Green Energy Can Stop Recession

Storing Solar Energy for the Night

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By Béla Lipták, columnist

The gross world product was estimated at $65.85 trillion in 2007, and the combined global debt is over $100 trillion. Future generations will inherit not only this debt, but also the melting ice caps, the atmosphere turned into a garbage dump, the nearly exhausted global resources, not to mention our military bases and nuclear warheads that can destroy the planet 25 times over. Yet warheads do not increase our reserves, only the likelihood of energy wars.

Mankind’s overloaded “ship” is sinking, yet some passengers argue that it is just rocking with the waves. Others believe that the leak will plug by itself, or the ship will drift to shore on its own. Still others argue that the leak is small, and there is no urgency to fix it or are sharpening their knives to fight their way get the remains in the kitchen. This series of articles speaks to those passengers who want to plug the hole and do not want our grandchildren to ask, “Why did you not act?”

The road to an inexhaustible and clean energy future is obvious. The third industrial revolution is already beginning: Just as we lead the world in developing the computers, we Americans must find the moral courage and determination to lead this revolution also. The process control profession (the only profession that is capable of integrating and optimizing complete processes) should be in the forefront of this effort.

In this series of articles, I am describing the components of this, the world’s first 1,000- MW solar-hydrogen electric power plant. Below I will describe the electrolyzer that converts solar energy into electricity during the day and uses that to make electricity at night. My invention is to develop the controls and optimization needed to convert this electrolyzer into a reversible fuel cell (RFC), so that the same RFC can be used at a fraction of the present cost to make solar energy continuously available.

Making Solar Energy Continuously Available

The development of the controls and optimization strategies of this new process will be difficult. Yet once we have figured it out, it will serve not only power plants, but also “energy free” households with solar roofs and electric cars. In these homes, the reversible fuel cells (RFCs) will generate hydrogen when the sun is out and will refill the hydrogen fuel tank, reducing the cost of transportation by a factor of three to five. When solar power is unavailable, it will use the inexpensive night-time electricity to make hydrogen to be used at peak periods during the day.

Hydrogen fuel is safe. It is used in space exploration to lift vehicles into orbit. The international space station uses an acre of solar collectors to provide it with electricity.

The main reason why hydrogen is safer than gasoline is its low molecular weight, which in case of an accident, causes it to rise instead of soaking into the ground. Hydrogen technology is well-established, used by industry, but practically unused in power plants.

In January, I was on a lecture tour in India describing the controls and optimization of the world’s first solar-hydrogen power plant. Here I will discuss only one aspect of this new power plant, the way how solar energy can be stored during the day so that it can be made available at night, thereby making solar energy continuously available.

In nature, hydrogen is produced by plants. Vegetation uses sunshine as the energy source to break down water into hydrogen and oxygen. The oxygen is released while a catalyst in the plants (chlorophyll) serves to decompose water and to generate hydrogen. Once water is decomposed, the plants use the hydrogen to react with the carbon dioxide in the air to produce glucose and cellulose.

Therefore, plants emit oxygen while taking up carbon dioxide. Animals and humans do just the opposite. They obtain their energy by oxidizing glucose and cellulose while inhaling oxygen and exhaling carbon dioxide. When the concentration of plant and animal life on the planet is in balance, the atmospheric concentration of carbon dioxide is constant. When mankind overpopulates and its lifestyle also generates more carbon dioxide while plant life shrinks, the balance is upset.

For the last million years the carbon dioxide concentration of the atmosphere stood at 280 ppm. As the industrial age began and the proportion of forests and plant life was, the carbon dioxide concentration of the atmosphere increased to 380 ppm, and soon will have doubled as our carbon footprint further increases. Yet,this balance can be reestablished by using sunshine to make hydrogen and burning hydrogen to meet our energy needs.

Figure 1: I held eleven lectures in six cities on the automation of renewable energy processes

The Electrolyzer

Today, the United States is using some 9 billion cubic feet of hydrogen a day in the petrochemical, food and rocket propulsion industries. Some 98% of the bulk hydrogen is produced by steam reformation of natural gas. When hydrogen is made from fossil fuels, the carbon is exhausted into the atmosphere, and this contributes to global warming.

In 1820, Faraday discovered electrolysis by passing electricity through water and thereby generating hydrogen at the negative electrode (cathode) and oxygen at the positive electrode (anode) of the electrolyzer. Thus he found that hydrogen can be produced from water. If the energy of the sun is used to drive this process (as is the case with plant life) the fuel is free, and the emission is only oxygen. This process is called electrolysis. The electricity for operating an electrolyzer can be provided by a battery (Figure 2) or by solar collectors.

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