In today's world, there are many ways to create power, some being more efficient than others. With all of the world's technological advancements, these ways of producing power are becoming more economical and feasible. In the past few decades, a new way of thinking came over the world of engineering in the form of green and sustainable engineering. This new way of thinking came about for many different reasons, but mainly due to the depletion of our natural resources, the initiative to clean up our environment, and fight global warming. The root cause for the three previously stated world problems is power generation. The way the world currently produces more than half of the electricity consumed is by burning the world's natural resources or fossil fuels. By doing this, carbon based emissions and particulates are exhausted into the atmosphere, causing global warming, air pollution and harmful gases to humans and animals.
* Solar Power
* Wind Power
In order to capture the energy of the sun and turn it into electricity, a photovoltaic cell system or solar PV panels are needed. These panels or PV cells are made up of one or two layers of semi-conducting material, and when sunlight shines upon the material, an electric field is created between the two layers. As we all know, once an electric field is created current begins to flow freely. At this point, all that needs to happen is a way to capture all of this current and direct it to where we want it. We will not discuss how that portion of the system works in this document. So as anyone can see, these PV panels can be used to power just about anything given the right application, and powering a house just happens to be one of those right applications.
Shown here is a picture of solar panels on top of a home. In many cases, it's most beneficial to install the solar panels, or photo voltaics, on top of the roof of your home to capture the most sunlight.
The cost of these PV systems are based on the size of the home, and how much electricity your family uses. A typical system ranges from 10 to 20 square meters and can put out between 1.5kWp (kilowatts peak) to 3.5kWp. These outputs are normally enough to power half of a houses' normal electrical demands. There are PV systems that can supply enough energy for the entire house's electrical demands, but in this document, we will focus on the range given above. According to the NREL (National Renewable Energy Laboratory) the cost for a grid-connected system is approximately $5,700/kW and the cost for a non-grid connected system is approximately $14,000/kW. This price is the initial cost of installing a PV system that will supply enough power to cover approximately half of your house's demands. The main difference between a PV system that is connected to the grid and one that is not connected to the grid, is that the PV system that is not connected to the grid needs to have an energy storage device. This accounts for the large increase in price that we can see.
- For a system that outputs 3kWp that is connected to the grid, it will cost the buyer around $17,000.
- For a system that outputs 3kWp that is not connected to the grid, it will cost the buyer around $42,000.
For both of these figures, the installation costs are included. This is because most manufacturers of solar panels have workers at the manufacturing plant that work directly for the company that are trained to install and handle their companies solar panels.
In this photo, it can be seen that it is possible to entirely cover one's roof with solar panels.
The maintenance needed and costs for maintenance of these solar panels are basically zero for the owner since almost all new PV systems come with a 10 - 20 year warranty. The only maintenance issue that could arise is if a non-grid system is owned. In this case, the energy storage device, a.k.a. the battery, would need checked every six months for its acid level. This is particularly important if lead-acid batteries are used.
PV systems are extremely feasible. At the moment, PV systems are used in more ways than one can imagine. PV systems are just starting to emerge as a way to power ones home, or to at least help lower the electric bill. Depending on ones budget, this system has the capability to fully power ones home. As seen in the above paragraphs, PV systems can have a fairly high initial cost. As a recommendation for anyone looking to install one of these units, purchase a system that is connected to the grid. This will keep the initial cost down, and will also allow you to sell electricity that is not used by your house back to the grid.
Wind power is made possible by converting the mechanical energy of the wind by turning blades like on a fan. This mechanical energy is converted into electrical energy by turning windings in a magnetic field in an electric generator. This works in much the same way as a standard turbine used in power plants with the exception of the power source. Obviously for wind power, the wind turns the blades and in a power plant it is typically high pressure steam that turns the blades. Wind power is made possible for personal and home use by its simplistic design and easy integration. The figure below shows a Skystream residential wind power device.
