Tag: wind energy

Technology is moving us to a world where energy is cheaper, smarter, and less carbon intensive

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The graph above is a graph of electricity demand on the Spanish electricity grid taken from the demand page of the grid management company Red Electrica de España.

The data comes from April 26th this year through to Mar 3rd. The sever small graphs along the bottom are daily demand curves, going from Tuesday April 26th on the left, through to Monday May 3rd on the right. You can see that the demand curves for each day are virtually the same.

Saturday and Sunday are however, obvious due to the lower demand on those days, and if you are wondering why Monday the 3rd looks to be lower than the rest of the weekdays, it is because that Monday was a holiday in Spain.

The large graph on top is a zoomed-in look at the demand on one of those days – Friday April 29th. From that you can see that the demand starts to rise early in the morning with the peak occurring between 8-11am. Demand then falls off until late afternoon when people are cooking their evening meals, peaking around 9pm, and then falling until it starts again the following day.

The pattern varies slightly by day of the week, as well as by season, but overall while it is variable, it is also highly predictable.

Graph of predicted energy demand vs actual demand on Spanish grid on April 29th
Graph of predicted energy demand (Green) vs actual demand (yellow) on Spanish grid on April 29th this year – graph from REE

This can be problematic though when you have high penetrations of variable energy suppliers, such as wind and solar.

Here is the energy supplied to the system by wind, for example on April 29th

Energy supplied by wind on the Spanish grid on April 29th this year
Wind energy on the 29th of April on the Spanish grid

As you can see, it doesn’t map well with the demand, and this is challenging for grid management companies, especially with increasing pressure on them to decarbonise.

That can lead to circumstances where wind power ends up supplying 140% of your demand, as happened in the Netherlands last summer. Fortunately, the Netherlands has good interconnects, and so was able to sell this excess energy to its neighbouring countries. This won’t always be the case though, and will become a more common issue as the penetration of wind and solar increases globally.

 

Obviously, if you can’t manage the supply side of the grid, what about managing the demand – how achievable is that?

Interestingly, this is now becoming a real possibility. Already there are companies who aggregate the demand of large organisations with facilities for reducing demand, if required, and sell that reduced demand to utility companies. This can save the utility from having to build new generation sources to meet the increased demand at times of peak load.

Demand flexibility graph
Demand flexibility

What if this were more widespread?

Looking at the chart above, if we could shift the yellow demand line up during its overnight dip, and then reduce the yellow demand line during the morning and evening, this would make the grid more stable, and allow for the introduction of more variable generators (solar and wind) onto the system, as well as reducing the requirement for expensive ‘peaker plants’.

Sounds great Tom, how to do that?

Well price is always a great motivator. In Germany last week where there was an excess of energy on the system, so pricing went negative, meaning large customers were being paid to use it.

Negative pricing on the German energy market
Graph of negative pricing on the German electricity market

Reduced, or negative pricing is a better option than wind farm curtailment because curtailment lowers the income for the wind farms, making them a less attractive investment for renewables developers, while reduced pricing moves the demand to a more suitable time.

Now, with the advent of the Internet of Things, everything starts to be smart and connected. If our electricity devices can listen for realtime electricity signals from the grid, they can adjust their consumption accordingly.

Of course, not all loads in the home are movable  – not many people will decide to cook their evening meal at 3am just because the wind is blowing and energy is cheap.

However, many loads are eminently movable. Pool pumps, are a good example. And also many loads that have a heating or cooling component associated with them, such as an electric hot water heater. When it is well insulated it doesn’t matter when it heats the water. Similarly for fridges, freezers, ice bank air conditioning, and so on. These are straightforward and affordable forms of energy storage.

Dish washers, washing machines, clothes dryers can also be made to listen to electricity pricing, and adjust their behaviour accordingly. Often, when you put the dish washer on in the evening, you don’t care when it comes on, as long as the dishes are clean and dry when you get up the following morning.

As more of our appliances become connected and smart, this will become the norm. Obviously, for widespread adoption, this kind of behaviour has to be totally automated. If the device owner has to think about it, it won’t happen.

Smart grid appliance

And then there are the real storage options, using batteries. This can be in the form of batteries in electric vehicles using vehicle-to-grid technologies, in-home batteries such as the ones Tesla, and others sell, or reconditioned electric vehicle batteries – a market that is just starting to get going.

So, good news, technology is moving us inexorably to a world where energy is getting cheaper, smarter, and less carbon intensive.

Using Energy Demand Management to increase wind energy in Ireland

Wind energy currently contributes around 6.5% of the electricity generation in Ireland. The government has committed to increasing this to 33% by 2025.

That is a good thing, right? Well yes, but it brings with it some problems which will have to be addressed before it can become a reality.

In 2006 the minimum demand on the electrical grid was 1.8GW (think 4am on a summer’s morning) and the maximum demand was 5GW (winter’s evening between 5pm and 7pm).

The wind energy output during 2006 varied from 0% (on a calm day) to 0.9GW or just over 45% (think 4am in the middle of a windy night).

Projections are that by 2025 the maximum electrical demand will be 10GW and the minimum will be 3.6GW. The governments plans to increase the wind energy means that the maximum wind energy output will be 6.3GW. If this happens when the country only needs 3.6GW there will be a surplus of 2.7GW.

On the other hand if the maximum demand of 10GW happens on a calm day (not unusual) there will need to be 10GW of generating capacity on the grid.

How do we facilitate this? We can’t control the supply (the wind blows, or it doesn’t!) but we can think about starting to manage the demand.

Imagine if EirGrid, the Energy grid operator, could control the diesel generators of any companies who own them. They could switch them on, thereby reducing the overall demand on the grid at times of electrical supply shortage.

Taken a step further, if EirGrid had control of the thermostats in refrigeration plants or in the hot water tanks of larger companies, they could ratchet them up or down one or two degrees to either consume extra electricity or to reduce demand.

Taken to a logical conclusion, plug-in hybrid cars, smart domestic appliances (fridges, clothes dryers, dish washers, etc.) and central heating could all be used to help stabilise the grid and allow more wind energy come onstream.

No James, we Irish are not complete gobshites

Or if we are, it is not for the reasons James thinks! James Corbett has a post today on his blog asking “Are we Irish complete gobshites?“. The post is lamenting the fact that we are not building wind farms to reduce our dependence on oil imports.

I would answer James in the comment section on his blog but

  1. the answer is complex and
  2. he has deployed a CAPTCHA on his blog which means commenting there is a pain 😛

I have talked about this in several of my talks about reducing ITs carbon footprint.

There are >2gW of outstanding applications for windfarms to come onto the electrical grid in Ireland. To put that in context, we typically use around 4.5gW of power in Ireland (fluctuating day/night and summer/winter, obviously). However, these applications are being held at bay by eirgrid, the grid management company.

Why are they holding these applications at bay? Are they rabidly anti-green? Maybe they are pro climate-change? No, the reason Eirgrid don’t want any more wind power on the grid is because it de-stabilises the network.

Consider the following scenario. It is 2am. Electricity demand across the country is at its lowest. There is a 40mph wind blowing across the country. Wind energy at this point can be supplying up to 30% of the country’s demand.

What happens now if the wind picks up to 50mph? The wind farms shut down to protect their mechanisms and suddenly Eirgrid are left scrambling trying to bring gas turbine stations online to meet the sudden fall-off of 30% of their supply. Gas turbine stations can take up to an hour to reach full generation capacity.

The more windfarms Eirgrid take onto the network, the greater a problem this becomes. Unless there was some kind of ready counter-balance to the instability of wind farms…