Wind power is the fastest advancing source of clean energy today. Want to understand the different parts of a wind turbine? LET'S EXPLORE ...

The main equipment needed to harness wind energy is a wind turbine – consisting of a tower, frame, turbine blades, and generator.

Other parts are required to deliver useable electricity, such as inverters, cabling, batteries, charge-controllers, and an electricity meter if you want to sell electricity back to the grid.

This article details the different parts of a wind turbine and how they work.

Wind Turbine Tower

Residential turbine towers stand around 10m tall - the taller the tower, the faster and more consistent the wind.

The fastest and most consistent winds are high above ground level, so turbines are raised on a tower in order to generate more electricity.

The main reason for this is that wind speeds are naturally faster and more consistent above ground level. Ground level winds also tend to be more turbulent.

Beyond naturally occurring physics, ground level wind speeds are interrupted and slowed by things like trees and buildings.

Most residential blade turbines use a tower around 10 metres tall. Larger commercial wind turbines stand up to 100 metres tall.

The tower is one of the most crucial parts of a wind turbine for increasing power production and cost efficiency. The U.S Department of Energy found that increasing the height of a 10 kW wind turbine from 18 meters to 30 meters resulted in a 25% increase in power production.

Turbines are designed with specific wind speed ranges in mind. These vary depending on the size and location of the turbine.

Speed controllers and cut-off switches are used to prevent damage in high winds.




Generating Wind Energy – Mechanical Parts of a Wind Turbine

The turbine itself consists of blades, frame, shaft, generator, and tail.

The frame holds the pieces together and strengthens the system. The wind turbine blades (normally two or three blades) are aerodynamically shaped to catch the wind, turning a shaft which is connected to a generator.

The generator transforms the mechanical energy into electricity through a process called electromagnetic induction.

A tail is used to keep the first-contact parts of a wind turbine, such as the turbine blades, at the optimal angle to the wind.

Inverting Wind Turbine Energy

Because the electricity produced by a wind turbine (DC) is different to that used by household appliances and fittings (AC), a small inverter is used to convert the wind turbine's DC electricity into useable AC electricity.

Inverters are used to connect wind turbines to the mains power of a building. Household appliances and fittings use AC (alternating current) electricity but wind turbines produce DC (direct current) electricity.

The wind turbine inverter converts the DC electricity to AC.

Some small-scale wind energy users don’t use inverters – instead using the wind-electricity to charge batteries then run appliances off the batteries.

 

Electrical Cabling for Wind Turbines

Wind turbine cabling transports electricity from the wind turbine to the building, battery bank, or electricity grid.

Cabling is a significant cost when installing wind turbines. Most people position turbines a long distance from buildings in order to reduce noise and aesthetic interruption, as well as getting the optimal wind position. Larger distances mean more wind turbine cabling and larger costs.

Wind Energy and Batteries

The intermittent nature of wind means sometimes more power will be produced than is needed, and at other times more power is needed than is produced.

For this reason most wind turbine installations use batteries to store excess electricity.

These deep cycle batteries are different than normal batteries in that they are suited to trickle charging, can often retain enough power to last for days, and can be recharged many times.

Using batteries is particularly useful for people in isolated rural areas where grid power is inaccessible or expensive.

Battery Charge Controllers for Wind Turbines

Battery charge controllers ensure that the batteries don’t over charge. They act as a cut-off switch, or may be automated to cease charging the full battery and start charging another battery.

This prevents degradation of batteries and potential problems such as overheating or exploding batteries.

Grid Connected Wind Electricity Meters

Instead of using batteries, many wind energy producers opt to stay connected to the grid.

When the wind is high, the building uses wind-generated electricity. When it's calm, the building uses grid electricity.

Excess wind-generated electricity can also be sold back to the electricity companies through the grid in many places.

Special meters are installed to monitor the electricity consumption and generation from a property. These either turn backwards when excess electricity is going into the grid or have separate consumption and production meters.

Meters are one of the electrical parts of a wind turbine that really make wind energy economically viable. Expensive capital costs can be mitigated by income from wind-generated electricity.

As well as the advantage of not being totally dependent on the winds, staying grid connected means battery costs can be avoided.




According to the United States Department of Energy (DOE), wind energy is the most rapidly advancing source of energy worldwide... LET'S EXPLORE...

Wind is created by the sun's uneven heating of the earth's surface.

The movement of air from an area of high to low pressure is what we refer to as wind.

Wind exists because the sun heats the surface of the earth unevenly. Cooler air fills the void left by hot air as it rises.

It’s a clean source of power that does not contaminate the environment. Wind energy is also one of the cheapest sources of renewable energy. Below are some interesting wind energy facts.




Wind Energy Fact #1 – Ancient history

Dutch windmill
The Dutch revolutionized blade design and used windmills as houses.

Wind energy was used by the Egyptians more than 5000 years ago for sailing ships on the River Nile.

Between 500 to 900 A.D. windmills were developed in Persia, they were used for the automation of grinding grain and pumping water.

In 1888 Charles Brush first used a windmill in America to produce electricity in Cleveland Ohio.

In the 1930's the Dutch revolutionized the windmill by enhancing the design of the blades, and affixing them onto multi level towers.

These windmills were designed especially for the process of grains and to provide accommodation for the families of the millers.

Wind Energy Fact #2 – Same concept, different outcomes

There are three major types of wind power; mechanical power, electrical power, and sail power. Each one of them generates power by using an airfoil.

Airfoils are surfaces that create an aerodynamic force - causing a boat to move or rotor blades to turn.

You can call a sail a simple airfoil; wind blown against the sail creates a curved area of high pressure, pushing the boat in a forwards direction.

A windmill is made up of several airfoils in the shape of a fan; the wind drives them around in a circle, which rotates the shaft.

The power of this rotation is what mechanical windmills use to do things such as turn a large stone for grinding grain into flour.

An electrical wind turbine follows the same concept, but instead turns a generator. Inside the generator, a coil is moved in and out of a magnetic field by the rotation, which is what generates an electric current.

Wind Energy Fact #3 – Size Matters

wind turbine height
Residential wind turbines stand around 10 meters tall while commercial turbines can be up to 100 meters tall.

There is significant variation in wind turbine size depending on purpose. Smaller turbines are generally used to power a single household and have a capacity under 100 kilowatts - most commonly around 2 kilowatts.

