Future energy sources

This article looks at future energy sources. This mainly includes sustainable energy sources which do not harm the environment, which we can use today and in the immediate future. In order to safeguard our environment and planet, the non-renewable and highly polluting fossil fuels will need to be phased out as soon as possible, they will run out one day, and nuclear fission will also need to be phased out as soon as possible as it produces radioactive waste which typically takes a very long time to decay, millions if not billions of years.

Solar and wind power on energy efficient buildings

Passivhaus compliant buildings, such as the flat shown
above, can have their own solar power.

Source: Passivhaus-Institut

In order to reduce our energy needs, every building should be constructed to be as energy efficient as possible, as 40% of all energy consumed is from existing buildings. One way to achieve this is to make all buildings conform to the Passive House or similar standard. Passive houses are recommended because buildings built to this standard are extremely energy efficient and comfortable to be in at the same time. It is not only new buildings that can be passive houses, existing buildings can also be retrofitted to this standard. Just doing this alone will tremendously reduce the energy requirements for the building.

These energy efficient buildings can and should also have their own solar energy, either as solar panels which are expensive, or better still (when available) using spray-on solar film for walls and windows and installing solar roof tiles which I would personally recommend. Such a building would at the very least be zero-energy (or minimal energy), and could even be a net exporter to the electricity-grid, especially if other energy sources are also added.  We can also have rainwater collection systems added not only to potentially generate more electricity (especially using nanotechnology), but also to provide water at the same time for gardening, washing machine, car washes, WCs, and (with a suitable filtration system) even for drinking water and showering.

Of course, the main electricity grid can still be used as backup for solar, and if installed, rainwater collection too. And of course the main water supply can still be used as backup for the rainwater collection based water supply.

If every building in your country was constructed to the passive house standard, with solar, and possibly even rainwater collection power generation for each building, imagine how much energy, especially electricity can be generated for the building, and how much surplus could be exported back to the electricity grid.  At the very least these type of buildings can really minimise energy consumption, especially when using OLED wallpapers for lighting in the future.

Solar power arrays and solar farms

It is recommended to carry on with existing solar power arrays. This is especially important for places which get a lot of sunshine. Having said that, simply having daylight alone (even on an overcast cloudy day) means a lot more sunshine than one thinks. Nanotechnology can also be used to make photovoltaic solar panels more efficient, this research is happening, as with spray-on solar film which also uses nanotechnology. But the photovoltaic solar panel is not the only solar power technology available. 

Solúcar PS10 solar power tower in Sanlúcar
la Mayor, Andalusia, Spain

Author: afloresm
Licensed under CC-BY 2.0

What can also be used instead is to have arrays of flat movable mirrors which can be used to reflect sunlight towards a tower and focus the sun's rays towards that tower, where the water in the water tank is heated to temperatures between 250 °C and 255 °C, and the resulting steam powers the turbine, generating electricity, this is called a solar power tower.  The Solúcar PS10 solar power tower, which is in Sanlúcar la Mayor, a small town 15 km west of Sevilla in Andalusia, Spain, is the world's first solar power plant is operational since 2007.  Construction of the nearby Solúcar PS20, the second generation solar plant began in 2006.   Both the PS10 and PS20 are estimated to generate enough energy to power the equivalent of the city of Sevilla, and are both scheduled to be complete in 2013. 

In the long term future, solar panels or solar panel arrays can even be put into space, current designs have the solar panels collecting the light and then transmitting the energy to receivers on Earth using microwave rays. Perhaps an alternative method of transmission might be discovered in the future. Solar panels in space would be consistently exposed to a high amount of solar radiation (significantly higher than on Earth) so is no longer dependent on weather conditions, but other problems would be meteoroid impacts and radiation damage in space.

However today and in the immediate future, solar power arrays are one way of using renewable energy to supply energy to the electricity grid, and their use should be expanded.

Wind farms

Wind farm in Ardrossan, Scotland

Author: Vincent van Zeijst
Licensed under CC-BY 3.0

It is also recommended to carry on with wind farms at the same time, whether offshore on onshore.  This is especially important to use in places where winds, especially strong winds, are common.  The existing wind farms can and should be retained, and wind farms can also be expanded. Of course, one of the main issues include safety for wildlife and wind farms should be kept away from bird migratory routes, and designed so that birds cannot come near the turbines if possible. There is the other issue that there are people who complain that wind farms ruin the scenery, to address these complaints why not make wind farms blend in with the scenery and complement it, and interesting designs could be considered too.  In the small Scottish town of Ardrossan, the local people even felt that the wind turbines there enhanced the landscape rather than spoiling it, and found that wind turbines were "silent workhorses" as one of the Ardrossan town councillors put it.  I believe this shows that the design can be used to make wind turbines enhance the landscape. Either way, the usage of wind power should be expanded.

Geothermal energy

Geothermal power station in Krafla, Iceland

Attribution: Mike Schiraldi, Wikipedia (English)
Licensed under CC-BY-SA 3.0

The usage of geothermal energy should also be expanded where practical. Geothermal energy, where thermal (heat) energy is extracted from the earth and converted into electricity, or used to heat water (as is done in Iceland). Geothermal power is scalable from a village to a big city, and is not a variable power source like solar or wind. Geothermal power also does not require anywhere near as much water for cooling compared to fossil fuel plants, and geothermal power only requires a minimal amount of land compared to conventional fossil fuel fired power plants.

