Using Energy Demand Management to increase uptake of wind power

Wind Farm_2Image by Mancio7B9 via FlickrI read an article this morning on which was makes the case for using more accurate weather forecasting to prevent blackouts and reduce pollution. Nothing wrong with this idea per se, but forecasting alone won’t go nearly far enough to solve instability problems introduced by increasing the amount of wind energy into a grid.

Ireland’s National Control Centre already makes extensive use of weather information and currently we generate, on average 6.5% of our power requirements from wind. However at 3am on a summer’s morning, with a 40mph wind blowing over the country, that can rise to almost 50% (demand at that time is typically 1.8GW and supply from the 40mph wind is around 0.9GW).

The Irish government has committed to raising the amount of power generated by wind to an average of 33% by 2025. When that happens on a similar summer’s morning at 3am with the increased number of wind farms deployed, lets say demand across the country has doubled to 3.6GW the supply from wind will be 6.3GW – that’s 2.7GW excess over demand! No amount of forecasting, however accurate, will fix that.

And no, you can’t shut down the wind farms because if there were any possibility of that, the banks would run a mile from financing them and you would never achieve your 33%.

Conversely the current peak demand in Ireland comes in around 5GW and if this grows to 10GW by 2025 this means Ireland could potentially need to invest in building installed generation capacity of 10GW from non-wind sources to cope with calm days.

So what do you do? Well, if you can’t control the supply, you have to control the demand. To do that you use Energy Demand Management (EDM). In other words you let the market set the price for electricity in real-time based on actual supply and demand. You publish the pricing in real-time using web services and demand will react accordingly.

When there is a shortage of electricity (on calm winter evenings when everyone has their Christmas lights on, for example) electricity pricing will spike. At this time, organisations with diesel generators or gas turbines, if notified of the increase in price will switch to their own generation if it is cheaper. This will take their demand out of the equation and there is the possibility of their selling any excess generation back into the grid helping to further alleviate the problem – a win-win.

In a domestic situation, smart meters capable of taking pricing information from the grid and controlling devices around the house accordingly, may decide to increase the temperature setting on the fridge by a degree or two, reduce the temperature on the central heating or immersion a degree or two, pause dishwashers or dryers until electricity is cheaper – all easily configurable by the house owner obviously.

In the situation where there is an excess of supply over demand, electricity pricing will go negative. In other words, in cases of a significant oversupply of energy (remember the 2.7GW example above?) we will be paid to consume power! Refrigeration plants can drop the settings on their thermostats, ice bank air conditioners can start cranking out the ice, swimming pools can turn up the heat and it may even be economical to start making hydrogen to store (and burn later as a clean energy source when the price increases again).

And, in the domestic situation, smart appliances can start up, thermostats can adjust to suck in power and plug-in hybrid vehicles can start to act as a national distributed energy store.

In 2007 the cost of electricity generation in Ireland varied from 6c per kWh to over 1€ per kWh. This variation in costs was never passed on to the consumer. Had it been I suspect we would have seen remarkably different patterns of usage.

If supply and demand are brought more into synch using demand side management, the instabilities normally associated with increased wind energy on the grid automatically become significantly more manageable thereby allowing for a far higher penetration of wind energy into the market.


  1. says

    While these are fine ideas and have some potential of helping, the answer is already in place and all you have to do is to get the regulations to STOP preventing the solution.

    For example in your situation above, one need only look at the economics of a newsprint mill. The pulp is generated by some power hungary devices called TMP or Thermo Mechanical Pulping. If you have excess energy at night, you simply turn on the TMP and store the pulp in large chests but keep the machine running at constant speed. This requires that the TMP capacity be larger than the machine capacity but that is usually the case.

    There are many other similar examples where users can adjust scheduling of energy demanding products at the right time, shifting the balance between power consumed and steam consumed by running heavy grades of paper, or (longer term) but crude oils that take more or less energy at the right times of the year.

    Raw material selection is critical – scrap steel/aluminium/glass are must less energy than virgin material, etc.

