Our energy storage future

Later this summer the Scottish Government will be publishing its new energy strategy for the forthcoming term and WWF Scotland have called on this to promise greater use of the country’s plentiful renewable energy sources.

The Scottish Government has pledged that all Scotland’s electricity will come from renewable sources by 2020. Renewable energy generation in Scotland does continue to increase as shown in the latest government figures. Homes with solar PV panels generated 100% of electricity demand in Aberdeen, Dundee, Edinburgh, Glasgow, and Inverness in May. Solar hot water panels generated 100% of hot water demand in Aberdeen and Dundee, 98% in Inverness, 97% in Edinburgh and 94% in Glasgow.

Wind power accounted for 692,896 MWh of electricity imported to the grid in May, enough on average to fulfil demand for 76% of Scottish households approximately 1.8 million homes. Also on 10 of May’s 31 days wind energy generated enough electricity to support all of Scotland’s homes. In total wind generated 36% of the country’s electricity needs for the entire month of May.

Speaking about the latest figures Lang Banks director of WWF Scotland said “These figures underline the fantastic progress Scotland has made on harnessing renewables, especially to generate electricity. However, with less than 13 per cent of our total energy needs coming from renewable sources, it’s now time to widen our attention on de-carbonising our economy beyond just our power sector.

“That’s why the forthcoming review of Scotland’s energy strategy must set a target of meeting at least half of all our energy needs from renewables by 2030. In the same way Ministers helped drive forward progress in renewable electricity through targets, setting higher ambition for covering all of our energy needs would help give clarity about the transition and the greater certainty to investors.”

Karen Robinson of WeatherEnergy added “The data clearly shows that there’s plenty of sunshine to meet a significant proportion of an average family’s electricity and hot water needs during some months of the year and that it isn’t just during the summer months that this contribution is felt.

“It’s clear that when it comes to generating clean power, Scotland is one country others are already watching closely. Imagine what a global leadership role Scotland could play if it now followed up its success on renewable electricity with steps to green its entire energy system.”

However in order for Scotland to realise its renewable potential and make best use of its plentiful sources more must be done in improving and implementing energy storage concepts. Such developments could harness the power or renewables and help shift our energy generation from a high carbon output to a low carbon output in turn bringing us in line with international targets.

Energy storage expert James Mashadi compiled a report on the diverse range of energy storage options with information on each.

Pumped hydro power

Pumped hydro power is generated by pumping water to an elevated height at non-peak times when electricity is cheaper and storing it behind a dam. When energy is required the water is released through the dam and is channelled down through turbines so as to generate electricity to be fed into the grid at times of peak demand when prices are higher.

Compressed air energy storage (CAES)

Like pumped hydro power, CAES is a mechanical type of energy storage technology.  The National Infrastructure Commission described CAES as being where “air is compressed and stored under pressure either in underground caverns or in above ground vessels” before being “released to drive a turbine and generate electricity.”

Flywheel

Flywheels are devices that spin at high speeds to generate electricity which is then released as the flywheel’s rotor is slowed.

Although pumped hydro power and CAES can offer a large amount of power it can take a while for that power to be generated and fed into the national grid. In contrast, flywheels offer access to power within a very short period of time, although the overall storage capacity is less in comparison. The devices offer the potential to help meet sudden demand for power.

Battery technologies – Lithium-Ion

Lithium-Ion (Li-Ion) batteries have been in commercial use for the past 25 years and have been common in a range of consumer products, from laptop computers to mobile phones.

Li-Ion batteries work by harnessing chemical reactions involved in the transfer of lithium ions between the cathode and anode components of the battery to first charge the battery then discharge that power.

Thermal

Together with flow batteries and pumped hydro power, thermal-to-electric storage is identified as one of the most promising energy storage technologies capable of delivering “the greatest benefit for the UK.” One thermodynamic energy storage method that has already undergone extensive testing is the Liquid Air Energy Storage (LAES) system.

According to lobby group the Liquid Air Energy Network, the LAES system works by first turning air into liquid and then turning that liquid into gas. Intense cooling systems can turn air into liquid air which can be stored in a tank. The liquid air can then be heated to make it boil and the boiling process turns the liquid air back into gas form. The volume of the gas produced in this process is approximately 700 times that of the liquid air and this change in condition can be used to spin turbines and generate power.

James’ report goes on to examine the benefits of energy storage systems with regards the environment and economy. It states that, according to the National Infrastructure Commission’s report energy storage could deliver 15GW of capacity to the National Grid by 2030 and electrical storage alone could reach over 50GW by 2050.

The report also states that the UK could become a global hub for energy storage innovation leading to a growth in our economy of up to £25 billion by 2050. James’ full report can be read here http://www.out-law.com/en/articles/2016/june/storage-technologies-central-to-the-uk-meeting-future-energy-needs-says-expert/

The importance of energy storage cannot be understated. The rise of renewable energy generation in Scotland has been very impressive however in order to utilise our resources fully, the full range of storage solutions must also be in place.

For example, in tends to be windier at night however during these periods demand for electricity tends to be lower. Therefore once the grid reaches capacity generation has to be paused and the resources from this period are wasted.

A full scale smart storage solution would allow for generation to continue, excess energy to be stored and when demand increases placed back into the grid ready for consumption.

The fact that many of the large energy providers are now starting to invest heavily in these technologies is a good indicator of where they envisage the future of energy storage. However like all fledgling industries a certain level of government support is required in order to attain the higher levels of investment required in order to advance the technologies.

The long term benefits are tangible and will benefit everyone. Working together, they can also be achievable.

 

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