for on-site power generation and storage
|The Acta Power ” the ‘Hydrogen Battery’ ” is a self-recharging fuel cell power system|
Hydrogen makes for the ideal choice of energy storage as it has high energy content. It is also clean, versatile and abundant. The key to unlocking hydrogen’s potential for energy is on-site hydrogen generation and storage, argues Paolo Bert.
With the world turning away from fossil fuels in the face of growing regulation and looming emissions targets, renewable energy sources are undoubtedly the future. However, as the Institution of Mechanical Engineers recently warned in a report entitled Energy Storage: The Missing Link in the UK’s Energy Commitments, the future viability of renewables relies largely on the ability to store renewably generated energy.
Since the shining sun and blowing wind may not coincide with energy demand, the sun or wind’s potential for energy generation will be lost if it is not somehow saved. This is the intermittency challenge of renewable energies. It is principally for this reason that energy storage is so important, as being able to store renewably generated energy means it can be consumed when needed, irrespective of weather conditions.
If energy storage is the problem, then hydrogen provides a solution.
How can hydrogen be used to store energy?
Through the process of electrolysis, where an electric current is passed through water, hydrogen and oxygen are produced. The electricity used to split the water into hydrogen and oxygen can be drawn from a grid supply, or indeed be taken directly from a renewable source, such as a wind turbine or solar panel.
Once the hydrogen is produced, it is essentially a fuel that can be turned into electricity at a later date. The hydrogen and its potential energy is stored in bottles ” this is stored energy or ‘bottled sunshine’.
To turn hydrogen into electricity at a later date so it can be used for electrical applications, it is passed through a fuel cell. Through a chemical reaction involving the stored hydrogen and oxygen from the air, the output from the fuel cell is electricity and water. The cycle is now complete ” from renewable power, to hydrogen generation, to storage, to utilisation.
Hydrogen makes for the ideal choice of energy storage as it has high energy content. It is also clean, versatile and abundant.
However, there are several challenges with using hydrogen which need to be addressed in order to make it commercially viable. Most significantly, the great majority of hydrogen is currently generated from fossil fuels, such as natural gas, and so not applicable as a means of renewable energy storage. In addition, there is a lack of hydrogen infrastructure, meaning current facilities for generating hydrogen may be far from the intended point of use. This places a significant burden on the commercial viability of using hydrogen as a source of energy, as transportation costs for moving bottled hydrogen from point of generation to point of consumption are significant ” up to 70% of compressed hydrogen cost is delivery. This is not to mention the logistics of transporting and delivering hydrogen bottles to difficult areas, such as rooftops and remote locations.
Given the challenges and associated costs of transportation for hydrogen, the answer to ensuring the adoption of hydrogen as a source of energy storage is on-site hydrogen generation.
Having identified the potential and challenges of hydrogen, Acta has developed a product known as the Acta Power which provides the whole hydrogen system ” generation, storage and conversion to electricity ” on-site. Acta refers to this system as the ‘Hydrogen Battery’.
The Acta Power integrates a fuel cell with an advanced hydrogen generator, which generates the system’s hydrogen reserve on-site with electricity from the grid if available or renewable sources if not, and water. In this way the need to replace empty cylinders with full ones is eliminated. The Acta Power is in effect a self-recharging fuel cell power system, meaning there is a perpetual supply of power on-site.
Central to the Acta Power is an electrolyser technology platform which is used to produce the hydrogen. Whilst electrolysis has been a known method for generating hydrogen since the 1800s, the two main methods historically used are either too costly or energy inefficient. One of the methods used is the PEM (proton exchange membrane)electrolyser, but the materials used to create it, namely platinum and related exotic components, make it very expensive. The other traditional method, the liquid alkaline electrolyser, is susceptible to contamination and has energy efficiency issues. Acta has designed and patented a new type of electrolyser, called an AEM membrane electrolyser, that negates the cost and energy efficiency shortcomings of the PEM and alkaline electrolysers. This has introduced a new technology that makes the adoption of hydrogen as a means of local energy storage commercially viable for the first time.
