Smart Grid Energy Storage: The Holy Grail of America’s Energy Revolution
To the uninitiated, it may seem that grid energy storage is a non-sequitur, since supply often barely meets demand. However, peak period shortfalls are precisely the reason grid power storage is so critical to a consistent power supply. Grid storage systems would preserve those kilowatts that would otherwise go to waste during low demand periods. This ability is key to conserving energy and keeping the cost of electricity at an affordable level. However, to date, no single grid energy storage alternative has earned widespread approval as both cost-effective and efficient on a large scale, although grid storage battery development is rapidly escalating, with vanadium redox flow battery technology outpacing the others.
Alternative Energy and the Power Grid
Environmentally-conscious entrepreneurs who invest in alternative energy farms often see their power sales stymied by inadequate transmission facilities. The most fertile areas for generating wind power, for example, are often remote from the population centers that need more juice. During peak demand periods, desperately needed adjunct energy from alternative, renewable sources frequently can't get from point A to point B, because top tier, traditional electricity producers such as coal-fired plants, nuclear facilities and hydroelectric dams are monopolizing the existing transmission line network. Without adequate and economical grid energy storage systems in place, this energy goes to waste, making it hard for wind and solar farmers to maintain their operations. Renewable grid storage would solve this difficulty.
The Adverse Effects of Deregulation
Deregulation of the power grid is at the root of the problem. Here is a paper from the US Departiment of energy. http://energy.gov/sites/prod/files/oeprod/DocumentsandMedia/issue_papers_091205.pdf . The Energy Policy Act of 1992 promoted the separation of electric power generation from transmission and distribution activities. By the late 1990s, utility companies began to sell their power generating capacity to such corporate power producers as Dynegy and the infamous Enron. This opened the power grid to freewheeling over usage, bringing considerable pressure to bear on the already overtaxed grid system. Environmentally speaking, the situation is untenable. Clean energy from wind and sunlight continue to be overshadowed by air polluting coal burners, health-threatening nuclear generators and fish-depleting hydroelectric plants. Not only would adequate renewable energy storage technologies preserve wind and solar products, but excess electricity generated by traditional methods during low demand periods could be economically stored to augment supply for peak demand periods. With the right grid power storage technology in place at a price that makes grid energy storage more cost-effective than consumption, the over worked North American electricity grid could realize a period of respite. End-users could draw power from locally accessible, dispatchable energy storage rather than put ever-increasing demands on overtaxed transmission lines. The existing power grid system is antiquated and inadequate, yet prohibitively expensive to overhaul. The beleaguered grid has experienced significant failures during usage spikes in big cities during the past decade. Low-cost, high capacity grid energy storage would significantly change that.
The Benefits of Large Scale Storage
If alternative energy must wait in line behind traditional power sources, the need to develop reliable, large-scale renewable energy storage becomes more compelling than ever. Storing supplies of clean energy for on-demand consumption can help even out the vagaries of consumer demand and make use of transmission corridors as they become available. Green energy storage would enable producers to supply increased amounts of clean energy For remote or self-sufficient industrial complexes, large scale renewable energy storage for electricity generated on site guarantees that production will not be delayed on cloudy or calm days. With cost-effective renewable energy storage facilities in place, manufacturers would save significantly with self-generated electricity. The current challenge for the alternative energy industry is to cultivate reliable, large renewable energy storage capacity in a cost-effective format. Several prototypes are in development, but to date no single renewable energy storage paradigm has claimed dominance. For energy investors, the field is ripe for speculation.
Wind Power Storage Options
As wind farm construction worldwide gains momentum, more and more forward-looking nations are enjoyingthe environmental and economic advantages of alternative energy. As of 2010, approximately 2.5 percent of the world’s total power was wind-generated, with an annual growth in new facilities of 25 percent. As a fossil fuel alternative, wind-generated power has several benefits. Unlike coal plants, wind turbines do not emit greenhouse gases. They draw on a plentiful, clean supply of renewable power and require relatively little land in comparison to fossil electric facilities. As of 2011, Denmark, Portugal and Spain led the international community in wind energy penetration --the percentage of wind power production to total power supply. The United States and China are the top wind-power producers in the world. According to data from the U.S. Energy Information Administration, the total cost to produce one kilowatt-hour (kWh) of wind-generated electricity is 9.7 cents. The comparative cost of conventional coal-generated power is 9.48 cents. These numbers reflect the facilities and operational costs but not tax incentives, which further reduce the cost of wind power. At present, energy gurus calculate that, at less than 20 percent grid penetration, weather-related variations inherent in wind power generation do not cause significant shortfalls in the total grid supply, and the cost of gaps in supply remains relative low. However, as long as this ceiling remains in place, the potential of renewable energy remains limited. The availability of cost-effective, dispatchable renewable energy storage for wind-generated power would successfully mitigate fluctuations in wind supply and discrepancies in demand. Traditionally, power generated by wind turbines feeds directly into electric substations that are wired in to the commercial grid. However, economical and efficient battery storage can provide wind dispatchable power on demand. Renewable energy storage can be located at the source – the wind farm – or it can be installed at the load location. On site wind farm energy storage is advantageous in terms of easy access, but the transmission of energy stores is then limited by line availability. Conversely, sending power for storage at the load site requires transmission capacity but guarantees a consistent supply at the destination. Energy losses during transmission will not affect the capacity of the load site storage system, whereas remote power storage must account for anticipated transmission losses.
