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Tag Archives: Renewable Hydrogen

Why should you choose Photovoltaic Hydrogen over Photovoltaic battery?

 Photovoltaic (PV) power is becoming popular worldwide as an alternative to grid power for various reasons. It gives an energy independence and freedom, it helps reduce greenhouse gas emission and combat global warming, it helps people taking advantage of various Government subsidies and incentives, and it also generates some revenue by selling surplus power back to the grid. At the end of the period you own the system and claim depreciation and some tax benefits. All these compelling factors may motivate people to opt for PV solar power. But you should also do some math and make a cost benefit analysis to choose a right system for you.

When there is a good sunshine day after day and throughout the year, PV solar is good proposition and can be really rewarding. Unfortunately that is not the reality. There may be many cloudy, rainy and fogging days in a year and your PV solar capacity may be overestimated or underestimated. You know the real data only after one or two years of life experience. It is a long-term financial and ethical decision one has to make and the decision should be absolutely right. You can make such a decision by carefully examining all the factors, not just by looking at the first cost but looking at operating and maintenance costs and all the costs and benefits associated with them.

Storage batteries are inevitable in PV solar systems, especially for grid independent systems. Even with grid connected PV solar system the design and installation of a correct battery bank, controllers and rectifier are important issues. In this article we will discuss about grid independent system because many developing countries in Africa and Asia do not have 24×7 uninterrupted grid power supplies. Many people living in islands have to manage their own power by using diesel generators. This is the stark reality.

Let us assume that you design a system assuming a daily average power consumption of 25,000 kwhrs/day, which is suitable even for a medium size family in US. We made an optimum design study between two  systems; first  containing PV solar,battery,controller for grid independent power supply; and second  system with PV solar, battery, water Electrolyzer,Hydrogen storage  and PEM Fuel cell and a rectifier for grid independent system,  based on the same power consumption of 25,000kwhrs/day. You can clearly see the difference between the two systems by the following data.This financial analysis was made assuming there is no Government subsidies and incentives.

Grid independent system with battery storage for 25,000kwhrs/day power:

Total NPV (net present value):$ 342,926

Levelized cost of energy: $2.94/kwhrs

Operating cost/yr: $22,764

Grid independent system with Hydrogen storage for 25,000kwhrs/day power:

Total NPV (net present value): $ 169,325

Levelized cost of energy : $ 1.452/kwhrs

Operating cost/yr: 8,330

The number of batteries required in the first case is 17 numbers. In the second case, number of batteries required is only 2.Obviously,  the levelized cost of power using  PV Hydrogen (storage) is less than 50% of the power generated using PV battery (storage) for the same energy consumption of 25,000kwhrs/day. The operating cost is only one-third for PV Hydrogen system compared to battery system. Batteries are indispensable in any renewable energy system but reducing their  numbers to the lowest level is important, when the life of the system varies from 25 years to 40 years. The numbers and the cost of batteries and their maintenance cost  will make all the difference.

 

How to power your home and fuel your car with Hydrogen?

There is a general opinion that Hydrogen is dangerous or explosive; people are often reminded of Hindenburg accident or Hydrogen bombs. Hydrogen is as safe as Gasoline or Butane gas. It should be handled with care like any combustible material. We have used Hydrogen in industries for so many decades and transported by pipelines across thousands of kilometers; the methods and procedures of handling Hydrogen is well established. It is a very light, colorless and odorless gas and it can easily escape into the atmosphere. Hydrogenation of vegetable oils for production of certain Margarines is one the classical industrial examples for Hydrogen usage. When 100m3 Hydrogen is compressed to 10,000psi pressure, it is reduced to just 0.163 m3 by vlume.That is how the Hydrogen storage space is reduced in passenger cars. This volume of gas can give a mileage of 652 miles, using Fuel cell power. The only emission is just pure water vapor! No noise, no smoke and it is entirely a new experience driving a Hydrogen Fuel cell car.

Powering your home with Hydrogen or fuelling your Fuel cell car is not very difficult. It is expensive compared to grid power for two simple reasons. Grid power is generated by power generation companies somewhere else using coal, oil or gas and transmitted across to millions of people.Therefore,  the  investment on power generation is shared by millions of people through their monthly energy bills. When you use the grid power, you do not pay any large sum except, a small deposit of few hundred dollars towards connection fee, and you pay your bills based on your monthly electricity usage.

