Starting tomorrow, the world’s first power plant generating power from salt water will be opened at Tofte in Norway.

Back in May, I did a little roundup of various ways to get power from water. One of the more experimental technologies I mentioned was salt power – or osmotic power, which is the more precise (and slightly more complicated sounding) name for it.

Europe’s largest renewable energy company, Statkraft, has now developed this technology far enough to open their first prototype power plant, with their sights set on building a commercially viable plant within a few year’s time (Statkraft’s press release).

How osmotic power/salt power works

I simplified things in the first paragraph to avoid scaring readers away. There’s a bit more to it than just salt water. Not much, though – the principle isn’t very complicated:

1. Water is pumped into a container, salty ocean water on one side and fresh water on the other side of a membrane.
2. The natural process osmosis pulls the freshwater through the membrane. Since the membrane only allows water to flow in this one direction, pressure builds on the salt water side.
3. The built-up pressure is used to power a turbine, thereby generating power.

This kind of power plant could be built anywhere fresh water flows into salt water, typically where a river flows into an ocean. Statkraft has calculated that the worldwide potential of osmotic power is somewhere between 1600 and 1700 TWh, roughly equivalent to 50 percent of the EU’s total production. Not too shabby.

What are the advantages of osmotic power?

So, you might ask, why bother developing this technology? Why develop an entirely new technology, instead of improving existing renewable technologies like, say solar power? Here are the reasons I can think of off the top of my head:

• No huge installations needed
  Osmotic power plants can be built in the basements of existing buildings.
• Virtually no unwanted side effects
  The power generation basically piggybacks on a natural process (ie. the mixing of fresh water and salt water) that would’ve occurred anyway. No birds or fish being killed by turbine blades, no huge dams flooding valleys and so on.
• Continuous power generation
  This is a big one. One of the more difficult aspects of moving to renewable energy is the intermittency of the power generation many of them provide. Solar power needs the sun to shine and wind power needs the wind to blow. Osmotic power just needs the river to not dry out.
• More choice
  No single technology will be a good fit for every situation and context. Solar power is good for deserts, wind power is good for windy areas (well, duh) and osmotic power is good for coastal areas with rivers running into the ocean. The greater the number of options available, the better.

I tried to come up with some disadvantages to osmotic powers, but couldn’t really think of any. Can you think of any? Or are there advantages I’ve missed? Set me straight in the comments

Related posts:

1. Water power and the ways it can be used
2. Solar energy and the ways it can be used
3. Renewable energy sources: What types are there?

A few weeks ago, I argued that it doesn’t matter whether climate change is manmade or not.

This article in the Guardian only reinforced that view.

A whistleblower employee of the International Energy Agency (IEA) is saying that his employer is knowingly exaggerating the size of the world’s total oil reserves, to avoid “angering the Americans” (ie. the US administration) and to prevent panic in the energy market.

In reality, he says (and many of his colleagues agree), the remaining reserves won’t be anywhere near big enough to satisfy the projected future demand.

If the actual, probable future production capacity were announced, apparently everybody and their grandma would go haywire and buy oil like crazy, driving the prices up. So they shut up about it, and oh, I don’t know, hope the whole problem will magically go away, I guess.

Well. Excuse the heck out of me, but that sounds like a crappy strategy to me.

If you’re outside, in sub-zero temperatures and you’re really cold, what do you do? Do you pee your pants and enjoy the short and sweet warmth this produces? Or do you put on extra clothes or perhaps even get out of the cold?

You go for the latter set of options, of course. It requires a bit more effort then and there, and you might have to endure the cold a little longer, but you won’t have to deal with the much worse, long-term consequences of the former choice.

No time like the present

Now, I’m pretty sure the IEA is right that there will be some form of panic if it publicly admits that oil reserves are way lower than previously assumed.

Investors and governments will race to stock up on oil while there’s still some of it left. Oil prices will soar. Poor, oil dependent countries will suffer. People will have to drive less due to increased gas prices. And so on.

This would, of course, mostly suck. But guess what? The problem isn’t going away by itself – magically or otherwise – and the longer we postpone dealing with it, the worse it’ll get.

The choice isn’t between “no oil crisis” and “oil crisis”. It’s between “a tough, but manageable crisis” and “a much worse crisis we might never recover from”.

