Enbala Blog

A Better Way

Posted by Malcolm Metcalfe on Oct 26, 2017 9:03:00 AM
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I read Milton Caplan's post entitled "An Inconvenient Reality: Nuclear Power is Needed to Achieve Climate Goals." I can certainly support much of the article, but it seems to miss one very key point and that is the need.

Science has told us that we need to reduce carbon emissions. The trouble starts when the political masters translated that to mean that we need to fully get rid of fossil fuels and switch entirely to renewables – and while at it, we need to get rid of nuclear as well. I wonder where that latter part came from? Nuclear is clean. Why was it lumped in with fossil fuel? Much of the opposition was based on past fears. The movie Pandora’s Promise shows how many of the opponents have, after a careful look, reversed their views..

 


Nuclear, solar and wind energyOne of the comments points out that there are the people that love to compare capacity with energy – and they come to some conclusions that are just plain wrong. In 2016, fossil fuel provided more than 80% of the total energy in the US, and renewables were much less than 10%, depending on how one counted large hydro. Some of these opponents consider that large-scale hydro is not renewable.  

We are going to need all the clean energy that we can get. Electricity, which appears destined to be the dominant means of delivering energy to users, is currently providing less than 20% of the total energy delivered to customers and more than 80% of that electricity is generated with fossil fuels. On that basis, renewables are providing less than 2% of the total energy needed, and the thought that we can increase that to 100% in a relatively short time seems a little unlikely.

Storage is another issue. I am convinced that storage will play a huge role in our future. But to most people, storage means batteries. There is no doubt that batteries will have a role, but they are far from being the only source of storage in the electric grid. Safety problems appear to be causing real problems for vendors of some types of batteries. The New York Fire Department apparently has not approved the use of Lithium Ion batteries, and airlines will not allow devices containing these batteries in checked luggage. This issue will need to be addressed, or eliminated,

Storage is a system that will move the time of use (or generation) of energy in the grid. Three types of storage are common, but one seems to get all the attention. Ironically, it is the most expensive, and potentially the least efficient of the three. It is, of course, battery storage.

Generating stations have been able to store fuel for many years. Our hydro systems often have storage dams that capture a part of the spring runoff and discharge it for generation or flood control during low water periods. This has been cost effective, and it has been well used for many years.

At the same time, load based storage is gaining ground in use at present. PJM released data in a speech by Terry Boston, its former CEO, explaining that electric domestic hot water tanks had large capability for storage of energy. Pulp and paper mills on our coasts have successfully stored energy with large wood chipping machines. The mill needs a constant supply, and by installing a slightly larger chipper, a future supply of chips can be stored for use, allowing the chipper to shut down during peak electrical demand periods. This shifts energy use into off peak periods – without impairing the operation of the mill.

Fuel and load-based storage require no conversions for use. They store the feedstock in a form in which it will be used. They simply allow the flexibility to move the time in which the energy is needed. Additionally, the cost of the equipment needed is largely paid for by the application that needs the output. The cost to the grid may be very small.

Battery systems, on the other hand, require a conversion from AC – to – DC followed by a conversion from electrical energy into a form of chemical energy. The reverse takes place when the storage is returned.

Batteries are going to play an important role, in particular where the storage is mobile as it is in EVs. But stationary grid storage may allow the use of other methods that are cheaper and potentially more efficient.

And then there are other services, provided by conventional generation, that are not provided in the amounts needed by renewables such as wind and solar. Inertia is one that is rarely mentioned, but is essential in grids that have even one large steam turbine generator. The best source of inertia is nuclear generation, because the weight of the rotating equipment is large, and the speed of rotation (1,800 or 3,600 RPM) is high. The Inertia (H constant) increases linearly with the mass of the equipment, and with the square of the speed of rotation.

It is time to put some real thought into this. We will need several key initiatives…

  1. Conserve electricity at the user level – this has already been done to a large extent with more efficient motors, VFDs and new lighting systems.
  2. Improve the overall efficiency of the grid – currently 30-35% driven largely by the steam cycle. Reduce delivery losses by reducing the flows of reactive power and smoothing the flows through either distributed generation, load management or storage. A focus on distributed generation that delivers power near the sites where it is used will also contribute.
  3. Prioritize the sources and uses of energy that are available and compare the needs with the supply. Coal with its very high emissions/GJ is probably a good place to have started. EVs seem to be supported by many, as their efficiency is about three times higher than a fossil fuel powered vehicle. But to fairly compare, the efficiency of the energy delivery to the vehicle must be considered. An EV charged with a local wind turbine or solar panel will be far more efficient than a conventional car, but if the source is a remote coal-fired generating station, the overall efficiency will be the same or less than the fuel powered vehicle.

Clearly this is a complex problem that needs many good minds. Like Al Gore, I am gaining some optimism, because people seem to want action – from the bottom – despite negative comments from the top.



CONCLUSION:

Last winter, many of us watched people in rural Ontario faced with a choice – buy food or pay for electricity – there was not enough money to do both. We cannot risk being in that state on a broad scale.

We need a careful and thoughtful examination of where this is going. My crude calculations suggest that we will need all the solar and wind that we can get. We will also need nuclear, hydro and perhaps other sources as well. We also need to conserve and take large steps to be more efficient, both in the grid operation and in the applications that use the electrical energy.

This is not a fight of nuclear vs wind or other comparison. We need to focus on our energy needs and options to deliver with low or zero emissions. Even natural gas may be needed, capturing some of the excellent energy efficiency levels that have been achieved.  We must find ways to meet a reduced need with what we can get – at an acceptable cost. That is not going to be easy.


 

Topics: Nuclear energy,, wind energy, Solar energy, energy balance, distributed energy

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