Wind turbines derive energy from the wind through changes in atmospheric air pressure. Those same changes also cause storms. Because of that, successful wind turbine farms placed in the path of prevailing winds can also be in danger from high storm winds. Most land-based wind turbines use grid power for operational control of various functions including pitch control of the turbine blades. However, grid power can be tenuous during storms so wind turbines also use back-up power supplies, or uninterruptable power supplies (UPS).
Without UPS power to control the pitch of the turbine blades, high wind forces could cause catastrophic damage to the wind turbine. This is seen especially in offshore wind turbines, which rely more heavily on UPS power as weather patterns change often and quickly over the flat expanse of water. The initial solution was a UPS utilizing lead acid batteries to provide back-up power. However, while lead acid batteries are a solution for automobiles and many critical systems, their weaknesses are exposed in wind power applications. Normal wind turbine operations require pitch to be constantly adjusted to adapt to power production strategies. Being in the path of constant wind and storms makes the likelihood of outages more frequent putting extra deep cycles on lead acid batteries, This also shortens their lifespan tremendously and causes additional expensive maintenance. Lead acid batteries needed a back-up to the back-up.
ULTRACAPACITORS ARE A BATTERY’S BEST FRIEND
Pitch control in high winds or storms takes huge amounts of torque. Circumstances where the wind changes often in a time when lead acid batteries are the main source of power discharges them to dangerous levels as the batteries are stressed to provide the high current needed to move the turbine blades. Augmenting this load with ultracapacitors helps relieve the lead acid batteries by allowing each component to work to its strengths. Lead acid batteries retain energy but share it slowly. Ultracapacitors do not have a high level of energy storage, but they can share copious amounts of energy instantly and recharge almost immediately (See Figure 1).
The whole point of a wind turbine is to produce usable energy for a profit. Ultracapacitors have proven effective helping efficiently and cost effectively solve critical power short comings of lead acid battery technology. Here are the leading reasons why they have been deployed in nearly 70,000 wind turbines in wind farms worldwide:
1. Ultracapacitors extend the life of the battery systems by two to three times. Ultracapacitors take on the heavy loads and leave the batteries to do what they do best—store power.
2. There is no maintenance with ultracapacitors. They have a cycle life of 1 million, are sealed and can perform in environments from -40°C to 65°C.
3. Lead acid batteries do not retain a 100% charge. The power source whether it be from what the wind turbine is generating to mains power from the grid, lead acid batteries need to be continuously topped off which has a negative effect on efficiency. Ultracapacitors start out with some leakage but improve over time which is the opposite of batteries. Ultracapacitors improve charge retention 50% over NEW lead acid batteries.
4. Ultracapacitors are lighter in weight. Whether having to reinforce the floor to hold battery racks in a data center or supporting weight 50 meters above the ground in a wind turbine, weight matters.
5. Ultracapacitors can even eliminate batteries to remove heating and cooling, maintenance, and give an even and predictable service life nearly anywhere on the planet.
6. Power generated from wind turbines can be uneven at best because wind is uneven. Ultracapacitors can help knock down the power spikes and support the power lags to help wind turbines supply conditioned power to the grid.
Ultracapacitors are lighter, work in a much wider variety of harsh environments, hold a charge longer, are made with no toxic chemicals or compounds and can be used to one million cycles. They have proven themselves in the harshest conditions and are ready to deploy indoors in datacenters and every critical power system. Ultracapacitors can start with augmenting the load of any type of battery, replacing batteries, or ground up designs for a new generation of UPS. Contact LICAP to find out how to make the most of your current or future system.
Global Product Team
LICAP Technologies, Inc. A Manufacturer of Premium Ultracapacitors
Contact us to learn more about how ultracapacitor modules can improve your critical power system.
Data centers, telecom infrastructure, 911 call centers, power grids, and airline ticketing are just some of the industries that must have 24/7/365 full operation without fail. These infrastructure systems at the Tier III and IV levels have multiple layers of back-up power schemes to provide critical services during power outages. The typical solution for shorter outages of a few seconds or less is a battery back-up. The typical solution for longer outages of over a few seconds would switch to back-up generators. While there are often new components, the basic idea of back-up systems has not changed much in the last fifty years. Lead acid technology still provides over 90% of batteries used in UPS systems and diesel generators still provide the main motive power when things really go wrong.
In the current critical infrastructure environment, the principle short term back-up components such as lead acid batteries need further support as battery failure is still the leading cause of downtime. According to a 2013 study of unplanned downtime performed by Ponemon, UPS battery failure was the leading cause of outages (See Figure 1). According to the Electric Power Research Institute (EPRI), 98% of power outages lasts fewer than 10 seconds. But even 10 seconds often enough can damage lead acid batteries and shorten their useful life.
Battery backed UPS systems are designed to cover 8-12 minutes for a generator system to power up or shut down. Modern UPS systems do not need that time as back-up generators can come on-line in less than five seconds. With the extra cooling, floor space, maintenance and relatively short life of lead acid batteries, it seems like the solution creates its own added problems.
