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 Solar energy is a particularly attractive option for several reasons. It may only account for 0.1% of the world’s electricity today (1) but the potential is enormous. The energy reaching the Earth’s surface from the sun in a single year greatly exceeds the Earth’s entire fossil fuel resources (2).
This energy is radiated constantly and at no cost. It can be micro-generated close to the point of use thus reducing transmission loss and freeing users from the need to connect to a grid. Solar energy, used in the form of electricity, also creates far fewer carbon emissions than burning oil.
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Grocery companies are finding it increasingly viable to exploit solar power | |
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Solar power therefore gives us hope of a complete solution to the world’s energy needs while also helping to resolve climate change, if we can tap into this resource efficiently.
Accelerating progress
There are promising signs that we can. Solar technology is advancing rapidly. The efficiency of leading edge photo-voltaic (PV) cells has improved from around 5% in the 1950s to 40% now. Global PV capacity has been growing at a rate of more than 40% per annum since 2000(1).
The cost is also falling. For households, the real cost of installing solar energy has dropped by around 85% over the last 20 years. Relatively cheap thin film cells can deliver 20% efficiency and so, for buildings in the right locations, solar power now gives a rapid payback.
With fossil fuel rising in price and with the extra imposition of carbon costing in some parts of the world, the financial equation keeps tilting towards solar. Tighter building regulations may mean that some form of solar power becomes mandatory for new buildings, irrespective of the economic case.
Grocery companies are finding it increasingly viable to exploit solar power. Modern store designs, even in the relatively cool conditions of Northern Europe (eg: Tesco in Ramsey, England), already incorporate various solar powered features.
Energy companies, universities and research laboratories across the world are prioritising solar energy and the pace of progress will probably accelerate with new nanomaterials offering the prospect of a rapid improvement in performance.
Just deserts
Major centralised solar power projects are creating particular excitement and a wave of construction is underway. For example, the Desertec Industrial Initiative in North Africa should come onstream around 2015.
The German Aerospace Centre forecasts that state of the art solar power plants like Desertec will produce energy at the rate of 6.5 US cents per kilowatt hour by 2020, less than half of the current domestic rate for electricity.
Longer term, centralised plants in the world’s sunniest spots could provide a high proportion of our energy needs. According to the TRANS-CSP study (involving a consortium of experts) about 17% of Europe’s total energy requirement will be met through imported solar power from desert areas by 2050.
This would require only 2,500 sq km of land, less than half of the area covered by Nasser reservoir near Aswan in Egypt, leaving plenty of scope for expansion. It would have the added social benefit of creating value for people living in a dry wasteland.
What’s holding us back?
There are certainly many reasons to feel optimistic about solar power. However, there remain some major obstacles and we have to surmount these before we can seriously think about a solar driven economy.
The sun’s output may be fairly constant but insolation (the energy striking a given area of the Earth’s surface in a given time) is highly variable. It depends on time of day, season, latitude and atmospheric conditions. To ensure a ready supply of energy, whenever and wherever it’s needed, we have to store and transport it.
Storing electrical power is expensive and involves a substantial energy loss, even though recent advances in electrochemical fuel cells offer promise for the future. Transmitting power also involves an energy loss, currently around 4% per 1,000 km of travel(3) with the distance from Cairo to Helsinki, to give an illustrative example, at 3,400 km.
Perhaps the single biggest obstacle though, is the amount of investment required. We not only need to invest in generating, storing and transmitting energy but also in the broader infrastructure. For example, to substitute solar power for fossil fuels in transport, vehicle manufacturing plants would need to be redesigned, a new network of refuelling stations installed and a wide range of oil based materials replaced… all at a time when demand is escalating.
For all of these reasons, solar energy will remain a supplementary source for the foreseeable future. The International Energy Agency estimates that solar power will be generating only 11% of the world’s electricity needs by 2050. Even our great grandchildren will still rely heavily on oil… if they can get it.
Projected growth of PV solar generated power
Source: International Energy Agency
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IGD Verdict
Solar technology could solve the majority of the world’s energy needs but only in the very long term. We face a century-long challenge to achieve a smooth transition from our oil-based economy to alternative energy sources
IGD’s advice:
- Think strategically on energy and anticipate ways that higher oil prices will reshape society
- Give urgent attention to saving energy at all points along your product supply chains
- Expect the price/performance ratio of solar energy to improve substantially and give it a high priority in your investment plan
References:
(1) International Energy Agency, Technology Roadmap
(2) Stanford University Global Climate and Energy Project, 2009
(3) TRANS CSP study |
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