Commercially sized turbines have a capacity of up to 5 million watts. In order to convert wind energy into electricity an average wind speed of 14 mph is required.

Wind turbine blade length and height are the main differences between commercial and residential turbines. Residential turbines generally stand at around 10 meters tall, while commercial turbines are anywhere from 30 to 100 meters tall.

Wind Energy Fact #4 – Wind Energy Isn’t Perfect

There are concerns about generating electricity with wind energy; these include the negative impact on the populations of birds and bats, and their visual effect on the sea and land, particularly in tourist locations.

Wind Energy Fact #5 – Wind is Intermittent

Since wind speeds are intermittent, sometimes blowing fast sometimes not at all, it is not likely that wind energy will be capable of meeting all energy requirements as a primary source.

Furthermore, a number of factors are required for a suitable location for wind power-generation. Not all locations are suitable.

However, according to an estimate by the DOE, it is possible that by 2030 wind power could produce 20 percent of the electricity in the United States.

The future of energy-production mentality is expected to change dramatically from the current state of 24/7 capabilities of conventional fuels to one where different energy sources are utilized in different circumstances and at different times.

Wind and solar energy would be used when the sun is shining and the wind is blowing, and other alternatives or conventional generation are used at other times - much like an energy production jigsaw puzzle.

Wind Energy Fact #6 – The World’s Largest

One of the most interesting wind energy facts is that Hawaii houses the largest wind turbine in the world. It has rotors that are the entire length of a football field. The turbine stands at 20 storeys high.

There is no limit for the available options to sustain ourselves through the use of green powered technology. Wind, solar, geothermal, and hydroelectric technology are giving us an interesting alternative to relying on natural gas and crude oil.




Wind Energy Growth and Feasibility

Since 1980, there has been significant growth in the output of global wind power by 10 percent or more every year apart from two. There does not appear to be any signs that the growth is going to slow down.

In 2007, there was enough wind power to provide power to approximately 70 million homes. In Denmark, over 19 percent of electric power comes from wind generators.

However the rest of the world is yet to catch up; for example, in the United States less than 1 percent of total electric power was provided by wind.

Financial Incentives

A major obstacle in the development of renewable energy projects is their high initial investment cost.

Fossil fuel power plants have lower investment or start-up costs but high operation costs due to the fuel consumed and constant labor. Wind energy has high start-up costs but low ongoing costs [2][3].

The introduction of governmental subsidies and tax cuts as well as policies such as Feed in Tariffs and Green Energy Certificates have enabled wind energy development companies to meet the financial requirements for wind power-generation.

Banks have also been influential in the take up of wind power, providing large long-term loans for the development of wind farms [4][5].

Wind Resource Assessment Technology

The most important aspect of wind farm development is the availability and nature of the resource.

Without a clear picture of how much power you can get out of the wind, no project is feasible. There have been major advancements in both the methodology and equipment used for wind resource assessment in order to reduce or mitigate risk on investment [6].

The incorporation of computational fluid dynamics and mesoscale numerical weather prediction (NWP) [6] [12] models enables wind analysts to simulate the wind characteristics over the previous 10 to 40 years which help wind farm developers to predict the wind resource over the lifespan of their project.

This assists with project planning and investment risk as wind farm output calculations will be more accurate and reliable.

Offshore Wind Farms

In Europe and parts of the USA, the public acceptance of wind farms has been a major hurdle in the development of wind energy [7].

A lot of social opposition has come up with people not wanting to have them close to the urban, residential and recreational areas pushing campaigns like NIMBY (Not-In-My-Back-Yard) [8].

This opposition forced wind farm developers to venture offshore.

As a result and through a lot of research work, 49 offshore wind farms are now operational in Europe alone.

The current offshore installed wind power capacity in Europe is 3,294 MW and another 5,603 MW are under construction.

Although offshore wind farm development is a lot more expensive than onshore, offshore allows developers to capitalize on uninterrupted wind regimes and the lack of public opposition.

 

Article References

References
[1] Illustrated History of Wind Power Development – Part 2 – 20th Century Developments: http://www.telosnet.com/wind/20th.html

[2] Wind Power Engineering and Development – Financial Incentives for Renewable Energy: http://www.windpowerengineering.com/clean-energy-standard/financial-incentives-for-renewable-energy/

[3] Database of State Incentives for Renewables & Efficiency (DSIRE) – Financial Incentives: http://www.dsireusa.org/incentives/index.cfm?EE=1&RE=1&SPV=0&ST=0&technology=Wind&sh=1

[4] Edie.net – European Business Briefs: Bank Loans and Wind Energy: http://www.edie.net/news/news_story.asp?id=6599&title=European+Business+Briefs%3A+bank+loans+and+wind+energy+

[5] Panchabuta-Renewable Energy & Cleantech in India – World Bank and International Finance Corporation (IFC), will double loans given to renewable energy projects to $2 Billion in The Next Three Years (Feb 2011): http://panchabuta.com/2011/02/16/world-bank-and-international-finance-corporation-ifc-will-double-loans-given-to-renewable-energy-projects-to-2-billion-in-the-next-three-years-in-india/

[6] Renewable Energy World – Mitigating Variability: Advances in Wind Resource Assessment and Modelling: http://www.renewableenergyworld.com/rea/news/article/2009/04/mitigating-variability-advances-in-wind-resource-assessment-and-modelling

[7] Green Planet Ethics – Offshore Wind Power Important to Future of Clean Energy Development: http://greenplanetethics.com/wordpress/offshore-wind-power-important-to-future-of-clean-energy-development/

[8] Clean Technica – NIMBYism Kills 45% of Clean Energy Projects: http://cleantechnica.com/2011/10/24/nimby-ism-kills-45-of-clean-energy-projects/

[9] Wind Gate Energy – Variable Speed Gearless Wind Turbine: http://windgateenergy.com/page2.htm

[10] Technology Review – Wind Turbines Shed Their Gears: http://www.technologyreview.com/energy/25188/?mod=related

[11] Danish Wind Industry Association – Power Control of Wind Turbines: http://www.motiva.fi/myllarin_tuulivoima/windpower%20web/en/tour/wtrb/powerreg.htm

[12] Computational Fluid Dynamics: http://computational-fluid-dynamics.com

Water heating accounts for 30% of energy consumption, so is a great place to begin cutting back on fossil fuel consumption.