Solar Power Storage
Unlike wind power, which currently qualifies as a “must-take” energy resource due to lack of adequate storage systems, solar power lends itself to renewable energy storage, both in its thermal form and after its conversion to electricity. Concentrating solar power (CSP) facilities can preserve collected heat from sunlight for later conversion and dispatch to the electric grid. However, solar power comes at a considerably higher cost per kWh than wind-generated electricity. While centralized photovoltaic (PV) plants and CSP power facilities produce solar power more economically than rooftop systems, the cost is still about 21 cents per kWh. That is more than twice the rate of wind power. Despite the common usage of solar batteries, solar power, like wind, is subject to weather conditions. It also is only available during daylight hours. Therefore, to become a major grid energy supply source, large capacity storage, such as vanadium flow batteries, are required to compensate for gaps in sunlight. The current grid energy storage technologies are either insufficient or cost-prohibitive for a sufficient remote solar power supply. High capacity, low cost grid energy storage for solar power would also lower its cost per kWh. The reserves of solar dispatchable power at existing facilities would offset the cost of operations with increased energy sales. The cost of solar energy could come down to a level more equitable to other energy sources. Combined with the downward trend in pricing for solar energy system components, a more cost-effective solar energy industry could quickly gain market share in power grid sales. The industry would experience exponential growth. That would be good news for the environment. By replacing coal plants, a chief emitter of those greenhouse gases that contribute to global climate change, with clean-producing remote power plant technology, solar would truly become an environmental -- and economic -- redeemer.
Current Energy Management and Grid Power Storage Capacities
The legacy of the power grid limits the expansion of cleaner, renewable energy power supplies. Ill-equipped to handle free trade of conventional electricity supplies during peak hours, the overtaxed high-voltage transmission network that spans Canada and the United States stymies transmission of remote dispatchable power. Although existing hydro and fossil facilities have the ability to generate additional electricity on demand, adequate grid power storage would be far more cost-efficient than re-firing the systems, given the appropriate grid energy storage technology.
Pumped-hydro Energy Storage
The largest capacity, most widely used grid power storage protocol to date is pumped-hydro energy storage (PHES). This system consists of reversible pumps that connect two reservoirs. During off-peak hours, the pumps draw relatively low-cost electricity to transfer water from the lower reservoir to the upper and then, on demand, reverse the flow to generate electricity at a higher, peak-demand price. While this “storage” method does recycle water, it does not really constitute grid power storage. In reality, it regenerates power for a higher profit.
Smart grid technology-- sometimes termed “electricity with a brain” -- is a developing means of managing the flow of energy through the power grid to avoid overuse and transmission line failures. Through the use of computerized remote control and processing, smart grid utility companies can improve grid efficiency and end-user energy efficiency too. Technology allows widespread data gathering that informs grid controls. Smart grid systems can:
Consumer Post Meter Energy Management and Storage
Residential smart meters are designed to work in conjunction with the upcoming smart grid to provide real-time data on energy use and cost during peak and non-peak times. Theoretically, this information will encourage consumers to focus on less expensive electricity use during non-peak periods, thus taking stress off the grid.
The development of cost-effective, large scale grid energy storage for all types of power generating systems would enable utility companies to:
Dispatchable Wind and Solar Power
Remote energy storage at wind and solar farms would compensate for gaps in supply with renewable dispatchable power. In effect, adequate storage would transform these sources of power from intermittent to dispatchable upon demand, bringing these clean energy sources into the mainstream of energy production.
Integrated Renewable Energy Systems (IRES)
The unpredictability of supply that is a given with wind and solar power need not disqualify either as a major source of grid power. Creative strategies for greater electricity supply control include:
• Using solar and wind together to even out supply deficits
Vanadium flow battery technology is particularly suited to integrated electrical storage, due to its ability to respond instantaneously to rapidly fluctuating energy loads and its adaptability to overload. Given these properties, vanadium flow batteries help balance the production flows of several different types of power sources in a single facility.
Looking Forward to Energy Independence
North American energy producers, utilities and end-users all look forward to increased energy independence in the coming decades. As smart grid technology and large-scale grid power storage technologies develop, the growth of the renewable power industry will escalate, reducing North America’s need for foreign fuel sources and fossil burning plants.
As more wind farms and solar installations come online, the need to augment the antiquated grid becomes increasingly critical. Developing cost-effective, large capacity grid power storage and wind dispatchable power technology is key to energy independence and reduction of greenhouse gas emissions.
To date, the most popular energy storage methods are, in order of prevalence:
By: Michael Hyslop, corporate communications for American Vanadium Corp.
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