Typical wind power systems range in height from 33-110 ft tall and blade diameters from 4-12 ft. They are also surprisingly lightweight and range from about 13-170 lbs. Most systems can be installed without requiring any sort of power source themselves. Additionally, the power that is obtained can go directly to the house for many systems. This would be the first energy consumed and if need be, extra energy can be pulled from the grid without any extra effort. This means that if the wind power is not sufficient, one can still simply pay for power from their electric company. This also works in the opposite way. If the wind power generates more electricity then one's home is consuming, it will be added to the grid and turn back the meter of the house. Other systems use the power generated to constantly charge a battery and are clearly not as efficient. Those smaller type units may be somewhat more convenient though as they can be attached directly to the roof of one's house. Some typical power outputs range from as little as 38 kWh/month to as much as 400 kWh/month with an average wind speed of 12 mph. The one model can work in wind speeds as low as 8 mph, but reaches maximum output at speeds in excess of 20 mph.
This aspect of wind power is probably one of the most beneficial when looking on a long term scale. This is of course due to the lack of fuel cost. Fuel is usually an expensive resource due to its limited abundance. Wind on the other hand is in high abundance at absolutely no cost. The main cost when considering this form of power is then turned to the initial cost incurred to purchase and install the equipment. There is also a minimal cost for maintenance that must be considered when determining the cost per kilowatt. To do this, the life of the system is a large factor as well. The longer the life, the more cost effective the system becomes. Again, this is due to the fact that most of the cost comes from the equipment and installation. Listed below are some values calculated from approximate figures provided by several wind power equipment manufacturers.
- Cost per kilowatt-hour: < $0.09/kWh
- Equipment cost:
- Air X < 400 W rated capacity - $700
- Skystream 1.8 kW rated capacity - $8,000 (Value found on a distributor website and was much lower then the MSRP of $12,000)
- Whisper 500 3 kW rated capacity - $13,500
*It is important to know that these capacities are not necessarily the figure to look at when considering the system appropriate for you. Depending on the system, the power output varies greatly with wind speed. For example the cheapest system is rated at 400 W when the wind speeds are in excess of 28 mph. So although it is cheap, it is not very effective. The skystream system on the other hand, is designed to work with low wind speeds and is still fairly productive at these lower speeds. Below is a chart showing the possible variation for the skystream system. Even this system is much more efficient at higher speeds.
- Maintenance cost: Many of these systems claim to be maintenance free. This is probably in large part due to the materials of construction and its location. They are intended to be constructed in areas without anything around them which means there should not be anything falling into them or debris collecting on them. The materials are typically high quality metals or engineered composites meant to resist the effects of the environment. Even unexpected high wind speeds are not a concern, as many of these systems have fail safes built in to slow the blades when certain speeds are exceeded. A larger industrial wind turbine was estimated as requiring 1.5 to 2 percent of the original cost of the turbine per year for maintenance. Another figure it gave was $0.01 per kWh of electricity produced. This is again due to the higher production at higher wind speeds putting more wear on the system at higher production rates.
One major cost benefit not visible here, is that because wind power will indeed be an environmentally friendly system, many times it is possible to get government rebates for using this technology. This means that in addition to the money you may already be saving just from generating your own power, you may have money given to you for doing so.
When debating the practicality of adding a wind power system to your home there are a few things that are important to consider. First, the community you live in must have the correct zoning laws to allow for the installation of a tall tower. It is also necessary to have a fair amount of land clear of obstruction recommended at about half an acre by one manufacturer. Aside from these requirements, one must consider the area where they live overall. Is it an area that has a reasonable amount of wind? Is that wind sustained year round?
