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Energy storage solutions for renewable energy

These forms of electricity storage are all likely to be needed, and they should be considered in conjunction with the much higher levels of renewable energy that will be required to “decarbonise” the electricity supply, which experts say will be necessary if global targets to reduce emissions by 50 per cent by 2050, compared with 1990 levels, are to be met.

Electricity storage: holy grail of the renewables industry, FT.com, By Fiona Harvey, Environment CorrespondentPublished: January 14 2011 Storing electricity reliably, safely and cheaply has long been the holy grail of the alternative energy industry.Vast amounts of energy – and money – are wasted in electricity grids the world over as suppliers struggle to keep the lights on while coping with the vagaries of demand.
If energy could be easily stored, this waste would stop and renewable energy sources such as wind power – that are intermittent by nature – would find a surer place in the electricity mix……………

Some of the ideas being explored for storing energy include “pumped storage”, using fuel cells, and harnessing the power of fleets of electric vehicles.

Pumped storage is an option where hydroelectric power is used.

The technique involves diverting electricity generated at times of low demand to pumping water up to a storage reservoir behind the turbines, or into another reservoir, such as one at a higher level, where it can then be released as needed at times of higher demand, or when other renewables such as wind or solar power are less productive.

This seems inefficient, because of the energy involved in pumping the water uphill, but it forms an effective means of load balancing when demand is lower than supply.

It is also one of the few readily available options for the storage of large amounts of potential electrical power, and one of the most convenient, as modern pumped storage systems can start generating electricity almost instantly when it is needed.

Tidal energy systems could be used in a similar way, as seawater can be pumped back to storage reservoirs behind tidal barrages or into tidal lagoons, to be released later.

Countries with large fleets of electric vehicles can also benefit from their storage capacity.

The batteries of electric vehicles are usually set to recharge overnight, when they are driven less and when electricity demand is lower.

As these vehicles are plugged into the grid, they provide an important means of soaking up excess generation capacity – for instance from wind turbines, which frequently produce more power at night than in the day.

But if there were a sudden surge of demand at night, energy could potentially be recovered from the vehicles’ batteries to be used elsewhere on the grid. Owners could also make their vehicles available for such “borrowing” when they were not in use for extended periods.

Fuel cells offer a different means of achieving widespread electricity storage.

Excess energy at times of low demand can be turned to generating hydrogen, which can then be stored for use in fuel cells, principally to fuel vehicles…..

These forms of electricity storage are all likely to be needed, and they should be considered in conjunction with the much higher levels of renewable energy that will be required to “decarbonise” the electricity supply, which experts say will be necessary if global targets to reduce emissions by 50 per cent by 2050, compared with 1990 levels, are to be met.Mr Stubbs says: “Making use of pumped storage and other forms of energy …..

FT.com / Reports – Electricity storage: holy grail of the renewables industry

January 15, 2011 - Posted by Christina Macpherson | 2 WORLD, energy storage