Clean Energy Types
You’ve decided to explore clean energy for your municipality, but what type is most appropriate? Perhaps you live in a community with untapped geothermal reserves or maybe you are perfectly positioned to take advantage of wind energy? To help you decide which clean energy is best suited for your community, the Municipal Clean Energy Toolkit contains information on all types of clean energy technologies, as defined by the General Laws of Massachusetts.
Each type of clean energy has a page that details information on: what the technology is and how it works; benefits and barriers; how to get started; relevant legislation; options for financing your installation; examples of other communities who have installed this clean energy type; and additional resources. These pages are intended to provide an overview of clean energy technologies available to municipalities; they should not be viewed as an all-inclusive resource.
Clean Energy Types
Biomass is biological material, such as woody and herbaceous plants, manure, and algae, found in natural or agricultural environments. Biomass generates energy when burned that can be used directly as heat or can be converted into electricity. Of all biomass types, wood is the most widely available form in Massachusetts.
Energy from Waste - There are two major ways to use waste to make energy: capturing landfill gas energy and waste to energy. Landfill gas energy is the collection of methane generated from the decomposition of solid waste in landfills that is then combusted to generate electricity. Waste to energy is referred to as the combustion of municipal solid waste to generate electricity.
Fuel Cells are energy conversion devices that convert chemical energy from fuel and an oxidant into electrical energy. In most cases, hydrogen fuel is used to power fuel cells, which is produced from fossil fuels. Fuel cells are still in the early stages of development, but are currently being used in Massachusetts.
Geothermal literally means heat (thermal) from the earth (geo). Geothermal energy can be harnessed by drilling into the ground and using the relatively warmer water or ground temperatures to heat and cool buildings. Geothermal energy can also be used to generate electricity by utilizing underground reservoirs of very hot water to run turbines. In Massachusetts, geothermal heat pumps for heating and cooling facilities are the most common use of geothermal energy.
Hydroelectric, or hydropower, refers to the use of water to power machinery or to generate electricity. Hydropower is the most used form of renewable energy in the United States, comprising 75% of renewable energy generation and approximately 10% of U.S. total electricity generation.
Ocean Energy - As the world's largest solar collectors, oceans are responsible for storing and transporting the vast majority of the earth’s energy. The two primary ways that oceans store and move energy are through water flow (currents, waves, and tides) and through thermal and salinity gradients. There are a number of approaches to extracting energy from the ocean, such as marine current power, salinity gradient power, tidal power, wave power, and ocean thermal energy conversion technologies. This Toolkit focuses on the last three of these technologies.
Solar Energy refers to the ways the sun’s energy can be used to directly generate heat, lighting, and electricity. Besides solar photovoltaic (PV) technology, there are other types of solar technology such as passive solar, solar heating and cooling, and solar thermal concentrating systems which are becoming popular. Solar PV is the most widely installed clean energy technology in Massachusetts, with over 400 systems installed as of December 2008.
Storage and Conversion Technologies are energy management technologies that store energy generated from any source when the demand for grid electricity is low, and then convert the stored energy back to electricity to send to the grid when the demand peaks. These energy management technologies are most relevant to municipalities that own or operate utilities or power plants.
Wind is created when cooler air is drawn close to the earth’s surface to replace hot air as it rises. To create energy, this wind is harnessed to create mechanical energy, most often by wind turbines which are able to transform the wind energy into electricity. In Massachusetts, wind energy is one of the most practical clean energy resources – from onsite and offshore installations to the purchasing of electricity generated from wind energy systems.