Green Energy not suitable for Grid Power

This post was written using the best available information found using Google and Wikipedia.  The purpose for writing this post was for putting things in the proper perspective in regards to sustainable energy at the global scale.  The words Sustainable Energy as used today refer to Energy that does not pollute and is not finite.

All carbon-based sources of energy are finite and pollute and nuclear process pollute and are also finite.  Hydroelectric is very limited and cannot be considered as a serious source for global energy. Other similar sources such as wave power and geothermal have the same limits and so this class although very suitable in some locations does not solve global needs.

Therefore the only real source of truly sustainable energy is the sun, and the only question then is how can we acquire it and how much is available? This potential energy availability takes two basic forms; the first directly converting sunlight to electricity with energy collection panels and the other indirectly capturing the movement of the solar heated atmosphere with wind turbines to create electricity.

Unfortunately there is no way to discuss this subject without using lots of numbers.  Their use has been minimized to the extent possible.  But to do so requires that some liberties were taken in the descriptions.  None of these liberties changes the basic facts presented here in any way.

Basic facts one, the earth is a sphere albeit not a perfect one but very, very close with a mean radius of 6,371 km and that is revolving around the sun at distance of between 147.1 (perihelion) and 152.1 (aphelion) million km with an orbital period of 365.2564 days.  The solar radiation (flux) at the surface of the sun is 6.4 X 10⁷ +/- .25% wm^-2 considering variations due to the fusion process going on in the sun.  By the time this solar energy reaches the earth it has been reduced to between 1,435 wm^-2 at perihelion and 1,345 wm^-2 at aphelion with a small variance of 90 wm^-2 between the two. The accepted “average” all this considered is 1,367 wm^-2 at the interface of outer space and the earth’s atmosphere

Basic facts two, the earth, to the sun, is only a flat disk, which has an effective area of 1.28 X 10¹⁴ m^-2 so that the 1,367 wm^-2 of the incoming radiation must be reduced by a factor of 2 to compensate for the 3D effect (sphere verse disk) on the surface. Considering only that adjustment we would have 683 wm^-2 on the surface but that level is further reduced by the earth’s albedo (the amount being reflected back into space) of about 30% so the net at the surface facing the sun is about 478 wm^-2 when these things are considered. We’ll ignore the various variations because they are relatively small.

Basic facts three, Continuing with our simple disk model the backside of the earth, that facing away from the sun, is radiating energy off the planet back into space. So therefore since the planet is in thermal equilibrium the backside is radiating 478 wm^-2 of energy back into space at a frequency shift down into the infrared range.  And the net mean temperature of the surface of the earth is 287.2 degrees K (Kelvin) as a result.

Note, this is a very simplistic thermal model of the Earth and the actual energy flows of a very large rotating sphere within a gaseous envelope being heated on one side is going to be very complex.  The above descriptions are meant only to give the feel for the energy flows even though the actual energy flows are not exactly as described.

Basic facts four, Of significant note is that the water vapor and water droplets in the atmosphere absorb the outgoing inferred as described in basic facts three delaying the back radiation going out and thereby raising the temperature of the planet (the so called greenhouse effect). That water acts as a thermal dampener and thereby raises the temperature of the plant by about 33 degrees Celsius.  In other words the temperature of the planet without atmospheric water and also the CO₂ would be 254.2 degrees Kelvin instead of the actual 287.2 degrees Kelvin and the Earth would be an ice ball with no life on it

Much to do has been made about using sustainable energy i.e. solar and wind in lieu of carbon based sources for two reasons.  The number one reason is that carbon based fuels produce CO₂ and that since CO₂ is a green house gas that it will raise the temperature of the planet by some unacceptable amount.  The second reason is that we will soon run out of carbon based fuels and we need to find a substitute.

The first reason is without any merit since historically the level of CO₂ in the atmosphere has ranged from historic lows of around 180 ppm (parts per million) in the recent past to well over 7,000 ppm in the distant past.  If an average were developed it would be in the range of about 1,200 ppm, which is 3 times what it is now.  When considering geological time frames there does not appear to be a causal relationship between CO₂ and temperature so it’s unlikely that even reaching 800 ppm today will have much effect on the planets temperature.  The temperature of the planet has, in geological time frames, only moved +/- 1.8% from the mean while CO₂ has moved +/- 274.1%.  That alone is enough of an issue to give pause to the current climate theories.

