In 2007, the governments of the European Union agreed to the Renewable Energy Roadmap which set out targets for governments to transfer power generation to renewable energy sources and also forecast a huge dependence on renewable energy by 2020, including 12% of our energy being generated by wind farms. Renewable energy is being treated very seriously by governments around the world and sees a lot of investment for the development of new technologies.

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Investment and commitment to renewable energy is very much a good thing. We do have to switch away from energy generation with oil, gas and coal at some stage. This is the cause of global warming and, perhaps more pressingly, we have to stop using it before it runs out. Renewable sources are hailed as the answer, our source of endless amounts of energy from systems that will never run out.

Are there environmental costs to renewable energies though? This seems to have been a subject somewhat overlooked and it’s an important one to consider so we make the right steps when we decide how to generate power in the future. Let’s look at some of the major players in the renewable energy market.

Wind Power

Wind Power conventionally means turbines and wind farms, either at high altitude or off the coast, where there is most wind for them to capture. Wind pushes the turbine blades around which then generate electricity.

We will always have wind so we will always have power – or will we? Wind is generated because some parts of the Earth are hotter than others at any given moment in time. The hot air is less dense and rises and cold air rushes in to fill its place. When air goes through a turbine it air loses this energy – that is simple conservation of momentum. So the air loses energy, cools and so stops rising. The net result – after it passes through a turbine there is less wind.

The idea that you can’t stop the wind is a fallacy. With enough wind turbines we effectively can stop the wind – this is exactly what turbines are designed to do. For the occasional windmill used to grind grain, this is not noticeable and poses no problem. For wind power to play a major part of global energy requires massive wind farms and plants however. This will potentially create a noticeable effect and it’s possible it will have a serious impact.

Hydropower

Hydropower, by which I mean wave and tidal power principally, is similar in many ways to wind power – it is generating power from a moving fluid. It is perhaps more obvious to see, particularly with wave power, and has been well documented by opponents of the technology.

To draw power from the waves we have to remove it from them. If we remove the energy in the waves then we remove, or at least lessen, the waves themselves. After the wave farm, assuming it is an efficient system, the sea is still and calm. This is bad for marine sports and beach lovers but may have a broader impact on the sea life as we change a major part of their ecosystem.

Tidal power has a similar impact. To draw power from the tides means the tides cannot move as much as they do now. The larger the tidal power plant the larger the difference must be so it is hard to consider while we still only have test rigs and examples built. But if the technology is to provide a significant amount of mankind’s power requirements to effects could be dramatic and the consequences cannot easily be foreseen.

Solar Power

Solar Power is essentially the conversion of the energy and photons from sunlight into electricity by means of a photovoltaic sensor. Currently this is an expensive technology but this price is expected to drop, allowing solar power to be a major player for future energy generation. With the sun’s rays we have a never ending source of power and we can all live happily ever after.

Having the sun’s rays falling on Earth isn’t a new thing. Photons hit the Earth now, and not without effect. Many of them are reflected but others heat the Earth. With global warming an issue there may be an argument that limiting this is not a bad thing but we will be limiting this at specific points on Earth’s surface – mostly the land masses and at specific sites. The effects of this are unknown at present but it is hard to believe that it will not impact on our environment.

So what does all this mean?

Of course, while these arguments warn of hidden dangers, I cannot begin to propose a solution. We must stop, or at least dramatically reduce, our use of fossil fuels and something needs to fill that void if we are still going to light and heat our homes. Increases in efficiency can only take us so far and there will be a constant demand for power.  Nuclear and geothermal power stations present potential solutions although these are fraught with their own inherent problems as well.

While renewable energy sources are not the magic pill that we would like them to be, they do present a route of going forward without generating an excess of greenhouse gases. At the moment this is the most important feature and gradual introduction of the systems might be enough for us to monitor any effects on the ecosystem. In the rush to stop production of greenhouse gases though, are we leaping from the frying pan into the fire?