Which is most environmentally-friendly: 1) Wind turbines (consider its elements, fossil fuels used to create elements, where it's installed), 2) Solar farms, 3) Generation at home (decentralized)?

Although there were enough warnings to address serious environmental issues of fossil fuel generation, it received no attention by the concerned players until this pandemic.  Ever since the pandemic broke out and the world coming to practically standstill, there has been growing recognition among the same who had brushed aside environmental issues earlier, to address them on urgent basis especially, the climate change. 

Renewable energy both solar and wind were at a snail pace trying to make inroads into the energy sector with their contribution.  But, pandemic perhaps opened up flood gates for them and they are now being recognized as a strong contender to address climate change issues.

In the meantime, renewables have undergone tremendous transformation in terms of technological advancements, cost effectiveness and flexibility.  What I intend presenting below is a summary of the renewable potential in terms of environmental aspects and grade them on priority.

Wind:

Wind energy is of three types – utility scale; offshore and distributed and presents certain advantages in being a clean fuel source, cost effective, creates jobs and is sustainable.  Wind being a clean source produces no air or water pollution; being free reduced operational cost (almost nil).  Mass production and technological advancement are making turbines cheaper and many governments off tax incentives to promote wind energy development.

Despite these major advantages, there are a few limitations as well – wind is inconsistent (one needs minimum velocity to turn the blades), turbines involves high capital investment and are a visual impact, believed to reduce bird population due to noise disturbances, turbines could be a safety hazard.  Requires large land area. 

The adverse environmental impacts include reducing, fragmenting or degrading habitat for wildlife, fish and plants.  Spinning blades are a threat to birds and bats.

Solar farms:

Similar to wind, solar also does not use water and release harmful gases and it is estimated that two decades of solar energy saves approximately 320,000 pounds of carbon dioxide. Undoubtedly, it is abundant and free.

However, they remove species within the habitat and renders habitat to less livable for plants and wildlife that have adapted to specific conditions.   Solar initial cost is high, expensive storage and location & sun availability is perhaps the main concern.  Solar panels modify the land use pattern, water use and more importantly uses hazardous materials in manufacturing.  There is further a big difference in Photovoltaic (PV) and Concentrating Solar Power (CSP).

Decentralised – electricity generation at home:

Smaller power generation plants and storage units (micro-renewables, heating and cooling) that get grid connected fall under the Decentralised category.  They generate less harmful emission, decreases transmission loss and can be built on residential areas. 

While initial installation costs are higher, there are economic benefits in the long, reduces carbon emissions and secured energy.

Renewable  (all three) has been a competitor to centralised power generation in significant savings through lower cost and efficient use of resources.  Not only does this meet customer’s energy requirement but often may generate additional revenue as well through selling excess capacity to the grid.

In addition to what has been mentioned under each category, tremendous technological advancement has taken place both in the solar and wind sector.  They have tried to consciously introduce noise free wind turbines and there has been a greater emphasis on the offshore windmills recently.  With the increased efficiency, land requirement (unit) will automatically reduce.   With the increased demand, capital cost investment hopefully should be affordable.  Wind turbine material has undergone tremendous change and lighter material may promote operation with lower wind velocities.

Solar and wind have the greatest advantage in limiting global carbon dioxide level.  Efforts on land reduction and reduced disturbance to the habitat disturbance need serious attention.

For a variety of reasons, roof mounted or wall mounted solar on every building (residential, commercial, industrial and public) where possible should be a requirement under all building codes of the future.  That individual building energy generation needs to be paired with energy storage. A comprehensive use of roof space and wall space on all buildings everywhere would make a big dent in our need to convert our energy supply to 100% renewables.

Roof top / wall mount is not the cheapest renewable energy solution, but it likely is the most environmentally friendly.  It also offers the opportunity for energy reliability in environments where the electricity supply is unstable due to weather events and fires.

Wind farms and solar farms built at scale are important, but one needs to realize that there is the line loss penalty where a significant share of the energy generated does not make it to the ultimate consumer.  In addition, given the issues that we will face for the foreseeable future, any power line that is not built underground will by its very nature have a risk and reliability issue.  As a side note, my hope is that our upcoming multi-trillion dollar effort to upgrade our badly neglected national infrastructure will include an active element to underground all high voltage and local distribution power lines.  Over the year look at the amount of money we have wasted to continually rebuild / replace power lines blown down by the wind.

