National Grid completes acquisition of Geronimo Energy

National Grid has completed its acquisition of this leading wind and solar developer in the US.
Lots of wind turbines offshore

Knowing the past helps us deliver a network for the consumers of the future

The energy sector is going through a revolution and the system of the future will not look like it does today! When considering the future direction of travel, it is often instructive to explore the past.

Nevertheless, when a colleague suggested I investigate how transmission networks have benefited consumers over the last 40 years to write this thought piece, my immediate reaction was ‘why isnt it obvious’, followed quickly by ‘surely the past doesnt matter given the pace of change?

Exploring the question further, I quickly recognised two interesting things; firstly, when we talk about the benefits of transmission at National Grid we often reach for a couple of important points, like our 99.999984%[i] reliability & being 5%[ii] of a typical domestic bill. We tend to assume the rest is obvious. Surprisingly, there’s not much in the public domain giving a comprehensive break down of the benefits and examples from history! Secondly, after trying to do a structuring the benefits I discovered some are core that don’t change into the future, despite the ongoing revolution. Transmission networks have already played an important role in facilitating some of the most significant changes in our energy landscape and are likely to continue doing so into the future.

This is a big topic to explore so I’m going to divide it into two thought pieces. In this first piece, I outline my take on how transmission networks have benefited consumers and give a few examples to make this real. In the second, I will build on this structure as a solid foundation for articulating the future role of transmission, even in the most decentralised of futures.

In this first piece, I outline my take on how transmission networks have benefited consumers and give a few examples to make this real.

– Chris Harris, Senior Strategy Analyst, National Grid

When we surveyed a representative sample of over 2000 consumers, they told us that a reliable energy supply, affordable energy bill and sustainable energy system were their priorities. In my view, there are three ways the transmission network has delivered these priorities:

  1. Connecting large capacity users to the system
  2. Providing bulk transfer of power to meet demand
  3. Providing flexibility for electricity system operation

1. Connecting large capacity users to the system

Without transmission networks, it wouldn’t have been practical to connect nuclear generators, combined cycle gas turbines (CCGTs) or large onshore and offshore windfarms to the system; three sources that now underpin much of our consumption and have played a significant role in reducing carbon emissions from the sector.

Just compare our energy landscape today to the early 1990’s; for example, in 1992 CCGTs accounted for 1%[iii] of energy supplied, by 2002 the dash for gas had grown that figure to a massive 36%, a change that wouldn’t have been practical without transmission! The growth in wind produced by major players[iv] is another interesting touch-point in 2007 1% of energy supplied, by 2016 10% of energy supplied driven primarily by government policy incentives!

Despite recent, and continuing, growth in distributed generation, large capacity users are still planning to connect to the system and the transmission network will need to be there to serve them.

2. Providing bulk transfer of power to meet demand

Like many people reading this when I first started learning about power systems I was taught that fundamentally a transmission system was needed because generation is typically located many miles from demand centres. Transmission facilitates a single market where everyone has access to the lowest cost sources of electricity always and the higher voltage reduces the electrical losses.

But I was challenged recently on this when someone asked me; ‘could you not just have meshed DNO networks facilitating the shifts in power?’ Intuitively there is some merit in the argument, in the context of higher levels of distribution generation and demand management solutions. But as I took a more detailed look at this point some interesting observations came out.

A quick back of the envelope calculation shows if you want to transfer 7GW over 70km (a distance that could fit easily inside a DNO region) using a 132kV overhead line would be four times more expensive compared to a 400kV overhead line and would require 8 DNO pylon routes (with over 2400 individual pylons!) compared to 1 transmission route (and just 225 individual pylons)! This is before you factor in the additional losses on a distribution route and the carbon impact of 8 pylon routes!

The facilitation of a single market where everyone has access to the lowest cost sources of electricity always is a key benefit of transmission’s scale. With more wind and solar in remoter communities expected and interconnection to other countries market access will be even more important.

3. Providing flexibility for electricity system operation

It’s easy to think of the transmission system as the quiet provider of our energy needs, there when we need it. But this stability and reliability doesn’t just come from luck. It comes from the inherent design of a system with multiple layers of redundancy and embedded flexibility to cope with swings and fluctuations, so that electricity is there whenever consumers want it, despite the stresses the system needs to cope with.

There are some good examples from ‘extreme periods in time’ where having transmission proved to be invaluable to the public at large, such as the 1987 hurricane and flooding in 2007 where transmission’s resilience ensured much of the country kept its power despite severe outages on local networks. Weather related events are a great example of transmission’s flexibility. But, as my next blog will discuss, having this flexibility will become increasingly important in an energy market that becomes more volatile.

In my next thought piece, I will use these three benefits as a foundation to show how transmission still has a pivotal role for consumers, even in the most decentralised of futures and in many cases, may be needed more than ever.


[i] National Grid annual report and accounts 2017-18


[iii] Digest of UK Energy Statistics (DUKES) 2017

[iv] DUKES 2017 main report paragraph 5.65 provides definition of major players for purpose of analysis