What's more, solar water heating can be added fairly easily to homes... Let's explore...

There are a number of options for a solar water heater; from purchasing ready-to-roll systems to making your own.

The basic model is that the sun’s energy is used to heat water. The process is called solar-thermal – conducting the sun’s energy as heat, as opposed to photovoltaic – converting the sun’s energy into electricity.




How do solar water heaters work?

roof mounted solar water heater
Roof Mounted Solar Water Heater - Cold water flows into the tubes, is heated by the sun, and flows out to an insulated cylinder.

A module of solar tubes is installed on a roof or sun-exposed area. Cold water passes through the tubes and is heated by the sun, flowing to an insulated cylinder once heated.

Alternate systems use chemicals such as glycol, which are easy to heat. The glycol flows through the solar tubes, then heats the water.

Most solar water heating systems require an electric powered backup heater known as a booster. The booster kicks in to further heat the water and kill any bacteria, or at night time and cloudy days when the system isn’t getting enough sun energy.

Some systems carry the water to a storage cylinder inside the house, whereas some storage tanks are outside (often connected to the solar module), or in the ground. The advantage of having the tank inside is better insulation. The advantage of outside is that installation is simpler and cheaper for retro-fitting.

There are also differences in how the water gets to the cylinder. Convection solar water heating systems use convection current principle - that hot water rises – to transfer hot water to the cylinder. This method stores the hot water above the module and doesn’t require any mechanics or electricity. Pump based systems use an electrical pump to transfer the water to the cylinder.

Buy solar water heaters or make your own?

Solar water heaters can be purchased as a package and installed by professionals or you can make your own.

The main advantage of a professional job is knowledge and experience; your solar water heater system will be tidy, installed with best practice, made from materials that have been tested and proven to last, be installed in the optimal spot for maximum sun exposure, and will likely come with some type of guarantee.

The downfall of using professionally made solar heating systems is expense.

There are large communities of people on the net who make their own alternative energy mechanisms, and many of them have instructions for building your own solar water heater.

It’s highly recommended you do some due diligence before diving in to either option. Installation is a big task so you only want to do it once.

Things to consider

Price: Never just go for the cheapest option, but have a look around and get a feel for prices, including installation and maintenance fees. Often sourcing locally is the best option as there’s easier access to follow up support, but have a look on the internet as well and get a broad gauge of the prices and packages available.

Kitset or pay for install and maintenance? If you’re an experienced tradesman you may be able to purchase from a company then install a solar water heater yourself. In this case you’ll be able to save a lot of money, but check with your dealer whether they offer product-only sales.

How much hot water do you need? A family of four uses a lot more hot water than a family of two, so make sure you’re thinking literage when you’re looking at your solar hot water options.

Solar company reputation: Take your time to get as much information as you can about your chosen solar hot water company. Look on a number of websites and read as many customer reviews as you can.

Your solar company should be happy to offer a free consultation before you commit. A good thing to consider is whether they can answer your questions without hassle. If they can answer your questions over the phone and without having to look things up every two seconds it’s one indicator that the staff have a good knowledge of solar and offer good customer service. If they tell you to just read their website it may not be a great indicator. Also remember to compare maintenance service and guarantees.

DIY solar reputation: Likewise if you’re building a DIY solar water heater, have a look around and scope out the best plans. Look for plans that have been used by many people and include good feedback. Join forums and learn from the experience of other alternative energy-ites. It’s also a good idea to discuss any plans with a builder, plumber or electrician, and research your local consent requirements.




Like anyone, I hate being told what to do. The intention of this article is not to guilt you, but to take a look at the current and historical recycling situation.




Michael Braungart and William McDonough’s book Cradle to Cradle discusses a window factory built during the industrial revolution. Forrest surrounded the factory at first, and was progressively cut down to make window frames.

They discuss the logical mindset of the time, that “factories situated themselves near natural resources for easy access and beside bodies of water, which they used both for manufacturing processes and to dispose of wastes.”

They describe the era when “resources seemed immeasurably vast. Nature itself was perceived as a ‘mother earth’ who, perpetually regenerative, would absorb all things and continue to grow.”




So why recycle today?

Since the industrial revolution, understanding of our interactions with the earth has grown immeasurably – particularly regarding carbon emissions, contamination, and natural resources.

Contemporary societies know that the earth’s resources are limited and that using the earth's resources is a balancing act - using what's needed but being frugal.

Below I'll look at the three main reasons to recycle; reducing landfill, preserving natural resources, and avoiding green house gas emissions.

Recycling and Landfill

Digging holes in the ground and filling them with rubbish isn’t sustainable or eco-friendly, particularly in a world of increased consumption, increased packaging, and a growing population.

As well as making the immediate landfill area unuseable, landfill waste produces methane gas (a green house gas), and can contaminate nearby soil and waterways through toxic leachate.

How long do different products take to breakdown in landfill?

Styrofoam                   1 million years

Aluminium can            200-500 years

Disposable Diaper       550 years

Paper bag                    1 month

Banana peel                 3-4 weeks

[1]




Recycling and Preserving Resources

Recycling helps to preserve precious and often limited raw materials.

The simplist example is recycling paper, which avoids the need to cut down another tree, or another forest of trees.

Wood products are a particularly good example to highlight the value of such raw materials. Trees are our best weapon against carbon in the atmosphere, but to take advantage of their ability to consume carbon and produce oxygen, they need to be alive.

A recent UN research paper estimates that each person uses 50kg of paper per year.

Reducing Carbon Emissions from extraction and manufacture

The process of extracting raw materials, refining, and manufacturing useable materials is very energy intensive – which creates green house gases and waste by-products.

Aluminium cans highlight the prudent potential of recycling.

For every ton of aluminium mined, a further four tons of bauxite is mined.

Mining five tons to get one ton is environmentally abusive not only in terms of the waste by-product, but it requires enormous energy resources for the extraction and refinement processes.

Each step of the way produces by-products and uses enormous resources, from the four tons of bauxite waste, the electricity used to heat the aluminium smelt, the emissions created by extraction, bauxite-grinding, and transporting five tons of material for one ton of product.

This entire process is extremely energy intensive and can be avoided by recycling previously-mined aluminium.