It’s time for the IEA to grow some backbone and report their actual findings, instead of making up numbers that set everyone up for a bigger fall. Angered US administration be damned.

With all the dawdling, feet-shuffling and political tap-dancing that’s been happening in the run-up to the UN climate change conference in Copenhagen this December, USA and everybody else needs to know about, admit to and deal with reality, not fiction.

Not in 20 years. Not in 10 or 5 years. Not even in one year. Now.

Related posts:

1. Why it doesn’t matter whether climate change is manmade or not

You can help reduce the needed energy production from dirty coal and other non-renewable resources – just by running your dishwasher and other appliances at night.

The demand for electricity is higher in the daytime than at night, particularly during office hours. The increase in demand starts in the morning when people and businesses switch on their lighting and other electricity-consuming devices, and peaks around mid-day.

Power sources largely have to produce electricity close to the time it will be used, since there aren’t really any good solutions for long-term storage of large quantities of electricity.

This means that we have to be able to produce enough electricity simultaneously to satisfy the mid-day peak in demand. The higher the peak, the more power plants we need.

With most countries in the world getting the majority of their electricity from coal, these new power plants will most often be dirty coal-fired ones.

By shifting our electricity use away from the daytime in general and mid-day peak in particular, we might prevent the building of them.

So, if you wash your laundry, start the dishwasher and run any other electricity-consuming appliances and gadgets as late in the evening as possible (or in the nighttime), you’ll do your part in helping prevent the building of new coal power plants.

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1. Renewable energy sources: What types are there?
2. Solar energy and the ways it can be used
3. 6 reasons why you worry too much about the mercury in CFLs

Following up my roundup of renewable energy sources, it’s now time for a look at water power (also called hydropower and hydraulic power) and its main uses.

Please note: Although tidal power and wave power are also forms of water power, I think they’re interesting enough to merit their own posts later. In this post, I’ll focus on other ways to generate useful power from water.

The most used renewable energy source

Water power is, by far, the renewable energy source that is the most used in the world. At the end of 2006, around 60% of the world’s renewable energy was generated by hydropower. This number combines both small and large scale installations.

A few countries even get the majority of their electricity generated by water power, with the top three being Venezuela (about 67%), Brazil (about 85%) and Norway (about 98%).

Using water power

Roughly speaking, water power can be utilized in the following ways:

• By using the movement of flowing or falling water to drive or move something.
• By exploiting the salt concentration difference between river and ocean water.
• By exploiting the temperature differences between shallow and deep waters.

Flowing or falling water/Hydroelectricity

This is the most common way to tap into water power. A waterwheel or turbine is placed in the water stream. The water’s motion turns the waterwheel or turbine, producing some kind of useful movement or conversion to electricity. Some examples of this are:

• Waterwheels powering mechanical machinery (in an old-fashioned flour mill, sawmill, factory or similar).
• Water stored in a dam, being let out in a concentrated flow to drive a turbine that generates electricity.
• Water being forced to form vortices by obstacles in rivers. The vortices drive turbines that generates electricity.

Salt concentration difference/
Osmotic power

Several techniques for utilizing the salt concentration difference between river and ocean water to generate electricity, but the most common one is so-called “pressure-retarded osmosis”.

That sounds terribly complicated, but the principle is relatively simple: Salty ocean water and freshwater are pumped into a tank. Separating these two types of water is a semi-permeable membrane. As the freshwater is drawn across this membrane, pressure builds in the tank. This pressure is then used to drive a turbine.

Norwegian power company Statkraft has been developing this technology over the past 10 years, and now reckons they could use it to generate about 10% of Norway’s total energy need.

UPDATE: Statkraft has now opened the world’s first osmotic power plant at Tofte in Norway.

Temperature difference

This technology relies on the temperature difference that exists between the surface water and bottom water in the ocean (or other large bodies of water) to generate energy. The cold bottom water and warmer surface water is used to power a heat engine, such as the Sterling engine.

Next up: Wind power

That concludes this summary of water power uses. Being a summary, it merely skims the surface of the existing possibilities. Future posts will look closer at the various technologies and products that are available.

If you think I’ve missed something, or want to comment on anything else, let me know in the comments section below. Next up for a similar look is wind energy and the various ways to harvest it.