But when you try to generate your own power using a solar panel or Fuel cell then you have to make an investment fully upfront. Of course, your bank can help you with the finance for the system. However, when you calculate the energy cost over the life period of 25 years then you can clearly see the value of such investment. The grid power cost will only increase and never decrease while your generation cost will decrease as the time passes. The future energy cost is likely to increase substantially due to various factors. You can export surplus power to the grid and your payback time will be reduced as the energy cost increases.

The first step in powering your home is to calculate your power requirements accurately in terms of watt.hrs.How many appliances you will be using  and how many hours you will using each of these appliances per day. Suppose you estimate 15,000 watt.hrs/day or 15kwhrs/day of power, and then a small Fuel cell consuming 1 Kg/day of Hydrogen or 30 kgs/month of Hydrogen will be sufficient to meet your power demand. Similarly you can calculate the amount of Hydrogen you will be using as a fuel for your Fuel cell car. For example, if you will be  driving your Fuel cell car for 1000 miles per month, then  your Hydrogen requirement will be about 14 kgs/month. Your Hydrogen requirement per month for both power and car together will be 44 kgs only.

Your total  power need to generate the above Hydrogen will be 2464 kwhrs/month costing less than $250 per month for both power and fuel. Of course you need to calculate other fixed costs on the investment. You can export your solar power at a higher tariff to the Government and import your power requirement from the grid during off-peak season at a lower tariff and generate Hydrogen and store it. You can generate your power as and when you need, and you are in complete control of your situation, even if there is a blackout due to grid failure!

Hydrogen assisted combustion

We have been using fossil fuels like diesel, petrol and natural gas for power generation and transportation from the time of industrial revolution. The basic fuel and the combustion technology are practically the same with efficiencies less than 40%. In fact we have become very complacent with both the fuel and the combustion technology and there were no major research and development on both the above issues. In fact we became completely dependent on these two issues and there was no real breakthrough either in substituting the fossil fuel or in the combustion technology. The basic reason behind this situation can be attributed to the discovery of electromagnetism, which opened the way for electricity generation as well as transportation. In both these industries, the key part is the motor which provided a rotary motion. This rotary motion generates electricity in turbines and such motion is created by combustion of a fuel, which is invariably a fossil fuel. We have carried on this for few decades before the emission of greenhouse started rising abnormally and became an issue.

We are now at cross roads wondering what the future holds for the world. Is it possible to carry on the business as usual or look for an alternative source of energy? We started looking at various sources of energy as an alternative. Any alternative energy source should meet two critical parameters namely the lower or no carbon emission and sustainability. Low carbon can be achieved by few methods. The immediate option is to maximize the energy efficiency of existing systems so that for the given input of fuel the output is much higher than what we have achieved all these years. But this increase in efficiency should be real to achieve the emission levels of greenhouse suggested by the UN panel on climate change.

The second option will be to switch over to different fuels with less carbon emission e.g., coal-fired power plants switching over to gas-fired power plants using combined cycle. Retrofitting organic Rankin cycle as a bottoming for steam turbines to squeeze out some extra energy. Decentralizing the power plants in a phased manner in favor of distributed energy systems where gas, instead of electricity, can be supplied to each industry, to generate their own power using CHP process. All these measures can help reduce the emission level but our dependency on fossil fuel will still continue.

W can look at a completely different fuel source and new technology for power generation and transportation. If we look at carefully there are not many alternative fuel sources except Hydrogen that could meet these limits. We are also trying to develop bio fuels. But biofuels are also organic chemicals with carbon backbone which will generate greenhouse emission. Moreover bio fuel sources such as palm oil, corn are also food sources. There is an indiscriminate deforestation and plantation of palm trees in tropical countries like Malaysia, Indonesia and PNG. The focus is now shifting to carbon based organic compounds like biofuel and biogas. This will create a situation where food crops will be substituted with energy crops creating food shortage.But the carbon dioxide level in the atmosphere may not be reduced drastically by these methods.

We need to develop an energy source which does not emit any carbon emission and at the same time we should be able to use existing technology to the possible extent. Only Hydrogen can meet these requirements. In the current situation it is impossible to substitute fossil fuels in a short span of time. We can cut fossil fuels by blending with Hydrogen to the most extent possible so that we can meet two goals. We can cut the carbon emission and at the same time we can deploy Hydrogen as a blended fuel with fossil fuel and not, pure Hydrogen. Since Hydrogen is a very light gas and readily forms an explosive mixture with oxygen, this opens up a new opportunity to develop Hydrogen assisted combustion process in power generation as well as in transportation. It will be easier to handle a mixture of natural gas and Hydrogen for combustion in Gas turbine, or spark ignited reciprocating engines, as well as, gasoline combustion engines in cars. This will also gives us an opportunity to develop advanced and competitive systems like Fuel cell as an alternative technology for combustion process in due course of time.