Zero Waste New Zealand estimates that recycling aluminium cans results in an overall energy saving of 70% [2].

Where are we with recycling?

Gaining a clear and conclusive picture of world recycling efforts is difficult. Although recycling has been an issue for a long time, concerted recycling initiatives are still in their relative infancy. As a result, consistent data is difficult to compile.

An OECD report shows that between 1980 and 2005, municipal waste generation increased by 62%. Contributing factors of the increase include increased use of packaging materials and disposable goods. [5]

In countries included in the report, approximately 18% of waste was recycled during the mid 90’s. By 2005, approximately 30% was recycled or composted. [5]

Over the past decade, many governments have stepped up recycling programmes, including public information campaigns, drop-off recycling centers, and door-to-door recycling collection.

One such country is New Zealand. In 2006, 73% of the population had access to kerbside recycling, compared to 20% in 1996 [3].

In that same time period, recycling of packaging-waste in New Zealand went from around 43kg per person per year to 85kg per person [3].

Summing up – why recycle?

Recycling is an important piece of the puzzle for tackling the degradation of the earth’s ecosystems.

Global warming, limited natural resources, and contaminated eco systems are very real issues that need to be balanced in this generation to avoid a legacy of resourcelessness and contamination for the next generation.




Article References

[1] Missouri Department of Transportation. (2011). Litter facts and research. No More Trash Online. Retrieved from http://extra.mdc.mo.gov/nomoretrash/facts/

[2] Zero Waste New Zealand. (2008). Climate change, sustainability, and waste. Zero Waste New Zealand. Retrieved from http://www.zerowaste.co.nz/what-can-you-do/climate-change-sustainability-and-waste/

[3] Statistics New Zealand. (2009). Measuring New Zealand’s progress using a sustainable development approach: 2008. Wellington: Statistics New Zealand.

[4] Braungart, M., & McDonough, W. (2009). Cradle to cradle: Re-making the way we make things. London: Vintage.

[5] OECD. (2011). Waste generation, recycling and prevention. Greening Household Behavior. OECD Publishing. Retrieved from http://www.keepeek.com/Digital-Asset-Management/oecd/environment/greening-household-behaviour/waste-generation-recycling-and-prevention_9789264096875-7-en

Green cleaning products refer to products that are environmentally friendly.

The main characteristics of green cleaning products is that they are biodegradable, don't contain harsh chemical compounds, and are often made from essential oils or plant extracts.

Products include green washing powder, dishwashing liquid, window and bathroom cleaners,  home discenfectant, green commercial cleaning products, car cleaners, and degreasers.




Why Green Cleaning Products?

The main goal of these products is to work in harmony with the ecosystems in which they're used.

The majority of gray water (water that goes down shower drains, from washing machines etc) eventually ends up in rivers or at sea.

Heavy chemical compounds found in conventional cleaning products can pollute the water - the natural habitat for fish, plants, and humans in summer.

This can lead to problems such as poisoning or covering fish in oily residue - the oily feeling you get when you stick your hands in washing powder suds.

What's more, some chemicals used in conventional cleaning products are non biodegradable, such as alkylphenol ethoxylate surfactants.

Being non-biodegradable, these chemicals are in the eco system permanently, where they can interfere with organisms' hormonal systems.

Green cleaning products are made with this in mind, and aim to use ingredients that have no impact, or a harmonious impact, when they reach waterways.

Other considerations of the environmental impact of cleaning products is manufacturing processes, toxins given off when used, and landfill impact.

Environmental awareness is as easy as running through a quick checklist in your head, e.g does the manufacture of a product require a lot of energy-intensive processes such as multiple chemical treatments, or does manufacture create toxic by-products or waste? Is packaging minimized, or able to be cleaned and recycled? If not, is the bottle biodegradable, and how big will the chemical effect be in the landfill? There’s no need to feel guilty if all the boxes aren’t ticked, but awareness is the first step to fitting green choices into your life.

Common ingredients found in green cleaning products include:

Why Buy Green Cleaning Products?

The fact that green cleaning products generally don’t contain toxic and harsh chemicals has another benefit - they’re hypoallergenic.

Being hypoallergenic means a product is less likely to cause conditions such as asthma, skin damage, and headaches that conventional cleaners can bring on.

A particular area where this is becoming utilized is in hospitals. Hospitals obviously accomodate alot of people with all types of allergies. Using hypoallergenic green cleaning products reduces the risk of allergic complications for patients and aids a comfortable stay.

It's All About Quantity,... And Quality

Another thing to remember when thinking about green cleaning products is quantity - particularly when using detergents or washing powder.

Today, many cleaning products are generic and made for a global or national market.

The problem with this is that water-type is not the same in every city - some cities have dirty water with alot of chlorine, some cities have reasonably clean water with minimal chlorine, other cities like Christchurch New Zealand have 100% pure water with no chlorine.

The amount of washing powder required depends on how "heavy" your water is, but the recommended amounts are measured on a worst-case, or heaviest-water, scenario.

So try cutting back the amount of detergent you use - if your clothes come out clean, it's working.

When purchasing green cleaning products look for certification of the environmentally friendliness of the ingredients and sustainability of the company practice. Look for certification  and awards from reliable green industry groups, and product websites that explain the reasons for individual ingredients contained in their products.




Green building materials is an umbrella term for building materials that are manufactured using sustainable practices and resources, reduce allergies or toxins in the environment, or are green because they can be used in a sustainable manner.

Below are a few of the latest green building materials on the market.

Green insulation
Green insulation is often bonded using heat instead of chemical bonding.

Before purchasing, you can investigate the green-ness of the specific building product you’re considering.

Do your research by looking for awards and green certification on the manufacturer’s website.

Write a list of the different ways in which different brand options are ‘green,’ and ask product reps to explain manufacture processes and sustainability of the product.




Green Insulation

A major problem with traditional fibre-glass insulation is that it’s allergenic – it causes a reaction when it touches your skin.

This is most noticeably a problem when installing insulation, however fibreglass fibres can also get through the miniscule cracks in your house and into the air. This can contribute to long term allergic and respiratory conditions such as asthma.

Green insulation comes in many varieties, and is often manufactured with non-chemical and environmentally friendly processes, such as heating instead of chemical bonding.

Commonly, green insulation is made from polyester fibres, which can be sourced from recycled PET plastic – such as your recycled drink bottle.