However realizing that this is a unconventional belief its not worth arguing about since well over 80% of the worlds energy is carbon based and that is not going to change in the next 40/50 years even with all the attempts being made at limiting the use of carbon based fuels.

So the real question is how do we transition from where we are which is using up finite resources to being able to have abundant energy that has no or minimal adverse effects on the planet and on humanity. One point of clarification is needed here and that is that although the carbon fuels i.e. coal, oil and natural gas are finite, they will last well into the next century.  We are not going to run out in the next 50 years. In fact, there appears to be in North America enough carbon based recoverable energy to last us between 100 and 200 years depending on usage rates. The point being that there is plenty of time to work out an alternative.

But back to our study, the first thing we need to know is not how much energy we use now that’s a given but how much will we need in the coming decades. The estimated level of energy produced and used world wide in 2008 was 474 exajoules or about 449 Quads and it was growing at about 5% per year as third world counties industrialize.  That would put total world energy usage at about 3,679.8 exajoules or 3,485.0 Quads at mid century if that growth rate were sustained.  That is the equivalent of 1,024,529.6 TWh (terawatt hour) used from a generating capacity of 117.0 TW (1,024,529.6 dived by 8760 hours) which is almost 8 times what we have now.  So the issue then is how much of that could be converted to wind or solar?

To determine the amount of energy we can get we first need to know how much of the available land area can be used to convert the incoming energy to a usable form with either solar or wind systems.  We’ll ignore the costs for now and only focus on the energy generation.  The Earth is 29.2% land or 148,940,000 km^-2 but not all of that is available for several reasons.  Those reasons being: the requirement of living which are having cities, crop land and other uses of the land for human work and pleasure; then that which makes the land unsuitable i.e. the polar areas, mountains, swamp land and other areas where putting wind turbines and PV panels would just not be practical.  For sake of discussion let’s assume that 10% of the land area of the planet is available for either wind or solar power and that calculates out to about 14,893,882 km^-2 of available land.  And that gets reduced by another 25% to 11,170,412 km^-2 for other reasons explained later.

Solar PV (Photovoltaic) is probably the most efficient method for collecting energy since we are not using the sun to heat air and then the air to move turbine blades.  Turbines are complex devices with a high mechanical content subject to breakdown and high maintenance, They are also not visually pleasing and they generate audio harmonics that cause humans and animals that are near them discomfort. Solar PV panels are the more practical means of collecting solar energy since they lend themselves to mass production and cost reductions better than wind systems.  There is a downside however as only half the planet is facing the sun at any one time and there is a certain amount of infrastructure required that also reduces the area actually available. That means when we factor all this in that we only have 5,585,206 km^-2 available at any one time for generating solar PV power out of a total installed base of 11,170,412 km^-2 worth of panels.

So how much power can we get? Well we know that on average the solar radiation is 474 wm^-2 and there are only 5,585,206 km^-2 available for generating power at any one point in time. There are many figures out there all using many different ways of determining solar PV capability and cost. We also need to consider incentives and grants as they do not change the cost of production only who pays for it. So rather then guess at the numbers we’ll use the actual published data of one of the world’s largest solar PV installations, the recently constructed solar PV panel generating plant in Sarnia Ontario, Canada that was finished in 2010.  On their website the stated generating capacity is 80 mW and it is expected to generate 120,000 mWh per year (we do not know if this is actuate yet).  This plant was said to cost about $400 million to build and consists of 966,000 m^-2 of high efficiency First Solar PV panels.

Using these numbers and considering these previously discussed facts: First that on average we only get sunlight for 12 hours on any one panel, the side facing the sun. There will also be a additional reductions for clouds and other atmosphere effects and dirt on the panels. And we also know that we will need access roads and other support structures as well as maintenance.  So we have 5,585,206 km^-2 of PV panels generating power and we end up getting 1,392,491 TWh of power as the theoretical maximum if all these assumptions hold true and although it’s true that that is a lot of power it is only about 35.9% more then required by mid century. Not much room for additional growth and not even enough if the growth in population is more to the high side then the low side of the UN projections. The population growth is discussed later.