    The issues then is not energy or the willingness of these users to help, the problem is that providing an energy storage service is called ancillary services and not permitted by regulations. Sending surplus power back to the grid at the CURRENT wholesale price (the only way to pay out resources that can be be brought on line at the pleasure of the owner) in order to do AGC (Automatic Grid Control) or peak shaving or ?? will not happen today because the retail user (who owns this resources) is not paid fairly for storage services, reserve services, and the other kinds of power you need, only the lowest form of power – net metering.

    We do not need more regulations, we need to rethink the regulations that we have that were built on the wrong model.

  2. Eric Hagedorn says

    An alternative to your solution would be to use a form of “pumped storage” of wind power by siphoning off excess electricity to run air compressors to store energy in the form of compressed air.

    When excess generating capacity is needed, you simply run the compressed air through a turbine to generate extra electricity.

    Compressed aiur can be stored for years without losing its pressure and is relatively cheap and environmentally friendly to store.

  3. says

    Hi Tom,

    Consise and precise as usual.

    I agree fully with Pats comments but I think he would be surprised as how much of this is happening for industrial users. Tom, you know that the price of electricity paid by CIX Ltd. varies from 6 cent to 21 cent. The fun will come over the next few years as domestic consumers will inevitably be pushed onto realtime pricing tariffs.

    Unfortunately electricity storage is not as easy as Eric thinks. There are a few compressed air storage plants in the world but they depend on having a large airtight cavern and are not a possibility for Ireland as we don’t have a suitable mine. The technology is called Compressed Air Energy Storage (CAES) and is not used by anyone to regenerate electricity directly (except in some data centres) but rather at part of an efficiency improvement in the combustion of Gas. connection.

    The other energy storage technology worth considering is pumped hydro. We already have a 300MW x 8hour facility in Turlough Hill. Dr. Eamon McKeogh in the environmental engineering department at UCC has been studying this for a long number of years. At the EirGrid customer conference in November 2007, a cost and carbon analysis for many grid stabilisation strategies, including pumped hydro, was presented and pumped hydro came out with a very low rating.

    Energy demand management based on realtime pricing is coming and very few people understand what this really means. The price of electricity will be a realtime commodity and we will all be able to buy and sell it when we chose based on the current price. This is an alien concept to most people. Its closer to eBay than to the way we currently think about buying electricity.

  4. says

    Unfortunately we’re still a long way behind in the UK (like with most environmental issues): the man from EDF came to change my meter the other day, because the night-tariff wasn’t working (turns out it was removed by the electrician who rewired my place, another proof he wasn’t good but I still got the part P certificate from his mate, says a lot about self-certification).

    Anyway, the point is that the man said having a dual tariff is often more expensive. I said I’d look into it but since my meter has 2 dials, I could do both. But as usual, it’s not simple: they would need to change the meter again to go back to single tariff (too complicated to add up 2 readings?).

    Bottom line:
    – Smart meters are still a long way in the UK (like reading through power lines, GSM chips or RFID + truck in the street). In many countries, all new builds have meters that can be accessed from the outside)…

    – It already takes a pHD to work out your better tariff, I wonder what consumer adoption is going to be -UNLESS, it’s fully automated. We’re a long long way of linking appliances to the meter to my mind….

  5. Uncle B says

    Once the American military release the final details of their Depleted Uranium batteries, small electric cars will become hugely popular and any excess power you have will be quickly absorbed to power them. The Americans plan on using their desert areas to produce electricity once the price of oil justifies the costs involved, so expect technological breakthroughs and mass produced equipment for this purpose to hit the world markets soon. These controls will be adaptable to windpower situations and much reduce the cost of development for any system, including small hydro-electric ones.

  6. leif says

    all sounds good but we should try and get people to recycle first . it hurts there pockets and they still pay

    200% increase in fuel for cars and do we drive less no

    if demand sit management will work will i only be able to wash my close when its wind e

    sounds like a few things are missing fortcating of wind is a bit variable at present