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Development aid and renewables: from aid to trade?

By Dave Elliott

Over the years, a lot of support has been provided for renewable energy projects in Africa, most recently under the UN Sustainable Energy for All programme, with the EU taking something of a lead. However, a shift in emphasis from development aid to economic partnership and trade is emerging, with private sector investment, local economic development and local enterprise seen as central, for example via Germany’s new ‘Compact with Africa’ initiative, the so-called Marshall Plan for Africa.

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Can nuclear be used to balance renewables?

By Dave Elliott

Nuclear plants are designed to run flat out, in part to recoup their large construction costs. Their output can be varied a bit, but this entails thermal stresses and potential safety issues with the build up of active xenon gas that is released when fission reactions are reduced. It needs time to decay. That limits how often and how quickly the plant can be ramped down and then back up so as to match changes in energy demand (“load following”) and the varying output of renewables. So basically nuclear plants are inflexible. Do they have any role for balancing variable renewables?  Continue reading

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Rotatiload! Synchronous inertia and frequency stability

By Dave Elliott

Power engineers worry that, as more renewables are added to the grid, replacing old coal, gas and nuclear plants, we will loose lock-step AC synchronous system stability, since the latter had large heavy rotating turbo-generators which provided system inertia against frequency perturbations. The big plants’ rotational inertia acts as a buffer to grid frequency changes, and to varying supply and inductive loads. However, PV solar has no rotational inertia, and wind turbines not much, though direct drive machines can provide some. With more renewables on the grid it will become more of an issue: https://arxiv.org/pdf/1312.6435.pdf

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Firm power parity metric

By Dave Elliott

A paper from Imperial College proposes a new conceptual framework for understanding competition in electricity markets that include variable input but marginal cost renewables. Noting that one of the primary drivers for consumers to switch from grid-supplied electricity to self-generated electricity (e.g. home roof-top PV with batteries) is cost savings, the researchers constructed a model that forecasts when going-it-alone ‘grid defection’ by consumers may become widespread. In reality, few domestic consumers in the UK are likely to want to go entirely off grid. At least not for some time. Grid links are   needed and useful for backup, e.g. for when there has not been enough sunshine for a while and consumers’ batteries are discharged, and also to sell any surplus power they can generate, beyond what they can store. However, the grid defection analysis is still a useful conceptual exercise, not least since it gives us some idea of the cost of balancing/backing up variable renewables. And, in time, some users may want to try the off grid option. Continue reading

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The cost of power: moving beyond LCOE

By Dave Elliott

How much does energy cost? LCOEs -Levelised Costs of Energy – are widely used as a comparative measure. They give an estimate for the cost of energy generation from specific plants, but do this by averaging out the investment and running costs over the plant’s lifetime and comparing that with the value of the electricity generated. However, the costs and earnings can and do vary over time and are hard to predict. LCOEs also omit any associated grid balancing/backup costs. So they have big shortcomings. Can we do better?

Certainly there are many weaknesses in the LCOE approach. Finance costs will depend on interest rates and inflation both of which can change over time, sometimes dramatically. So may fuel and labour costs. Energy output may also vary for many reasons and in the case of renewables will vary with the weather. In that case, use is usually made of ‘capacity factors’ to reflect average likely delivered outputs, but in reality these variations are dealt with by balancing capacity and services, the cost of which, arguably, should be added to the cost of generation.

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Solar heating shines again

By Dave Elliott

The UK may be doing reasonably well on green power, but it is not making much progress on green heat. What about solar heating? The familiar roof-top solar heat collector, with a flat glass plate on top of a box with pipework for cooling water, has been upgraded over the years to more efficient evacuated tube and focused solar and hybrid PV/Thermal variants. These systems can offer cost-effective no/low carbon heating in some locations and are mostly scalable, suitable for a range of small or large-scale applications. And you can store solar heat for use later and also use it to drive cooling systems. All in all, it’s an energy source with multiple attractions.

The UK Solar Trade Association (STA) says: It’s time to look again at solar thermal. The strategic importance of this mature, proven technology is growing as our homes become more thermally efficient and require less space heating – we will continue to need hot water. The UK also needs to do much more to decarbonise heat, where we lag badly behind in Europe.’

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100% of all energy from renewables?

By Dave Elliott

The energy scenario now offered by BEIS implies that renewables might be supplying around 50% of UK electricity by 2035, with 45GW expected to be in place by then, mostly wind and solar PV. There are more ambitious scenarios, like the one produced for the UK/Ireland by Finland’s LUT and the German Energy Watch Group as a subset of their global 100% renewables scenario. That has renewables supplying all the electricity used in the UK/Ireland by around 2040:  That may be ambitious, but near 100% by 2050 certainly now seem credible for electricity, given the political will. Scotland is already at over 60%. But what about heat and transport? Continue reading

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100% renewables – a fantasy?

By Dave Elliott

‘Electricity comprises just one fifth of annual energy demand in the UK, so creating a 100% renewable energy economy would be an order of magnitude more difficult than the already challenging task of powering our existing electricity grid with 100% renewable sources’. So says a report from the Policy Exchange, putting the case for Small Modular Reactors. It’s a familiar line – 100% for power will be very tough, 100% for all energy impossible.

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Nuclear power – game over?

By Dave Elliott

Foratom, the European nuclear trade body, commenting on the European Commission’s ‘Clean Energy for All Europeans’ plan, says the EU’s aim to decarbonise the economy by over 80% by 2050 cannot be achieved without nuclear power. ‘Nuclear energy accounts for half of the low-CO2 base-load electricity currently generated in the EU. It provides reliable low-CO2 base-load electricity and can provide the flexibility of dispatch required to balance the increasing share of intermittent energy sources, hence continuing to contribute to security of supply.’ It wants an end to preferential treatment and ‘priority dispatch’ rules for renewables.

Foratom is not alone in pressing the case for nuclear. The World Nuclear Association is looking to an extra 1000 GW of nuclear capacity globally by 2050, while a Global Nexus Initiative report says it will be extremely hard, if not impossible, to meet the Paris COP21 climate goals ‘without a significant contribution from nuclear power’ – globally 4000 GW will be needed by 2100.

Given the somewhat constrained situation facing the nuclear industry at present, stuck at around a 11% global contribution while renewables roar ahead to 24% and beyond, with prices continually falling, is there any reality in these nuclear ambitions?

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In praise of (total) demand response

By Dave Elliott

‘If we could manage to adjust all energy demand to variable solar and wind resources, there would be no need for grid extensions, balancing capacity or overbuilding renewable power plants. Likewise, all the energy produced by solar panels and wind turbines would be utilised, with no transmission losses and no need for curtailment or energy storage’.

So says an interesting, wide ranging but wellreferenced article in Low Tech Magazine. It goes on ‘of course, adjusting energy demand to energy supply at all times is impossible, because not all energy using activities can be postponed. However, the adjustment of energy demand to supply should take priority, while the other strategies should play a supportive role’. Continue reading

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