Polyester-only insulation can be easily recycled once again at the end of its life.

The biggest advantage of non-toxic and non-allergenic green insulation for the end user is that it creates a healthy home environment – installation doesn’t cause itchy allergic reactions and the air inside the home is free from miniscule fibres that can contribute to health problems.

Green Roofs

Building a roof is a great place to take advantage of green building materials as there are so many different ways to make sustainable choices.

Green roofs can be extreme and show of your environmentalist side if you’re that way inclined, or can seamlessly fit in with normal roofs while employing sustainable methods.

The first and foremost consideration is durability and maintenance commitments.

Recycled Metal Roofing

This is a pretty standard but good option. Metal roofs can be considered green if made from recycled metal, which many roofing companies offer.

Metal roofing sheets can again be recycled years down the line.

With this consideration, metal roofing is a much greener option than an asphalt or concrete tiled roof – which use environmentally harsh chemicals and manufacture processes.

Solar roofing

Solar roofing is a great way to reduce your reliance on fossil fuel electricity, and a great use of a roof's surface. Solar technology has come ahead in leaps and bounds in the last few years.

Options for solar roofing include high-efficiency but bulky traditional crystalline silicon solar modules, or new technology thin-film solar panels.

Thin-film solar panels are lower efficiency but much more flexible in terms of applications.

Solar roof-tiles are a new thin-film application. The roof tiles are durable, and look and are installed the same as conventional roofing tiles, but provide your home with electricity.

Rooftop solar water heating is another popular option, whereby your water is heated on the roof then connected to your hot water tank.

Living green roofs

Imagine your roof covered in grass! These roofs are becoming more popular, and have many advantages if you’re happy with the extra effort.

green roofs
Living green roofs provide excellent insulation but it's imperative they're built properly first time round.

Living green roofs consist of a protective layer, then soil, then grass or other plant [3].

The main advantage of living green roofs is that they provide excellent insulation in winter and cooling in summer.

They can also last longer than exposed roofs, look unique, provide fresh air, encourage neighbourhood awareness of green living, and make good use of rain water.

Of course, green roofs are expensive, require upkeep, and it’s vital you have quality construction to avoid leaks.

Green Adhesives and Green Paints

Adhesives and paints offer huge benefits as green building materials. The manufacturing processes of adhesives and paints are often extremely environmentally un-friendly, involving harsh chemicals and toxic by-products. Furthermore, large volumes of these materials end up in landfill.

Today there is a growing variety of green adhesives and paints available. The most common characteristic of these products is that they are water-based and solvent free.

There are green options for most types of applications used in the building process, from green carpet adhesive to roofing glue, paints, and even powder coating methods that at least minimize environmental impact.

The best advice is to read as many trade-reviews of green building materials and look at specifications on the websites of manufacturers before using them.

The technology and quality of products is constantly and rapidly getting better, however there are some green products that will do an inferior job or require different application methods.

Green Concrete

green building materials - concrete
Recycled concrete helps to reduce environmental damage through reduced landfill, manufacturing waste, and energy usage.

Concrete is widely known as a major environmentally problematic building material. Producing one ton of cement, a core ingredient of concrete, creates approximately one additional ton of CO2 [1].

Cement production requires a lot of harsh chemicals and is extremely energy intensive. Concrete also contributes huge volumes to landfills.

But wait, there are options for greener concrete!

Recycling concrete is a comparatively very green option. One option is to use recycled aggregate, such as crushed old concrete, for non-structural applications like driveways and paths [2].

Another option is to use materials such as fly-ash (a waste by-product of coal) to replace cement used in concrete. In North America, fly-ash is used to reduce cement use by up to 8% [1].

Both options recycle materials (old concrete and fly-ash) that generally have no other purpose, therefore would otherwise go to landfill. Both options also reduced energy intense extraction of raw materials and refining processes.

If recycled concrete were the world standard, it would be a huge contribution to preservation of the environment as concrete is the most used building material around the world [1].

Concrete can also be used as a green building material through exploiting its thermal qualities. Concrete conducts and holds the sun’s heat, which can be used for winter heating if placed correctly.

Final note on green building materials

When considering which green building materials to use, remember that green business practices are just as important as the materials sold.

Many companies these days outline their sustainable company initiatives on their websites or brochures – such as how they minimize waste by-products and transport distances, or even that they plant X number of trees or reduce X kg’s of waste paper. These are all good indicators of a company that actually practices an environmental awareness ethos, as are the many sustainable workplace certificates and awards that businesses can participate in.

Article References

[1] EcoSmart Concrete. (retrieved December 2011). Environmental impact: cement production and the CO2 challenge. retrieved from http://www.ecosmartconcrete.com/enviro_cement.cfm and http://www.ecosmartconcrete.com/facts_what.cfm#Supplementary.

[2] Park, S, G. (2001). Effect of recycled concrete aggregate on new concrete. Branz, SR101: Judgeford.

[3] Keenan, A., Georges, D. (2002). Green Building: Project Planning and Cost Estimating. Kingston: Construction Publishers and Consultants.

Alternative energy sources refers to non-fossil fuel energy, normally electricity. Let's explore them below.

Solar power is one of the most popular privately owned alternative energy sources.

Alternative energies allow us to produce much needed electricity for homes, businesses, and cities to function in a manner that is environmentally friendly and sustainable.

The most popular alternative energy sources are solar photovoltaics, solar thermal, wind power, hydro-electric, tidal, and geothermal.

Solar Power

Solar power is produced by conducting the sun’s energy and transforming it into useable electricity.

Solar panels capture the sun’s radiation energy, through exposing silicon cells to the sun.




The process that solar panels use is called photovoltaic - literally light (photo) into electrical current (voltaic).

Solar power is a great alternative energy source as it can be captured in so many applications, on both large and small scale.

Solar farms are large scale solar operations which connect directly into the power grid and feed clean solar electricity to the population.

Solar also comes in the form of smaller scale private solar panel systems. These can take the form of individual solar modules feeding power to offices or houses, or more creative applications such as solar roofing tiles – which essentially turn your entire roof into one large solar panel.

Learn more about How Solar Panels Work.

Solar Thermal

Solar Thermal similarly conducts the sun’s energy, but by capturing thermal (heat) rather than photo (light) energy.