Related posts:

1. Solar energy and the ways it can be used
2. World’s first salt power plant opens tomorrow
3. Renewable energy sources: What types are there?

Wired has a fascinating article today:

Using 192 separate lasers and a 400-foot-long series of amplifiers and filters, scientists at Lawrence Livermore’s National Ignition Facility (NIF) hope to create a self-sustaining fusion reaction like the ones in the sun or the explosion of a nuclear bomb – only on a much smaller scale.

In doing this, they hope that this reaction will release more energy than the lasers use, thus providing insight into how fusion reactions work and possibly making a new form of nuclear energy possible.

The main advantage of fusion nuclear energy over fission nuclear energy is that very little radiation is released during fusion – whereas fission is a terribly “dirty” process in that respect.

While the science and technology geek in me is thoroughly fascinated by the lasers, amplifiers and sci-fi overtones of the installation, I can’t help but wonder if all the resources that went into this project couldn’t have been spent in a better way.

The ridiculous amounts of money – not to mention the time and brainpower that’s been spent on the construction of this somewhat megalomaniacal undertaking, could have made some real headway in other areas.

Such as renewable technologies that has been proven scientifically and practically to work, and really just need improvements to cost efficiency and a big push to get widely implemented.

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1. Repair stuff, save both kinds of green
2. Water power and the ways it can be used
3. World’s first salt power plant opens tomorrow

Last week, in my roundup of renewable energy sources, I promised to give each source a closer look in future posts. Let’s start off with the Sun and its abundance of solar energy.

As noted in my previous roundup, the Sun radiates almost inconceivable amounts of energy in our direction. If we could utilize even just a small percentage of this solar energy, we could leave all our lights on, never turn any appliance off and generally just splurge on electricity non stop – and still have vast amounts of energy left over.

Realistically, of course, we can’t really utilize every last bit of solar energy. Space requirements and other limitations restrict how much is practically available to us. One thing is for sure, though: there’s certainly enough potential to make solar energy one of the biggest contributors to world energy production.

The Sun is the source of (almost) everything

The focus of this post is on the direct utilization of solar energy. It’s worth noting that the Sun is lurking around in the background of many other renewable energy sources, indirectly driving them:

• Through the water cycle, the Sun drives the processes that make hydroelectricity possible.
• The Sun’s heating of air causes pressure changes in the Earth’s atmosphere. These pressure changes cause air to rush from high pressure areas to low pressure areas, resulting in the wind that makes wind power possible.
• The wind created by the Sun’s heat blows across ocean surfaces, creating the waves that make wave power possible.
• The plants and organic material used for biomass can’t grow without sunlight. Consequently, the Sun is an indirect source of the energy we get from biofuels and biomass.

Using solar energy

Roughly speaking, solar energy can be utilized in two ways:

• The Sun’s heat can heat something
• The Sun’s light can cause an electric reaction

Each of these two main ways come in more than one shape or form.

Solar heating

The most obvious way to take advantage of the Sun’s heat is by directly heating a space, object or liquid. A few examples:

• Heating a room by letting the Sun shine through a window
• Cooking with a solar oven
• Heating the water in a swimming pool

The heat of the Sun is also useful in more indirect ways:

• Heating a liquid in a solar collector used for heating water
• Superheating water into pressurized steam, and then using the steam for generating electricity
• Vaporizing and condensing water in a solar still, to purify and desalinate it
• Powering an engine through heat differences, for example a Stirling engine

Electric reactions to sunlight

While perhaps sounding a bit complicated, most of you will be familiar with at least the first one of these:

• Generating electricity through the use of photovoltaic cells – this is what most people think of as solar cells
• Generating electricity through the use of photochemical cells – currently an experimental technology

Water is next

That’s the end of this summary of solar energy uses. Since it is precisely that – a summary – it merely skims the surface of the existing possibilities. Future posts will look closer at the various technologies and products that are available.

If you think I’ve missed something, or want to comment anything else, let me know in the comments section below.

Next week, I’ll have a similar look at how the energy in flowing or falling water might be put to use. Stay tuned!

