ESF Task Force For Clean Solar Energy
Strasbourg, France – The European Union and its member states are being urged by leading scientists to make a
major multi million Euro commitment to solar driven production of environmentally clean
electricity, hydrogen and other fuels, as the only sustainable long-term solution for
global energy needs.
The most promising routes to eventual full-scale commercial solar energy conversion
directly into fuels were identified at a recent international meeting in Regensburg,
sponsored by the European Science Foundation (ESF). An interdisplinary task force was
established at this meeting to make the case for substantial investments in these
technologies to EU and national government decision makers.
The fundamental issue is that total annual global energy consumption is set to at
least double from its current level of 14 TW by 2050, while fossil fuels will start to
run out. The use of fossil fuels also produces unacceptable levels of carbon dioxide,
causing global warming and has disastrous effects in many areas, such as food production.
Apart from solar energy, the shortfall can only be made up by renewable sources such
as wind, along with the other non-fossil, non-renewable fuel source of energy, nuclear. But these will be unable to satisfy the predicted increased energy needs and certainly
will not be able to replace fossil fuels entirely, even for electricity production alone.
Another problem is that they will not readily yield stored fuels. Without an unexpected
breakthrough in electricity storage, there will be a continued need for fuels for around
70of total global energy requirements, particularly in transportation, manufacturing, and
domestic heating. Electricity only accounts for 30 of global energy consumption at
However solar energy is plentiful since enough reaches the earth’s surface every hour
to meet the world’s annual energy needs. The problem lies in harnessing it. Nature has
perfected, in photosynthesis, a highly efficient and flexible means of doing this across
a wide variety of scales, from isolated bacterial colonies to large forests.
Substantial progress has been made recently, particularly in Europe, in understanding
and mimicking these natural processes, sufficient for scientists to be confident that
they could use them to produce fuels on a commercial scale. The focus of research should
therefore be on drawing inspiration from biological systems for the creation of both
natural and artificial solar energy conversion systems that allow in the long run for a
stable and sustainable energy supply. There should also be an aim to reduce the human
ecological footprint and thereby increase the global ecological capacity using technology
that is environmentally clean, for instance by conversion of carbon dioxide back into
fuels in a cyclic process.
The ESF task force is recommending that three parallel avenues of solar energy
research for generating clean fuel cycles should be pursued in Europe:
- Extending and adapting current photovoltaic technology to generate clean fuels
directly from solar radiation.
- Constructing artificial chemical and biomimetic devices mimicking photosynthesis to
collect, direct, and apply solar radiation, for example to split water, convert
atmospheric carbon dioxide and thus produce various forms of environmentally clean fuels.
- Tuning natural systems to produce fuels such as hydrogen and methanol directly
rather than carbohydrates that are converted into fuels in an indirect and inefficient
These three research themes will overlap, and all will exploit fundamental research
elucidating the precise molecular mechanism involved in the splitting of water into
hydrogen and oxygen in photosynthesis by both plants and oxygenic bacteria. This process,
which evolved 2.5 billion years ago, created the conditions for animal life by converting
atmospheric carbon dioxide into oxygen and carbohydrates, and also produced all the
fossil fuels, which humans are turning back into carbon dioxide at an increasing rate,
threatening catastrophic environmental effects. The same process now holds our salvation
Although the principal products of photosynthesis in plants and bacteria are
carbohydrates, some hydrogen is produced in certain algae and bacteria, providing a basis
for genetic modification to increase yields, and for the creation of suitable artificial
systems. Furthermore, photosynthesis is capable of generating other chemicals currently
made industrially, such as nitrates amino acids, and other compounds of high value for
chemical industry. The European research programme will therefore seek to develop systems
for converting solar energy directly into such chemicals with much greater efficiency,
offering the prospect not just of producing unlimited energy, but also fixing atmospheric
carbon dioxide to bring concentrations back down to pre-industrial levels as part of the
overall thrust for clean renewable energy.
There are considerable challenges, with the first being to mimick the functioning of
natural photosynthetic systems, particularly photosystem II, the enzyme complex in the
leaves of plants that splits water into hydrogen and water via a catalyst comprising four
manganese atoms along with some calcium. Significant progress has been made recently on
this front. Participants at the ESF’s brainstorming conference, describe the solar fuels
project as the quest for building the "artificial leaf". There is growing conviction in
Europe and elsewhere that, by 2050, a large proportion of our fuels will come from such
"artificial leaves", and that there is no time to lose starting the crucial enabling
research, in order to gain technology leadership in this important future key technology.