Wind Power Kicks Fossil Power Butt

What if you ran the numbers for wind power replacing all fossil fuel and nuclear electricity in Canada? How could it work? How much would it cost?

WHO:  L.D. Danny Harvey, Department of Geography, University of Toronto, Canada

WHAT: Mapping and calculating the potential for wind electricity to completely replace fossil fuel and nuclear electricity in Canada

WHEN: February 1st, 2013

WHERE: Energy Vol. 50, 1 February 2013

TITLE: The potential of wind energy to largely displace existing Canadian fossil fuel and nuclear electricity generation (subs req.)

As a kid, I really loved the TV series Captain Planet. I used to play it in the school yard with my friends and I always wanted to be the one with the wind power. Mostly because my favourite colour is blue, but also because I thought the girl with the wind power was tough.

Go Planet! Combining the power of wind, water, earth, fire and heart (Wikimedia commons)

Go Planet! Combining the power of wind, water, earth, fire and heart (Wikimedia commons)

What’s my childhood got to do with this scientific paper? Well, what if you looked at the Canadian Wind Energy Atlas and worked out whether we could harness the power of wind in Canada to replace ALL fossil fuel and nuclear electricity? How would you do it? How much would it cost? That’s what this researcher set out to discover (in the only paper I’ve written about yet that has a single author!)

Refreshingly, the introduction to the paper has what I like to call real talk about climate change. He points out that the last time global average temperatures increased by 1oC, sea levels were 6.6 – 9.4m higher, which means ‘clearly, large and rapid reductions in emissions of CO2 and other greenhouse gases are required on a worldwide basis’.

Of global greenhouse gas emissions electricity counts for about 25%, and while there have been studies in the US and Europe looking at the spacing of wind farms to reduce variability for large scale electricity generation, no-one has looked at Canada yet.

So how does Canada stack up? Really well. In fact, the paper found that Canada has equivalent wind energy available for many times the current demand for electricity!

The researcher looked at onshore wind and offshore wind for 30m, 50m and 80m above the ground for each season to calculate the average wind speed and power generation.  Taking into account the wake effect of other turbines and eliminating areas that can’t have wind farms like cities, mountains above 1,600m elevation (to avoid wind farms on the Rocky Mountains), shorelines (to avoid wind farms on your beach) and wetlands, the paper took the Wind Energy Atlas and broke the map into cells.

For calculating your wind farm potential there are generally three options; you can maximise the electricity production, maximise the capacity factor, or minimise the cost of the electricity. The paper looked at all three options and found that the best overall option (which gives you a better average cost in some cases) was to aim for maximum capacity.

Using wind data and electricity demand data from 2007, the researcher ran the numbers. In 2007, the total capacity of fossil fuel and nuclear electricity was 49.0GW (Gigawatts), or 249.8TWh (Terrawatt hours) of generation. This is 40% of the total national electricity capacity for Canada of 123.9GW or 616.3TWh generation.

To deal with the issue of wind power being intermittent, the paper noted that there’s already the storage capacity for several years electricity through hydro in Quebec and Manitoba, as well as many other options for supply-demand mismatches (which this paper doesn’t address) making a national wind electricity grid feasible.

To run the numbers, the country was split into 5 sectors and starting with the sector with the greatest wind energy potential, the numbers were run until a combination was found where the wind energy in each sector met the national fossil fuel and nuclear requirements.

Wind farms required in each sector to provide enough electricity to completely replace the fossil fuel and nuclear power used in 2007 (from paper)

Wind farms required in each sector to provide enough electricity to completely replace the fossil fuel and nuclear power used in 2007 (from paper)

Once the researcher worked out that you could power the whole country’s fossil fuel and nuclear electricity with the wind energy from any sector, he looked at minimising costs and meeting the demand required for each province.

He looked at what size of wind farm would be needed, and then calculated the costs for infrastructure (building the turbines) as well as transmission (getting the electricity from the farm to the demand). Some offshore wind in BC, Hudson Bay, and Newfoundland and Labrador, combined with some onshore wind in the prairies and Quebec and that’s all we need.

The cost recovery for the investment on the infrastructure was calculated for 20 years for the turbines and 40 years for the transmission lines. The paper found that minimising transmission line distance resulted in the largest waste generation in winter, but smallest waste in the summer, however overall, the best method was to aim for maximising the capacity factor for the wind farms.

But the important question – how much would your power cost? On average, 5-7 cents per kWh (kilowatt hour), which is on par with the 7c/kWh that BC Hydro currently charges in Vancouver. Extra bonus – wind power comes without needing to mine coal or store radioactive nuclear waste for millions of years!

