While the large-scale pumped hydro storage has been a viable solution for the centralised power system of the past, it may not be an ideal choice for an increasingly decentralised power system of today and tomorrow.
Alina Bakhareva
Alina Bakhareva, Renewable Energy Research Manager at Frost & Sullivan, explains how energy storage could facilitate the power industry’s transition into a low-carbon era…
Energy storage, in the context of the modern utility industry, is the accumulation of generated electricity or heat inside a store of some type, whether mechanical, chemical or electrical, and the controlled release of the accumulated energy at a time when it is needed. One of the basic assumptions the modern electrical power generation and distribution system has been built on is that electricity cannot be stored.
The early 1930s architecture and construction of the electrical power system has been largely reactive to the consumer demand pattern, with base-load stations bearing the brunt of the demand, and peaking plants that are turned on to meet the demand during the time of maximum consumption.
For decades, the only viable technology to store excess electricity has been pumped hydro storage.
The operating principle for the pumped hydro storage is simple – during the time of low demand, excess or often cheaper night time off-peak electricity is used to pump water into a higher reservoir for it to be released into a lower reservoir through an electricity-generating turbine during peak demand for energy. Pump storage has one of the lowest cost in terms of kilowatt-hours (kWh) and proven track record; however, there are a few major bottlenecks for its continued deployment. High capital construction costs, lack of geographically appropriate sites and environmental concerns are among major issues around construction of a new pumped hydro storage facility. Also, to achieve economies of scale, a pumped hydro storage plant has to be of a large size, which may require additional grid infrastructure to be built around it, further increasing the cost.
While the large-scale pumped hydro storage has been a viable solution for the centralised power system of the past, it may not be an ideal choice for an increasingly decentralised power system of today and tomorrow.
What drives the need for energy storage?
Electrical power generation in the UK, as well as other countries, has been facing many critical challenges in the last decade.
Firstly, power plants have to reach maximum efficiency in order not to waste ever more expensive fuel; secondly, environmental concerns about rising level of carbon emissions are driving a wider adoption of renewable sources of energy, many of which are intermittent by nature, which creates uncertainty on how much energy would be produced during a day/hour/minute. Additionally, the power generation industry structure is changing dramatically with many smaller power stations generating electricity for industrial and large commercial premises and district networks. In addition to a rising demand for power from existing applications and users, entirely new user categories, such as electric vehicles (EVs), with yet unpredictable consumption pattern are about to plug in to the grid.
The set of new drivers and challenges in the power generation and distribution creates a strong case for energy storage technologies as they can decouple production and consumption of electricity by creating a buffer. Energy storage significantly increases the effectiveness of wind, solar and tidal generated electricity because the energy is time-shifted to peak demand, which strengthens the business case for investment in a renewable generation scheme.
This new sub-segment of power industry is already taking shape. A host of energy storage technologies are on the brink of becoming commercially available. New business models will have to emerge and some innovative solutions such as mobile energy storage solutions are already being prototyped and tested.
With a number of companies looking to launch their full-scale prototype into testing, it is likely that new commercially available energy storage devices will become available in the next two to four years.
Applications for energy storage – there is a solution for every need
Energy storage technologies can provide a variety of on and off-grid applications along the entire value chain of the electrical system: from generation to transmission and distribution, to end-customer use.
Major benefits for an end-user will include;
• Reduction in energy bills though reaching more efficient utilisation of on-site power generation facilities or optimised purchasing from the grid;
• Enable renewable generation solutions at a higher return on investment;
• In countries where power cuts and outages are frequent, on-site energy storage can significantly contribute to running industrial processes smoothly at a lower capital and running cost than back-up diesel generators.
For utilities and network operators, energy storage technologies will make predicting and managing input from intermittent renewables easier. Investment in new transmission and distribution (T&D) lines can be deferred through placing the energy storage solutions at the demand side to relieve over-worked transformers and other equipment.
Key challenges – reducing cost and getting new products ready for commercial deployment
As any emerging industry, the energy storage will have to overcome a number of challenges before it becomes a widely adopted and universally deployed enabler for increasing efficiency and reducing operating costs in the power industry. At present, the costs of the alternative solutions (rather than pump hydro storage) are either too high or still unproven. However, as with other technologies, the most recent example being wind and solar energy, costs will come down as more systems are deployed. Experience and learning curve come into effect through aspects that can be predicted through mathematical models:
• Standardisation, specialisation and production methods improvements;
• Better use of equipment;
• Product redesign;
• Labour efficiency;
• Technology-Driven Learning.
Is energy storage set to be a key growth market for investors?
Despite existing gaps in legislation and a lack of government support for energy storage technologies, there is a considerable interest in the energy storage technologies from the investment community. With the majority of the technologies developed by SMEs and university spin-offs, the fledgling energy storage industry will welcome funds for proof of concept and testing of large-scale prototypes, and given the benefits energy storage solutions can deliver, a tipping point is already in sight.
As we are not nocturnal animals by nature, then we must benefit from sunlight, in several ways. It then follows that we can deal with sunlight - maybe we need to be more in touch with how to deal with exposure. This research shows that we do not know all the ways that we use sunlight naturally, which is probably true of other environmental factors. I will be very interested in outcomes of further research. Is there any research about sunlight and cognition?
Presently, pumped hydro storage - a technically and economically viable energy storage option (used in the past to some extent) - faces serious environmental concerns. Other options, either chemical or mechanical, face a range of challenges: they involve high costs, are bulky, are heavy, and require massive importation of materials.
I agree with you that energy storage has a brilliant future. Firstly, in countries where hydro potential (an important technology that can cope with base load) is no longer a large electricity-generation option because it has been extensively exploited, and where fossil fuels (which produce most of the electricity consumed in the world) are getting scarce, more expensive and are on their way to run out, the new alternatives available (solar, wind, wave, marine current and others) are intermittent and require some sort of storage.
Secondly, on the commercial side of electricity businesses, the new trends to decentralisation of electricity production and consumption, and the ever-increasing use of use renewable energy systems, are opening great opportunities for energy storage technologies.
And thirdly, energy storage will play a very important role in making possible rural electrification in the context of 'Universal Energy Access', since the options are mainly stand-alone and micro- and mini-grids based on renewable energy technologies.
Teo Sanchez - Rugby, United Kingdom