Acta’s AEM membrane electrolyser does not use expensive noble metals like the PEM electrolyser, and the unique membrane makes it more efficient than the alkaline electrolyser, as well as capable of performing in unforgiving real-world environments.
Once the hydrogen has been generated via the electrolyser situated in the Acta Power, it is then stored on-site in a cylinder which, again, is integral to the Acta Power system.
|Being able to store renewably generated energy means it can be consumed when the energy is needed, irrespective of weather conditions|
So that the stored hydrogen can be converted into energy, the Acta Power contains a fuel cell. The stored hydrogen is passed through the fuel cell with electricity produced as a result.
Meanwhile the electrolyser will produce more hydrogen whenever required to refill the tank, via either grid electricity or renewable energy. This self-perpetuating process all happens on-site, without the need for hydrogen delivery.
Furthermore, the Acta Power has a complete wireless GSM communication system for remote management, control, alarm and assistance. This allows the Acta Power to be controlled via a hand-held device, such as an iPad, from the other side of the world. The system also provides analytics which produce realtime feedback on a variety of elements, including hydrogen stored and power output.
The Acta Power, with a power output of up to 4 kW, can be used for a variety of applications. It is important to note that the Acta Power could be scaled up to provide greater output if required. Three examples of current applications using Acta’s hydrogen generators are:
à¢€¢ Cheshire farm, UK ” Energy storage for heating: In order to cope with the UK’s increasing supply of renewable energy, the National Grid is beginning to impose restrictions on the amount of renewable energy that can be exported to the grid. Those wanting to install a wind turbine, for example, have to demonstrate that surplus energy produced by the turbine that cannot be exported is being used in a useful way, in order to be granted a building permit.
The Cheshire farm has a 20 kW turbine. Of the produced energy, 3.68 kW (the maximum amount permitted) is constantly exported to the grid, with the farmhouse using approximately 6 kW. Acta has installed an electrolyser converting the excess power into hydrogen for storage. The hydrogen is then used to power a hydrogen boiler that provides heating in the farmhouse.
à¢€¢ Lighthouse, Singapore ” Primary power for off-grid communities: By storing renewable energy for later use when needed, the Acta Power can be used as the primary power source by off-grid communities. An Acta Power system has been sold for an evaluation project in Singapore where it will store renewable energy from solar and a wind turbine on an off-grid island. The potential of this application seems enormous: according to the International Energy Agency, currently 1.3 billion people worldwide live without access to electricity, mostly in Asia and sub-Saharan Africa.
à¢€¢ Telecom base stations ” Backup power: The Acta Power has been trialled at a number of telecom base stations in Australia, Africa, the Philippines and other countries to provide backup power. This is also a good example of traditional solutions, i.e., diesel gensets, being usurped by new, clean methods of on-site power production.
Telecom base stations
Telecom base stations, which ensure mobile network coverage, are ubiquitous with 1.2 million of them worldwide. But what happens when their power supply fails? With blackouts common in developing countries, and with growing grid instability even in developed countries such as the US, telecommunications companies have spent billions on diesel and battery backup power solutions to ensure they can maintain network coverage for their customers even when the primary source of power is unavailable. However, as diesel prices and transportation costs have increased, and as batteries have proven to be expensive in the long run, as well as inefficient outside a particular environment, the Acta Power provides a proven alternative.
Furthermore, as the Acta Power is designed to be a logistics-free backup power solution that eliminates the need for refueling, as well as dramatically reducing overall operating costs and expensive maintenance visits, it can save telecommunications operators both time and money. Ultimately, the Acta Power provides clean energy and allows users to get rid of batteries and gensets, thus eliminating fuel logistics, heavy maintenance, frequent substitution and fuel price uncertainty.
There are essentially three working modes for the Acta Power when used in the field:
à¢€¢ Power production: When there is a power outage, the Acta Power generates power, converting the stored hydrogen into power needed to meet the load and, as a by-product, also producing water;
à¢€¢ Hydrogen production: When the grid is available, or from renewable sources for when off-grid, the Acta Power generates and stores hydrogen, converting the electricity from the grid and using the water (this can be rain or tap water);
à¢€¢ Standby: When the grid is available and the hydrogen storage is full, the equipment simply stands by.
