National Grid, the UK electricity network operator, has produced a new report on its visions for net zero UK carbon futures. Unsurprisingly, renewables play the major role on the supply side
in National Grid ESO’s four Future Energy Scenarios, with PV solar reaching
around 70 GW by 2050 in the electricity-led Consumer Transformation (CT) scenario, and wind reaching 150 GW by
2050 in the fast change Leading the Way
(LW) scenario. By contrast, natural gas use
falls away significantly in all but Steady
Progress (SP), the slowest
decarbonisation scenario, and shale gas makes little contribution in all but SP
‘due mainly to reduced support from government
and consumers’.
Green gas
is however developed at various levels in the other scenarios, both biogas,
from plant biomass/waste sources, and syngas, like hydrogen, made via either
from fossil gas with CCS or via electrolysis using renewable power. In all,
National Grid says that at least 190 TWh of hydrogen will be needed by 2050, providing between
21% and 59% of user energy needs. Some of it will be used for flexible balancing power, some
for heating and some for transport and in industry. Biomass/biogas also play similar
multiple roles, including for flexible balancing.
However, National
Grid says there may be some conflicts. For example, since bio-sources are also
needed for negative emissions technology and in hard-to-decarbonise industrial sectors,
‘this limits the amount of green gas
available for injection into the grid’ for heat’. That may well be the case
if, as is proposed, net negative carbon emissions are provided by 8-10 GW of
Biomass Energy with Carbon Capture and Storage (BECCS). Not everyone is
convinced that BECCS (and indeed CCS) will be viable at any significant scale,
but the report warns that the UK may not be able to meet
its legally binding ambition to reduce carbon emissions to net zero by 2050
without negative emissions from bioenergy combined with carbon capture & storage.
Heating is
the other area of potential problems. National Grid’s Consumer Transformation scenario assumes that there is a switch
from gas boilers to electric heat pumps. Not everyone thinks this is possible
given the limits of the power grid and National Grid do provide a System Transformation (ST) scenario, in
which hydrogen gas is the main heating route, at least initially, using the old
gas mains. But it also looks to heat
networks ‘which use heat from industrial
processes, deep geothermal, data centres and biomass boilers where available’.
On the
demand side, energy efficiency
measures are seen as vital in all sectors and are ‘a fundamental step to get to net zero in Consumer Transformation.
Here, the high efficiency levels of appliances and the use of heat pumps reduce
total energy demand to more than 30% lower than in System Transformation by
2050’. In addition, demand management
can contribute significantly to demand reduction and also to flexibility to
help balance the high levels of variable renewable generation, although
National Grid also see a balancing role for extra grid interconnectors, up
20-25GW or more, in the 2030s, depending on the scenario. The rise of use of electric vehicles in all the scenarios can increase
demand for power but may also offer V2G power storage capacity. At the same
time, we may be able to look to further demand reduction: for example, in Leading the Way, there is ‘a 75%
reduction in total energy demand for road transport due to a
combination of electrification, automation and changing consumer behaviour’.
Nuclear
Be that as
it may, National Grid certainly see nuclear still playing a role, but mostly longer
term. They say in System Transformation, ‘the ambition to decarbonise with more
centralised technologies leads to a focus on large-scale nuclear generation,
while in Consumer Transformation,
despite the focus on decentralised generation, we still see nuclear as
transmission connected, but with greater uptake of small modular reactors. Steady Progression and Leading the Way have low levels of
nuclear capacity. In Leading the Way there
is a mix of technologies to decarbonise, including development of
small
modular reactors in 2031. Despite this, rapid deployment of renewable
and BECCS generation, combined with lower electricity demands than the other
net zero scenarios, reduces the need for new nuclear. In Steady Progression there is some
ambition to develop new nuclear projects; however, the first new project after
2030 doesn’t come online until
the 2040s’. A very long way off then, with, in total,
only 9GW in SP by 2050, and only 16 GW by then even in CT.
There are other more optimistic views
on nuclear, as I will explore in my next post, but National Grid clearly do not
see it expanding much, and given the state of play so far with new nuclear
projects, even the long run-in times and low energy inputs predicted by
National Grid may be seen as wishful
thinking, whereas renewables are clearly roaring ahead. Mark Herring,
the head of strategy at National Grid ESO, said ‘Across all scenarios, we
see growth in renewable energy generation, including significant expansion in installed
offshore wind capacity’. If we do need more power, and National Grid
suggests we may, then that is likely to be where it can come from, although it
may also be possible to reduce demand more than they assume, even in Leading the Way. The extent to which
consumer behaviour changed during the Covid lockdown came as a surprise to some-
and that was not factored in National Grid’s analysis.
Hydrogen
However, we do not know if demand reductions can be
relied and we also do not know if P2G conversion efficiency improvements can be
made to allow hydrogen to pay a major role. In the System Transformation scenario electrolysis only supplies a small
part of the hydrogen used -most is from fossil gas conversion with CCS. Given
the need for CO2 storage space, that does not seem likely to be the best way
ahead, whereas, if P2G could expand then green
hydrogen could play many useful roles in flexible power balancing, storable
fuels for transport, and pipe-delivered energy for heating. Perhaps well beyond the 190 TWh or so
National Grid envision by 2050 in Leading
the Way…
That is just my speculation. More
certain is that, as National Grid say, at least 3 GW of wind and 1.4 GW of
solar need to be built every year from now until 2050, with zero marginal cost
generation like this then providing up to 71% of generation output in 2030, and
up to 80% in 2050. That includes a input from up to 10 GW of tidal power. A bit
less convincing is National Grid’s view that Vehicle-to-grid (V2G) services
could provide up to 38 GW of storage flexibility
from the batteries in 5.5m electric vehicles (EV). Could the local grid cope, even if that capacity was full
and usable when needed e.g. in the early evening?
The power grid may be strained by EV re-charging
and V2G transfers, and also if it has to provide power for heat pumps, but probably
more likely than a full heat pump heating system, or one based just on piped
hydrogen, is one with a mixed hybrid approach, electric heat pumps combined
with hydrogen-fired boilers, the latter being used flexibly to meet peak
demand. National Grid look to there
being ‘over 8m hybrid heat pumps
responding to market signals and shifting demand between hydrogen and
electricity systems by 2050.’ Well we shall see if that compromise works
out: it’s the governments favoured option at present.
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