The hydrogen assisted combustion technology is much easier, faster and economical and at the same time cut the greenhouse emission to an accepted level. But the source of such Hydrogen cannot be natural gas but only renewable sources. The renewable technologies such as solar, wind, geothermal, OTEC (ocean thermal energy conversion) should generate renewable Hydrogen. This is the key for sustainability as well as for greenhouse gas mitigation. These two benefits are too attractive to ignore and it is time we move from total fossil fuel to Hydrogen blended fossil fuel. The blended fuel along with the energy efficiency measures suggested above should go hand in hand, so that we may get over this turbulent period of financial crisis and global warming.

It is also possible that Hydrogen assisted combustion be adopted for coal-fired power plants by simply firing coal slurry, finely powdered coal blended with water and conveyed pneumatically for firing boilers and also for gasification process to generate syngas for IGCC (Integrated gasification and combined cycle) applications. Syngas production will be critical in the near future for a smoother transition from fossil economy to Hydrogen economy irrespective of the route we adopt.

Hydrogen-the key to sustainability

Renewable energy is one of the fastest growing energy sources of our times. But still there are many obstacles to overcome, before it can substitute current methods of electricity generation using fossil fuels, or substitute petrol in cars. The main obstacle is, the intermittent and unpredictable nature of renewable energy sources, such as wind and solar. Wind blows only certain seasons of the year and then wind velocity fluctuates widely in a day. Similarly sun shines only certain hours in a day and the intensity of radiation varies widely in a day. The wind velocity and sun’s radiation intensity are critical components in designing a reliable energy system. It is an anomalous situation, when we need power, there is no sun or wind; when sun shines or wind blows, we may not need any power. How to overcome this anomaly? That is the key, in successfully deploying renewable energy technologies.

Currently we are using batteries to store the energy. When there is a wind with reasonable velocity or sunshine with reasonable radiation intensity, we can generate power and store them in batteries. The wind velocity should be above certain threshold limit, say such as, a least wind velocity of 3mts/sec for amount of hours, while designing a wind based energy system. The same principle applies to solar energy and we need certain minimum solar   intensity and several hours. But in reality, we don’t get these minimum operating parameters, which make the design of a renewable system more complicated.

Batteries can accumulate these small energy generations by intermittent sources of wind and sun, and store them. But these batteries have certain life between 3-5 years and requires regular maintenance, replacements.They also have certain charging and discharging cycles and limitations. At the end of its life, it has to be disposed carefully because these batteries are made of lead and acid, which are toxic materials. Many companies are trying to introduce better technologies such as ‘flow batteries’. But experience shows that such batteries are confined to only smaller capacities. Large scale storage is expensive and sometimes it is not economically feasible. Lithium-ion batteries are more efficient than Lead-acid batteries, but they are more expensive so the renewable energy projects become expensive and cannot compete with conventional fossil fuels, in spite of higher tariffs offered by Government as incentives. Moreover the demand for Lithium-ion batteries will increase substantially in the future, as more and more Electric cars are produced. But lithium sources are limited and it is not sustainable.

The best option to develop renewable energy systems is to generate Hydrogen using renewable energy and store them, instead of storing them in batteries. We can use stored Hydrogen to generate power, or use as fuel for the car, as and when we need. There are no maintenance or disposal problems with Hydrogen storage, when comparing with batteries. Hydrogen generators (electrolyzers) can generate Hydrogen when the intermittent power flows from wind or sun. They can run from a range of capacities from 5 to 100% of rated capacity and they are more suitable for renewable energy sources. But there will be a loss of energy, because the amount of power required to generate Hydrogen, is more than the power generated from the resulting Hydrogen by a Fuelcell.The initial cost will be higher, but it will give operational flexibility with least maintenance, and even adoptable to remote sites. Technology is improving to cut the cost of fuel cells and electrolyzers so that Hydrogen based renewable energy will become a sustainable source of energy in the future. Hydrogen is the only solution that can solve both power generation and transportation problems the world is currently facing.

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