The obvious place, and where traditionally where the first geothermal power plants were constructed, is to build close to the surface where tectonic activity happens, typically geysers, or near volcanoes. Binary cycle power plants is one modern type of geothermal plant, first introduced in the USSR in the 1960s. A more recent development is in Enhanced Geothermal Systems (EGS) which do not require convective hydrothermal resources, and which involve deep drilling, injecting high pressure water, then extracting the resulting heat from the steam. Depths for the EGS wells can be 3-5 km deep.

Although there can be emissions including carbon dioxide, hydrogen sulphide, methane, and ammonia, as these are obtained via fluids drawn from deep earth, existing geothermal plants emit 33.9 g/GJ (122 g/MWh) of carbon dioxide, which is a small fraction of the emission intensity of conventional fossil fuel power plants per GJ of power generated. Geothermal sources can also contain trace amounts of toxins such as mercury, arsenic, boron, and antimony, but the modern practice of injecting cooled geothermal fluids back to Earth mitigates this environmental risk.

Some caution is advised however with geothermal power plants (especially with deep level heat extraction), as geothermal power plant construction can adversely affect land stability and in extreme cases cause seismic activity (earthquakes) as happened in Basel, so care needs to be taken, especially in or near earthquake zones (Basel is in an earthquake zone). It must be also noted that it is very expensive to drill very deep.

Despite this the usage of geothermal can and should be expanded, and EGS is also worth considering where practical, and where care is taken during construction and/or drilling.  Although the easiest method still remains to construct near tectonic boundaries where practical.

Tidal power

SeaGen - world's first commercial tidal power
generator, Strangford Lough, Northern Ireland

Author: Fundy
Licensed under CC-BY-SA 3.0

The power from sea waves can be harnessed, and converted into electricity and other useful forms of energy. Tidal power is more predictable compared to solar and wind power.

There have been recent design improvements (dynamic tidal power and tidal lagoons for example), and turbine technology (including axial turbines, and crossflow turbines), which shows that tidal power is much more available than was previously thought.

Since the Earth's tides are dependent on Earth's rotation, as well as the gravitational attraction of the Sun and the Moon, this source of energy is limitless. This power source has great potential, and should definitely be considered. 

Nuclear fusion (long term future)

Deuterium-tritium fusion reaction

This is an energy source for the future, perhaps the late 21st Century or the 22nd Century onwards. Nuclear fusion works by fusing two or more atomic nuclei to form a single heavier atomic nucleus, currently known to operate at very high temperatures in the order of 1 million-100 million °C, and this releases vast amounts of energy. Nuclear fusion happens in the core of stars.

For fusion reactors, current designs involve two isotopes of hydrogen, deuterium and tritium, which get fused together, and this reaction generates six times as much energy compared to the equivalent fission reaction. 1g of nuclear fusion fuel (deuterium and tritium) would generate as much energy as 11t of coal.

Concerns however include to stop neutrons (a byproduct) from escaping although these would be absorbed by a material (for example a vanadium alloy or some material which can absorb neutrons), as well as tritium which has a radioactive half-life of 12.32 years.  This means that having secure and fail-safe systems which prevent any leakage would still be extremely important for fusion power plants, as it is with nuclear fission today.

There is no risk of a major tragedy caused unlike with fission (but industrial accidents are still a risk). Waste products are the radioisotopes which would result from material surrounding the plasma absorbing the neutrons from the reactor core, these radioisotopes would have a comparatively short half life at 50 years as radioactive mater, become low level waste in 100 years, and have the same radioactivity as coal ash in 300 years. However, as with fission, this waste has to be handled. By contrast, nuclear fission produces waste products which can have a half-life of thousands of years at least. A fuller analysis of nuclear fusion is shown in the publication Fusion as a future energy source: Recent achievements and prospects.

Although fusion is technically non-renewable, there is enough deuterium in seawater on Earth to 150 billion years based on the 1995 global power output.  However, to make tritium, lithium is required, and the lithium needs to be split in a nuclear fission reaction to make tritium (as well as the helium-4 byproduct.  Although lithium is quite abundant on earth, it is still needed for other purposes, including Li-ion batteries for example, and it is not infinite because the known lithium reserves are estimated to last 3000 years, and lithium from seawater would last approximately 60 million years.

The International Thermonuclear Experimental Reactor (ITER) in France, the Wendelstein 7-X in Germany, and the Large Helical Device in Japan, are demonstration proof-of-concept fusion reactors, whose development is in progress. Actual power generation for homes would be expected in the late 21st Century or the 22nd Century. Fusion Energy can also be used to propel spacecraft in the long term future (or could even be used just for spacecraft engines, should renewable energy meet all our energy needs on Earth).

Nuclear fusion is an energy source for the future.  There might be also alternative designs for fusion reactors, or new ways of igniting a fusion reaction in the future which have not been invented yet (fusion reactions have to be ignited, and then contained). Having said that, renewable energy will always have a very important role to play in meeting our energy needs, so will need to co-exist with fusion, once fusion is introduced. At the same time, while research continues into viable nuclear fusion energy, there is no need to wait until the first fusion power plant is made, we can have renewable energy now.