While still backing nuclear (although not the current type!), the
Guardian’s George Monbiot had a go at PV: ‘If
every square metre of roof and suitable wall in the UK were covered with solar
panels, they would produce 9% of the energy currently provided by fossil
fuels’. www.theguardian.com/commentisfree/2013/oct/21/farce-hinckley-nuclear-reactor-haunt-britain
No one
suggests that PV could meet all our energy needs. But UK PV trade lobbyist Solar Portal has
suggested that PV on only 1% of total UK land area could meet all the UK’s electricity needs: www.solarpowerportal.co.uk/news/if_solar_covered_one_percent_of_the_uk_it_would_meet_the_countrys_2356
That may be oversimplified, and it does mean building a lot
of solar farms, but the general point is clear- PV could supply a lot of
electricity. But so could wind, on and offshore. And wave and tidal. Which
means that, since we could at times have a lot of surplus green electricity, some
of the PV output could perhaps
also be used supply some heat, thus saving gas. You could for example run the spare PV
electricity into storage heater system or an immersion heater. See for example www.immersun.co.uk. There are also some
interesting PV-thermal hybrid systems emerging which absorb heat as well as
light. The technical point is that PV cell efficiency falls of with rising
temperatures so it is helpful to cool them. Adding a solar heat absorber does
just that, increasing the units overall energy efficiency dramatically. Naked
Energy’s ‘Virtu’ hybrid PV/solar thermal panel is claimed to be able to supply ~ 3 times as
much energy (as heat and electricity ) as a normal PV panel of the same
power rating. http://www.nakedenergy.co.uk
Surplus PV electricity can also be used to charge battery
Electric Vehicles. So it would be offsetting petrol use too. It is also
possible to used PV electricity make
hydrogen by electrolysis and from there you can produce synfuels for
vehicles. So there are technologies that would allow PV to meet heat, power and
transport needs. Not all of them, but some.
How
much can we expect? Last summer the UK’s then 2.3 GW of PV briefly
supplied about 2% of UK
electricity. By 2020 DECC say PV might expand to 10GW or even 20GW in the UK, in which case, on these
figures, at times it might supply up to around 23% of UK electricity, although
by then demand may have risen slightly, so say just 20%. For comparison, Germany has 32GW of PV
at present, which sometimes supplies nearly 50% of its electricity needs.
Globally
there is over 100GW of PV in use, and its adoption in accelerating, as costs
fall. The World Energy Council notes that in
one its new scenarios ‘by 2050, globally, almost as much electricity is
produced from solar PV as from coal,’ and Shells recent Oceans scenario
envisaged solar as being the largest single energy source globally by 2060. Large and small, PV looks good.
That
said there are some drawbacks. PV cells don't work at night and light intensity
varies a lot during the day and over the year. That means that there will be a
need for costly backup and grid balancing if there is a large PV contribution,
much more than is needed for wind, which is often strong at night and certainly
during the winter when energy demand is high. But PV does match well to some
energy loads- daytime offices and their summer air-conditioning especially. And
as cost continue to fall, and grid balancing and energy storage systems spread,
PV can make a significant contribution.
Interestingly,
the Solar Trade Association (STA) claims that the cost of PV will fall below
the £92.5/MWh CfD strike price set for the proposed new Hinkley nuclear plant
by 2018- 5 years before its expected to start up (in 2023) if it get EC
permission. www.solarpowerportal.co.uk/guest_blog/solar_set_to_beat_nuclear_on_headline_strike_price_by_2018_never_mind_2023
DECC
seem to have backed a looser there. And that is assuming all goes well with
getting the finance for Hinkley agreed with the EU and then getting the plant
built without delays. It could be a lot later and the price could escalate, as
has happened with the EPRs being built in France and Finland. For the UK, the tragedy is that under
the CfD 35 year contracts, consumers will be locked into paying (EDF) for it
until 2058, assuming a 2023 startup! The STA may be optimistic in its forecast
for PV cost reductions, but by 2023, PV and on-land wind do look like beating
the Hinkley CfD price and offshore wind shouldn’t be far behind, followed a bit
later by wave and tidal. And by 2058, if it goes ahead, Hinkley is going to
look decidedly out of place- with supposedly 25 years more then still to run!
Maybe it will go bust and be shut early, and the large site will be converted
in to solar farm or wind farm…We could of course do that now and avoid paying
£1bn a year to EDF for it!
Amusingly, that's just what UK PV company Lightsource has suggested. It wrote to David Cameron claiming that PV could
match the output of Hinkley within two years at comparable cost. http://www.clickgreen.org.uk/opinion/opinion/123982-renewable-energy-boss-tells-pm-solar-power-could-match-hinkley-in-2-years.html
That may be overstating the case,
but it does look like PV is going to be big, even in the cloudy UK. And maybe bigger than
nuclear, with, as in Germany, much of the running being made by individuals and
groups buying into it. Half a million UK consumers who had enough disposable
income have already invested in PV systems- bringing the total to around 2.7 GW
so far. It’s cold just now in wintery Britain, but sunny. Good PV weather. And
PV can only get better.
