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Renewables

Renewables

Can we get to net zero emissions?

10 Oct 2018 Dave Elliott
Illustration of renewable energy technologies

The European Commission has signalled that it is considering a “net zero” emissions goal and, in the UK, the Labour Party now has that as a key policy – net zero by 2050 rather than the current 80% emissions cut target by 2050. What does net zero mean, and is it possible? The first part is easy. Net zero means that carbon dioxide and other greenhouse gas emissions are reduced 100%, to zero, although some can be allowed if compensatory carbon negative processes are introduced, for example, air capture of carbon dioxide.

How to achieve this is a bit more complex. The most obvious approach is not to produce any more carbon dioxide. In the energy sector that means using non-fossil energy sources, i.e. nuclear or renewables. However, neither is entirely carbon-free – at present we use fossil fuel to make the materials for the energy conversion technologies involved and, in the case of nuclear, to extract and process nuclear fuel. Nevertheless, they are both low-carbon options.

In its new Green Transformation pamphlet, the Labour Party says it will use both nuclear and renewables to ensure that 60% of the UK’s energy comes from low-carbon or renewable sources within 12 years of coming to power”, i.e. by 2030 if that event happens soon. The inclusion of some new nuclear is controversial but together, renewables and nuclear would supply 85% of UK electricity, up from 50% now (30% renewables, 20% nuclear). However, renewables would no doubt continue to dominate the mix and presumably then be ramped up further to get to near 100% of supply by 2050.

Europe will need to compensate for some of its emissions by going net-negative after 2050

European Climate Foundation

To make this viable with variable renewables, Labour says it will “upgrade and invest in flexible energy networks capable of supporting a transition to decentralised renewable energy, by bringing the UK’s energy transmission and distribution networks back into public ownership”. This, it says, means “making more use of local, micro grids and of batteries to store and balance fluctuating renewable energy, and providing the necessary investment to connect renewable energy sources to the grid”.

The plan would involve a sevenfold increase in offshore wind-farms (to 52 GW), a tripling of solar power (to 35 GW) and doubling of onshore wind farms (to 30 GW) by 2030. That would go a long way to meeting the 60% energy target. However, although energy for transport is excluded in the 60% target, it does include heat, and for that the plan is to provide 44% of heat from renewable sources by 2030 and reduce heat demand from buildings by 23%. For example, Labour wants to reinstate the Zero Carbon Home programme.

Zero appearance

Even so, there would still be some way to go to net zero — 100% zero carbon across the board. What would that actually look like?  Some idea comes from a new study by the European Climate Foundation (ECF) of EU pathways to zero emissions. It says that “commercially available solutions can already take us about 75% of the way to net-zero if deployed at scale. The remaining 25% can be achieved based on known approaches and technologies for which further scaling up and commercialization is needed”.

The report looks well beyond energy supply technology and says that, to get to net zero, “we need to widen the range of options being used, including by putting more focus on how we operate as a society. Innovation in our consumption patterns and increasing potential natural carbon sinks need to be combined with the more typical technical options such as energy efficiency, fuel shift, zero-carbon power production and electrification.”

So the ECF offers three possible 2050 scenarios. The “Shared efforts” scenario assumes a comparable level of effort is maintained across all sectors and “levers”, i.e. there is no emphasis on any specific carbon mitigation option. The “Technology” scenario emphasizes efficiency and innovative technological options by raising their ambition to the highest levels, e.g. energy efficiency, electrification, hydrogen, and carbon capture and storage. It leads to a 41% energy demand cut by 2050. The “Demand-focus” scenario uses demand-side levers to reduce the overall demand further, e.g. for energy (with a target of -64% by 2050), as well as for products, including meat, which implies that technological levers can be reduced compared to the Shared efforts scenario.

The ECF says it won’t be easy to make some of these changes, but suggests that most of the gains will come from efficiency and energy use changes, not from renewables or other supply-side changes. It also says “negative emission” options (like BECCS, Biomass with CCS) will only make up a small part, though land-use changes may provide a bit more.

Nevertheless, the report stresses “the importance of deploying all mitigation actions possible including land-use sinks and other options for removal of GHG [greenhouse gases] from the atmosphere”, and notes that “in our three scenarios, improved land-use practices could support around 600 megatonnes of CO2 equivalent  per year of GHG sinks, which amounts to about 10% of 1990 emissions and can help us reach net-zero by 2050”. However, that’s still quite small and it notes “other options to remove GHG from the atmosphere (e.g. biomass use combined with CCS) have significant limitations as well”.

Overall then, “the European carbon emissions budget is very tight and reaching net-zero by 2050 is unlikely to be sufficient” to reduce cumulative emissions longer term, and so it concludes that “Europe will need to compensate for some of its emissions by going net-negative after 2050”. This means that, since they will be needed later on, in the short term the “limited natural sinks and other carbon dioxide removal (CDR) options will not be an alternative for the emitting sectors. Each sector needs to reach close to zero emissions around mid-century or shortly after.”                                       

 That may all sound quite onerous and likely to be expensive, and as I have noted in earlier posts, not everyone thinks that large-scale negative emission options like BECCS will be needed or viable. However, big changes will be needed, although the cost pattern for each scenario differs. Crucially, the ECF report says that all the scenarios cost less than the business-as-usual scenario — cutting carbon saves money.

Plan check

So how does Labour’s plan stack up against these major requirements for rapid change? Its energy supply proposals are ambitious, but with costs falling rapidly, the UK should be able to go well beyond the 63 GW of renewables suggested as possible by 2030 in the most recent UK government projections. Though the 117 GW total that Labour proposes may be stretching it, and would surely not all be needed by 2030 — energy demand is actually falling. At present, the UK has around 40 GW of renewables, delivering around 30% of its electricity, so very roughly 80 GW might deliver 60% of electricity. However, there could also be a need for some extra electricity for heating, depending on how this is done. So maybe 100 GW or more might be required in all, if the aim is to get 44% of heat demand met from renewables — although not all of that would have to be met via electricity-generating renewables.

As noted above, provocatively, Labour’s 60% target also includes the use of nuclear power, which is arguably only retained due to the political strength of the nuclear lobby. With costs rising and demand falling, it seems an odd choice. There are plenty of non-nuclear scenarios around, with renewables expanding to supply all energy needed in the power, heat and road transport sectors. What’s more, what emerges from many of these scenarios is that including nuclear would make the whole thing harder – more costly, less flexible and less able to balance variable renewables. Basically it’s not needed and gets in the way of the emerging distributed-supply flexible-demand smart grid system.

However, leaving that political battle aside, in terms of the rest of the zero emissions programme, Labour’s approach so far, at least as outlined in the new pamphlet, is a little thin. The party says it wants more public transport — trains and buses — with more electrification to cut emissions, and it is also looking to a major tree-planting programme, working with farmers and foresters to promote biodiversity. These are, arguably, very good ideas, but we will need a lot more detail. Especially now we have the requirements outlined in the new IPCC climate report on 1.5° warming to live up to. I will look at that in my next post, but it suggests that up to 60% of global electricity could come from renewables by 2030 and 85% by 2050.

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