An Overview of Renewable Energy Technology

The world rapidly realizes the importance of renewable energy technology in meeting future global energy needs. This is especially true in light of the increasing awareness of the adverse impacts of nonrenewable energy sources and the threat posed by climate change.

There are various renewable resources and technologies, each with strengths and limitations. Therefore, it is essential for policy makers to ensure that each technology is adequately treated in a way that achieves national goals.

Biomass is a renewable source of energy that can be used to generate electricity. Typically, it comes from trees and plants, but other materials, including municipal waste and algae, can also be used.

A growing number of countries are turning to biomass to reduce their dependence on fossil fuels while helping the environment and lessening greenhouse gas emissions. But this energy technology still has some kinks that need to be worked out.

One of the biggest kinks is that burning biomass releases pollutants and particulates into the air. These include dreaded greenhouse gases like carbon dioxide, which contribute to global warming.

Geothermal energy uses heat buried beneath the earth’s surface, and it can be used to generate electricity. It’s the most abundant of all renewable energy sources and has many advantages over solar, hydropower, and wind power.

Flash-steam plants use naturally occurring underground sources of hot water and steam (typically ranging from 182degC to 370degC). The water “flashes” into mist, funneling to a turbine to spin a generator to make electricity.

A newer technology, called a binary cycle plant, runs fluids from the ground past a heat exchanger to generate electricity. The unique plant can generate electricity from as little as 100degC up, but getting the heat up there is a challenge.

Hydropower is a renewable energy technology that can generate electricity by harnessing the energy in moving water. Because the power comes from water, hydropower plants are generally located on or near a water source, such as a river or lake.

Unlike solar and wind power, which only create electricity when the sun shines and winds blow, hydropower can store excess energy to be used later. This type of hydropower is called pumped storage, which can hold vast amounts of energy for months.

Although hydropower is one of the most developed forms of renewable energy, it does have some limitations. Weather and climate changes, for example, can significantly reduce the amount of available power. However, hydropower can also be flexible enough to go from zero strength to maximum output quickly.

Ocean energy technology uses the natural cycles of tides, waves, currents, and thermal gradients to generate electricity. Various technologies convert the energy from these sources to produce baseload power, the electricity that is consistent and reliable.

Oscillating wave surge converters and wave carpets use the movement of waves to push seawater up and down a flexible membrane. This seawater drives pressurized water through piping to an onshore turbine that produces electricity.

Tidal stream devices harness tidal currents using winged “kite” devices steered in a figure-of-eight pattern to create flow several times higher than the actual tidal current speed. Other ocean energy technologies include seawater air conditioning (SWAC) and ocean thermal energy conversion (OTEC), which generate power from the temperature differential between cold deep seawater and warmer surface water.

Solar energy, radiant light, and sun heat can be harnessed in several ways. It can be used to generate electricity, as well as to warm and cool buildings.

Photovoltaic technology (PV) converts sunlight into electricity by exchanging electrons with atoms in semiconductor materials. This technology is a leading renewable power source and can supply homes, businesses, and even large power plants.

Concentrated solar power (CSP) uses mirrors to focus a large amount of sunlight, creating electricity that can be stored and sold back to the grid. The most common CSP systems use parabolic troughs. But, newer technology, such as concentrating solar towers, is gaining popularity.