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 maths 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 a 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 actual 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 initial cost but looking at operating and maintenance costs during the life cycle 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 rectifiers are important issues. In this article we will discuss about grid independent system because many developing countries in Africa and Asia do not have 24x7 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,controlle for grid independent power supply; and second system with PV solar, battery, water Electrolyzer,Hydrogen storage and PEMFuel 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 energy cost: $ 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 battery will make all the difference.

Tame the Renewable with Hydrogen

The sun is bright and warm and your roof top solar panels and solar heaters are working hard to generate power and hot water. But the rate of power generated is too small to use immediately. The hot water is not hot enough for your shower. Your 200watt rooftop solar panel generates only 0.12 kwhrs after 5 hours of hard work. It does not meet your expectations. You expect 200 watts solar panel to generate about 1000 watt.hrs (1kwhr) in 5 hours. It is not happening. You don’t think renewable energy can meet your electricity demand. There is a strong wind in the island and the wind turbines are rotating faster than usual but there are hardly any people living there. Wind turbine generates good power when the wind velocity is above certain level. But the electricity generated by the wind has no immediate takers. There is a good rain this year and the dams are overflowing and the Hydro is generating surplus power but not many people are living near the catchment area. The power has to be transmitted hundred of kilometers to the nearby town through a sub-station. When the dams are dry there is hardly any power generation and power supply is rationed to the town. When there is a demand for power Mother Nature does not offer the resources for power generation. When Mother Nature offers the resource we do not need power. This anomalous situation is the single largest obstacle that is undermining the potential of renewable energy. Of course, the high initial cost and half-hearted approach by Governments to offer subsidies or grants for renewable energy are other factors that add to the anomaly. The only option to get over this situation is to store the energy 24x7 when it is generated and use them when we need them. It requires good storage technology, automation and information technology that can communicate with Natures energy resources and harness them, store them and deploy them judiciously and intelligently to meet our demands. Current battery technology cannot be a long term sustainable solution; it is expensive, requires constant maintenance and replacement, which adds to the expensive initial investment on renewable systems. The best option is to generate Hydrogen on-site whenever sun shines or wind blows and store them under pressure that can be used as and when we require electricity using Fuel cell. It is easier to handle gas than stored electricity in batteries. Batteries are very heavy, has a limited life cycle and poses health hazard and not suitable for large scale power storage and not sustainable in the long run. An Elecrolyzer can generate Hydrogen from water onsite whenever there is a sun or wind energy available and they can operate from 10% to 100% capacity depending upon the availability of renewable resources. The surplus power from Hydro can be converted into Hydrogen and stored. With so much advancement in information and communication technology, harnessing nature’s energy, storing them and deploying them in a timely manner is not major issue. Hydrogen can bridge the gap between Natural resource availability and human demand. This is what science is all about. We developed science by learning from Nature or duplicating Nature and Renewable energy is nothing different.