Estimated wind power costs for Canada (from paper)

Estimated wind power costs for Canada (from paper)

Some more food for thought – the researcher noted that the estimated cost for coal fired electricity with (still unproven) carbon capture and storage technology is likely to be around 9c/kWh, while the current cost for nuclear generated electricity is between 10-23c/kWh. Also, the technical capacity factor for turbines is likely to increase as the technology rapidly improves, which will reduce the cost of producing wind electricity all over again.

This is all great news – Canada has the wind energy and the potential to build a new industry to not only wean ourselves off the fossil fuels that are damaging and destabilising our atmosphere, but to export that knowledge as well. We can be an energy superpower for 21st Century fuels, not fossil fuels. I say let’s do it!

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How Does Your Wind Farm Grow?

Calculating what the global saturation point for wind energy would be and if we can generate enough wind power to power half the globe.

WHO: Mark Z. Jacobson (Department of Civil and Environmental Engineering, Stanford University, Stanford, CA)
Cristina L. Archer (College of Earth, Ocean, and Environment, University of Delaware, Newark, DE)

WHAT: Predicting the effectiveness of scaling up wind power to provide half the world’s power requirements by 2030.

WHEN:  September 25 2012 PNAS, Vol 109, No. 39

WHERE: Proceedings of the National Academy of Sciences of the United States of America

TITLE: Saturation wind power potential and its implications for wind energy

I learnt about a new law today; Betz’s Law. Betz was a guy who decided to calculate exactly how much energy could be extracted from the wind by a turbine at any given time mathematically (as you do). He worked out that no turbine can take any more than 59.3% of the energy from the wind. To be able to conceptualise this, you have to think about wind like a physicist. The first law of thermodynamics states that you can’t create or destroy energy; you can only convert it to different forms. Therefore, all wind is just energy in a certain form, and in any system there is a point where the transformation is most efficient and beyond there it takes a lot of effort to get any more energy from the system.

There’s a really cool project being done in the US, where a website has taken data from the National Digital Forecast Database and created a visual representation of what wind would look like if you could see it move. It’s strikingly beautiful, and looks a lot like a Van Gogh painting.

Wind Map by Fernanda Viegas and Martin Wattenberg of hint.fm

The question this paper looks at is: since there is a limit to the amount of energy you can take from a turbine, what is the maximum wind power that can be extracted from a geographical area? They called it the ‘Saturation Wind Power Potential’.

They came up with some interesting findings, as well as probably having a lot of fun along the way because they used 3D Models to do it (I’m telling you, my chemistry molecular model kit was much more like playing with Lego than actual ‘science’). They got into the detail and calculated the potential wind power at 10m off the ground, 100m off the ground (the standard height of a wind turbine) and 10km off the ground in the jet stream.

They then looked at whether it would be possible to scale up wind power globally to meet 50% of the world’s power needs by 2030. Actually measuring the wind power potential for more than 1 Terrawatt (TW) of energy is not possible as there isn’t enough wind power installed yet. But they did mathematically work out that we would need 4million 5 Megawatt (MW) turbines to supply half of the world’s electricity needs in 2030 (5.75TW).

They did four simulations with different turbine densities, because how close together wind turbines are affects their ability to produce power. Put them too close together and they start stealing their neighbour’s wind power. Overall, up to 715TW, the increased number of turbines increases the amount of power in a linear straight line. Once you get above that it slows down and flattens out – once again you need to put much more effort in to get power out.

Predicted wind power saturation potential (from paper)
Grey line – global wind power potential, black line – wind power potential on land only

The saturation point, where no matter how many more turbines you add, they’ll just be stealing energy from each other and not adding anything to the total, was 2,870TW of power globally. Interestingly, they found the wind power available in the jet stream (10km above the ground) was 150% greater than the wind power available 100m above the ground.

There were also some big changes to the results depending on the density. If we placed 4million 5MW turbines and packed them in at 11.3 Watts per m2 (W/m2), they would be too close together and the collected power wouldn’t match the target for half the world’s power by 2030. If you spread them out to 5.6W/m2 the output is still too low. However, once you’ve got them spaced at 2.9W/m2, they produce enough power to meet the required demand.

4million turbines meet demand when they’re 2.9W/m2 apart or further (from paper)

So it turns out wind turbines don’t like it when you cramp their style. But, you can pack them in a bit tighter, only if you then have enough space between your wind farm and your neighbour’s wind farm. It’s a bit like playing wind farm Tetris.

What does this mean though? It means that we can ramp up world wind power production to levels that will meet half our power needs in 2030, which can be integrated with hydro, solar and other renewables with smart grids to power our cities and lifestyles without burning fossil fuels. But it also means we need to think about where we are putting wind farms and how much space they need to be as efficient as possible. We need that renewable energy, so we can’t cramp the wind turbines’ style!