 This lesson is going to be on alternative and renewable energy sources The main types that we're going to talk about are wind hydro solar Geothermal and biomass wind power once was used for mechanical drives only it's gaining a popularity as a clean alternative source of electricity using turbine generators you know the old Windmills as they were called we used on farms to draw water up from aquifers to serve as wells on their land and Way way back. They actually did things like Ground flour and corn and those types of things Today we have large wind farms are being built across the country where wind becomes a natural resource Some of the concerns with these obviously noise pollution in the area for the residents of that area and there have been numerous reported deaths to flocks of birds flying in those areas and as you can see the picture on the left there just shows what are some 750 kilowatt turbines in the state of Minnesota on a large wind farm there Hydro power basically using water force as as energy traditionally it had been used to churn mills. That's why we would have those Water mills and again they did several things with those from a mechanical energy standpoint, but today we have hydroelectric generators We have most predominantly hydroelectric dams But we also have what are known as tidal powered turbines and these are actually Utilizing the current flows Generally in and out of a river or in and out of some type of an inlet They use these in the North Sea off of Scotland. There's an experimental one in the East River in New York City as well again, there are subsurface Turbines that actually spin as the current goes in one direction or another and those drive a generator which produces the electricity So all our energy has been around for quite some time the Interest in it and the expansion of it really began with the oil embargo of 1973 and 1974 and then the second embargo in 1979 caused even more interest in it The idea is to collect heat and energy from the Sun and use it for things such as pure heating generation of steam for electric turbines or to actually create electricity directly which be would be the use of photovoltaic cells In a lot of cases it's used to you know heat water even for space heating And we generally have two types the passive solar energy is using the direct heat of the Sun There are solar collectors And they can Direct the heat in a particular area It's primarily used for space and water heating and it can also used to be used to create steam So some of the panels you might see on office buildings or Residences may be maybe doing nothing more than circulating water through for hot water heating others Even you would probably recognize the difference or the photo photo will take ones that are producing power And again, this gets this brings us to the active part It's the photovoltaic conversion of sunlight to electricity using Semiconductive materials it's dependent on the atmosphere condition and the Earth's position relative to the Sun and obviously off to the right there you see a photovoltaic array Small-scale use here, but you see them more and more throughout. They're using them now for traffic signs communication systems Pipeline companies or any type of long-distance Lines or cables or whatever else signals are transmitted in the powers coming from photovoltaic cells Geothermal energy we generally think of geothermal energy as natural steam, you know coming from geysers and from other places And in those cases it could be used for direct space heating. It can also be used directly for industrial processes Steam will also drive Steam turbines at a power plant or on site somewhere where there is the geothermal steam coming up But a flip side of that which a lot of people are not necessarily aware of is the fact that you also have Geothermal energy that's used for space cooling, you know after all if you go several feet below the surface the The soil and the temperatures down there are much cooler than above ground And so you can literally drill down into cooler area and Draw up cool air to use for space cooling. This is becoming more and more prevalent I have personally seen large homes that use this as well as Oh mid-size office buildings Biomass these are the various types when we talk about biomass and energy coming from biomass We're talking about things like wood garbage crops Various alcohol fruits, so there's fruits that produce some type of an alcohol that can be burned as energy and then landfill gas Biomass the one form here is landfill gas. You basically you have decaying trash That's in landfills and it's going to create methane You know all the biological material that breaks down and decays will end up giving off methane methane gas and Over time the older landfills will actually have pockets of methane within them and there are You know people who will go out and they literally will poke a hole down into the landfill And they will get the pockets of natural gas and they'll use it on site mostly They can use it to drive some small turbines or small generators To create power on site some cases they may have a process whereby they need to Create some steam and so we use the natural gas for that as well Another form of biomass is to actually take solid waste and convert it to energy or trash to energy This is where using solid waste that would normally go to a landfill You're using it as a fuel to create heat via combustion and in turn create steam from the boilers Where the combustion is taking place the steam can actually be sold for industrial purposes or generation or the generation of electricity can be Accomplished by using the steam as well now there's a company in Fairfield, New Jersey by the name of cogentrics Corp And they actually build and operate several of these trash to energy or solid waste to energy facilities around the United States wood and wood waste These are normally the byproducts from large You know wood mills and paper mills and what they'll do is again to be efficient and to be Environmentally conscious they'll go ahead and use the wood or the wood waste the wood pulp They can actually burn it and then it becomes a heat source where they can create their own steam That they'll use in the process say for instance for making Particle board or even paper they can also use the heat source to run small generators on site for their own consumption and operations the warehouse or company a huge manufacturer of various forms of lumber and wood and Particle board and those types of things Does this on location with a couple of their very large facilities they have in southeast Oklahoma and Most of us are more familiar with this type of biomass We're we're making fuel from things like crops grasses and biodegradable matter One of the more well-known ones of course is making ethanol that we use as an additive to gasoline in our cars and The primary food source there is corn, but there's also Sugars that can be broken down into alcohol as well as certain types of grasses and on the biodiesel front We could use vegetable oil peanut oil soybean oil and then recycled grease from restaurants once it's it's cleaned You can burn any of these in an existing diesel powered vehicle