A micro-CHP is a small combined heat and power unit that can be installed into individual houses or businesses. This is basically a small cogeneration system that is easily installed and incorporated into an already built house or during the construction process. Most current micro-CHP systems run off of natural gas. This is convenient because most homes already have natural gas available to them for use in cooking or heating. Micro cogeneration systems are very efficient and usually produce more than enough power than the house needs. This power can be sold off to the grid because the United States requires that any power added to the grid must be paid for by the utilities. Honda is one of the main companies trying to advance micro-CHP technology. They want to make cheap reliable micro-CHPs available to everyone. Honda claims that their new micro-CHP is so efficient that it will be able to create all of a households heating and 50% of its electricity needs with the amount of gas that was currently used just to heat the house. These systems produce about 12,000BTU/hr of heat that can be used to heat the house and create hot water. They also produce about 1.2kW of electricity for household use. The overall efficiency is between 83% and 93% depending on situation. There is also almost no transmission losses in the electricity and the heat has little time to escape before it is used. Japan and the UK are the two countries using this technology the most but many laws in the United States have been passed that will help people with tax breaks for using one of these power generators so that the capital cost of installing one will be lower.
One of the problems with these systems is their relatively high capital cost. To have a basic system installed it can run from $10,000 to $20,000. As more people use these systems the prices should come down because of the higher demand. These systems also produce greenhouse gasses through burning the natural gas. Even though they do produce greenhouse gasses, natural gas burns much cleaner than the current coal or oil plants that could be powering the home otherwise. Honda says that their micro-CHP systems produce less CO2 and less NOX than one burner on a standard gas stove. They do not produce large clouds of grey smoke and the exhaust is odorless.
- $/kW - dependent on your natural gas costs.
- Installation/Initial - $10,000 - $20,000 but is decreasing rapidly
- Maintenance - these systems are maintained like standard gas furnaces
Installing and using a micro-CHP system is very feasible. They do not take up much space and are quiet. They produce heat just as any furnace but more efficiently. They also produce electricity which gas furnaces do not produce. If they produce more power than is necessary for the house, the extra electricity can be sold to the power utilities which could help offset the cost of the natural gas. While installation costs are higher than some other systems, these prices should decline sharply in the near future and many more of these systems will be put into place. These systems obviously need access to natural gas so some rural areas may not be practical for installing one of these systems. It would be possible to do so however, if the rural house had a large storage tank for natural gas. It seems that these systems do not have many limitations and as the technology advances should become more popular as an alternative more efficient energy.
Depending on what sort of criteria one has, whether it be overall power generation capacity, cost effectiveness, or environmental concern, each of these options may be viable. Micro-CHP systems have the largest potential for energy creation, but the cost of fuel and maintenance may make it less economical in the long run. Although, when considering this cost compared to the current heating and power costs for a home it would be better. One should, at this point in time, be largely concerned with the environmental impacts of the things they do as well. This is why either solar or wind power should be added to many homes as either a supplementary power source or as a producer of the full power requirement of the home. Both of these options have little to no negative impact on the environment where as the micro-CHP system still requires some emissions. What separate these two options are the power capacity, maintenance, and local restrictions.
As far as wind power is concerned, it seems like a very reasonable and practical alternative or additional power source for your home, restrictions permitting. Not only does it provide power without the need of any limited and valuable resources, but it can do so without any adverse affects to the environment. They are also constructed to be as aesthetically pleasing as possible and are fairly unobtrusive. They are up very high and would not really get in the way of anything. This also reduces any discomfort caused by excessive noise which may be found in the micro-CHP systems. They have a typical lifetime of 20 years or 120,000 hours and require very little maintenance throughout that time.
Solar power has similar advantages to the wind power option. This system would again have little adverse effects to the environment with no harmful emissions or fuel consumption. It seems to be slightly more expensive initially, but requires no more maintenance than cleaning off the panels due to the extensive warranties available for these systems. The set-backs a system like this can have are geographic location. Some areas are more suitable for solar technology as they get much more direct sunlight each year. Also, individual houses may not have a roof facing the ideal direction without any obstructions.
All in all, each of these power options provides an efficient way to power your own home and the opportunity to improve the environment. Even the system that does require fuel makes use of it in a more effective manor helping to reduce unnecessary consumption and emissions. Some of these options may not be available to everyone due to the restrictions described above, but one should consider what they may be able to do to be a part of the solution and possibly save a few dollars along the way.