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Do batteries and EVs ‘change everything’?

By Dave Elliott

You almost need to draw a line under what has come before and start again. There is no doubt that batteries completely and utterly metamorphose the market in that they make the uncontrollable controllable. It makes the arguments against renewable energy fall away’. Nick Boyle, founder of Europe’s largest solar operator, Lightsource.

And batteries in electric vehicles (EVs) take it to a new level, with IRENA claiming that ‘EVs can be used to enable a higher share of variable renewable energy in the power system’. So does all this add up to technological revolution?

Certainly energy storage is useful as way to balance variable renewables but there are gain-sayers, who note that there are other grid balancing and storage options.

And as for EVs, some worry that there will not be enough green power to charge them all, or insufficient power grid capacity to service the evening peak demand for both EV charging and home heating, although there may be resolutions to that – see my last post.

However, for good or ill, the battery/EV bandwagon rolls on. OPEC has boosted its forecast of electric-vehicle sales by 500 per cent compared to last year. The International Energy Agency has more than doubled its estimate about global electric-vehicle sales. Meanwhile, Exxon, BP and Statoil all now expect at least 100 million electric vehicles to hit the roads globally between 2030 and 2035. BNEF is even more bullish. It says 530 million cumulative electric cars will be sold by 2040, representing about one-third of the market for automobiles. But car makers are more cautious. According to BNEF, the world’s biggest auto manufacturers are only planning to sell a combined 8 million electric cars per year by 2030.

IRENA claims that, far from being a drain of renewable supplies and grids, EVs can help renewables, for example by ‘actively using the mobile battery storage system in the vehicle in V2G applications’ and by ‘the use of second-hand batteries in a “second life” role as stationary battery storage systems’. It also sees EV offering ancillary grid services, including frequency regulation, shaving peak demand, and grid power support.

IRENA says ‘One of the main advantages of EVs are their high level of flexibility in charging times which can efficiently support operation of the grid’. According to its REmap analysis, based on renewables supplying 30% of global energy by 2030, if a target of 160 million EVs worldwide can be reached by 2030, ‘this will provide around 8,000 gigawatt-hours (GWh)/year in battery storage that could help to accommodate higher shares of variable renewable energy. This is equivalent to approximately 1,200 GW of battery storage capacity. Along with the pumped hydro storage and second-hand batteries estimated under REmap by 2030, this adds up to a total of 1,650 GW. This compares with approx. 3,700 GW of variable renewable power capacity’. So storage capacity could be over a third of generation capacity.

However, it’s not all unproblematic. ‘Uncontrolled charging of EVs could significantly increase the evening load peak’, which (see my last post) could overwhelm the grids delivery capacity or even generation capacity. But IRENA says there are smart grid Load Management Systems (LMS) that could limit this. For example, Honda’s Home Energy Management System (HEMSx) monitors and controls household electricity consumption, including EV charging. It can help consumers decide when to buy power and when to sell it back to the grid. Though, if it is to be helpful in delaying EV charging it would need a variable pricing regime, to deter use at peak times. The use of EV batteries in Vehicle to Grid (V2G) mode also means more cycling from full to empty, and that can age them more rapidly. But IRENA says that this could be limited by smart charging controls to avoid deep discharge. So once again smart power management is vital.

All in all, assuming such systems are in place, IRENA sees EVs as a boon to renewables, leading to an increased demand for renewable power. That may be true, although an EV boom might also increase demand for other sources of power – nuclear, for example. Indeed, that’s how the nuclear industry has often seen EVs – as an ideal way to offload the surplus power inflexible nuclear plants produce at night. That would improve their economics. It would also avoid the need to vary nuclear output in response to the variable availability of some renewables – something that nuclear plants are not good at doing. And it would also avoid the need for energy storage.

What we are talking about is two different approaches: one using fixed nuclear generation, using night-time surpluses to meet EV demand at night, the other using varying renewables and flexible balancing systems to meet variable demand, including that from EVs. Which approach would be best? Even given potential for offsetting the cost with EV charging sales, nuclear is expensive, while renewable costs are falling. On that basis, few would choose the nuclear option. However, balancing and storage would add to the costs of the renewables option. Batteries may be getting cheaper, but they are only helpful for short-term storage. Power to Gas (P2G) conversion of surplus renewable electricity to hydrogen is an option for long-term storage possibilities for long wind/PV lulls, although P2G is often said to be too costly: ‘the costs of power to gas to power systems are far too high and their round-trip efficiencies too low to be deployed commercially for seasonal grid electricity storage applications within the foreseeable future, but they could perhaps be deployed within the 2050 timeframe’.

However, there are other views which suggests that, with the linked potential for long term storage of hydrogen, despite its costs, P2G might be better than compressed air storage (CASES) and even pumped hydro (PHES), its main rivals for long term storage: The comparison in terms of cost and efficiency showed that PHES is better than P2G and CAES. And P2G has many benefits such as: conversion of energy vector from electricity to gas which is available for renewable thermal and transport energy; longest storage time; and minimal impact on the environment. From sustainable development strategy perspective, the evaluation results of P2G, PHES and CAES are 4.03, 2.46 and 2.16, respectively. Which means P2G was assessed as preferable.’

That still all leaves batteries with a fairly clear field for short-term storage of renewable surpluses. Although there are contrary views – quite apart from the nuclear/EV charging  option, which might avoid the need for any type of storage. The prize for the boldest anti-battery view should perhaps go to IDTechEx Research. It says batteries have serious limitations of cost, weight, space, toxicity, flammability, explosions, energy density, power density, leakage current, reliability, maintenance and/or life. Its provocative new report ‘Battery Elimination in Electronics and Electrical Engineering 2018-2028’ examines many ways of eliminating batteries, seeking to confound the sceptics with examples that are currently operating, including large electric buses with supercapacitors enjoying four times the life of batteries. It adds ‘Hundreds of thousands of buildings already have electronic climate controls and electric actuators with no energy storage, pointing the way to how the Internet of Things can succeed’. It looks to the eventual complete elimination of energy storage by new forms of energy harvesting that are almost continuous. Brave new stuff!


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