Solar thermal systems involve heating water through exposure to the sun, which is used as the hot water supply.

Learn more about how a solar water heater works.

Wind Power

A clean energy wind farm

Wind Power is produced by large turbines being turned by the wind and generating electricity.

Wind farms are often located on remote hills or out at sea – places that are exposed to a lot of wind but far enough away from people to minimize interruption of turbine noise and changing the landscape.

Wind power generators are most commonly in large scale projects rather than individually owned turbines.

This is due to a few factors, including the need for consistent wind, noise and aesthetic considerations, and expense of the technology.

Learn more about How Wind Energy Works.

 

Geothermal

Geothermal energy is sourced from heat within the ground, originating in the earth’s core.

Hot magma rises from the earth's core through fractures in the earth’s crust, heating up rock and water – which then rises to create hot pools, geysers, and sub surface reservoirs.

These sub surface reservoirs can reach temperatures of up to 350 degrees celcius (660 degrees fareinheit).

Electricity is generated by utilising the pressure created by steam - directing steam through condensing steam turbines.

Geothermal power plants are large scale, expensive operations, which yield a fairly low amount of electricity.

Geothermal plants are by in large driven by economy-of-scale factors and the demand to cut pollution and harness clean alternative energy sources.

Where fractures in the earth’s crust and the flow of magma ocurrs is obviously beyond the control of humans, so geothermal operations are only available in locations where nature wills – often near the edges of continental plates.

Hydroelectric

Hydroelectric power: Using natural kinetic energy to produce clean electricity.

Hydroelectric power comes from capturing the energy of flowing water with dams.

A dam is constructed across a river, then the water is directed through tunnels in the dam, where it turns turbines and generates electricity.

Once the water has passed through the turbines, it's feed back into the river and continues downstream.

Hydroelectric power stations are large scale, expensive operations, connected directly into the grid.

In many countries, hydroelectric is by the largest of the alternative energy sources. In some countries, such as New Zealand, hydro is the single biggest electricity source.

Learn more about hydroelectric energy

 

The last 20 years have seen massive developments for solar.

Let's explore the key advantages and disadvantages of solar energy today.

Advantages of Solar Energy

1. Reduced green house gases

The first and foremost advantage of solar energy is that, beyond panel production, solar does not emit green house gases.

Solar energy is produced by conducting the sun’s radiation – a process void of any smoke, gas, or other chemical by-product.

This is the main driving force behind all green energy technology, as nations attempt to curb emissions.

Italy’s Montalto di Castro solar park is an example. It avoids 20,000 tonnes per year of carbon emissions compared to fossil fuel energy production.

2. Ongoing Free Energy

Another advantage of using solar energy is that beyond initial installation and maintenance, solar energy is free.

Solar doesn’t require expensive and ongoing raw materials like oil or coal, and requires significantly lower operational labor than conventional power production. Raw materials don't have to be constantly extracted, refined, and transported to the power plant.

Life expectancy ranges between manufacturers, but many panels produced today carry a 25-30 year warranty - with a life expectancy of up to 40 years.

3. Decentralization of power

Solar energy offers decentralization in most (sunny) locations, meaning self-reliant societies.

Oil, coal, and gas used to produce conventional electricity is often transported cross-country or internationally. This transportation has a myriad of additional costs, including monetary costs, pollution costs of transport, and roading wear and tear costs, all of which is avoided with solar.

Of course, decentralization has its limits as some locations get more sunlight than others.

4. Going off the grid with solar

Solar energy can be produced on or off the grid.

On grid means a house remains connected to the state electricity grid. Off grid has no connection to the electricity grid, so the house, business or whatever being powered is relying solely on solar or solar-hybrid.

The ability to produce electricity off the grid is a major advantage of solar energy for people who live in isolated and rural areas. Power prices and the cost of installing power lines are often exorbitantly high in these places and many have frequent power-cuts.

Many city-dwellers are also choosing to go off the grid with their alternate energy as part of a self-reliant lifestyle.

5. Jobs

A particularly relevant and advantageous feature of solar energy production is that it creates jobs.

The EIAA states that Europe’s solar industry has created 100,000 jobs so far.

Solar jobs come in many forms, from manufacturing, installing, monitoring and maintaining solar panels, to research and design, development, cultural integration, and policy jobs.

The book Natural Capitalism offers a good perspective on the employment potential of green design and a prudent approach to using resources.

The book proposes that while green technology and associated employment can be expensive, much greater money can be saved when combined with proven "whole-system" efficiency strategies (e.g passive lighting and airflow).

With solar energy currently contributing only an estimated 4% of the world’s electricity, and an economic-model where raw materials don’t have to be indefinitely purchased and transported, it’s reasonable so assume solar jobs are sustainable if the solar industry can survive the recession.

6. Solar’s separation from politics and price volatility

One of the biggest advantages of solar energy is the ability to avoid the politics and price volatility that is increasingly characterizing fossil fuel markets.

The sun is an unlimited commodity that can be sourced from many locations, meaning solar is less vulnerable to the price manipulations and politics that have more than doubled the price of many fossil fuels in the past decade.

While the price of fossil fuels have increased, the per watt price of solar energy production has more than halved in the past decade – and is set to become even cheaper in the near future as better technology and economies of scale take effect.

Furthermore, the ever-abundant nature of the sun’s energy would hint at a democratic and competitive energy market – where wars aren’t fought over oil fields and high-demand raw materials aren’t controlled by monopolies.

Of course, a new form of politics has emerged with regard to government incentives and the adoption of solar, however these politics are arguably minor compared to the fossil fuel status quo.

7. Saving eco-systems and livelihoods

Because solar doesn’t rely on constantly mining raw materials, it doesn’t result in the destruction of forests and eco-systems that occurs with many fossil fuel operations.

Destruction can come in many forms, from destruction through accepted extraction methods, to more irresponsible practices in vulnerable areas, to accidents.

Major examples include Canada’s tar sands mining which involves the systematic destruction of the Boreal Forest (which accounts for 25% of the world’s intact forest land), and creates large toxic by-product ponds [1].

The Niger Delta is an example where excessive and irresponsible oil extraction practices have poisoned fishing deltas previously used by villagers as the main source of food and employment, creating extremely desperate poverty and essentially decimating villages [2].

