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LostInParadise's avatar

What are the limits to renewable energy?

Asked by LostInParadise (28166points) September 25th, 2009

It looks like renewable energy is going to be of increasingly greater importance. How much of it can we use, compared to our current energy usage? Are there any downsides? It seems to me that wind turbine sites take up a lot of land. If we use solar power, will we be taking sun away from plants?

I do not wish to appear downbeat, but I was just wondering how much use we can realistically expect to make of renewable energy sources.

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14 Answers

dpworkin's avatar

It may be unlimited, if we, could establish fusion, if hydrogen batteries could be made economically, if we could harness the power of the sea. No one knows yet, because we have been in love with fossil fuels for a long time now.

oratio's avatar

Yes, it will be unlimited, if we can harness it. Not any time soon, but we are getting there.

mattbrowne's avatar

The only limit I know of is the speed of the migration strategy. Fossil fuels and renewables will have to coexist for the next 20–30 years. Projects like Desertec will take many years to implement. But we have to get going NOW.

LostInParadise's avatar

I am glad to see everybody is so upbeat about renewable energy. The skeptic in me says that there must be some limits on its use. I remember people talking about nuclear energy in these same glowing (pun unintended) terms.

YARNLADY's avatar

Wind turbines are ugly, take up a lot of room, and are dangerous to the indigenous flora and fauna population. Solar power generators are ugly, take up a lot of room, and severely disturb the climate, and natural environment. Electricity created by water (dams) destroys the local environment, and has been shown to have far reaching, unexpected consequences by blocking fish, water, and even sand from reaching the beaches hundreds of miles away.

People simply do not take the environmental costs into consideration when talking about ‘renewable’ energy.

oratio's avatar

@LostInParadise I don’t see that there is a problem with fission power per se. The waste products are another story. Fusion is coming. There are so many different technologies that we will use in tandem. Besides fission and fusion there are solar power, tidal power, wave power, wind power, energy forests, Geothermal heat and Hydropower. We will have all the energy we need and more, it’s going to be clean and unlimited in human scope. But as Matt says, we will use fossil fuel for a couple of decades more.

LostInParadise's avatar

The waste products from fission is a major factor, as are the points brought up by @YARNLADY . We will be shifting to renewables and the transition period is likely to be messy. There will also be continued research to improve the efficiency of all types of energy production. I am concerned that in making use of renewable energy seem like a panacea, we may be ignoring shortcomings. At one time the use of corn to produce fuel seemed like a great idea. Now we realize that fuel use of corn competes with the food use of corn.

Renewables, either directly or indirectly, make use of solar energy. There is a lot of solar energy, but there is only a finite amount of it and much is already being used by plants. Fusion remains a distant possibility, but fusion research has been going on for some time and it is not clear whether it will ever be possible to make use of it and if we do finally figure out how to use it, there may be associated drawbacks.

oratio's avatar

@LostInParadise I agree to that waste from fission is a problem, but not so much for the environment as it is a problem for us. It doesn’t affect the climate and the waste from fossil fuel gets spread all over.

Imagine all the rooftops and car roofs covered by solar panels. There is plenty of space the wouldn’t change much if they were use for this purpose. You are right, I don’t believe in covering many square miles with panels to pool electricity. That would be a bad idea. But we will not rely on one or few different technologies, but many simultaneously, which will be both locally produced or nationwide.

I agree that fusion might have it’s drawbacks as well. Most energy production do. Hydro power is changing natures condition, wind mills can be obstructive, fission and it’s waste and so on.

I see your point in that available energy must have a finite point, and we will always need more energy. I just don’t think it’s likely that we will reach that cap. There is nothing but energy around us, as everything exists in an energy state. But of course, what we are looking for are the most efficient production methods that will be clean as well.

Something that worries me is the frozen methane under the north pole. There seems to be consideration about using it as fuel. It seems as if it represents more energy than all the oil in the world. Not clean to burn if you are afraid of CO2 though.

mattbrowne's avatar

@YARNLADY – Wind turbines don’t have a significant influence on flora and fauna. This is a myth created by the fossil and nuclear fuel industry. The impact on flora and fauna by burning fossil fuels is hundreds of times greater. If we can’t slow down climate change Earth’s ecosystems will become totally different later this century. Many species won’t have time to adapt.

YARNLADY's avatar

@mattbrowne In terms of realtive damage, you may be correct, but I have personally witnessed the overall damage caused through the years by the wind turbines on the Altamont Pass in California, and it looks quite intense locally.

Edit: I have also personally witnessed the huge amount of damage caused by the oil refineries in near by Pittsburgh California, plus the oil fields in Bakersfield and along the Santa Barbara coastline, and they are by far worse than any wind turbine farm.

Critter38's avatar

@LostInParadise I think the strongest arguments I have seen regarding the limitations of renewable energy hinge entirely on just what is being asked of it: For example, just how much base load power is expected to be contributed by renewables, how soon, and what the aim is (meeting current energy demands in the first world (no change in lifestyle), reduced energy demand in the first world (increased efficiency), energy equity (some minimum standard for 9 billion people by 2050…(eg. electric light, refrigeration, etc…??). So everything has limitations, the question is only answerable relative to what the expectation is. Some people answer these limitations by insisting that nuclear (III or IV generation) reactors will have to be part of the equation.

See this for a brief insight to the size of the transition being discussed for just the U.S.

This is a post that discusses the size of the global challenge and how small a current contribution there is from renewables…basically it advocates nukes as an important part of the solution.

(@mattbrowne—-it mentions the situation in Germany…would be good to get some local feedback on that…)

I think the quick and easy answer is that there is no silver bullet and I see renewables gradually increasing their relative contribution to energy supply as a part of smart grids.

Unfortunately I don’t see it happening fast enough. I think collectively we have underestimated the rate at which the climate is changing, the contribution from feedback mechanisms, while concurrently overestimating the speed at which nations can respond to such a global threat and the rate at which such responses will make a difference.

I think many people don’t realise that we have to approximately halve emissions before greenhouse gases in the atmosphere will even stablize (that’s a best case scenario as it doesn’t factor in decreasing work being done by natural sinks, and tipping points and feedbacks from natural sources).

I’m deeply concerned to be honest….I sincerely wish for something to occur that far exceeds my current expectations at Cop 15…we’ll see. The UK met office has just released some not exactly comforting projections at a recent conference.

Critter38's avatar

If you have access to Science, get a hold of “Renewables test IQ of the grid” for a relevant discussion of the issue of providing reliable base load power.

Hopefully this link will work for you.

mattbrowne's avatar

@Critter38 – The term massive subsidies in Germany used in the article is incorrect. What they mean is the so-called feed-in tariff scheme, see

I own a 5.5 kW photovoltaics system and the utility has to pay me around 50 euro cents per kWh. This is being paid for by the utilities customers.

The real limits to renewable energy consists of two things

1) Ignoring the energy efficiency potential
2) Unwillingness to change to a sustainable life style

Too many buildings in the US are badly insulated. We could power a AC unit with electricity generated by renewable sources. But if the cool air isn’t contained properly the electricity demand remains huge (limit number 1). If in addition people leave open the windows while the AC is on and they also set it to 60 Fahrenheit because they like to wear a sweater in the summer the demand remains huge (limit number 2).

Critter38's avatar

Thanks for the insights Matt.

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