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1. Water power and the ways it can be used
2. Renewable energy sources: What types are there?
3. Book review: Solar energy projects for the evil genius

There are many sources of environmentally friendly, renewable energy. This post is a brief roundup covering most of them. I’ll cover each one and their general uses in more detail in other posts, linking to them from this post in the process. Feel free to leave a comment if you think I forgot one!

The Sun/Solar energy

If you ask someone to name examples of environmentally friendly and renewable energy sources, the Sun will probably come up pretty quickly. And for good reason: the Sun radiates enormous amounts of energy in our direction. In one year, the Earth’s oceans, land masses and atmosphere absorbs somewhere around 3.850.000 exajoules of solar energy. To put that ridiculously large number into perspective; in one hour, the Sun delivers more energy to us than the whole world used in the whole year of 2002. Another equally dazzling perspective: The energy delivered by the Sun in one year is about twice as much as the Earth’s stored non-renewable resources combined. That’s right; if we spend every last bit of oil, coal, natural gas and mined uranium we can squeeze out of the planet, we’ll get the energy equivalent of about half a year’s radiation from the Sun. You’ll find more about solar energy in Solar energy uses.

Flowing or falling water/Hydroelectricity

Water is another source that would feature in one of the top spots of a list of renewable energy sources. In fact, if widespread use were the main criterion, it would feature very high indeed – hydroelectricity is one of the most widely used forms of renewable energy. More than half of the world’s energy production from renewable sources in 2005 was from hydroelectricity. It could be argued that the source of the power we can harvest from flowing or falling water is actually the Sun – since the Sun drives the water cycle. In fact, the same could be said about almost any energy source, since they can all ultimately be traced back to the Sun – except for tidal power and some types of geothermal power. I’m going to ignore this for the purposes of this post, though. A List Of Three Does Not A Decent Roundup Make, after all. You’ll find more about water power in Water power uses

Wind/Wind power

Wind is the third source that is likely to be mentioned quickly if you ask someone to list a few sources of renewable energy. Although only about 1.5% of worldwide electricity use in 2008 was from wind power, it’s growing at a healthy pace. Between 2005 and 2008, the worldwide percentage doubled. The potential of wind power is high compared to the world’s total consumption. While the numbers aren’t quite as spectacular as with solar energy, they still reach respectable heights: the Earth’s total commercially viable wind power resources has been estimated to 72 terawatts. That’s almost five times as much as the 15 terawatts that was the average global consumption from all sources in 2005.

Waves/Wave power

The near-constant undulations of ocean waves holds a great deal of energy. The problem so far has been harvesting that power in a reliable and economical way. While many experimental techniques have been tested since the end of the 17th century, the first commercial wave power plants have only begun appearing the last few years – consequently the amount of energy generated from wave power at the moment is close to negligible.

Tides/Tidal power

Water streaming in and out of straits and other narrow necks of water during tides can be used to generate energy. Few commercial scale facilities exist, although the field is the subject of extensive research and show great promise as the technology developed becomes sturdier. Tidal power is far more dependable than solar power and wind energy. After all, tides are the result of the Earth’s position relative to the Sun and the Moon, which follows a predictable cycle. This eliminates a common disadvantage of renewable energy sources  – intermittency – making it easier to plan for a dependable energy supply.

Geothermal

The Earth itself holds a lot of energy, stored as heat. This heat has several origins: solar energy absorbed by the Earth’s surface, radioactive mineral decay and the original formation of the planet. Regardless of origins, this heat can be used for several purposes, the main ones being the heating of spaces and water and energy generation. For energy generation, about 10 gigawatts of capacity were installed worldwide as of 2007 – about 0.3% of the world’s electricity demand. For heating and other uses, about 28 additional gigawatts were installed.

Biofuels and biomass

While technically two different things, I’ll lump these two together in one brief definition: biological material and/or waste that in some way or another can be converted to something we can burn to produce energy. This includes – among others – manure, garden waste, chips from forestry and crop stalks. While burning biofuels and biomass releases carbon dioxide and other greenhouse gases to the atmosphere, these are gases that were already bound by the biological processes that produced them. Therefore, their production are considered carbon neutral.

That concludes my roundup of renewable energy sources – I can’t think of any more. If you can, let me know in the comments!

Related posts:

1. Solar energy and the ways it can be used
2. Water power and the ways it can be used
3. World’s first salt power plant opens tomorrow