It might be time to evaluate the entire UPS strategy and optimize UPS to all of the assets of the datacenter environment. Space, manpower/maintenance, cooling, power quality, efficiency, and environmental proactivity should be considered as a complete solution. Ultracapacitors are now proven to comprehensively solve most of the lead acid battery’s deficiencies. Please see Figure 2 that highlights the differences in technology and performance.
Space is at a premium. Building new or adding on anywhere is difficult and expensive, and lead acid battery systems take up a lot of existing space for low value. Efficient utilization of existing space pays off big, and modern ultracapacitor or lithium-ion battery systems take up less than 1/3 of their lead acid predecessors. Racks of servers and storage provide income. UPS systems do not create income; they hedge against failure. Costs for a modern ultracapacitor or lithium ion battery systems should be judged against the full life cycle. If the new system takes 1/3 the space of the existing lead acid battery system, what is the production value gained from that reclaimed space? Reclaiming that space would also be a double reduction in the measure of Power Usage Effectiveness (PUE) as that space already has cooling and power supplied. In addition, batteries draw power to continually recharge them. That reclaimed power can be redirected. According to Google, operators of some of the most efficient datacenters in the world, as lead acid batteryUPS systems and cooling are the biggest things that adversely affect PUE.
The next obvious cost point is maintenance and manpower. Lead acid batteries require cooling, regular monthly maintenance and monitoring, reinforced floors or racks, have a short life cycle, and are full of lead along with other toxic chemicals. The maintenance cost alone justifies moving into newer, safer systems. Ultracapacitors on their own or hybridized with lithium ion batteries decrease the need for constant maintenance. With a long life of 15-20 years, ultracapacitors rarely need to be checked on, while lithium ion batteries have a life of 10-15 years and need only cursory maintenance once a year. In addition, ultracapacitors are designed to run one million cycles. The best batteries of any type can just reach a tiny fraction of that amount (See Figure 2), which means spare batteries must be purchased ahead of time and stocked close at hand, adding to costs and space constraints. Once converted to ultracapacitors, resources formerly dedicated to constant monitoring and maintenance can be applied elsewhere.
Not every data center can be located in the Arctic Circle surrounded by cool air. Cooling is a constant cost driver in lead acid battery systems and one of the more stubborn factors in lowering PUE. Ultracapacitors, meanwhile, do not need to be kept cool. The same is true for lithium ion batteries. In addition, ultracapacitors work at temperatures from -40°C to 65C. For over a decade, ultracapacitors have been used in extreme conditions to start large diesel engines anywhere on Earth. Whether in heating or cooling, the ultracapacitor has a clear advantage.
Power quality is inconsistent even in the most developed parts of the world. Online double conversion is the leading method of switching seamlessly to battery back-ups, smooth spikes and sags in power, and correct frequency variations. However, all those little dips and frequency changes have an effect on battery life. Furthermore, sudden draws on power can overcome the output of the battery system. Ultracapacitors have 25-40 times the ready power of even the best lithium ion battery and 120 times more ready power than lead acid batteries. Just installing ultracapacitors into existing UPS systems with lead acid batteries will take an immense load off the batteries and extend the life of them substantially. Optimized correctly in the UPS circuit, ultracapacitors can even make up short term gaps in power availability when input is at its maximum. Further optimization would allow ultracapacitors to eliminate extra conversion back to AC by providing pure DC power directly to servers and storage, serve as short term back up, and provide for any immediate load in computing or writing to memory. This would completely isolate each rack from mains power and from any other rack. Four banks of ultracapacitors constantly switching to shoulder the load could give a life span of nearly 12 years with each bank contributing 75% of its million cycles with zero maintenance and zero additional cooling.
Everything covered so far has contributed to efficiency gains. Less space, less cooling, less manpower, less maintenance, and improved power quality. An optimized system that reduced the amount of power conversion would be even better. Lead acid batteries are familiar, predictable and known, but flawed. They lose charge almost immediately and power has to be diverted to keep them charged. Ultracapacitors actually improve energy retention as they age. They are at their worst in the first week of use and over a relatively short period of use improve charge retention over 50% compared to new lead acid batteries. Like lithium ion batteries, ultracapacitors can retain their charge for long periods of time even in hot environments.
According to Forbes, global data centers used more than 416 terawatts of powerin 2016. That amount exceeds the entire power usage of the United Kingdom by 40%. Amazon, Apple and other large data center owners have been targeted by environmental groups for environmental harm. Apple announced in 2017 that its datacenters will operate on renewable energy which is a significant cost but mitigates pressure from environmental groups. Lead is toxic and not all lead used in batteries is recycled despite the solid attempts by governments and the lead acid battery manufacturers. Using ultracapacitors to augment or replace lead-acid batteries would have positive environmental consequences, both in terms of material safety and in battery discharge.
We have discussed ultracapacitor advantages in the use of space, manpower/maintenance, cooling, power quality, efficiency, and environmental proactivity. These topics are all part of the equation to design and maintain critical power systems on small and large scales. Ultracapacitors can start with augmenting the load of any type of battery, replacing batteries, or ground up designs for a new generation of UPS. Contact LICAP to find out how to make the most of your current or future system.
Global Product Team
LICAP Technologies, Inc.