus solving the intermittency problem.

Is renewable energy too expensive? Not at all - wind, hydroelectric, geothermal and tidal power are all well-proven, mature technologies of comparable cost to fossil fuel. Wave energy technologies are not far behind. Recent advances in Solar PV now make it possible to produce solar cells at similar prices to fossil fuel energy. With economies of scale in manufacturing, all renewable technologies can compete with fossil fuel. If the external costs due to global warming caused by fossil fuels are included then renewables are far cheaper than fossil fuel-based energy.

Thus the problems are almost entirely political, not economic or technical. This involves confronting the powerful interests such as oil-and-gas corporations and the politicians in their pay.

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