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The Future of Solar Energy

Concentrating Solar Thermal Power- a first generation technology, but now with the ability to concentrate solar power using parabolic trough plates unrestricted by scarce material availability, with rare earths and silvered mirrors replaced by common commodities such as stainless steel, aluminium and glass.

The Director of the Future Planet Research Centre- David Hunter Tow predicts that recent advances in solar technology may be sufficient to shift the balance from fossil to renewable energy just in time to save humanity from a likely heat death.

Solar technology is about to take off and may finally be on the threshold of displacing a large chunk of fossil fuel dependancy.

This is very good news indeed- for humans, life on Earth and possibly the Universe at large if we are the only super intelligent life form that calls it home.

Just as it seemed that the mega fossil fuel producers of coal, natural gas and oil would drive Planet Earth over the carbon cliff, major improvements in the efficiency of solar power, in tandem with advances in the sustainability of homes, workplaces and cities, has at last opened a small window of opportunity to reverse the slide to oblivion.

The solar energy absorbed by the earth’s oceans, atmosphere and land in less than two hours is more than the total energy the world uses in a year, and is twice as much as will ever be extracted from its fossil resources. The Sun therefore not only rises every day, but every day provides the means for possible salvation.

And just in time, as the planet teeters on the brink of ecosystem collapse.

A massive surge in research and innovation has pushed solar energy to the point where crossover from fossil to renewable energy is feasible, at least for most domestic, transport and light industrial applications, within the next few years.

Panic about the world’s prognosis hasn’t quite set in yet but it’s getting close, with geo-engineering trials already beginning. These involve for example the spraying of chemicals into the atmosphere to reflect sunlight to cool the earth. But the risks are high, including the possibility of reducing global rainfall and causing further damage to the ozone layer, thus threatening food supplies to billions of people and in addition allowing high polluting industries to continue to free ride, causing further irrevocable damage.

A State of the Future Report just released, with contributions by 2700 experts backed by UNESCO and the World Bank, presents another grim vision of the shortages and violence that will certainly eventuate if a solution is not found; as does the latest projections of extreme weather events by the UN International Panel for Climate Change.

With half the world facing poverty, pandemics, unemployment and violence due to scarce water, food and energy supplies, rapid climate change will be the biggest crisis the world has ever faced. But on the positive side it might also offer the incentive for humanity to become more ethically responsible in its future management of the planet, investing in the next generation of greener technologies, with Governments cooperating to achieve permanent economic sustainability, democratisation and eventually peace.

But in the meantime the situation is becoming dire and according to projections a tipping point is fast approaching. Carbon levels have reached 400 ppm in the Arctic, the same as 3 million years ago during the Pliocene era, so it’s not just a matter of short term natural variability. CO2 emissions have increased in 2011 by 3% above 2010 levels, but emissions need to decline by 3% per year to have any chance of stabilising global warming, so that by 2050 they can be at 50% of present levels.

This will be an extremely difficult goal to reach. By 2015 India and China will both have outstripped the US in energy consumption by a large margin and although making progress on the renewables front are still totally dependent on fossil fuels.

But there’s no choice about making the switch if humans are to survive. The US has just experienced one of the most extreme droughts and heat waves in its history. This is leading to massive grain and fresh water shortages globally, while at the same time putting major strains on existing electricity grid infrastructure and fuel dependency- a pattern becoming more common across the world, particularly in the developing counties of Africa and Asia.

Recently the combined strain of an expanding consumer population and a bad monsoon season, plus the high cost of imported fuel and a dysfunctional grid system, caused a rolling blackout affecting 600 million people in India – over half its population. Only the use of expensive diesel generators kept essential services such as hospitals, schools, banks and communication centres operational.

Current breakthroughs in renewable energy, particularly solar, are therefore essential. Right now with concerted action, solar plants could be built to more than meet projected electricity demand in the future, but it won’t happen quickly, because of deeply entrenched fossil fuel dependencies.

But on the bright side a number of industrial baseload energy projects are already under development including-

Desertec –part of the Great African Grid- a proof of concept project based in Morocco, aiming to supply 15% of Europe’s energy from the solar power of the Saharan desert, initially to Germany, but longer term with 56 partners from 15 countries.

Medgrid- another North African project linking solar and wind farms, with 20GW of generating capacity of which 5GW would be exported to Europe.

These and other renewable energy projects would in turn become components of a future European SuperGrid, channelling renewable energy across North Africa, the Middle East and Europe; serving as the backbone of a larger European SuperSmart Grid

A more futuristic concept is being planned by the Japanese, aiming to create the Lunar Ring project on the moon, maintained by robots, using superconducting cables to channel power from reflected sunlight to transmission centres and a receiving station near the earth’s equator for distribution to cities and towns.

At the same time, countries such as China and Germany are leading the charge in solar technology manufacturing as well as other renewables such as wind. China leads the market in green economy products such as solar cells with a huge push to reduce carbon intensity- the ratio of CO2 levels to GDP.

Germany already generates 4% of its energy from solar power. On a sunny day this can increase to over 35%, including energy from a million solar panels on houses, buildings and the sides of highways- more solar panels than rest of world combined.

