Soon solar will be the
cheapest power everywhere
Chris Goodall in The
Ecologist
Towards the end of last year, Shell CEO Ben van Beurden made
a little-noticed remark. He said that solar would become the "dominant
backbone" of the world's energy system.
He didn't give a date for his prediction, or indeed define
what 'dominant' means, but he accepted that the sun will eventually provide the
cheapest energy source across almost all of the world.
This is what my new book, The Switch, is about.
Just how long will it take to wean the world off fossil fuels using just the
forces of the free market rather than quixotic governments? What technologies
will we need to complement the intermittent power of the sun?
In some ways, van Beurden's thought is an obvious one. The
light and heat coming from the sun provides a continuous stream of about 90,000
terawatts of energy to the planet. (Don't worry about the unit of measurement.
The important thing is that this number is six thousand times the requirements
of the entire world).
Energy needs will rise - probably doubling in the next 30
years - but even then we will only need to capture three hours' worth of
sunshine to provide everybody around the world with as much energy as they need
every year.
For comparison, the power of the wind averages less than
1,000 terawatts, or two orders of magnitude less than solar energy. Wind is
more difficult to collect and tends to blow far from centres of population. All
other potential sources of renewable energy are smaller still, usually by
factors of ten or one hundred.
Solar
is already beating fossil fuels on price
Solar is also cheap, and getting cheaper every month. The
price reduction has been steep and surprisingly consistent. Panels are being
produced today for about one three hundredth - 0.3% - of the cost in the
mid-1970s.
These cost reductions have been principally driven by the
yearly increases in the volumes produced; since the commercialisation of
photovoltaic panels began half a century ago the number of panels produced has
grown by an average of about 40% a year. Solar installations continue to grow,
now principally in China, India and other industrialising countries, and the
volumes of panels installed continues to grow year after year, helping drive
costs even lower.
In many parts of the world solar power is already the
cheapest way of delivering electricity. In places as diverse as Chile, Abu
Dhabi, parts of India or the islands of Hawai'i, recent auctions for new
electricity generation capacity have demonstrated that photovoltaics can beat
fossil fuels on price - no subsidy or special favours required.
As cost reductions continue, solar's price advantage will
spread almost everywhere around the globe. In remote mining settlements,
villages in Kenya and rooftops in California PV is already being installed
without a thought of alternatives. It is already, in van Beurden's words, the
backbone of energy supply in many locations.
Research scientists around the world are continuing to invent
new ways of turning light into electricity using simpler and cheaper materials.
In the book I talk to several technologists who are pioneering the next
generation of solar panels. These will be incorporated in the glass of windows
or hung on the outside of buildings.
Innovation in collecting energy from the sun at lower and
lower cost has at least another half century of progress to come.
And
this is only the beginning ...
One of the things that most surprised me in the research for
the book was how people in countries like Nigeria, where the electricity grid
doesn't come close to half the population, see solar photovoltaics as
democratising and accessible.
The analogy in their minds is the arrival of the mobile
phone. Fifteen years ago the fixed line phone network was struggling to expand
and only reached a few percent of the people in Nigeria. Then the mobile
arrived and now almost everybody has a phone, rich and poor.
Unsurprisingly, hopes are high in countries like this that
photovoltaics will grow in a similarly explosive fashion, providing power to
everybody, usually via small 'microgrids' rather than a hugely expensive
national network.
For the nearly 50% of the world's population living in the
tropics, overnight needs for energy will be provided by large commercial
batteries which have stored electricity from the day. Like photovoltaics, these
batteries are also getting cheaper by the month. Over the last five years,
prices have tumbled at least 75% and these reductions look set to continue into
the indefinite future.
As with photovoltaic panels the growing volume of batteries
being produced, increasingly for electric cars, is helping drive costs down to
levels thought unachievable even a few years ago.
Alongside batteries, minute-by-minute variations in solar
output can be managed by using appliances that can adjust their power
requirements to match the availability of power. Almost every machine in the
home, office and factory - including air conditioning systems, refrigerators,
pumps and heaters - can be easily modified to vary its use of electricity on a
signal from the energy supplier.
Other electricity generation technologies can complement
solar at night. The sun's daytime heat can be stored in molten salt and used to
turn turbines when the sun is down. Cheaper and lighter wind turbines are
becoming available. Anaerobic digestion of biomass is also seeing huge advances
around the world and can be engineered to produce power only at night.
New
solutions for high latitude countries - like the UK
Of course we in the UK know that solar is not enough, even
with batteries, wind power and demand that responds to the scarcity of power.
We northern Europeans are unrepresentative, of course, because less than 10% of
the world's population lives north of London. But the UK needs energy in winter
when the sun doesn't shine and the backup of wind power isn't available.
The answer to our needs is to convert surplus power in the summer
and during winter gales into easily storable liquid fuels and gases. These can
then be burnt to make electricity on dark, still days.
Companies like Electrochaea in Germany are showing the way.
Electrochaea makes hydrogen using simple electrolysis of water and then uses
the hydrogen along with waste carbon dioxide from sewage farms. An ancient
microbe 'eats' the two gases and exudes 100% methane, the main constituent of
natural gas. This is a completely green fuel since its carbon atoms come from biological
sources.
Other companies in the US and elsewhere are showing us how to
take CO2 and process it to make oils for transportation. These
processes require large amounts of energy but as solar power becomes cheaper,
this is increasingly less of an obstacle.
Bill Gates recently wrote that he is optimistic that the
world will solve the energy problem soon. In The Switch I try
to show that his optimism is more than justified. In fact, the outlines of the
route to abandoning fossil fuel energy around the world are already here.
Low cost photovoltaics, electricity storage and technologies
that turn surplus summer power into green gases and oils will give all 9
billion people on the planet a secure supply of energy faster than we thought
possible.
