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Transitional green power issues – sectorial conflicts

By Dave Elliott

It is often said that, whereas it should be possible to meet electricity needs from renewables, heating is harder and transport harder still. While wind and solar and other renewables can generate electricity and replace the use of fossil plants, heating and vehicle transport use of fossil fuels are harder to replace. Except possibly by the use of renewable electricity. Although some disagree, there should be enough renewable electricity output to meet all energy needs in time. However, even enthusiasts accept that there may not be enough to go around initially. So there may be sectorial conflicts at some stages.

Some worry that, given the high market value of power for private transport, if electric- vehicle (EV) use booms, renewable electricity will be used heavily for them, eating into what’s available for other uses, for power for lighting, heating, cooling and so on. This may not matter if renewables can expand rapidly, but there may initially be some market conflicts. Put more bluntly, should we be using renewables to power private cars at the expense of other uses, including other more sustainable transport uses? Conflicts have already emerged in terms of biomass use. Liquid biofuels for private vehicles can get higher market prices than biomass for electricity generation or heating.

The potential conflicts become more subtle if renewable electricity is used to make vehicle synfuels via Power-to-Liquid (P2L) conversion. That involves using wind/PV output to make hydrogen gas by electrolysis of water and reacting it with captured CO2 to make synthetic hydrocarbon fuel, such as methanol. Fuels like that are operationally attractive for vehicles since they are similar to conventional liquid fuels in handling terms. So their use could expand, again eating into the renewable electricity resource. Moreover, it may also be an environmentally inappropriate use of renewables. Euroactiv claims that a vehicle running on synthetic fossil fuels would emit a similar amount of CO2 as a conventional petrol-powered car.

That’s debatable. Yes, there would be CO2 produced by hydrocarbon synfuel combustion, but it would be balanced, at least partly, by the CO2 used to make the synfuel – captured from power plant emissions, or (less easily) from the air. The exact carbon balance would depend on the P2L conversion losses and it could be argued that you would get a better outcome by using the renewable power direct in electric vehicles. However, the attraction of liquid fuels, including synfuels, is that, unlike electricity, they can be easily stored on board and at fueling depots, and the store can be more easily and quickly charged.

Some gaseous fuels have similar attractions (e.g. methane), and in the case of hydrogen, although it’s harder to store and transfer, there is no CO2 debt from its Power to Gas (P2G) production from wind/PV and its subsequent use. So hydrogen, from surplus wind/PV output, may be a winner for some transport applications – although possibly, given its higher cost, only in niche markets, at least initially. For example, the European Marine Energy Centre (EMEC) on Orkney has a 500 kW electrolyser using excess power from its tidal arrays and from a local wind turbine. The hydrogen is fed to a fuel cell, but may later be used as ferry fuel. Fuel-cell powered cars are another option: ITM Power’s PEM electrolyser is being used to provide hydrogen derived from wind for some at a hydrogen-powered vehicle refueling centre off M1 Junction 33.

However, P2G and P2L conversion of renewable electricity for transport use may still conflict with other uses for renewables, including for grid balancing. As variable renewables expand, there will be a need for fuel for backup plants. The P2G option looks very sensible for that – using gas made from surplus wind and PV to provide storable backup fuel for use in gas turbines or fuel cells, when wind and PV availability is low. But will there be enough surplus available if the transport sector has hoovered it all up?

Overall, what seems to emerge from the above is that, depending on what is available in total, we may initially have to dedicate some sources for some uses and not just leave it up to market economics to decide who gets what. End-use priorities can be debated, but it may mean initial limitations on the low-carbon electrification of transport and also possibly heating – another large source of energy demand. A limit is something that may be required anyway, since power grids will have problems delivering the large amount of extra power necessary to charge EVs and also to run domestic heat pumps (see my earlier post).

That is a basic technical conflict, not a market based one – no conceivable amount of money can make the UK power grid carry four times what it does already, which is roughly what it would have to do to supply all heating demand, much less private vehicle demand, both of which have large evening-time peaks. Some are more sanguine about EVs, arguing that there is plenty of spare capacity for charging them and, once charged, they offer a Vehicle to Grid balancing resource. Certainly local power storage might help a bit, but that is expensive. Smart grid management could also help – by shifting peaks. And EV charging times might be regulated to avoid demand peaks e.g. by variable pricing. However, other energy options will also have to be explored for heating and transport – including AD biogas from wastes for vehicles and heating and solar for heating.

All energy sources try to identify favourable market niches, and some of the sector conflicts looked at above are market-driven. However, as I have argued, there may be a need for some direction on the basis of wider strategic concerns. It may be hard to come up with optimals, given the changing situation, but obvious conflicts can surely be avoided. For the moment, it looks like transport could be one area where end-use conflicts will emerge, but it depends on how the overall system develops. For example, if we decide to install large amounts of offshore wind capacity, enough, on average, to meet demand most of the time, there would at times be a very large surplus. Some of this could be used, via P2G, for balancing, when there are wind lulls, but there may be enough for making storable transport fuels too.

National Grid has produced some new UK energy scenarios which explore issue like this. It says that the UK’s renewable generating capacity, currently 34% of total installed capacity, could increase to 60% by 2050. In 2016, installed capacity from distributed generation reached 26GW. Looking to 2050, it says this could rise to 93GW. So even if, as it projects, EVs add maybe 8GW to power demand by 2030, there may be enough! Without nuclear. Moreover, storage and smart grid demand scheduling would help to reduce expensive-to-meet peaks, as could the other transport fuel options. However, while National Grid sees gas still supplying a lot of heat and power, it looks to hydrogen for some end-uses, including for cars, supplying more energy than EVs use in its ‘2 degrees’ green 2050 scenario.

The debate over the right mix continues with, inevitably, some seeing all this as justification for more nuclear – though that assumes the power could be delivered by the grid to users or stored for when the grid could handle it. However, if EVs are only going to add 10% more power demand by 2050, as some suggest, and EV charging can be delayed to later in the night, then the conflict issues may not be as big as we might fear, with renewables able to cope.

It may depend on how many EVs there are. As I report in my next post, there is a lot of enthusiasm for EVs, but we will have to wait and see just how many hit the roads – and what will then happen to lithium supplies. And also to some other key materials, limits on the availability of which might constrain EV expansion.

Still plenty of potential for conflicts with other sectors there, in this case for key materials which they may also want.

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