Even in Saudi Arabia, the largest exporter of crude oil, the tide is turning. It produces 8.3 million barrels of crude oil daily- half consumed by the domestic market and its industries. Domestic demand will double by 2028 which would compromise lucrative export capacity. The alternative is to substitute gas for utilities. But with gas currently subsidised to 15 cents a litre it is battling to balance a high standard of living for its population and long term energy security.

It has therefore Announced a $109 billion plan to create a solar industry based on thermal concentrated solar power-CSP, to generate a third of the nation’s electricity by 2032, focussing the sun with mirrors to drive turbines and storing the energy in molten salt. With this technology the Saudis could export solar energy for next twenty centuries.

Saudi Arabia also has lots of sand rich in silicon, needed to make high quality polysilicon solar cells and has already announced partnerships with Germany and South Korea to produce up to 10,000 tonnes of extra pure polysilicon for solar cell production per year.

Despite the doomsayers, transition to a green energy regime would not reduce overall energy sector employment. The global renewables sector currently employs 5 million workers. This is estimated to increase to 30 million within two decades.

But as well as breakthroughs in technology, a major driver for adoption of renewables is the shift towards sustainable architectures for urban living. The recent advances in solar technologies referred to below, are ideally placed to support this evolution.

The transition within cities will take the form of small self-sufficient interconnected neighbourhoods, within walking or cycling distance of essential service centres. These will provide the full range of communication, education, work, health, leisure and social resources. Local transport systems will utilise advanced battery or hydrogen cell electric power technology using sunlight to split water, which will continue to improve energy density outputs.

Within ten years the impact of global warming will dominate city planning. Buildings will be designed to conserve energy, with surfaces utilising flexible thin film and organic solar panels. In addition, high growth public gardens, green belts and mini-parks will generate cooling air-flows and most surfaces will be utilised to collect runoff water to support sustainable horticulture. Efficiency and recycling savings of the order of 30% on today’s levels will be available from the application of smart adaptive technologies in power grids, communication, distribution and transport networks, manufacturing plants and consumer households. Garbage will be totally recycled, with organic waste generating significant levels of methane energy for local heating and power grid usage. Excess capacity will be fed to the major power grids, providing a constant re-balancing of energy supply across the world.

The new solar technologies are now positioned to mesh with this revolution and include advances in the following areas –

Photovoltaics – Solar photovoltaic thermal systems that can generate both heat and electricity- using amorphous silicon cells, both cheaper and with 10% greater electric output than existing crystal silicon cells. In addition low cost, high efficiency solar cells can now be tailored from any common semiconductor material such as metal oxides and sulphides. Such cells also have the potential to convert 28% of sunlight into electricity using a new technique of photon recycling.

Solar cell advances- with active layers made from carbon nano-materials having the same advantages as polymer based cells. They are flexible, tuneable and photo-stable. Advances in organic solar cells that can split particles in the polymer layer have also been achieved. These are not as efficient as inorganic solar cells but much more cost effective.

Concentrating Solar Thermal Power- a first generation technology, but now with the ability to concentrate solar power using parabolic trough plates unrestricted by scarce material availability, with rare earths and silvered mirrors replaced by common commodities such as stainless steel, aluminium and glass.

Solar Film Surface Coatings- solar power generating surface coatings using nanotechnology- allowing windows and glazed surfaces to be used as luminescent solar concentrators, with thin films absorbing sunlight and directing it to narrow solar cells at the perimeter of windows. Such surface coatings can also be used on the glazed facades of office blocks and houses. Film coatings can even be wrapped over vehicles and buildings to gain maximum sun exposure. This is a less expensive and toxic method than using non-film materials. Polymer plastic cling film solar cells that use flexible layers deposited over large areas can also be applied to produce efficient solar structures.

Printing and paint-on solar panels- ultra cheap solar energy panels for domestic and industrial using can be created using high volume printing methods, producing nanoscale films of solar cells 1000 time thinner than width of human hair. Also paint-on solar cells, using quantum dot nanoparticles of titanium dioxide painted on the outside of homes or buildings can be used to power appliances and equipment inside.

Artificial Photosynthesis- this technology mimics the natural process in plants and bacteria, converting sunlight into energy by splitting water molecules into Hydrogen and Oxygen creating free protons and electrons. Plants achieve 95% efficiency compared to 10-15% in human photovoltaic cells. Quantum effects have been discovered in first stage of plant photosynthesis, allowing different pigment molecules responsible for absorbing energy carried by light to be excited by a single photon simultaneously.

Optimised photosynthesis can be achieved by learning the deep secrets from plants and marine algae, which have natural antenna- complexes composed of chlorophyll to route the flow of energy using principles of quantum mechanics.

The above advances in solar power generation portend economies of scale, efficiency and cost that will soon begin to challenge the economics of fossil fuels, supporting commercial application, quite apart from the small issue of saving humanity from a Venusian future.
The sun has always been the dominant driver of new life for all civilisations- ancient and modern. Now it is being asked to apply its awesome power to allow 21st century life to survive. The question is – can the sun rise fast enough to save its planetary offspring?

David Tow,