Renewable Technology

About Renewable Energy

Renewable energy comes from resources that, unlike fossil fuels, are not finite. These resources include wind, solar, hydropower, biomass, and fuel cells.

Wind Energy

Wind is a form of solar energy that is caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Renewable energy from wind is generated by wind turbines, which consist of a tower, a rotor and a generator. The rotor harnesses the wind's energy; the generator converts that energy into electricity; and the tower supports the whole apparatus.

Solar Energy

Solar energy is generated by Photovoltaic (PV) technologies that convert sunlight directly into electricity. PV cells are made of at least two layers of semiconductor material. One layer has a positive charge, the other negative. When light enters the cell, some of the photons from the light are absorbed by the semiconductor atoms, freeing electrons from the cell’s negative layer to flow through an external circuit and back into the positive layer. This flow of electrons produces electric current.

PV Modules: One way of increasing the flexibility and efficiency of solar facilities is to interconnect a large number of PV cells in a sealed, weatherproof package called a module. When two modules are wired together in a series, their voltage is doubled while the current stays constant. When two modules are wired in parallel, their current is doubled while the voltage stays constant. To achieve the desired voltage and current, modules are wired in a series and parallel into what is called a PV array. The flexibility of the modular PV system allows designers to create solar power systems that can meet a wide variety of electrical needs, no matter how large or small.

Types Solar Electric systems
Advantages and disadvantages of photovoltaics
Current State of Solar Power in Massachusetts and Berkshire County
Financial Incentives
Calculating Costs

Solar hot water

In a solar hot water system, the sun heats antifreeze liquid, and the heat is transferred by way of a heat exchanger to the domestic hot water supply.

Types of solar hot water systems

Hydropower

Hydropower systems use the kinetic energy in flowing water to produce electricity or mechanical energy. There are several types of hydroelectric power plants. The most common one is an impoundment system that uses dams on rivers to store water in reservoirs. The water released from the reservoir flows through a turbine and activates a generator to produce electricity. A diversion hydropower plant does not require the use of a dam because it channels a portion of a river through a canal to a turbine. Pumped storage plants can store power. They use two reservoirs, one at a high elevation and one at a lower elevation. When energy demand is low, water is pumped from the lower reservoir to the upper reservoir for storage. Hydropower is currently the largest source of renewable power, generating nearly 10% of the electricity used in the United States.

Biomass

Biomass is organic matter that can be used to provide heat, make fuels, and generate electricity. Wood is the most common type of organic matter used to generate bioenergy, but other types of biomass such as plants, residue from agriculture or forestry, and the organic component of municipal and industrial wastes can be used as fuel. The cost to generate electricity from biomass depends on the type of technology used, the size of the power plant, and the cost of biomass fuel supply. The cost is approximately 9 cents per kilowatt-hour in today’s direct-fired biomass power plants.

Fuel Cells

Fuel cells convert chemical energy directly into electricity and heat.

Renewable energy sources have several common advantages. They are locally available resources that do not need to be imported from other regions of the country or across the world, and they are a clean energy source because they produce virtually no harmful air or water pollution.