Renewable Energy: Current Status and Impact

By: Frank Caprio | On: March 1, 2016

There is a lot of talk these days about renewable energy and sustainable resources. Increasing the supply of renewable energy would allow us to replace carbon-intensive energy sources and significantly reduce U.S. global warming emissions. But renewable energy is used for more than just generating electricity; it may also be a source of heating and cooling, or it may be a fuel that can be used in industry and for transportation. The U.S. Energy Information Administration (EIA) estimates that about 11% of world marketed energy consumption is from renewable energy sources (biofuels, biomass, geothermal, hydropower, solar, and wind) with a projection for 15% by 2040. Let’s look at the various types of renewable energy and how each stands as a reliable source for future energy demand.

Renewable Energy Uses

Renewable fuels were used back when our Neolithic ancestors burned wood and other biomass for warmth and cooking, and were the only fuel source for thousands of years afterward. More recently there has been great progress in developing and concentrating these renewable energy sources to decrease our reliance on fossil fuels and reduce emissions. Per the International Energy Agency (IEA), renewable electricity expanded at its fastest rate to date (130 gigawatts) in 2014 and accounted for more than 45% of net additions to world capacity in the power sector. They account for almost two thirds of the expansion by 2020, with non-hydro sources nearly half of the total. The renewable share of generation rises from 22% in 2013 to over 26% in 2020. To date, the progress of renewables in the heating sector, which comprises almost half of total final energy consumption, and transport, accounting for a quarter of consumption, has been slower than in electricity.

Bioenergy

Bioenergy is created from biomass, which consists of wood, biofuels, and waste biomass. Biomass is derived from recently living organisms, which includes plants, animals and their byproducts. Some biomass is burned to create heat, which can then be put to use or converted into electricity. Examples of this include wood, straw, manure, peat, and municipal solid waste. Other biomass is converted into fuels that are then used to create heat and/or electricity. Examples of this include corn, algae, landfill gas, and sugarcane. Various processes are used to convert these products into fuels that provide energy, but most processes involve some type of fermentation. Currently, most bioenergy is derived either from burning biomass or producing ethanol and biodiesel from renewable crops, mostly corn. When burning biomass instead of fossil fuel, fewer nitrogen oxides (NOx) and sulfur oxides (SOx) are created, but higher amounts of particulate matter are produced, requiring baghouses, electrostatic precipitators, or other filtering equipment to remove particulates from the emissions. Although there are other bioenergy sources are under development, most of them are not economical enough to displace fossil fuels.

Hydro-energy

Hydroelectric power has been around for ages, and remains a competitive source of renewable energy, providing over 16% of worldwide electricity and 85% of total renewable electricity. It also provides an ongoing supply of water for consumption or irrigation as well as helping prevent flooding or drought. Hydro-energy can come from hydroelectric plants located on a river or reservoir, or it may be a PSP (pumped storage plant), where water is pumped from a lower reservoir into an upper reservoir when power rates are lower, then released through the plant during peak periods of demand.

New technologies are being developed to convert wave, tidal, and ocean energy into electricity. While not yet commercially available, these technologies have huge potential and are seeing rapid advancements in technology.

Wind power

Wind turbines use blades to collect the wind’s kinetic energy and convert it to electricity. Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid. A large number of wind turbines may be built close together to form a wind plant, also known as a wind farm. The amount of electricity generated from wind has grown significantly in recent years but still only accounts for about 4% of total U.S. electricity generation.

Geothermal

Geothermal energy harnesses heat from the earth. This heat can be drawn from hot water or steam reservoirs deep underground, or from the shallow ground near the Earth’s surface that maintains a relatively constant temperature of 50°–60°F. This heat can be used directly, or it can be used to produce electricity in geothermal power plants. There are three types of geothermal power plants: dry steam, flash steam, and binary cycle. Dry steam power plants draw from underground resources of steam, which is piped directly to the steam turbine to generate electricity. The only dry steam plants in the country are at The Geysers in northern California. Flash steam power plants use geothermal reservoirs of very hot water (with temperatures greater than 360°F). As this water flows up through wells in the ground under its own pressure, the pressure decreases and some of the hot water boils into steam, which is sent to the turbine. Any leftover water and condensed steam are injected back into the reservoir, making this a sustainable resource and the most common type of geothermal plant. Binary cycle power plants operate on water at lower temperatures of about 225°–360°F, which is used to boil a thermal fluid that is then vaporized and piped to the turbine. The water is then injected back into the ground to be reheated. The water and the working fluid are kept separated so no contamination of the resource occurs.

Solar

There are two main types of solar power: Photovoltaic (PV) and Thermal energy. Thermal energy is further divided into two subgroups: Low Temperature Thermal and Concentrated Solar Power (CSP). Low Temperature Thermal uses sunlight for direct heating in residential, industrial, and commercial applications. It typically operates at temperatures less than 212°F, and accounts for roughly 70% of global solar power. Concentrated Solar Power collects and concentrates solar radiation using mirrors and converts it to very-high-temperature heat. This heat is then converted into electricity. Photovoltaic energy uses solar cells to convert sunlight directly into an electrical current.

It is important to remember that any process involving steam requires flexible metal hoses and expansion joints in properly designed steam piping systems. If the steam is created by burning biomass or some other fuel, there are many more applications for our products in and around the furnace, and in pollution control equipment. If thermal fluids are used (as in CSP or binary cycles), metal hoses and expansion joints are incorporated into these piping systems as well. Knowledge of the processes and applications within each of the above technologies is crucial in order to properly specify, design, and fabricate the best flexible metallic connector possible, which is why we offer a training program not found anywhere else in the industry. Visit our Hose Master University page today to find out more about how you can become better educated about these and other applications for our products.