The frequency, duration, and strength of storms, flooding, and forest fires are increasing, as we see every day in the news. Experts are predicting things will get worse, a lot worse, unless the countries of the world take aggressive action. Even previous conservative naysayers are changing their views on the situation. Most of the debates are over except for what aggressive actions should be taken. The focus item is to reduce the emissions of CO₂ into the atmosphere. One of the tools to accomplish the reduction is the use of renewable energy.

Renewable energy is energy from sources which naturally replenish themselves. Although limited in the amount of energy available per unit of time, renewable resources are inexhaustible in duration. The types of renewable energy sources include the following.

First is biomass, which is plant or animal material used as fuel to produce electricity or heat. Examples are wood and wood waste, municipal solid waste, landfill gas (sometimes called biogas), and waste from forests, yards, or farms. Biomass also includes ethanol, an organic chemical compound and biodiesel, a form of diesel fuel derived from plants or animals.

Hydropower, or hydroelectric power, is a renewable source of energy which generates power by using a dam or diversion structure to alter the natural flow of a river or other body of water. In effect water is the fuel which produces electricity. Because hydropower uses water to generate electricity, hydroelectric plants are usually located on or near a water source. For example, where I live in the summer is on Lake Wallenpaupack in the Pocono Mountains of Pennsylvania. The Wallenpaupack hydroelectric plant is powered by the water contained by a 1,280-foot-long and 70-foot-high dam, which creates the 5,700-acre recreational Lake Wallenpaupack. The generation process begins when water from the bottom of the lake flows into a 14-foot-wide pipe called a flow line. The water travels 3.5 miles through the flow line to the power plant where the rushing water spins two turbines. The turbines spin within each of two generators to create 44 megawatts of electricity, enough power for about 35,000 typical homes. Hydroelectric power represents approximately 25% of total renewable energy.

Geothermal energy is derived from the heat under the surface of the Earth. Scientists have discovered the temperature of the earth’s inner core is about 10,800 degrees Fahrenheit (°F), which is as hot as the surface of the sun. Temperatures in the mantle range from about 392°F at the upper boundary of the earth’s crust to approximately 7,230°F further below. Consumers are saving thousands by replacing their traditional systems with a heat pump inside the home. Buried under the yard are pipe systems, called ground loops, which circulate heat transfer fluid. The heat pump and circulating fluid continuously transfer heat. During summer, the geothermal system draws heat from the air in the home and transfers it to the ground. During winter, it draws heat from the ground and transfers it to the home. Geothermal energy represents only 2% of renewal energy, but it has potential.

Ocean wave power is very small today but also has potential. A machine that exploits wave power is a wave energy converter. It uses the power of waves and converts it to electricity.

Looking at the big picture, renewable energy represents 12% of energy consumption, but is growing steadily and, I believe, will accelerate. Wind represents 26% and solar 11%. Both are growing rapidly. Nuclear power at 9% has struggled but new technology may make it a key renewable. Petroleum, natural gas, and coal represent 80%. That is the challenge. I am optimistic.

Two additional renewal energy sources are on the horizon, hydrogen and fusion. Some are extolling the virtues of hydrogen fuel cells as an alternative source of electrical power. The fuel cell operates quite differently than a traditional battery. It generates electrical current from a chemical reaction between hydrogen and oxygen. The oxygen comes from the air. Hydrogen is compressed, stored in a tank on board a car or truck, and is replenished at a filling station. As of 2018, there were 39 publicly available hydrogen stations. Unlike a battery, a fuel cell creates exhaust, but the exhaust is simply the result of the reaction between hydrogen and oxygen. The exhaust is water. Hydrogen has been the fuel of the future for decades, always promising to deliver huge benefits in about five years. The potential is great, but we need to see more breakthroughs.

Fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles. The result of the reaction is the release of energy. Tremendous amounts of energy, enough to supply the world with unlimited renewable energy with no emissions. Research is underway in more than 50 countries. Billions have been invested by the U.S. government for its energy labs plus venture investments in startups who claim to have fusion figured out. Many are skeptical but this week revealed a breakthrough.

The Lawrence Livermore National Laboratory announced a key achievement in fusion research. One hundred ninety-two giant lasers were focused onto a target the size of a BB which resulted in what the laboratory described as, “a hot-spot the diameter of a human hair, generating more than 10 quadrillion watts of fusion power for 100 trillionths of a second.” The development is being cheered by industry watchers, but there is still a long way to go before fusion will be commercially viable. The 100 trillionths of a second is not very long, but it spurred a burst of optimism for fusion scientists who believe fusion will be an energy source like the sun and won’t emit CO₂.