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Tag Archives: grid balancing

Prosumer integration

By Dave Elliott

The German Environment Agency (UBA) has produced a comprehensive review of options for removing almost all (95%) greenhouse gas emission by 2050, based on the existing 80% renewables programme for electricity supply, but also looking at all the other sectors – including heating and transport. As I said in my coverage in an earlier post, that is pretty challenging. But it says it can be done. www.umweltbundesamt.de/publikationen/germany-2050-a-greenhouse-gas-neutral-country

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Greenpeace 2030 UK energy scenario

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

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Could tidal power be big?

By Dave Elliott

IRENA, the International Renewable Energy Agency, puts the technically available global tidal resource at near 1 TW. That is for all types of tidal system, those using vertical tidal ranges (barrages and lagoons) and those based on tidal streams, using the horizontal ebbs and flows (tidal current turbines). In practice, local limitations, access problems and other constraints will limit what may actually be achievable. So how much might be available? (more…)

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Why not nuclear and renewables?

By Dave Elliott

Nuclear plants do not generate carbon dioxide, so why can’t we have nuclear AND renewables, supporting each other, as a response to climate change? In evidence to the Energy and Climate Change Select Committee in July Amber Rudd MP, DECC Secretary of State, suggested that despite its high cost nuclear baseload ‘enables us to support more renewables’ and was needed since, ‘as we all know, until we get storage right, renewables are unreliable’. Can nuclear really support renewables, and is it really low carbon?

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Plenty of renewables – and they can be balanced

By Dave Elliott

Is there enough renewable energy to meet global needs and can the use of variable sources be effectively balanced?  Recent reports say yes on both counts. In terms of the total resource, a GIS-based study of land/sea use/availability has put the total 2070 global potential for renewable electricity at up to 3,810 EJ, led by solar PV, with about a third of the PV being on buildings. The total estimated resource was roughly in line with most other global renewable studies, like that from the IPCC, and well above likely total global electricity demand, put at around 400 EJ: www.sciencedirect.com/science/article/pii/S0959378015000072 (more…)

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World Bank looks to renewable integration

By Dave Elliott

‘With the right combination of new policies and investments, countries can integrate unprecedented shares of variable renewable energy into their grids without compromising adequacy, reliability or affordability’. So says the World Bank in a study of renewable integration and grid balancing options, focusing on energy storage and gas fired- back up plants, but also looking at other balancing options . (more…)

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Capacity Market – the first UK auction

By Dave Elliott

In a fully free-market energy supply system there is no direct commercial incentive for generation companies to ensure that the lights stay on long term, by investing in new and/or backup capacity. Given that some old plants are scheduled for closure and more reliance on sometimes variable renewables is planned, the UK government has stepped in to create a new ‘capacity market’ to try to fill the potential gap in terms of reserve capacity and grid balancing capacity. (more…)

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Balancing variable renewables

By Dave Elliott

There is now a range of books looking at the technical and policy options available for managing the use of variable energy resources such as wind and solar energy. The pioneering text in this area was Earthscan’s “Renewable Electricity and the Grid” from 2007, edited by Godfrey Boyle , with contributions from many of the UK top experts. But the field has since expanded with, for example, a lot of new work being done in the US. (more…)

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Europe and supergrids – balancing grids across the EU

By Dave Elliott

A pan-European supergrid network could play a major role in helping Europe achieve an ambitious 45% share of renewable energy by 2030 at low extra cost, by balancing grids and limiting curtailment,  according to a new Greenpeace report,  PowE[R]2030, based on analysis by Energynautics, and using data from the International Energy Agency.

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Smart meters and smart grids

By Dave Elliott

The newly emerging energy system will need new grids of various types. In my previous two posts I looked at international low-loss High Voltage Direct Current supergrids, and suggested that though they may well be developed in the years ahead, the process could be uneven and incremental, starting with local/national smart grids designed to aid local balancing of variable supply and demand. (more…)

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