A more widely known, but arguably lower human-cost incident is the 2010 BP oil spill in the Gulf of Mexico. It killed 11 people and spilled 780 thousand cubic meters of crude oil into the sea.

8. The best is yet to come

Solar technology is currently improving in leaps and bounds. Across the world, and particularly in Europe, savvy clean technology researchers are making enormous developments in solar technology.

What was expensive, bulky, and inefficient yesterday, is becoming cheaper, more accessible, and vastly more efficient each week.

Disadvantages of Solar Energy

1. Solar doesn’t work at night

The biggest disadvantage of solar energy is that it's not constant. To produce solar electricity there must be sunlight. So energy must be stored or sourced elsewhere at night.

Beyond daily fluctuations, solar production decreases over winter months when there are less sunlight hours and sun radiation is less intense.

2. Solar Inefficiency

A very common criticism is that solar energy production is relatively inefficient.

Currently, widespread solar panel efficiency – how much of the sun’s energy a solar panel can convert into electrical energy – is at around 22%. This means that a fairly vast amount of surface area is required to produce adequate electricity.

However, efficiency has developed dramatically over the last five years, and solar panel efficiency should continue to rise steadily over the next five years.

For the moment though, low efficiency is a relevant disadvantage of solar.

Solar inefficiency is an interesting argument, as efficiency is relative. One could ask “inefficient compared to what?” And “What determines efficiency?” Solar panels currently only have a radiation efficiency of up to 22%, however they don't create the carbon by-product that coal produces and doesn’t require constant extraction, refinement, and transportation - all of which surely carry weight on efficiency scales.

4. Batteries to store solar produced energy

Solar electricity storage technology has not reached its potential yet.

While there are many solar drip feed batteries available, these are currently costly and bulky, and more appropriate to small scale home solar panels than large solar farms.

5. Solar panels are bulky

Solar panels are bulky. This is particularly true of the traditional silicon crystalline wafer solar modules. These are the large solar panels that are covered in glass.

New technology thin-film solar modules are much less bulky, and have recently been developed as applications such as solar roof tiles and “amorphous” flexible solar modules. The downfall is that thin-film is currently less efficient than crystalline wafer solar.

What's next for solar?

One feature of solar energy is that it spurs discussion and re-assessment of the importance and interaction between economics, environment, and investment.

There is debate and polarization of perspectives and interests.

While not everybody is in favor of solar, the fact that there is discussion about the validity of the status quo is a fascinating development. The monopolistic nature of many industries, the pitfalls of solely focusing on economics, and environmental disregard, are increasingly central topics.

At a practical level, many governments and state authorities are encouraging solar use through incentives such as subsidies, rebates and tariffs. California is an interesting example of such measures in action.




Wind is a clean and infinite energy source, which can be a big piece of the energy puzzle. Here we'll walk through how wind energy works.

A brief history

Although modern wind turbines are new technology, harnessing wind energy is not a new concept.

Throughout history we’ve harnessed the wind’s energy, with sail boats and windmills used to pump water and process grain.

How wind energy works - turbines

Diagram of how wind energy works

Turbines are the most common electricity-generating method. The wind turns large turbine blades, which spins a generator shaft and produces electricity (more about the parts of a wind turbine)

The electricity can then charge batteries, be connected to a building’s mains power, or connected to the power grid.

Wind turbines come in all shapes and sizes, from large scale wind farms to small scale wind turbines used to power a single home or business.

The European Union is leading the way with 48 percent of the world’s installed wind power capacity. In 2009, wind turbines installed in the EU produced 163 TWh of electricity – avoiding 106 million tonnes of carbon emissions [1].

Residential wind options include small wind turbines such as 500w rated turbine generators – enough to run lighting or a few appliances – to larger scale turbines such as a 2kw rated – enough to power an entire house plus sell some to the national grid depending on how much you use.

The most common model is the blade turbine, however a new style of turbine has recently emerged – vertical axis turbines.

Vertical axis turbines are smaller, lower to the ground, and create less noise – so are good for residential areas.

The praticalities of how wind energy works is simple, but socially and economically, not so simple.




How much electricity can a turbine produce?

Electricity output depends on a number of variables including location (how much wind there is), turbine size and style, and rotar diameter.

Wind turbines have a rated capacity
- how much electricity they will produce at optimal wind speeds. A 2kW rated wind turbine will produce 2 kWh of electricity for every hour it's exposed to optimal wind.

Generally, residential wind turbines are designed to function with wind speeds between 11 and 15 meters per second [3]. Larger turbines are often positioned in high wind-exposure locations, so are designed to function at higher wind speeds - thus producing more electricity.

Because of the intermittent nature of wind, general guidelines are that wind turbines will output between 10-40% of their rated capacity [3].

A realistic estimate of how much electricity a wind turbine would produce can be calculated using the average wind speed and hours for your location and turbine model specifications.You can calculate this yourself, or a local dealer will have all the measurements.

The debates for and against wind power

The main hindrance to wind power’s proliferation is the capital costs. Wind turbines are large and cost a lot of money to construct. They also require a reasonable amount of land, which is another expense that makes this free energy not so free.

Interfering with the aesthetics of the land is another issue with wind turbines. The ideal location for a wind turbine is often rural and natural landscapes. Just as any issue of social policy, some people don’t mind seeing wind turbines out their front window, and some do.

Another issue with wind power is that wind is intermittent. It’s not windy all the time in every location, so wind power production doesn’t happen around the clock. The true power of wind energy is positioned as a contributing piece to the clean energy puzzle.

A secondary cost consideration is savings on carbon taxes and Emissions Trading Schemes – which are set at a per kg amount. A report on the New Zealand wind energy economy states that increasing wind energy installations to supply 20% of the country’s electricity needs will mean nationwide savings of $390 per person per year – based on production and carbon-tax reductions. [2]

An interesting discussion is the cost of developing clean energy technologies – and the lack of commercial viability compared to conventional energy such as coal or nuclear. An interesting fact to note is that early nuclear development was subsidised by approximately $19/ kilowatt hour. Early wind technology worldwide was subsidised at approximately $0.57 / kilowatt hour.

Unlike conventional energy production, wind is infinite and it doesn’t produce any toxic by-products such as carbon or ethane.

It also doesn’t require any ongoing raw resources, which are expensive in terms of energy used for extraction, pollution from extraction and transportation, as well as financial costs of equipment and ongoing labour hours.