Recognising the demand for small backup systems, Acta has recently developed the Acta Power Cube. This is another self-recharging fuel cell backup power system, but with a power output from 200″1100 W, it has been designed for mass-market applications in railway signalling, telecommunications, transport, security and government.
Importantly, however, Acta’s technology has uses beyond backup power applications. As the fuel cell vehicle market develops, there will be greater demand for efficient hydrogen generation, especially from renewable energy and on a localised basis.
Remote or off-grid communities and installations are another diverse example of on-site generated hydrogen’s use for electricity. These examples are just a few of the many applications hydrogen can power, although Acta has specifically targeted the telecom base station market as the opportunities are easily identifiable and immediately apparent.
The business case
For telecom operators considering any technology, most will make comparisons between the total cost of ownership (TCO) of the new technology and what they currently spend. It is rare for ‘green power’ to be a major consideration; in all cases the introduction of any new technology must provide a better service level, as well as a lower TCO value. Ultimately, the more savings that can be achieved without compromising or, better still, while improving the service level, the more compelling the proposition.
|Figure 1. Five-year total cost of ownership analysis showing savings with Acta Power|
With these criteria in mind, considerations for the deployment of an Acta Power system to provide backup power for a telecom base station include:
à¢€¢ Produce hydrogen on-site and store this for use in power outages;
à¢€¢ Backup time depends on the size of the storage tanks and the ratio of charging time to supply time;
à¢€¢ Autonomy can be increased by adding additional low-pressure vessels;
à¢€¢ Similar CAPEX to existing technology but reduced additional equipment and less complex operation;
à¢€¢ Logistics costs drastically reduced, as maintenance is minimal and no refueling is required;
à¢€¢ Can be used in conjunction with grid or renewables, which may make some remote locations commercially viable.
A typical TCO analysis that would be undertaken by a telecommunications company includes comparing an Acta Power system to the existing capital and operating costs of all relevant site equipment including generators, batteries and cooling equipment, as well as evaluating the total site energy requirement, such as air conditioning and lighting. This method of evaluation allows for the costs and benefits of the Acta Power solution to be fully compared to traditional approaches (large batteries, diesel generators, cycle charging, etc) for various operational scenarios.
The result for a typical TCO of a genset at a telecom base station in Southeast Asia is shown in Figure 1 (see p.41). Importantly, however, this TCO does not factor in fuel theft, which can run as high as 50% in some cases, or battery theft, which is typically recorded as 10″18%, particularly in remote locations. Adding these issues in, even with conservative estimates, would obviously increase the overall TCO, thus making the typical genset even less competitive than the Acta Power.
On the TCO analysis an Acta Power system had a similar CAPEX cost compared to existing technology. However, producing fuel on-site versus consuming diesel resulted in the Acta Power providing a much lower operational cost, with a total cost saving of over $31,000 in five years.
It is important to give the context for the site discussed above in order to understand their need for backup power. The site in question has a power requirement of 4 kW and currently experiences grid outages of 120 hours per month, ranging from many interruptions lasting a few minutes to outages of up to eight hours in some cases. During certain times of the year the local utility also imposes enforced outages of up to four to six hours during periods when regional consumption of electricity stresses the grid. Having a reliable and cost-effective backup power solution is clearly important for the site in question, in order to ensure that mobile operators can provide their customers with uninterrupted network coverage.
A fuel for the future
Hydrogen may not be the only way to store clean energy economically, but its potential is undeniable and, through new products and technology, it is becoming more effective and commercially viable.
The key to unlocking the potential of hydrogen for energy is on-site hydrogen generation and storage. By producing hydrogen at the point of use, this eliminates the traditional barriers of transportation and logistics that make hydrogen less viable as an energy source.
As a closed-loop self-sufficient energy source, the Acta Power provides the answers to these problems. With similar innovation and developments, the potential of hydrogen for energy will surely be unlocked.
Paolo Bert is CEO of Acta. SpA. For more information, visit www.actaspa.com.
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