New technologies, including small rooftop wind turbines and windows that make electricity, already in the marketplace and coming into the marketplace, will make the idea of building by building energy generation both practical and economical. 

Hope this helps your thinking on the subject.

Larry

Environmentally-friendly is a little vague as a term. There are several metrics one could evaluate:

• Carbon footprint during construction, operation, and decommissioning
• Material toxicity
• Recyclability of materials
• Watts/square foot

They both take advantage of naturally available processes to generate electricity. This makes it so that they need to be in the right locations to work optimally. Wind and commercial-scale solar need large, open places to maximize exposure to their processes. After both solar and wind are manufactured and installed, they spend the rest of their useful lives creating carbon-free energy. 

As far as carbon footprint goes in manufacturing these materials, there is a lot of imbued energy. Metals require a lot of heat to manufacture as does the silicon in solar. In construction, wind requires heavy equipment to transport, lift, and install. On-shore wind often needs civil work to straighten roads to get the enormous components to their sites. Moving roads disturbs the land and changes property lines. End-of-life is simpler for wind because it's mostly metal. There is a considerable amount of concrete but, if that is removed, it can be reused as rip-rap on other sites or in restoring aquatic ecosystems. 

Material toxicity - I can't testify to this. None of the statistics I've heard were supported in any fact. The same goes for rumors of wind killing a lot of birds. I don't know what the numbers are. I do know that they have figured that painting wind turbine blades darker colors has dramatically reduced the kill rates of wildlife.

Recyclability of materials - Both solar and wind turbines are recyclable. It costs a lot to recycle solar panels so it is something markets and governments must solve as more solar comes to their end-of-life. 

Watts/square foot - a lot of this depends on the location of the installation. Residential solar is expanding like wildfire. In areas where electrical rates are high, it is everywhere. Residential solar does not always get ideal efficiency though because it has to work with the directions of roofs. As a result, 1 MW of installed capacity on residential roofs will not produce as much as 1 MW of commercial. Residential installs have varying pitches, orientations, shading, and efficiencies. A MW of commercial must contend with changes in topography but it will always have the ideal azimuth and zero shade. Commercial arrays can use larger panels that produce more power. Commercial ground-mounts also have the ability to use tracking types of mounts. A single-axis tracker can optimize the time spent with the best solar incidence thereby maximizing the amount of MWh produced each day. At current efficiency levels, a MW of capacity of commercial solar takes a couple acres. Wind on the other hand can produce 2-3 MW per turbine. The only issues with wind are that sites present challenges with NIMBY, adequate wind flow, and government support. Commercial solar has a much smaller visual profile and can often be hidden with strategic plantings. 

Which one is the most environmentally friendly? I'm torn between wind and commercial solar. In the end though, they're all more environmentally friendly than fossil fuels. 

Nick Klank

Coperniq.io

The question, as posed, is rather vague relative to any kind of demonstrable answer. All of these technologies are dependent upon their location to produce output. Thus, if rooftop solar PV were to be used in Nome, Alaska, I suspect that the total output over the life of the solar cells would be a lot lower than if it were to be used in the Mojave Desert. That would impact the number of PV cells that would be needed to get a particular output. Further, the need for that output would likely be higher in Alaska. Then there is the orientation of the house, as well as weather factors that would influence the overall environmental impact.  Likewise, the size of a solar farm to generate sizable amounts of electricity would substantially greater in Alaska to get the same annual electrical output.  Wind has its own issues relative to location.  A wind farm in Oklahoma might do reasonably well, as there tends to be steady wind there.  A wind farm in the state forests of Maine might not do so well.  In addition, the folks in Maine may not want the state forest to be disturbed.  As with most energy issues, the answer will most likely be site specific.  Generalizations are dangerous.

Jim, you offer a false trichotomy. The most environmentally-friendly way to generate clean electricity is by splitting the atom - no CO2 emissions, a tiny amount of land use, a generation facility that is capable of lasting 80-100 years, zero dependence on fossil fuel, and a tiny, tiny amount of waste for the amount of energy it generates - waste that has never harmed a single human, plant, or animal.

Split - Don't Emit.

Solar PV on your home is the best. It makes the most power during the day which is when it is needed. The system makes you aware of it's output and your use since you live with it. Any problem and you will notice right way. You become more efficient as you see the use all the time. It can be GRID tied and help out you neighborhood.