Solar Versus Wind

Is solar power the answer to all of our prayers? Or will wind turbines continue to play an important role in our energy future?  Two HBS students from the Energy and the Environment Club debate this critical issue.

Solar is the Future of Renewable Energy Generation

by Evan Hindman (OI)

Solar PowerWith the rise of atmospheric carbon and the depletion of finite reserves of natural resources, it is clear that our energy future will inevitably have a larger percentage of renewable energy generation in the total energy mix than exists today.  However, of the two dominant sources of renewable energy currently deployed, wind and solar, solar has some distinct advantages over wind that convince me that the US and the world should be aggressively pursuing increases in installed solar generation capacity.

Solar is modular: A single solar panel is about the size of a standard coffee table, making panels easy to transport, install and use in projects ranging from just a few kW on a residential rooftop to hundreds of MW in the middle of the Nevada desert. Modern wind turbines have blade lengths of 50 meters or more, creating substantial transportation and installation difficulties.

Solar produces its maximum power output exactly when it is needed most: Solar panels produce the most power on hot, sunny days – exactly when the need for electricity is highest (primarily to run air conditioning).  Solar can therefore be a cost-effective replacement for expensive gas or diesel peaker plants that remain idle for 90+% of their asset life.  Wind, on the other hand, generally produces the most power at night, when the demand for electricity is lowest.

Solar is cheap, and getting cheaper:  Prices for solar panels have been decreasing exponentially replica breitling, dropping from an average of $3.50/W in 2008 to just over $1.00/W today.  The US SunShot initiative aims to decrease that by at least another 50% by 2020, which would make large-scale solar installations cost-competitive with today’s cheapest and dirtiest coal plants.  Prices for wind turbines, on the other hand, have been flat or increasing since 2000, according to the US Department of Energy.

There are few siting concerns with solar power:  Wind turbines are big, loud, and kill birds.  Solar panels are small, silent, and have no moving parts.  It should come as no surprise, then, that countless wind projects have been held up or cancelled due to opposition by local citizens. (The Cape Wind project is just one high-profile example of this).  Solar has faced little to no community backlash.

There is only one true renewable energy resource on Earth – the sun:  Every source of fuel on earth – including fossil fuels – ultimately originated as electromagnetic radiation from the massive nuclear reactor 93 million miles away.  Even wind energy is created by the sun via pressure differentials of hot air moving from one region to another.  Total global electricity demand could be met by collecting just 0.000001% (yes, five zeroes) of the direct solar radiation the earth receives every year.  Doesn’t it make sense to start harnessing that energy directly?


Why Wind Energy Should not be in Solar Shadows

by Sylvain Mansier (OF)

The recent growth in installed solar energy capacity in the U.S. (over 100% increase in 2010) has sparked significant interest in solar energy potential, seemingly relegating wind energy to a diminished ‘stepchild-like’ status.  The solutions to our energy challenges should include a diversified portfolio approach, however, and the relative benefits of wind energy should not be ignored.  Although solar panel cost curves are declining, wind energy still delivers a less expensive source of power.  What’s more, continuing innovations with wind turbine generators are leading to improvements in efficiency and productivity factors, which result in a lower cost of power.  In addition, wind turbine generators have a longer track record in the field, which translates into a better understanding of lifetime operating costs for wind energy projects.

In order to make a real impact on the generation mix, significant deployment of renewable energy is necessary.  Currently, there are 42,400 megawatts of installed wind energy capacity, and approximately 3,100 of solar in the U.S.  The unit generation potential of commercialized equipment allows for a greater scale of development with wind energy technologies—each wind turbine generator can provide 2.5+ megawatts (2,500,000 watts) of capacity, whereas each solar panel provides approximately 275 watts.  This point about the relative scale of capacity becomes increasingly compelling when taking land use policy into account.

Although many renewable energy projects are constructed in far-outlying, uninhabited areas, the nature of integration, transmission, and distribution costs suggests that smaller distributed generation projects located closer to concentrated demand areas are preferable replica watches uk.   Land use, therefore, is an important consideration, particularly in places where the land for energy projects could otherwise be used for productive agricultural purposes.   The typical footprint of a utility-scale wind turbine generator is around one-quarter acre, whereas an equal amount of generation capacity from photovoltaic panels would have a footprint of approximately 1.75 acres.   In other words, PV solar energy projects are currently 7 times more land intensive from a ground cover perspective than wind farms.

Policies all over the country target solar-specific energy development.   These ‘one-size-fits-all strategies’, which do not consider meaningful geographic differences, simply do not make sense.  Siting solar projects where there are low insulation levels is tantamount to developing a wind park surrounded by a 15 story wind-blocking wall.  In summary, while solar energy is a critical part of the solution, the continued deployment of wind energy generation with scalable, proven technologies should not be discounted.


  1. Such a ignorant article, as if photovoltaics do not indeed require natural resources that are sparse in nature. As if they are not found amongst the most toxic of metals- mined and refined and many set into the air… Shame to look at just the end product in your descriptions. If you want to talk about foot prints, mining of materials required to build it, energy required to refine and produce these systems. There is only one option on top. Nuclear and holding that back is why we have mountains of waste building up. Instead of building new plants that utilize the waste as an energy source, new plants that are far less dangerous we are participating in a charade of which industry will recieve the most in subsidies- and who will get punished the most….

  2. While I am tempted to respond to EgadsNo, I’ll ignore him for now since he failed to include any data upon which he is making his claims regarding the comparative usage of toxic metals or waste production between power generation technologies . My sense however, is that he is wrong across the board and has probably never visited a Uranium Mine or a Coal mine for that matter, nor is he aware that many of the rare earth metals that will supply advance electronics industries are actually found in the tailings from Coal, Copper and other mines and increasingly are the primary contributor to their profitability.

    For Evan and Sylvain, I am curious if in your analysis you gave any consideration to the difference between distributed and centralized generation and how Wind and Solar may play quite differently in each application. At RMI we believe that Solar has tremendous potential as a source of Distributed Generation in the 500Kw 10 10MW range, however has significant challenges with respect to centralized utility scale generation due to land use issues. Whereas wind probably has limited potential as a source of DG especially within urban distribution grids and much more promise as a source of centralized power generation. We have found it hard to assess or predict the future of either technology without a the same time considering how our T&D architecture may evolve as well.

  3. Ned, you bring up a good point regarding how siting of projects using the two different technologies will impact their potential deployment. I would agree that solar works better on a DG basis, but I suspect that the majority of installations will be smaller, perhaps smaller than even 500 kW. From a land use perspective, the smartest place to put solar panels on the rooftops of existing buildings, where no new land is required. In addition, ‘behind-the-meter’ installations clearly provide end consumers with the best economics, as T&D costs are avoided. Certainly, for smaller solar PV installations, the ability to tie directly into the distribution grid is also a plus.

    As far as wind energy goes, it does seem that central scale projects are the most likely due to siting difficulties. Given zoning restrictions and the like, it would be difficult to site large wind turbine generators (WTGs) in or near urban load centers. However, urban wind at a DG scale can be seen in places such as the Netherlands and the UK. Improvements and innovation in micro and small WTGs (i.e < 100 kW), such as better designs in vertical axis wind turbines that can be used on building tops, could lead to more urban wind installation.

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