Very in-depth explanation and reading needed. Also please specify each section i
ID: 2268336 • Letter: V
Question
Very in-depth explanation and reading needed. Also please specify each section i.e. (i),(ii),(iii), and so on. As an energy engineer you have been asked to work in the field grid based energy storage systems; your brief is as follows: i. Explain the outline principles of operation of such systems and why they are used i.e. advantages. ii. Review the mechanical design features materials, construction and so on of two types of energy storage system ii. Give examples of energy storage schemes in operation iii. Design; produce an outline a design for energy storage system based on existing the technology that will deliver 0.5 MVA on a short term basis (you can choose the short term period based on an evaluation of the constraints that would be in place) to a 50 Hz grid system v. Summary (l need in depth explanation please).Explanation / Answer
Grid energy storage (also called large-scale energy storage) is a collection of methods used to store electrical energy on a large scale within an electrical power grid. Electrical energy is stored during times when production (especially from intermittent power plants such as renewable electricity sources such as wind power, tidal power, solar power) exceeds consumption, and returned to the grid when production falls below consumption.As of 2017, the largest form of grid energy storage is dammed hydroelectricity, with both conventional hydroelectric generation as well as pumped storage. Alternatives include rail potential energy storage, where rail cars carrying 300 ton weights are moved up or down a 8 mile section of inclined rail track, storing or releasing energy as a result or disused oil well potential energy storage, where 100 ton weights are raised or lowered in a 12,000 ft deep decommissioned oil well.
Benefits of storage and managing peak load
The stores are used – feeding power to the grids – at times when consumption that cannot be deferred or delayed exceeds production. In this way, electricity production need not be drastically scaled up and down to meet momentary consumption – instead, transmission from the combination of generators plus storage facilities is maintained at a more constant level.
An alternate and complementary approach to achieve the similar effect as grid energy storage is to use a smart grid communication infrastructure to enable Demand response. These technologies shift electricity consumption and electricity production from one time (when it's not useful) to another (when it's in demand).
Any electrical power grid must match electricity production to consumption, both of which vary drastically over time. Any combination of energy storage and demand response has these advantages:
fuel-based power plants (i.e. coal, oil, gas, nuclear) can be more efficiently and easily operated at constant production levels
electricity generated by intermittent sources can be stored and used later, whereas it would otherwise have to be transmitted for sale elsewhere, or shut down
peak generating or transmission capacity can be reduced by the total potential of all storage plus deferrable loads (see demand side management), saving the expense of this capacity
more stable pricing – the cost of the storage or demand management is included in pricing so there is less variation in power rates charged to customers, or alternatively (if rates are kept stable by law) less loss to the utility from expensive on-peak wholesale power rates when peak demand must be met by imported wholesale power
emergency preparedness – vital needs can be met reliably even with no transmission or generation going on while non-essential needs are deferred
Energy derived from solar, tidal and wind sources inherently varies – the amount of electricity produced varies with time of day, moon phase, season, and random factors such as the weather. Thus, renewables in the absence of storage present special challenges to electric utilities. While hooking up many separate wind sources can reduce the overall variability, solar is reliably not available at night, and tidal power shifts with the moon, so slack tides occur four times a day.
How much this affects any given utility varies significantly. In a summer peak utility, more solar can generally be absorbed and matched to demand. In winter peak utilities, to a lesser degree, wind correlates to heating demand and can be used to meet that demand. Depending on these factors, beyond about 20–40% of total generation, grid-connected intermittent sources such as solar power and wind turbines tend to require investment in grid interconnections, grid energy storage or demand side management.
In an electrical grid without energy storage, generation that relies on energy stored within fuels (coal, biomass, natural gas, nuclear) must be scaled up and down to match the rise and fall of electrical production from intermittent sources (see load following power plant). While hydroelectric and natural gas plants can be quickly scaled up or down to follow the wind, coal and nuclear plants take considerable time to respond to load. Utilities with less natural gas or hydroelectric generation are thus more reliant on demand management, grid interconnections or costly pumped storage.
Demand side management and grid storage
The demand side can also store electricity from the grid, for example charging a battery electric vehicle stores energy for a vehicle and storage heaters, district heating storage or ice storage provide thermal storage for buildings.The need for grid storage to provide peak power is reduced by demand side time of use pricing, one of the benefits of smart meters. At the household level, consumers may choose less expensive off-peak times for clothes washer/dryers, dishwashers, showers and cooking. As well commercial and industrial users will take advantage of cost savings by deferring some processes to off-peak times.
Regional impacts from the unpredictable operation of wind power has created a new need for interactive demand response, where the utility communicates with the demand. Historically this was only done in cooperation with large industrial consumers, but now may be expanded to entire grids.For instance a few large scale projects in Europe link variations in wind power to change industrial food freezer loads, causing small variations in temperature. If communicated on a grid-wide scale, small changes to heating/cooling temperatures would instantly change consumption across the grid.
A report released in December 2013 by the United States Department of Energy further describes the potential benefits of energy storage and demand side technologies to the electric grid: “Modernizing the electric system will help the nation meet the challenge of handling projected energy needs—including addressing climate change by integrating more energy from renewable sources and enhancing efficiency from non-renewable energy processes. Advances to the electric grid must maintain a robust and resilient electricity delivery system, and energy storage can play a significant role in meeting these challenges by improving the operating capabilities of the grid, lowering cost and ensuring high reliability, as well as deferring and reducing infrastructure investments. Finally, energy storage can be instrumental for emergency preparedness because of its ability to provide backup power as well as grid stabilization services.
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