By Dave Elliott
85% of UK electric power could be supplied from renewables and low carbon sources by 2030, says a report for Greenpeace, produced by Demand Energy Equality.org. Basically it looks at a Greenpeace high renewables 2030 supply scenario to see if it can meet demand over the year, given demand peaks and weather changes – it uses 11 years of hourly weather data. And crucially it tests whether it is possible to meet a large part of the heat demand from renewable electricity, given that ‘even modest levels of heat electriﬁcation result in large increases in peak electrical demand’. It concludes that it is, but that this will only be possible if domestic heat demand is reduced dramatically, by near 60%. That is seen as vital since ‘electriﬁcation increases the size of demand peaks on the electricity network; while decarbonisation (via renewables) in turn decreases the predictability of supply intended to meet those (now increased) peaks’. And so ‘if electricity is the medium by which a reliable and clean energy future is to be delivered, then heating demand reduction must be achieved alongside heating electriﬁcation’. www.demandenergyequality.org/2030-energy-scenario.html
On the supply side it sees wind energy growing from 13 GW to 77 GW, 55 GW offshore, 22 GW onshore, with PV solar rising from 5 GW to 28 GW. There is also 8 GW of tidal, some biogas use (but no biomass imports), including around 20 GW of local CHP (fired with gas and some biomass), but no new nuclear and no CCS, just around 20 GW of gas CCGT and some demand side management (DSM), to help with balancing. However, interestingly, domestic DSM only ‘plays a modest role in mitigating periods of deﬁcit. Fewer than 7 periods in which total demand shifting exceeds 3 GW occur on average each year’. That is partly because DSM is as yet in its infancy and the report focuses on established technology. But it does report some interesting DSM developments in the industrial sector – where Flexitricity is the ﬁrst and largest UK provider of national supply-demand balancing services. http://www.flexitricity.com
However it notes ‘the technical, administrative and logistical feasibility of interacting with corporate and large scale power users in this way has not been matched, thus far, in a domestic setting’. That would require National Grid to negotiate contracts to provide demand reduction at peak times with every UK household, and communicate directly with each when needed. Smart meters might allow that, but are still in their trial phase, with many issues to be resolved.
You could say the same of the electric heat pumps that the report seems to see as a key domestic heat supply option; only meeting 25% of the heat demand, not the 90% envisaged in the DECC 2050 High Renewables modeling, but still a lot more than now. Why not also look at green gas for heating (including biogas and Power to Gas conversion) and to the gas grid for supply? It’s already there, with much more capacity than the power grid! While the report does propose some CHP (oddly seen as inflexible) for heat and power, there’s no mention of solar heating and large community-scaled heat stores (as used now in Denmark), and overall it seems overly focused on electricity.
Rather than offering a clever way to balance surpluses from variable renewables, by being able to ramp down power production and ramp up heat production for storage, for use when heat demand was high, CHP is simply seen as producing too much heat in summer. So there is only around 20 GW of CHP included, compared to over 52 GW in the recent Transition Pathways’ Thousand Flowers scenario. And, on the issue of the inevitable occasional electricity surpluses from its large variable renewable capacity, rather than portraying this as a problem, why didn’t it look more to Power to Gas (P2G) to turn it into a solution – making green gas for grid balancing as well as for heating and transport use? It only talks of using P2G hydrogen for vehicles. And why not look to 2-way supergrid links for balancing? As it is, ‘exports only occur once any surpluses have been utilised to the greatest possible extent domestically’, with the level of interconnector exchanges seen as only around 12 TWh p.a. That seems odd, since there is a lot more excess available (apparently near 43 TWh on average) and there may be times when exports of surplus can earn a lot of money, and be more useful/valuable than P2G conversion or other types of storage, helping to balance the cost of importing more when needed at other times. DECC’s 2050 pathway had 30 TWh of imports/exports. It’s a little odd that supergrid links are left to one side, playing a relatively small role in this study, since an earlier Greenpeace report talked them up as a key EU balancing option: http://www.energynautics.com/news/#GP_EU
Trying to get to 80% renewables by 2030 is pretty demanding. The Pugwash high renewables pathway, on which I worked two years back, only reached around 80% by 2050, pushing it quite hard, with around 100 GW of wind and 35 GW each of PV and tidal: http://britishpugwash.org/pathways-to-2050-three-possible-uk-energy-strategies/ However, that excluded nuclear, long gone by 2050, had 70 TWh p.a of supergrid imports/exports, and only looked to 40% energy savings. By contrast, the new 2030 Greenpeace scenario still retains some left-over nuclear (Sizewell B) and goes for much higher levels of energy saving – and by 2030. That’s a bit of a stretch. It’s akin to the Centre for Alternative Technology’s pioneering Zero Carbon Britain 2030 scenario and adding to the list of challenging and visionary high renewables scenarios: http://zerocarbonbritain.org/ready-for-zero
What it adds in particular is an interesting and helpful test of the operational viability of an ambitious energy mix, although, sadly, it does not provide an economic analysis, arguing that costs are changing too fast to make that useful. While that may be true (and the report does present some examples of falling costs), the absence of full costing may weaken the impact of the analysis – just at the point when the falling cost of renewables ought to be giving them a better chance. Even so, it’s a welcome addition to the pile of studies making the case for renewables, with balancing, as a technically and operationally viable set of options.
* Economic and financial support issues are to the fore in a new global Greenpeace scenario, which I will review shortly. It looks to getting 100% of all energy from renewables by 2050, at no extra net cost, given the fuel cost savings: http://www.greenpeace.org/international/Global/international/publications/climate/2015/Energy-Revolution-2015-Full.pdf