Clearly a massive switch to Solar PV cannot solve the issue of world energy needs, as the land area available is just not there.  By 2060 to 2070 that 35.9% reserve will be gone. Putting it into perspective if the entire land area of the United States were covered in solar PV panels, which is not possible, it would only generate about two thirds of the required power of the planet by mid century. Is using up this much land for this purpose something that we really want to do?  Keep in mind that these installations are going to be placed on good land not mountain tops.

Then there is one other factor that has not been considered about installing global scale solar PV power systems.  Solar PV panels are back and are designed to absorb energy.  At a global scale this will change the albedo of the planet to something less then it is now.  That will change the thermodynamic balance of the planet and possibly raise the temperature more then that feared for by the increasing CO₂ levels — unintended consequences lurk behind every decision that we make.

Baring a major break through in developing fusion power there is only one real alternative for sustainable energy that can match the population growth without a corresponding reduction in the standard of living.  So let’s assume that the goal is to bring everyone in the world up to at minimum the “present” standard of living of America.  In round numbers we Americans used about 100 Quad of energy before the 2008 financial collapse and there were about 300,000,000 people.  So we can say that we will need .333 Quad per 1,000,000 people.

By mid century it’s estimated that there will be between 7.5 and 10.5 Billion people on the planet according to UN projections.  However that low end appears to be unrealistic since we are or almost at 7.0 Billon right now.  So lets use 9.5 Billion people and that would translate into 3,166 Quad worth of energy verses the 3,485 previously calculated. So the previous 5% assumed growth rate in energy is not far off if we want to raise the standard of living of everyone.  However that does also imply that our American standard of living cannot increase or we would need more energy.

Baring some major breakthrough the method being described here reaches a maximum amount of energy possible, from solar PV, by mid century plus or minus a few years so from that point on we must either get rid of people or lower the standard of living.  Either way that creates haves and have nots and that is not a good idea.  There would also be a very large cost as 11.2 million square km^-2 of solar PV panels would cost $462.5 Trillion to produce and install at $41.41 per mWh, which is only 10% per mWh of the actual cost of the Sarnia project.  That is a huge reduction which is probably not achievable when the raw resources to make this happen are considered.

Is there another way?  Yes there is we could put the PV panels in orbit around the Earth where the sun shines 24/7 and there is no loss of energy in the atmosphere. The same amount of power could be generated with an array only 250 by 250 miles and at $122.41 per mWh (three times that on the surface), it would probably cost under $52 Trillion to install. NASA studied this concept back in the ‘70’s when oil was still cheap and solar PV panels were a lot more expensive then they are today. Orbital PV power was assumed to not be feasible as it was assumed that we would be using nuclear (fission) power by now.  The point to this is that a lot of the conceptual groundwork has already been done.  All it needs is to be dusted off and updated.  Although there would be some land use required on the surface of the planet for receiving the power it would only be a fraction of that required with the panels on the surface. Back then in was microwaves now lasers could be used. So less money and a lot less land — and more importantly this is very scalable.

The last thing we need to consider is that solar panels lose capacity at a rate of about 1% per year.  At that rate panels need to be replaced at about 25 years of life or when they reach 75% of their original capacity.  Using that number and the goal of having an objective of generating the maximum amount that we can from solar by mid century plus or minus a few years we find that if they are on the ground we need to get to a sustained production rate of 340,000 km^-2 per year and then stay at that rate forever.  This will cost about $14.1 Trillion per year and will maintain above 1,024,529.6 TWh of power. Using the same assumptions but using power satellites we can get the same amount of power from 13,000 km^-2 of panels costing $1.7 Trillion per year to maintain.  Either of these options will take care of about 85% of the world’s power, some things like planes, boats and other heavy equipment will still have the need for carbon based fuels.

Whether these capabilities or time frames are actually achievable or not this project would certainly put a lot of people to work and focus our attentions on something other then trying to redistribute the existing resources of the planet to no real long range benefit to all the citizens of the planet.  With our current policies we end up fighting over a smaller and smaller pot of energy and available land.  America is the technological leader in the world — we are the ones that need to think this way or the Facebook and Tweeter users will not have the electricity to run their phones and laptops.