Summary

In summing up, wind is a low cost, low maintenance energy production method.

Wind energy works by harnessing natural wind movements, capturing it as kinetic energy through turbine blades, then converting the kinetic energy into electricity through an electro magnetic generator at the top of the turbine.




References

[1] European Wind Energy Association (EWEA). (2011). Statistics and targets.

[2] Infometrics Ltd. (2011). The potential contribution of wind generation to the economy: Report to New Zealand Wind Energy Association.

[3] Energy Efficiency and Conservation Authority (EECA). (retrieved 2011). Small Wind Turbines. Retrieved from http://www.energywise.govt.nz/how-to-be-energy-efficient/generating-renewable-energy-at-home/small-wind-turbines#the

 

The term photovoltaic literally means light producing electricity. Turning photo (light) into voltaic (electrical current), is the basis of how solar panels work.

So, photovoltaic efficiency refers to how efficiently a solar cell or solar module produces electricity.

Photovoltaic efficiency describes the efficiency or conductivity of solar panels - the percentage of radiation (sun) energy that can be converted into electrical energy.

Currently, photovoltaic efficiency of silicon crystalline solar panel modules is up to 22% [1] - meaning those systems convert up to 22% of the sun's energy they're exposed to into useable electricity. Crystalline silicon was the first mainstream solar technology, and continues to be the most commonly used.

New technology silicon thin-film photovoltaic module efficiency is up to 8% [1]. Although thin-film is less efficient, its advantages are that it's less bulky, has more applications, and is easier and cheaper to produce and install.




It's important to note that these records are for solar panel module efficiency (a circuit of multiple cells), not individual solar cells. Individual solar cell efficiency records are higher but less consistent.

Thin film solar panels are expected to become vastly more efficient as the solar and alternative energy race heats up.  Alta Devices Inc have developed a thin-film solar cell that’s achieved 28.4% efficiency. It uses gallium arsenide (GaAs) as a conductor, rather than the traditional silicon based conductors. [2]

 

Module Efficiency of Different Photovoltaic Technologies

Photovoltaic TechnologyEfficiency*
Silicon Crystalline22%
Silicon thin-film8%
Gallium arsenide crystalline (GaAs)21%
GalnP/GaAs/GalnNAs Multijunction cell*43%
* Figures rounded down to nearest percentage point.
** Multijunction data only available for individual cells - no module data available.
Data taken from the Solar Cell Efficiency Tables (version 38) [4].

Photovoltaic efficiency not the only factor

Additional factors affect how much electricity a solar panel module will actually produce. Technical photovoltaic efficiency doesn't necessarily mean solar panel efficiency.

Angle and location also weigh in on the efficiency of solar panels. You'll need to figure out the optimal placement for your location to get maximum sun exposure hours.

In New Zealand, the north facing side of the house gets most sun exposure so New Zealanders install solar panels to face north, whereas solar panels in the United States generally face south.

New Solar Technology

Solar Tracking

Solar tracker technology is another development which increases overall solar panel efficiency.

As the sun moves, the panels change angle... boosting efficiency throughout the day.

solar trackers
Solar tracking: As the sun moves, the solar panels change angle.

Commercial solar farms like the Montalto di Castro solar park in Italy use sun tracking systems to maximize the amount of time that solar panels are exposed to the sun's radiation [3].

Similar systems are available for smaller scale private solar panels, however are less popular than static due to increased setup costs and maintenance.

Multijunction solar cells

Multijunction solar cells are another exciting new solar innovation. Individual solar cells (normally silicon) only react to a certain range of light depending on their molecular makeup - some silicon conducts and reacts to ultra-violet light, while other silicon reacts to infra-red light.

Multijunction solar cells combine layers of differently tuned silicon - so a single multijunction cell covers greater range of light and thus has a greater electricity production potential.

Concentrated solar

concentrated solar
Concentrated Solar: Large angled mirrors concentrate the sun's radiation onto a few solar cells

Concentrated solar is another technology increasing efficiency.

This involves using mirrors to concentrate sun radiation on a single cell. Concentrated solar exposure equals greater power production.

 




Measures Beyond Efficiency of Solar Panels

Other measurements to be aware of when researching solar power are photovoltaic capacity and watt hours.

Photovoltaic Capacity

Photovoltaic capacity refers to the maximum power output a solar panel module is designed to produce – if the solar module were exposed to constant and direct radiation.

Photovoltaic power capacity ranges from large solar farm installations, such as Montalto di Castro with a peak capacity of 24 mega watts [3], to small residential solar modules with a capacity of 180 watts.

It’s important to note that photovoltaic efficiency and capacity of solar panels are useful as indications only – they’re not measures of actual production.

Time of day, amount of sunshine or cloud, location, and numerous other factors will influence actual solar power production levels.

For these reasons, worldwide solar production is estimated to be around 25% of peak capacity levels.

Watt hours - the measurement of actual electricity produced.

Watt hours is arguably the most useful indication of a solar installation’s value as it can be directly compared to watt hours of electricity produced by traditional fossil fuel energy production or to how many watt hours a town or individual family uses.

Looking at watt hours presents a tangible cost comparison that solar panel efficiency doesn’t. The Montalto di Castro solar park for example produces around 40,000 mega watt hours (MWh) per year – enough to supply approximately 13,000 Italian houses [5].

Furthermore, by looking at expected watt hour generation, a cost per kWh figure can be calculated and compared.

 

Article References

[1] Green, M, A., Emery, K., Hishikawa, Y., Warta, W. (2011). Solar cell efficiency tables (version 37). Progress in Photovoltaics: Research and Applications, 19, 84-92.

[2] Jeanne Roberts. (2011). Alt Devices Inc. hits “sweet spot” in thin-film efficiency ratings. Energy Boom.

[3] SMA. (2011). Solar Park Montalto di Castro. SMA.

[4] Green, M, A., Emery, K., Hishikawa, Y., Warta, W., Dunlop, E, D. (2011). Solar cell efficiency tables (Version 38). Progress in Photovoltaics: Research and Applications, 19, 565-572.

[5] SunPower. Largest Solar Power Plant in Italy Completed. Retrieved from http://us.sunpowercorp.com/about/newsroom/press-releases/?relID=23297


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